turbo SHO vs E85 compression

[somedude_001]

The question is for my SHO powered camaro project. The engine is a 3.2 block from a 94 ATX. I have 2 that I am going to have inspected. One is the origional engine from my 94 turbo SHO and has 242K and was removed due to a cracked piston. Engine is very clean inside the other block is also from a 94 with 67K and has 2 spun bearings. Needs 2 rods but the crank is good. At any rate

3.2L block bored to 3.3 with ported heads and +1mm valves. I have not decided what cams I am going to go with yet, EH runners, deleted butterflies and shafts. This will eventually loose the SHO intake in favor of 2 large tanks with short runners down the road. The car is getting a electronic boost controller to set boost VS rpm or maf and the boost will regulate to maintain a flat tq curve to a RPM of my choosing (probably 7500-8000)

My question is what compression do I want to go with? I do not know where the knock limits are for the stock compression on 93 octane. I will be changing between E85 or E100 and pump 93 octane. I do know that E85 can support much higher compression than regular pump gas. Talking to a few people on here via PM and on the phone I was originally going to settle for 9.0:1 and use meth or water injection if knock was a problem down the road, but now that I am setting up the car for E85 I want to keep the compression as high as possible. I was considering 10:1 or even 10.5:1. I know it is not the same engine but I have been comparing Audi S4's and supras to see what they use.I have had 2 personal experiences with good friends of mine running 24psi with no problems on S4's. school me on what the SHO engine likes from a detonation stand point.

oh yeah this is getting a small shot of NO2 also but the shot size has yet to be determined.

 

[ycode90]

I run 12-14 psi on near stock timing -about 3-5degrees way up top . I never had a problem with 92+ octane with stock compression 3.2l. Not sure if that helps.

 

[yamahaSHO]

If it were me:

I would go with somewhere between 9:1 - 9.5:1 as this would give you good off-boost power and be safe with gas if you need to run 91-93 at any time. There is no need to go any higher. E85 will provide more power for the same boost and should improve spool due to the extra exhaust volume. At the same time you'll see lower EGT's.

E85 will likely allow you to advance timing to a point where you will no longer make anymore considerable power and you still won't see knock. With that said, timing for max power on E85 and gas isn't so far off from each other either, so don't expect that you'll add 5-10 degrees of timing as you will create issues for yourself.

Quite honestly, with E85, there isn't much point in a 'small' shot of N2O. If you're looking to run N2O on top of E85, go big or go home. If you plan on running E85 pretty much all the time, I wouldn't add the complexity of N2O or meth/water inejection. Just remember, any shot of N2O will require even more fuel flow over what you would expect with gas.

I have no doubt that if I do end up converting my car to E85, I can gain 100+whp with the same pulley and just tuning and keeping the rev limit at 7k RPM. With that said, with an intercooler and E85, I think you'll find yourself in the 10's if you really want to be.


Additional info: I have 9.5:1 compression and run 26* of total timing at 14 (7k RPM) PSI. I run nothing but safe "street" tunes as it's nice to know I can get on it whenever I want and not worry. That setup (with no tune and electrical issues) made 438whp on it's last dyno. My STi is going through and E85 conversion right now as well.

 

[somedude_001]

I

E85 will likely allow you to advance timing to a point where you will no longer make anymore considerable power and you still won't see knock. With that said, timing for max power on E85 and gas isn't so far off from each other either, so don't expect that you'll add 5-10 degrees of timing as you will create issues for yourself.
.

if E85 will allow me to advance the timing to the point where no more power can be gained wouldn't it be beneficial to increase the compression at that point? This is not being built to be a daily drive. I want to build a engine for e85 and if i need to I can also run pump gas on it with lower boost settings. I would like to push this engine to its limits now that it is in a platform where the engine is now the weak link. I just don't want the engine to fail because I had a poor tune or not be able to reach the limit because the compression is too high or have poor low end power because it is too low.

I was actually thinking 10.0:1 or 10.5:1 being that E85 will be the primary fuel. Would it be safe to say that at a give boost level E85 will make about the same power as gas? I was always under the impression that you had to run more boost or higher compression to make the same power with e85.

