thorne Posted July 23, 2008 Report Share Posted July 23, 2008 I've been reading that running a 30% blend of E85 will work in a stock WRX. So I was thinkingh of using it to raise my octane. What would be the calculated octane with that mix? Would that still change stoiche to 9.x? Hoping nate or someone will chime in here. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 My car used to be tuned on E85. Its super knock resistant, allowed for shit tons of timing, and the increase amount of fuel required seemed to even spool the turbo faster. It usually requires 30% more fuel if running all E85, so I am assuming that a 30% blend would require roughly 9% more fuel overall. As long as your not already running > 90% IDC you should be fine just be rescaling the injectors and adding some timing. I don't know of anyone that has had a lot of success mixing it, but I guess it might be worth a shot. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 btw e-85 stoich is 9.7, but with a blend I am not sure what it would be. Quote Link to comment Share on other sites More sharing options...
Rally Pat Posted July 23, 2008 Report Share Posted July 23, 2008 I have a question that is kind of related, and I have always wondered this: What is the density of gasoline vs ethanol? The same? How do you keep one from floating on top of the other? Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 I don't have time to tune E85 before track day. Plus I'm not sure if a few more degree of timng would be worth the hassle. I was trying to understand from my reading that Stoiche changes. So my AFR would not be correct eather. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 Also knock index octane is (R+M)/2. So if your running 93 your R and M average is 93, so for arguement sake let say (93+93+105)/3 = 97 <-- this is just a guess Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 I have a question that is kind of related, and I have always wondered this: What is the density of gasoline vs ethanol? The same? How do you keep one from floating on top of the other? I couldnt tell you the density, but I can tell you that a lot of gas stations already use up to 10% ethanol anyways Quote Link to comment Share on other sites More sharing options...
Guest Mindhacler Posted July 23, 2008 Report Share Posted July 23, 2008 I have a question that is kind of related, and I have always wondered this: What is the density of gasoline vs ethanol? The same? How do you keep one from floating on top of the other? They dissolve into each other. Sorta like water and ethanol... otherwise your 100proof vodka would be a layer of alc over a layer of water. Quote Link to comment Share on other sites More sharing options...
Lustalbert Posted July 23, 2008 Report Share Posted July 23, 2008 Etoh and gasoline are soluable in each other. Just like 30wt and gasoline are diferent specific gravity, whey will still mix. The amount of agitation is the question, and I am unsure of the answer. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 I don't have time to tune E85 before track day. Plus I'm not sure if a few more degree of timng would be worth the hassle. I was trying to understand from my reading that Stoiche changes. So my AFR would not be correct eather. Honestly without tuning for it don't bother. If you are not getting knock on your current tune adding fuel that is less combustible is not going to help you. Quote Link to comment Share on other sites More sharing options...
shm21284 Posted July 23, 2008 Report Share Posted July 23, 2008 It WILL change your stoich, and you are only harming your engine by causing it to run lean by attempting to raise the octane rating. For example, a friend's engine was calibrated on pure gasoline (E0) for a target afr of 11.5. After he moved to michigan, where E10 is used everywhere, the afr, when put into gasoline terms, is 12.6. This is with only a 10% ethanol content. 30% would probably be very bad. Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 I will have knock after my IC gets completely soaked. Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 DAmn I need to get on the dyno and retune for this some time. What I was thinking was making a injector change in my scaling to adjust. Normally for 100% E85 you run 30% more fuel. SO. 15*2=30% So If I added 30% E85 to e0 I would get (1.30x.30) ? Blah Fuck it not worth the hassle. Some time I am going to play with this more when I have time. Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 Scale injectors by 30%of 30% should solve that but again I don't have time to tune for it. Might be fun later. a stock WRX Ecu can run 30% and not have any knock issues according to nasioc But I don't always believe what I read on there because some people are idiots Quote Link to comment Share on other sites More sharing options...
shm21284 Posted July 23, 2008 Report Share Posted July 23, 2008 ? How will your intercooler condensing from ethanol's higher (than gasoline) latent heat vaporization cause knock? Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 I will have knock after my IC gets completely soaked. If your IC is that inefficient then its time for an upgrade. I only see about 10 degrees of variance in intake temps through a 1-4 gear pull with my BR race FMIC It makes the tune so much better. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 Scale injectors by 30%of 30% should solve that but again I don't have time to tune for it. Might be fun later. a stock WRX Ecu can run 30% and not have any knock issues according to nasioc But I don't always believe what I read on there because some people are idiots I believe it won't knock. Ofcoarse it wont knock. BUT if the knock you are having is due to intake temps and not the tune, you are going to be hindering your performance by using less combustible gas when your intake temps are low, and putting a bandaid on the real problem when they are high Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 If you are going to bandaid it, get a meth kit and my first triple Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 The intercooler is a TMIC. The TMIC Blwos donkey dick. I have the largest TMIC I could find and wish i would have just went FMIC. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 buy a front mount and sell your top mount on NASIOC. We just put an APS front mount Addicted2boost's WRX, and its sweet. He doesnt have a post IC AIT to log, but I know his top mount would get hot to the touch and the outlet side on this one did not. Quote Link to comment Share on other sites More sharing options...
shm21284 Posted July 23, 2008 Report Share Posted July 23, 2008 I wouldn't trust it unless it came from an engineering source, or someone with YEARS of experience. How do they know for sure its not knocking?? Just by listening to it? Engines are not that primitive anymore... You CAN simply use your existing tune and modify the size of your injectors. I recently read an SAE paper on a study of E85; they did just that. You can't just scale them up by 30%, though, you have to calculate the amount that the stoich is changed. Example: E85 requires ~40% more fuel and is (obviously) 85% ethanol. Ethanol's stoichiometric ratio is roughly 9.0:1, gasoline is roughly 14.7:1. You will need about 63% more fuel when running pure ethanol. In your E30 case, your stoich will be close to 12.99:1, which will require about 12% more fuel. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 You can tell how much knock you have from logging the KNOCK SENSOR. If you are not tuning for E85 other than injector scaling you are wasting your time. Quote Link to comment Share on other sites More sharing options...
thorne Posted July 23, 2008 Author Report Share Posted July 23, 2008 I have a bug eye and they don't make a cheap one that will work without removing my fog lights. Quote Link to comment Share on other sites More sharing options...
2highpsi Posted July 23, 2008 Report Share Posted July 23, 2008 His is a bugeye and his foglights are still in. We do need to trim the corners of the foglight housings though to make it fit perfect. The APS unit is not cheap, but you can find decent deals on used ones on NASIOC Quote Link to comment Share on other sites More sharing options...
tristanlee85 Posted July 23, 2008 Report Share Posted July 23, 2008 I'm not sure if you got your answer or not so here is my $.02. I run E85 in my car. No blend with gasoline other than the obvious 15% already blended. That puts me at 9.7:1 stoich. Thats close to 103 octane. I'm not sure on the calculation to determine your stoich value, but you will need to increase the fuel. Going from E10 to E85 requires an approximate fuel increase of 47%. I don't know how your car is set up as far as wideband to the ECU, but I'm guessing the voltage output or display is 0 - 5V for gasoline AFR. Assuming the output is for gasoline, you still tune for your desired gas AFRs since the sensor reads lambda, which is the same for gasoline, ethanol, methanol, etc. Quote Link to comment Share on other sites More sharing options...
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