13 To 1 Compression What Octane

8:1 really even that much?. Still, as the I-5 is a high-compression engine, I'm just curious what some of you guys are running in your tank. 5:1, so, using "stock" is a good way to make a bad mistake. But, there are so many exceptions to that rule. I've been running 89 octane for years in my truck. Charts will also show a variety of information related to the range of both the boost and the compression. Higher compression motors need higher octane to prevent pre ignition of the fuel air mixture. Author Topic: Compression vs. HIGHER Compression Engines. Cars built from 1955–1972 which were designed for high- octane leaded gasoline, which allowed compression ratios up to 13∶1. 1 "compression ratio" doesn't work like it does with a conventional gas engine. 643 108lsa Super Victor Pro Systems 1050cfm 110 Octane TH400 8. It is not so much an indication of a fuel’s ability to make power, but rather a fuel’s ability to make power safely, i. However this potential power increase is only available if the gasoline octane allows running the engine at the MBT timing value without detonation. Doing the math, there was zero savings for me running 87 octane, and minimal savings with the discount 91. 3 : 1 or less will safely operate with unleaded 87 octane fuel. There are engines today that take 87 octane fuel at 13:1 compression, like Mazda's SKYACTIV, and some engines at 10:1 compression require 93 octane, such as the LS3 V8 in the Corvette. Engine cell data of Table 5-1 at a compression ratio of 8:1 show that the 1969 heads with the higher squish area gave a two number higher octane requirement with primary and full boiling range fuels. I am just wondering if the initial premise is still valid considering the quality of fuel nowadays produced and considering the fact that many modern day engines have much higher compression ratios and operate knock-free without the pre-ignition problems. 2 :1 compression ratio? Save Share. Pretty simple question actually (or so my ignorant mind thinks): At what compression ratio would an engine benefit from higher octane fuel? The Focus I drive is just over 10:1, and I've heard some. I think higher octane is for turbocharged or supercharged cars but some people say they can feel a difference. Prevents phase separation. Try this experiment pour a pint of 87 & a pint of 110 octane fuel on your concrete driveway and light them at the same time and see which one burns. you see, i'm curious why people think that high octane fuel gives their engine more power. but go to the drag strip you will have a problem. The closer to 200 lbs cranking compression, the more high test you need, and the more responsive the engine is. Ran 92 octane all day long, even with 150 shot of nitrous when I was playingcomes down to dynamic compression that includes cam timing/valve timing. It sounds like 11:1 is the max for pump gas. I purchased a racing 340 engine that currently has a compression ratio of 13:1 - This was built for race fuel obviously. Those of us who have been around awhile will remember the days of leaded fuels. 1:1 - 92 octane 6. 5:1 on my LS1 engine on 93 octane with no issues but my dynamic compression was around 8. Enter the cylinder bore diameter, stroke length, and the minimum clearance at end of the compression stroke. Race engines, using high octane race gas, can tolerate higher DCR's with 8. 73:1 roller rockers flat top pistons (acl race series) weiand xcelerator 750 dp carb competition ceramic headers I do not know what the compression ration with the above combination will be and if it will be safe with 95 octane fuel. 5 to 1 when built, you risk detonation, which will be worse with lower octane fuel and a stock carb. 6C increases the octane requirement of an engine by 0. Its to bad you guys only get 91, if you had 93 it would run a little smoother for you. and 100LL is $6/gal, the difference in engine costs is made up in 100 hours. 5:1 is a pretty low comp these days and won't have det issues on 87, could even run lower than that, not that you could get it. In California the highest I can get is 91 and that is what I use. Some websites say 93, some say 105+ The car is tuned and is running on 93. 3:1 3,000 cc engine that ran on 90 octane car gas, they might make the same power, and the 3,000 would cost $1,200 more in parts to build, but if Boat gas is $3/gal. She wants to benefit African coffee growers, and she wants a meeting point for people in her community. Anything under 12. Engine building book I have says 5 point of octane per each point of compression increase. 5 cfm Peak flow equals (298. Running higher octane depends mostly on your compression ratio and susceptibility to knock. So using a lower octane fuel in a higher compression engine is WORSE then using a higher octane fuel in a lower compression engine. These maps Honda engineered Y axis RPM and X axis load. I ran a 12. I have read where 8. It is a function of: 1. You should only do so if you have a cam (and intake) that is designed to run with compression that high. The 13:1, sure, he could put a big cam in, ground late, but it'd be a pig and need a ton of timing to run, the correct combo with less compression would walk all over it in almost every situation. So those numbers are where my power stopped at. The calculator will evaluate and display the compression ration of the engine. Many owners who operate vehicles designed to operate on 87 octane fuel experience ping and knock. So calling 92 octane unleaded automotive fuel “High Octane” is kind of a joke and paying. A higher octane fuel is needed because counter intuitively a higher octane fuel requires a higher compression to ignite compared to a lower octane. 