 

[rubydist]

E85 requires a/f ratios of more like 12.5:1 rather than 14.7:1 for gasoline. This will not result in enough difference in exhaust volume to change turbo spooling response much, if its even noticeable.

Effective octane of E85 is in the 95-96 range (not the 103 that sometimes gets printed), so you can run some additional spark advance or increase compression ratio somewhat but not huge amounts. I would also think somewhere in the 9:1 - 9.5:1 would be a good place to be.

Intercooling and/or water/meth injection still has the same positives with E85 as it does w/ gasoline, especially if the engine has slightly higher compression ratios than the gasoline version.

You do not need more boost or higher c/r to get the same power out of E85, you just need more fuel. Typical flex fuel engines get slightly more power out of E85 because they can run slightly more spark advance.

 

[yamahaSHO]

if E85 will allow me to advance the timing to the point where no more power can be gained wouldn't it be beneficial to increase the compression at that point? This is not being built to be a daily drive. I want to build a engine for e85 and if i need to I can also run pump gas on it with lower boost settings. I would like to push this engine to its limits now that it is in a platform where the engine is now the weak link. I just don't want the engine to fail because I had a poor tune or not be able to reach the limit because the compression is too high or have poor low end power because it is too low.

You can get away with higher compression, however, if you have to ever switch to gas for any reason, you'll have to be a bit more cautious. 9:1 - 9.5:1 should be high enough and if you desire more power, add more boost, IMHO and YMMV. I believe the STi is 8.3:1 and people are getting rediculous numbers with E85 (11 second ET's with stock LB and turbo).

I was actually thinking 10.0:1 or 10.5:1 being that E85 will be the primary fuel. Would it be safe to say that at a give boost level E85 will make about the same power as gas? I was always under the impression that you had to run more boost or higher compression to make the same power with e85.

At the same boost level, you'll require more fuel and a tune, but you're going to see MORE power.

E85 requires a/f ratios of more like 12.5:1 rather than 14.7:1 for gasoline. This will not result in enough difference in exhaust volume to change turbo spooling response much, if its even noticeable.

12.5 is still within gas range... In fact, I shoot for 12.5:1 with my 91 octane blower car. Try something closer to 9.7:1 for stoich.... Roughly 30% more volume.

Effective octane of E85 is in the 95-96 range (not the 103 that sometimes gets printed), so you can run some additional spark advance or increase compression ratio somewhat but not huge amounts. I would also think somewhere in the 9:1 - 9.5:1 would be a good place to be.

E85 is closer to 105 octane.

Intercooling and/or water/meth injection still has the same positives with E85 as it does w/ gasoline, especially if the engine has slightly higher compression ratios than the gasoline version.

Intercooling is a given, however, meth will offer very little in the power range he'll have to realistically shoot for with running E85. Not only is E85 a higher octane, but it burns cooler. One of the guys that stopped by my house last week had a built block w/ a big turbo STi on E85 and he said his EGT's went down 200F.

You do not need more boost or higher c/r to get the same power out of E85, you just need more fuel. Typical flex fuel engines get slightly more power out of E85 because they can run slightly more spark advance.

You'd be amazed that gas and E85 spark advance are very similar when shooting for MBT.

 

[SuperchargedSHOguy]

I also vote low to mid 9:1 compression. This will keep you safe when on 93 octane for sure especially with methanol injection.

 

[rubydist]

12.5 is still within gas range... In fact, I shoot for 12.5:1 with my 91 octane blower car. Try something closer to 9.7:1 for stoich.... Roughly 30% more volume.

E85 is closer to 105 octane.

You'd be amazed that gas and E85 spark advance are very similar when shooting for MBT.

My bad - I grabbed the wrong value in my haste this morning - 9.8:1 is correct for stoich on E85. My point was that the volume of gas exiting the combustion chamber is not significantly different between a gasoline fueled or a E85 fueled engine, so the spooling time of the turbo should not be noticeably affected. In fact, with the exhaust gas temps reduced, there is less energy there for the turbo to use.