5:1 since i'm running 93 pump gas octane all the time now. June 23, 2014. So unless your riding the highest compression XJ (stock but not turbo) at sea level, you can run 87. The motor is going in my 1978 Hallett jet boat with Berkeley pump, going to be a lake/river cruiser with some kick to it. Anything under 12. You don't gain the power from the higher octane fuel, you gain the power from the higher compression ratio, and it is required that you use a higher octane fuel in order to prevent knock. The higher octane fuels burn at a slower rate. Car Tech 101: Octane demystified. from 10:1 to 11:1) increases power by about 3%. 643 108lsa Super Victor Pro Systems 1050cfm 110 Octane TH400 8. tried 92~94 before, no change in performance and mileage. 98-RON E30 fuel at equal performance levels in engines having compression ratio raised from 10:1 to 13:1. under 12:1 a bike will go bar to bar or to work just fine on 85 - 87 O fuel. 5:1 Compression on pump gas just fine, my stock raptor ping'd with 87 octane it's all in the combination. On a built 10:1 compression motor - designed for e85, but with flex fuel to accomodate 93. Im worried if I use the 13:7:1 with it being bored to 89mm and the deck of the block and the head being milled slightly that may be to much compression for those cylinders. 7 and trhe 4. 8:1 compression engine will run OK on low octane fuel. This high heat can be a source of ignition. and this was after he cc'd everything. 87 Octane is both a high and low compression fuel. 4:1 are not recommended for use with "pump gas". My car has 9. The stuf that says it will boost octane 4 or 6 points. check out honda-tech. 1l with 8,5 compression I think. Maybe a member down under can supply the name. 5-1 compression, iron head 406 on the Power Tour using 91, and sometimes less octane. Jeff Smith: This is an interesting question that came out of last month's discussion about E85. 0:1 for example, will compress the mixture to 1/9th of it's original volume. The Octane Coffee and Tea House takes its name from a 1920s gasoline station. Going from 10. For instance, som diesels only have 17:1 compression run the race gas man, or change the compression. فى الفديو ده هنفهم يعنى يه Compression ratio و علاقتها بالــ Octane No و سعتها هـتفم ليه لما بتحط بنزين 90 بدل الــ 92. It is loud for the first 5 seconds after starting due to fuel enrichment, then it sounds and runs great. Proper octane is a highly debated topic, which is why I say 11:1 on 92 octane since its a pretty safe place to be and still get lots of power. Less dense than water and insoluble in water. And even now with direct injection you can still run 87 in cars as high as 14:1 like the skyactiv engines in the new Mazdas. With cast iron heads, compression ratios should be limited to 13:1 Rockett Brand TM 100 Unleaded Racing Gasoline is street legal in all states and is used in current perfor-mance cars. _InFlow requirements for the cylinder heads would be: Mean flow equals (1194 / 4)= 298. While the Z900 motor is high compression at 11. in fact it gives less performance and less economy in studies done by numerous car and science magazines. If the formula above is true 160/14. Although using higher octane gasolines are a waste of $, on the other hand, more pricey gasolines have better cleaning solvents than cheaper ones, will clean better, burn better, produce less carbon buil up on pistons & cylinder head specially if you are a non carbon guard products user at all. 8:1 compression engine will run OK on low octane fuel. The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. I'm with 57fairlane: Get a custom and tell them everything vital about your combo and that you have to run on 91 octane. 21 13% Annual Averages (Bulk) – Higher compression. 1st of all you have to know that what is octaneso Octane is measurement to a mixture of isooctane (an isomer of octane) and n-heptane. 11:1 for high rpm N. 5:1 on 92/93. I absolutely recommend and whole heartedly endorse Boostane , I recently purchased a highly modified G37 twin turbo coupe and before the turbo’s where added it’s a 11:1 compression motor at only 4lbs of boost your now looking ya 13:5 to 14:1 compression so cheap low octane gas isn’t not an option when you have 20k invested in the 2 turbos alone. The octane rating of fuel is a measure of its performance in engines. The calculator will evaluate and display the compression ration of the engine. Impossible to answer without more information. 5 to 1 compression and in my 408 sbc and I need to mix race fuel and super unleaded. I have experienced fuel system problems. There's 13 to 1 and there's 13 to 1; which is to say you've got to get at the Dynamic Compression Ratio. If you use an MSD box and want to cruise around with 87, just pull some timing. 6:1 static compression but I can run 92 octane just fine because I run aluminum heads and my dynamic compression ratio is 8. In California the highest I can get is 91 and that is what I use. We divide the volume at BDC with the volume at TDC: 650cc/50cc = 13/1, denoted as a ratio of 13:1. Octane and Cetane number of fuel Fuel Research Octane Number (ROM) Motor Octane Number (MON) Cetane number Boiling point (ºC) Gasoline 92-98 80-90 0-5 37-205 Diesel -25 - 45-55 140-360 Methanol 106 92 5 65 Ethanol 107 89 5 79 Propane (LPG) 112 97 -2 -42. I looked into the compression ratio after accidentally pumped 87 octane gas and didn’t notice any performance difference from the retard timing due to knock sensor when accerating hard. 77 TGL 2", 20 Foot Tow. BEST ANSWER: no, to my understanding its intended to raise the stock Honda carb 250’s compression from 13. If you are building your engine from scratch, it is a good idea to try to build it with a relatively low compression ratio, such as 7. 5:1 ratio, after everything was said and done with head gasket thickness, chamber size, depth piston was in the hole it came out to 11. Still running 10. 3 litre V12. Enter the cylinder bore diameter, stroke length, and the minimum clearance at end of the compression stroke. The higher the octane rating, the more resistant the gas is to ignite and can be subjected to more compression without auto-ignition issues. Ussually dynamic compression is in the 7. 5:1 on his 383 stroker and it was "pinging" which I believe what he ment by that was spark knocking on pump gas. In a turbo car, especially these days with all the electronics, the lower octane fuel you put in, the less performance, and EVEN possibly economy can suffer. #5 sam spade 2 , Nov 13, 2018. 530 bore X 4. Re: Dynamic compression for e85 ? Cool, I've been playing with the idea of running my '71 Camaro on E85. I have experienced fuel system problems. Compression is when the Air and Fuel mixture is compressed in the combustion chamber this is calculated by the Stoichiometric ex: 11:1, 12:1, 13:1, 14:1 which means that the mixture of air and fuel is compressed a lot, This is referred as High Compression. In many cases a high performance fuel pump may be necessary. It's meaningful to talk about 12. 91 octane will make it sound like a coffee can full of marbles if you're running 13-1. Barker has run 12. When the combined effects of air temperature and humidity are considered, it is often possible to use one octane grade in summer,. The purpose built machine with a high compression ratio is to increase efficiency (fuel efficient) and reduce levels of emissions. 5:1 and higher then you're going to need the higher octane. Different octanes have different flashpoints. The thing is if you get a bad load of pump gas that is lower than 94, or 93, you might destroy the. My daily driver has 14:1 compression ratio and runs great on 87 octane. * In engines running exclusively on LPG or CNG, the CR may be higher, due to the higher octane rating of these fuels. compression ratio being the big one. So running to high of an octane can actually decrease performance. The more controlled combustion is to reduce detonation in high compression engines. Generally, engines with compression ratios of 9. I checked the cranking compression on my Toyota tundra and it was 225 psi. GT-100 Unleaded, is a clear fuel with a pump octane of 100, and will handle compression ratios of up to 12:1, and is street legal in all 50 states. Will using 87 octane on a regular basis harm my vehicle? From what I understand, today's hi-tech cars are designed to compensate or automatically adjust to lower octane unleaded gas so as to avoid "knocking" or "pinging". Effective Compression Calculator This is pretty straight forward enter the following - Boost in PSI or BAR Static Compression Ratio And the results will be the Effective Compression Ratio. Offers the benefits and octane of a leaded fuel at a lower cost than more exotic race fuels. In a turbo car, especially these days with all the electronics, the lower octane fuel you put in, the less performance, and EVEN possibly economy can suffer. 2hp at the fly ( 900 kilogram car :d). Considering I have 5 gallons of 91 octane in the tank, I would multiply (91 X 5 = 455), Then add 100 octane accordingly to achieve 93 octane: (1. The higher octane the less explosive it is to higher compression. 8:1 to 9:1 a good DCR to shoot for. This high heat can be a source of ignition. A full tank of 93 Octane will cost $35. One says 94 octane and another says 100 octane and the other says 96. I am running and have been told three diffrent things from three diffrent places. Using your values I do get the same 9. Octane burns at 100% and 87 octane gasoline produces 13% less energy than pure octane. 030 13:1 compression pistons (that's what he was told they are) he pulled out of a 340 motor that he swapped all back to original. 5-1 with the roller cam and that octane with conservative timing. One of my friends was runnin' 12 to 1 compression in a 327. Maybe a member down under can supply the name. I would suggest that >91 octane only necessary for compression ratios > 10:1. It was not pressure charged but 13. 5mm stroke, redline 14,000 rpm. Discussion Starter • #1 • Aug 19, 2003 Will I have knock or detonation problems using 93 octane gas if I'm running at 11. (We used to work on antique/vintage autos). Because there is more to required octane than just compression ratio. 7 and trhe 4. 5:1 since i'm running 93 pump gas octane all the time now. Apr 11, 2019 - Apr 24, 2019 (13 days). The higher heat can (and does) ignite the air/fuel mixture prematurely -resulting in pre-detonation. Prevents phase separation. A noticeable lower performance, but still good at temps of up to 95F, but beyond 95F, and especially 100+F, some serious lagging and weak performance. Example: Going from 10. I drove my 14. 5:1 compression that runs just fine on 87 octane gasoline. Premium is 91 octane. Sunoco Standard is designed for compression ratios up to about 13:1 in conventional V8 engines with iron cylinder heads. I ran 571 whp and 608 trq at 9 psi, but that was with a fuel problem that stopped the horsepower at 4500 rpm. However I'm not sure if they're referring to only the 13. 5 degrees of timing total on the engine dyno. 1 "compression ratio" doesn't work like it does with a conventional gas engine. 5:1 compression ratio. 4:1 compression ratio and it calls for 87 octane only. so if ur car is modded and the timing is advanced run higher octane, if not then dont. I'm with 57fairlane: Get a custom and tell them everything vital about your combo and that you have to run on 91 octane. But are we ready to pay that super premium price? Let’s get real; buying a 5 gallon can of 100 octane “race gas” will set you back $7-10 per gallon. richard96, Jul 30, 2010 #8. Combustion chamber design plays a part equally important as both geometric compression ratio and fuel octane rating. I use Shell V-power, 99 octane. Octane Chart (TSR Docs) (Read 1633 times). i run nothing but 93 in my Z with 180,000. As it is now, 93 octane gas and a dozen cans of octane booster won't jack up the octane to satisfy 12. So, if the gas you're bying is 87 Octane, then it burns as easily as a mixture of 13% heptane and 87% octane. if u want more ummp then there are lots of low octane racing fuel that is oxygenated like VP U4. So the pistons are coming out. Like the rzr that takes 87 octane. You need to very precisely calculate dynamic compression based on IATs and Fuel Octane. Works well on the latest generation of electronically-controlled turbo engines. We have a gas station here in southern Cali that pumps 100. Re: What type o gas you'all run in you CRF's I personally run 93 with the octane booster made my yami to jack up the octane to around 97, which is the suggested octane to use. I have experienced fuel system problems. The K75S has an 11. This means about 97 octane or about a 50/50 mix of race gas and regular. The other 30% need a higher octane gasoline. Its not uncommon to hear of compression ratios in excess of 13. (12lbs / 14. Timing set at 22 idle, 32 at 3000 RPM. Apr 11, 2019 - Apr 24, 2019 (13 days). Octane ratings are, as this How Stuff Works article points out, a measurement of the gasoline. 2 to be exact) LESS than running 91 octane. If you were to analyze it using the typical R+M/2 method (by which pump gas is scored), then it would likely come it at about 106 R+M/2 octane, give or take. This will get you to approximately 6% more fuel volume. 5:1 which required purple avgas (115+ octane racing fuel). 5mm stroke, redline 14,000 rpm. Compression ratio 11:1. 1 compression ratio suggests because the gas is not only compressed, but the work done to compress the gas has also heated the gas and the. Like others said, you should probably do some reading on octane. 12:1 will run out later. In order to feel a little more comfortable that the nozzle you select is the right one for both your vehicle and your wallet, it's helpful to understand terms like compression ratio and octane ratings. 4:1 compression ratio and it calls for 87 octane only. I absolutely recommend and whole heartedly endorse Boostane , I recently purchased a highly modified G37 twin turbo coupe and before the turbo’s where added it’s a 11:1 compression motor at only 4lbs of boost your now looking ya 13:5 to 14:1 compression so cheap low octane gas isn’t not an option when you have 20k invested in the 2 turbos alone. Quick Sportys are a lot of fun. If a high octane fuel (such as 93 octane) is used in a low compression engine (such as an older flathead garden tractor engine) the air/fuel mixture will not burn fast enough. In the 1960's, gasoline was produced anywhere from 80 to 140 octane. 1 compression. It depends on a lot more than just compression ratio. 2:1 flat top engine with the same cam and 461 double humps and it ran fine. An Octane Booster that allows. 2 to be exact) LESS than running 91 octane. A S&S Super E w/ a yost tube feeds it and a Hooker 2:1 routes out the exhaust. The on board computer guts will adjust if you are burning lower octane fuel. Back in the day that would require Premium fuel, with engine computers that not the case today. By the way, these are incredible compression numbers for unleaded gas, far higher than cars from the 1970's running 10:1 compression that used to require leaded. Higher octane fuel burns slower, reducing the chance of pinging or knocking in high-compression engines. Currently have XC800 and was planning to take it, but can't get any ECU mapping to allow for low octane fuel. It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. I am looking at buying a CHP dynotec longlock 347 with 11:1 compression that makes 500 flywheel horsepower and 460 lb of torque. if your car is stock why pay. 5:1 compression ratio, yet "regular" gas is called for in the manuals. The closer to 200 lbs cranking compression, the more high test you need, and the more responsive the engine is. 5:1 DCR is considered to be the maximum for iron heads and 92 octane fuel (MON + RON divided by 2). 1:1 was high when most cars were below 10:1 at that point. Going from 10. This minimizes the compression and pumping work while maintaining the 13:1 expansion stroke which helps thermal efficiency. 5:1), then you will be fine with the highest octane at any gas station. 2 CR on my 350ci, we have 88 octane here in France. Octane rating is the amount of octane vs the amount of heptane in the gas. A useful rule of thumb is that raising the compression ratio one point (i. It sounds like 11:1 is the max for pump gas. I'm with 57fairlane: Get a custom and tell them everything vital about your combo and that you have to run on 91 octane. 91 octane fuel has more potential power than 87 octane fuel. If it pings, go up to the next grade and see if it stops, the VTX's are designed for 87 octane. The 5:1 effective compression ratio is the result of IVC at 63 degrees BTDC (Figure 6). When I used to drag race in the early 80s, we ran Moroso Octane booster - came in a 1 gallon can - was supposed to work well and it did stop the pinging on my 11:1 engine - 240lbs cranking pressure on compression tests. The available range of Compression Ratio is 4:1 to 18:1, which allows testing a wide range of fuel. Car Tech 101: Octane demystified. Also, almost all gasoline in the US contains 10 percent ethanol. you have PLENTY of research yet to do if you think this is true. Suzuki specifies 87 octane fuel for my 05 GSXR600 which has 12. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other. Expand this section. Now you can gain power from race fuel even with low compression if the fuel is oxygenated. No pinging. Engines with higher compression ratios require gasolines with higher octane ratings. 5/1 effective compression ratio, the effective displacement would be 37. Maybe Bill O'neal has some ideas. Since displacement ratio is always 1 less than compression ratio, we use 8. 50 and the price for 87 Octane is $3. Typically I am using 93 octane since that is what is around here. May style combustion chambers were used in the Jaguar XJS HE, 5. 2:1 flat top engine with the same cam and 461 double humps and it ran fine. 5 compression and i had to etiher swap the pistons out or run race gas. During typical engine operation, the piston drops to the bottom of the combustion cylinder, which then fills with a mixture of fuel and air. The calculator will evaluate and display the compression ration of the engine. This is where the octane rating of gas comes in. Race engines, using high octane race gas, can tolerate higher DCR's with 8. But those are cars. Human Octane Elite Compression Tights. It also stresses the crankshaft. The cam is timed at 1* advanced, at 100* intake centerline. It is a function of: 1. You don't need high octane fuel until you start getting into the 11-12:1 comp ratios. 9:1 not needing a special head and still run on pump gas like any new bike. built on a 13. Iron heads, 12:1 compresion, and a short duration cam will make crazy cylinder pressure. But genderaly vehicles with compression ratio of less than or equal to 10:1 shouldn't be having any problems with regular petrol ie 87 octane petrol. Factory gaseous Onan engines have high-compression pistons/heads, but getting anywhere near 12:1 in an Onan is, well good luck, especially if it's a flathead. However, an uncontrolled ignition is a BAD THING! A fuel with a higher octane rating can be run at a higher compression ratio without causing detonation and we know compression or boost is directly related to power. That engine would likely ping under load on 93 octane gas. 13:1 or whatever if we're discussing one particular engine--especially if that engine will use the same cam specifications with the various pistons. 8:1, and added 1986 E6 Mustang style high swirl ramps and EECIV TFI spark reduction stratergy. What now? By aus (Read 630 times) Compression Ratio 9. This is certainly a bit of a no-man’s land since there probably aren’t too many people with practical experience along these lines,. Check the compression ratio stamped between 2 and 3 next to the engine number. I believe they call for 87 octane. 5:1, had higher thermal efficiencies than many of today’s engines. Since the reciprocating mass of the engine increases in proportion to the displacement of the engine, E85 has a higher potential efficiency for an engine of equal power. The on board computer guts will adjust if you are burning lower octane fuel. Since that first day of testing we have tested Race-Gas against everything from 98 octane to 116 octane distilled racing fuel and in engines as large as a 550 CI at 13. The quickest passes I ever made were on a mix of Arco 91 and a little C-12. Comparatively, if you had an ultra high compression 2700 that had to have 100LL vs an 8. Engine building book I have says 5 point of octane per each point of compression increase. Endurance training experts specializing in triathlon, swimming, road cycling & mountain biking, and road & trail running. "There's no sense even trying it with this boost and compression," Urban says. The calculator will evaluate and display the compression ration of the engine. 73 gear 195* engine temp sbc 331 10. 5 to 1 compression via the Atkinson cycle engine but uses regular fuel. That's pretty wound up for a NA motor. 5 has modest effect on efficiency and MPG, but doubles the ethanol consumption. Barker has run 12. Click to expand Sounds goodthe reason I ask is due to the fellow that works with me told me the he had 10. Most gas stations offer three grades of octane, with regular rated typically at 87, mid-grade at 89 and premium at 92 or 93 [source: Federal Trade Commission]. 5 to 15:1 if tuned properly. 1 with a 200 shot do i need all out c116 ? just trying to figuare expenses with fuel feeding these giants thanks guys. But, there are so many exceptions to that rule. Example: Going from 10. That's pretty wound up for a NA motor. This means about 97 octane or about a 50/50 mix of race gas and regular. Engine performance and efficiency increase with increasing compression ratio. 5:1 is about the max our cars need and E85 will support that with lots of room to advance timing and deal with hot days and E70 fuel if you encounter it. 1:1 - 92 octane 6. Since my Frontier seems to be drinking gas at a more alarming rate than I first thought, I will try 89 octane on this next fill-up and see what happens. I would also consider running 93 with a leaded octane booster. Ordinarily you will never see an ordinary everyday automobile gasoline fueled engine with a compression ratio higher than about twelve to one, which is stretching it to the limit on ninety three octane, except in a computer controlled engine. Manufacturers compression ratio will be tested and the octane necessary will be in an owners manual. generally, what octane does a 13-13. When knock occurs the ECU pulls timing because it thinks the motor is detonating fuel too early in the combustion chamber. Buy Racing Octane Booster. just drove a total of 300 miles to and from a show including cruising the streets in ocean city, md. The octane rating for E15 (15% ethanol) is 88 octane and E85 (85% ethanol) is 108 octane. If it's a REAL 13-1 mechanical compression using 105 octane, it will melt Pistons and create damage. I, for one will be happy to have my first vehicle ever that does not need 91 Lensync58 , Kidcia , FitBliss and 11 others like this. Octane number 1. It's worth mentioning that diesels use extremely high compression ratios, generally from 14 to 25:1, to initiate combustion, which is why they're able to achieve greater levels of efficiency compared to gasoline engines. The octane rating for E15 (15% ethanol) is 88 octane and E85 (85% ethanol) is 108 octane. the car performed. Engine building book I have says 5 point of octane per each point of compression increase. With cast iron heads, compression ratios should be limited to 13:1 Rockett Brand TM 100 Unleaded Racing Gasoline is street legal in all states and is used in current perfor-mance cars. You will note there are no comparable test results for pump gas with this combination. The more controlled combustion is to reduce detonation in high compression engines. 5:1 compression ratio, 6 degrees btdc ignition timing whereas they suggest 90 octane gas for my 03 1000 which has only 12:1 compression ratio, 8 degrees btdc for cylinders 1 and 4 and 4 degrees for cylinders 2 and 3. 5:1 is about the max our cars need and E85 will support that with lots of room to advance timing and deal with hot days and E70 fuel if you encounter it. It's easy to find what octane rating a gas has. We have a gas station here in southern Cali that pumps 100. 5:1 to even better, low 13s:1. The reason has to do with the compression and ignition timing characteristics of the engine. 1 sec at 104 mph. Now, when I look up compression ratios and their appropriate octane I should theoretically be using over 100 octane fuel. For instance, som diesels only have 17:1 compression run the race gas man, or change the compression. I recall an article by hot rod or car craft on rod ratios on compression, basically they were getting 12:1 compression with a mild cam on 87 pump gas. 5:1 is a 9% gain. So the higher the ethanol content, the higher the octane. The 12-1 is pushing your luck with the fuel and with the use of iron heads. It does you more harm than good to run higher octane fuels in something than required. 5 litre BMW motor will be built for 12:1 compression, too. In a turbo car, especially these days with all the electronics, the lower octane fuel you put in, the less performance, and EVEN possibly economy can suffer. Thus, lower compression ratio engines will have a lower efficiency, but they can use lower octane fuels which are cheaper. 0:1 will only compress it to 1/7th of it's volume. 5 to one race engines and run them on 87 with no issues. A: Generally, retarding ignition timing by 4-8 degrees (1 to 1-1/2 degrees timing retard per 50 HP gain). 5:1 is the highest you can expect 93/94 octane to handle, and would provide alot more torque (acceleration) than 9:1 pistons. and 100LL is $6/gal, the difference in engine costs is made up in 100 hours. I, for one will be happy to have my first vehicle ever that does not need 91 Lensync58 , Kidcia , FitBliss and 11 others like this. 2:1 for twins and 12:1 for triples) Any engine with compression over 11:1 has to have a "Premium" gas. Discount 91 octane averaged 0. Today I received an original copy of the M. I am second guessing that a bit. This is approximately 8% more fuel. actually, some people even use "high octane" as a metaphor for something energetic and full of power, but given the real nature of high octane fuel (it's resistance to combustion), this association becomes ironic. I think higher octane is for turbocharged or supercharged cars but some people say they can feel a difference. The lead substitute would mainly be to protect the valves. 1:1, way beyond our 12:1 figure. Lets assume that your car is properly tuned for your current combo of compression and 87 octane. And even now with direct injection you can still run 87 in cars as high as 14:1 like the skyactiv engines in the new Mazdas. Enter the cylinder bore diameter, stroke length, and the minimum clearance at end of the compression stroke. A great standard grade of racing fuel. 27-12-12 dirt devil2 tires on stock 12-6 crusher rims all four corners, 3500lbs warn winch. History Version 1. One says 94 octane and another says 100 octane and the other says 96. Back in the day 10:1 and 11:1 compression engines required higher octane fuel. occasionally, ill run 91 with a bottle of octane boost, but thats as low as ill go. Expensive, yes. 3:1 on street fuel so long as your dynamic ratio is 8. 6L engine a couple years ago that called for 87 octane but hand calculations over many months proved that it got better fuel economy on 89 or higher octane. Type V-Twin, liquid-cooled Displacement 1179 cm3 Bore X Stroke 4. I drove my 14. In other words, they burn at a more controllable rate. The compression ratio depends on the size of the dome on the pistons (in cc's) and the combustion chamber size of the heads (cc's) among a few other things. However I'm not sure if they're referring to only the 13. This is a great option on the street We did testing back to back A-B-A with the 100LL AV Gas and Sunoco Blue and tested some, Its the same fuel. Custom body work and paint. if your car is stock why pay. 13:1 compression ratio. The higher the octane number, the slower the burn. 13 to 1 as a static is used in race enignes as a means of improving off idle to torque peak performance that is otherwise lost when very long duration which brings a late to close intake valve. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. '06 Road Glide 95" w/ 10. 6:1 static compression but I can run 92 octane just fine because I run aluminum heads and my dynamic compression ratio is 8. The available range of Compression Ratio is 4:1 to 18:1, which allows testing a wide range of fuel. 5:1 compression and thats cool. It is not so much an indication of a fuel’s ability to make power, but rather a fuel’s ability to make power safely, i. Still running 10. 5/1 effective compression ratio, the effective displacement would be 37. Historical View there was a demand for more powerful engines. Well, high compression is why a lot of performance engines need premium fuel, or high-octane gasoline. Once you do that, you actually make your machine run worse and you'll slow it down. I agree mostly. 1:1 C/R @ 9 psi and made 307 whp with no problems. Octane and Cetane number of fuel Fuel Research Octane Number (ROM) Motor Octane Number (MON) Cetane number Boiling point (ºC) Gasoline 92-98 80-90 0-5 37-205 Diesel -25 - 45-55 140-360 Methanol 106 92 5 65 Ethanol 107 89 5 79 Propane (LPG) 112 97 -2 -42. 5mm stroke, redline 14,000 rpm. 1:1 compression ratio. 1 with a 200 shot do i need all out c116 ? just trying to figuare expenses with fuel feeding these giants. The 2007 Tundra I have with the 5. 3:1 on street fuel so long as your dynamic ratio is 8. 4:1 - 100 octane 8. The motor is going in my 1978 Hallett jet boat with Berkeley pump, going to be a lake/river cruiser with some kick to it. Expand this section. This means about 97 octane or about a 50/50 mix of race gas and regular. 02-23-13 01:06 PM - Post# 2319895 In response to Jim. 8:1, KTM250SX-F 13. #5 sam spade 2 , Nov 13, 2018. For most engines and designs, even if you went to 10. * In engines running exclusively on LPG or CNG, the CR may be higher, due to the higher octane rating of these fuels. You should be able to run a 7-8 psi blower with a 9:1 static compression ratio and the engine might run fine on 91 octane fuel. The idea of super premium octane levels (100 octane range) is not a new concept, and many of you have already seen the benefits in your hot rod engines. Quite simply, octane ratings are a measurement of a gas's ability to resist detonation. Some websites say 93, some say 105+ The car is tuned and is running on 93. Ussually dynamic compression is in the 7. A S&S Super E w/ a yost tube feeds it and a Hooker 2:1 routes out the exhaust. They increased the compression ratio, while keeping the displacement the same, by decreasing the volume of the combustion chambers in the heads. that head your running is a 4500 Ft + head. 2:1 for twins and 12:1 for triples) Any engine with compression over 11:1 has to have a "Premium" gas. Just a side note, 95 octane costs around $3. 5-1, being safe, or even a bit higher 12-1 with an iron headed motor on premium pump gas. 6 still has a low compression of something like 11. One way to increase the horsepower of an engine of a given displacement is to increase its compression ratio. I buy it by the barrel and it is just easier to put it in everything and not worry about mixing up fuel jugs. Might have to email them on that. 3-1 compression Duration 254/262, Lift. E-85 has an equivalent octane rating of 105, and with an expected operating temperature of around 180°F, the maximum dynamic CR is slightly above 10. '13 Road Glide Ultra in Midnight Pearl. 5:1 compression and run fine on 87 octane regular. Doing the math, there was zero savings for me running 87 octane, and minimal savings with the discount 91. 5:1 and I think that was held over for the injected models too. And while low compression engines aren't as fussy, feeding it fuel with too high an octane rating may result in incomplete combustion, unburnt fuel, and less power. On a built 10:1 compression motor - designed for e85, but with flex fuel to accomodate 93. 75 YES I did tune the computer for my. That said, the car probably has fairly aggressive timing and a fast burning head. D2As changed at some point from 8. Most claimed to add 2-3 octane but the test showed they average between 0. 73:1 roller rockers flat top pistons (acl race series) weiand xcelerator 750 dp carb competition ceramic headers I do not know what the compression ration with the above combination will be and if it will be safe with 95 octane fuel. It runs fine on 91 RON now - never pings. Comparatively, if you had an ultra high compression 2700 that had to have 100LL vs an 8. You would have to use 91 or 93 is you were over 13. Higher compression engines require more octane to prevent detonation. No Vacumn advance. Jeff Smith: This is an interesting question that came out of last month's discussion about E85. This high heat can be a source of ignition. It is found that greater the compression ratio more will be the power output of the engine. The higher octane rating will allow it to be used in higher compression engines which tend to produce more power per unit of displacement than their gasoline counterparts. I recall an article by hot rod or car craft on rod ratios on compression, basically they were getting 12:1 compression with a mild cam on 87 pump gas. 8:1 compression and you shouldn't have any trouble running pump gas with stock cdi. Spyder engines have a very high compression ratio (12. 5-1 rated piston were actually only 13-1 in the real world, because my old heads had a huge chamber from all the porting. High octane fuel, therefore, helps reduce or eliminate knocking, pinging or rattling in engines. Back in the day 10:1 and 11:1 compression engines required higher octane fuel. Which was not a result of the baby boom that followed world war ii answers APEX. Another thing my 15. 3:1 3,000 cc engine that ran on 90 octane car gas, they might make the same power, and the 3,000 would cost $1,200 more in parts to build, but if Boat gas is $3/gal. It runs the 1/8 mile at 6. It ran fine between 8 and 10 initial. 2:1 flat top engine with the same cam and 461 double humps and it ran fine. Anything over 12. My 03 manual states 92 octane. In a high compression research engine, high- octane 13. This is a great option on the street We did testing back to back A-B-A with the 100LL AV Gas and Sunoco Blue and tested some, Its the same fuel. one of they guys on here explained on day that the octane level is how much compression the air/fuel mixture can take before it ignites. * #N#What octane do you need? #N#What is the lowest octane you are. Because of the pistons compression rate if your running 91 in it it can actually damage the rods over time. With 10-liters of compressible cargo space and a 2-liter Crux™ reservoir, the Octane™ 10 is a multi-task, multi-sport workhorse. '06 Road Glide 95" w/ 10. 91 from a good has station like shell or chevron. Today I received an original copy of the M. 30, the block was then decked to gain the compression back. Spark advance 3. If you put a mild cam in a 13:1 compression engine, the dynamic cylinder pressure might be equivalent to 15:1 with a larger cam. The total ignition lead lets say is 38*. It runs the 1/8 mile at 6. Combustion chamber design plays a part equally important as both geometric compression ratio and fuel octane rating. This allowed it to burn the lower octane fuels of the day. 5:1 Compression ratio for the engine. Compression ratio 8. 92 octane for a 9. At sea level, most XJ's compression numbers put the 'ideal' octane rating at 89. 11:1 runs out of steam at somepoint from a dynamic cylinder pressure perspective. The motor is going in my 1978 Hallett jet boat with Berkeley pump, going to be a lake/river cruiser with some kick to it. The DA 100 has a compression ratio above 8-1. Reduced Engine Knocking and Pinging. Propane has an equivalent octane rating of around 100, good for up to 12:1 compression ratio. In the 1960’s, gasoline was produced anywhere from 80 to 140 octane. I am not sure about the bigger displacements for compression ratio and octane level. 5--1 full point increase in compression ration will increase horsepower output by approximately 2 percent. , without blowing your engine. Dec 13, 2012 1,938 S. Read ahead to get a grasp of some of the most important terms you need to understand in order to choose the right gas. For higher compression applications, see VP's DRT formula. It was not pressure charged but 13. It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio. Gasoline octane is a critical factor in engine design. just drove a total of 300 miles to and from a show including cruising the streets in ocean city, md. 1 with alum heads and the cam is a solid roller with 270deg dur. 13:1 Compression on a Pump Gas Engine. I ran it last year with a 10. I run 91 octane gas and have never experienced any detonation with this engine. Likewise, if the dynamic compression were 8:1 @ one atmosphere, under the improved VE it would rise to 9. Can I run this on 93 octane? should I mix with 116 race gas? or should I just buy some 104 octane booster and drop that in everytime I fill up? thanks. 2:1 and a common aftermarket compression ratio for a boosted NSX engine is 9. This means about 97 octane or about a 50/50 mix of race gas and regular. 91 octane fuel has more potential power than 87 octane fuel. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). 93 octane would be my choice. I buy it by the barrel and it is just easier to put it in everything and not worry about mixing up fuel jugs. It's all about pre-ignition. You need fuel that is EASIER to ignite and burns faster in a low compression engine. Pump gas is not enough and I add some octane booster to get up to about 100 octane to smooth it out. Back "in the day" anything over 10:1 was considered a high compression engine and called for "premium" gas. I was just wondering if you go out for a cruise and need fuel what to do so i can prepare for it. if you can tell which is which then go ahead and buy the higher octane. While most racers use this fuel in naturally aspirated applications, it is also a. Pro Circuit claims that their high compression piston is designed to run on pump gas. 05/gallon over 84. Works well on the latest generation of electronically-controlled turbo engines. This is easily achievable with a 10. I have read where 8. Honestly they could have probaly got away with 10. 00 dollars and the cost per mile will $0. Re: Compression Ratio on Pump Gas (94 Octane) I ran a near stock 351C4V with a factory compression ratio of 11. Higher compression engines require more octane to prevent detonation. ive been searching google, ect and the shops arent very convenient for me. I can get leaded 92 if I want to pay the price. 5 or more to 1 and it spark knocks on 110 leaded with the timing retarded. The compression ratio of your engine determines the octane rating of the gas you must use in the car. Suzuki specifies 87 octane fuel for my 05 GSXR600 which has 12. 8:1 compression and you shouldn't have any trouble running pump gas with stock cdi. Car Tech 101: Octane demystified. Calc your ratio and I will check it on my chart I don't know the answer when you dilute it with regular pump gas. For the same size engine, the older engine would have been more fuel efficient if they had the fuel, cylinder head and ignition technologies of today combined with the high-octane. (Skyactiv engines in other countries run 14:1 compression ratio but must run 91 or higher octane fuel). It might seem odd that fuels with higher octane ratings are used in more powerful engines, since the fuel ignites less easily. 50 and sometimes 4. It will probably not be sufficient for a supercha. So far, it doesnt seem like Im having any detonation. you see, i'm curious why people think that high octane fuel gives their engine more power. 8:1 93 octane, 13:1 100 octane, 13. one of they guys on here explained on day that the octane level is how much compression the air/fuel mixture can take before it ignites. 5:1 compression ratio, 6 degrees btdc ignition timing whereas they suggest 90 octane gas for my 03 1000 which has only 12:1 compression ratio, 8 degrees btdc for cylinders 1 and 4 and 4 degrees for cylinders 2 and 3. Manufacturers compression ratio will be tested and the octane necessary will be in an owners manual. 5 to 1 compression via the Atkinson cycle engine but uses regular fuel. This is accomplished by better combustion space design, as well as superior air-fuel ratio control through electronic fuel injection (EFI). The calculator will evaluate and display the compression ration of the engine. Understand, my old Cherokee 140 was designed to run on 80 octane but all I could buy was 100LL. 6:1 compression ratios on LS engines without issue from what I can tell. 570 lift cam. If Mazda had it their way, they’d be running 80 octane fuel in their SPCCI engines rather than the elitist 87 you find on the affordable nozzle. 5 = 206cc, which is less than half of the total intake stroke. You will note there are no comparable test results for pump gas with this combination. 02-23-13 01:06 PM - Post# 2319895 In response to Jim. 1st of all you have to know that what is octaneso Octane is measurement to a mixture of isooctane (an isomer of octane) and n-heptane. w/ an advanced timing motor, you might be over w/ pump gas. While much of your effective (running) compression depends on your camshaft, a static compression of 9. you have PLENTY of research yet to do if you think this is true. While there’s a lot of voodoo, myth and misunder-standing surrounding octane, one important aspect of octane is the gasoline’s ability to resist sponta-neous combustion under compres-sion.