Here's a more detailed description of the octane issue:
Ethanol has a Motor Octane Number (MON) of 96 and a Research Octane Number (RON) of 130. Typical gasolines are labeled at the pump as (RON+MON)/2, so Ethanol would be labeled as 113, and E85 would be labeled as ~105 depending on how its formulated. However, this is significantly misleading for Ethanol because gasoline does not have a 30+ point spread between MON and RON (gasoline is typically within 8 points), and in actual usage the MON is more important, particularly under higher loads.

Why is MON more important? Because the Motor test is conducted w/ 300*F intake air and the Research test is conducted w/ 120*F intake air. Therefore, people working with forced induction engines should be much more interested in the MON rating.

In my view, the lower exhaust gas temperatures are not caused by "burning cooler", but are a combination of 2 factors: more evaporative cooling of charge air on the intake stroke due to more mass of fuel, and slightly faster burning of E85, which allows the engine to capture more of the energy and leaves slightly less energy in the exhaust.

The slight increase in rate of burn allows flex fuel engines to produce around 1% additional torque/power with exactly the same timing as gasoline. The higher resistance to knock allows more spark advance in the E85 timing curves, so that typical production flex fuel engines produce some 5-10% more torque/power on E85.

Depending on how effective the intercooler is, it could be possible to cool the charge air enough that water/meth injection would have little effect, but I haven't seen that low of intake temps in real life. Therefore, I expect that water/meth injection would have the same value as on a gasoline powered engine.

MBT timing will be very similar between E85 and gasoline, but the difference is that virtually no gasoline engine will run at MBT on any gas that you can get out of a pump - you would have detonation before you got that much spark advance. With E85, you can run closer to that MBT spark value.

 

[yamahaSHO]

My bad - I grabbed the wrong value in my haste this morning - 9.8:1 is correct for stoich on E85. My point was that the volume of gas exiting the combustion chamber is not significantly different between a gasoline fueled or a E85 fueled engine, so the spooling time of the turbo should not be noticeably affected. In fact, with the exhaust gas temps reduced, there is less energy there for the turbo to use.

9.765 to be exact. As far as volume and turbo spool, talk to the STi and EVO guys who HAVE done it, they'll disagree with you I will have my own report very shortly, however, it is already widely known.

Here's a more detailed description of the octane issue:
Ethanol has a Motor Octane Number (MON) of 96 and a Research Octane Number (RON) of 130. Typical gasolines are labeled at the pump as (RON+MON)/2, so Ethanol would be labeled as 113, and E85 would be labeled as ~105 depending on how its formulated. However, this is significantly misleading for Ethanol because gasoline does not have a 30+ point spread between MON and RON (gasoline is typically within 8 points), and in actual usage the MON is more important, particularly under higher loads.

Why is MON more important? Because the Motor test is conducted w/ 300*F intake air and the Research test is conducted w/ 120*F intake air. Therefore, people working with forced induction engines should be much more interested in the MON rating.

In my view, the lower exhaust gas temperatures are not caused by "burning cooler", but are a combination of 2 factors: more evaporative cooling of charge air on the intake stroke due to more mass of fuel, and slightly faster burning of E85, which allows the engine to capture more of the energy and leaves slightly less energy in the exhaust.

The slight increase in rate of burn allows flex fuel engines to produce around 1% additional torque/power with exactly the same timing as gasoline. The higher resistance to knock allows more spark advance in the E85 timing curves, so that typical production flex fuel engines produce some 5-10% more torque/power on E85.

Depending on how effective the intercooler is, it could be possible to cool the charge air enough that water/meth injection would have little effect, but I haven't seen that low of intake temps in real life. Therefore, I expect that water/meth injection would have the same value as on a gasoline powered engine.

MBT timing will be very similar between E85 and gasoline, but the difference is that virtually no gasoline engine will run at MBT on any gas that you can get out of a pump - you would have detonation before you got that much spark advance. With E85, you can run closer to that MBT spark value.

Good cut and paste Pretty much what I said.... Just with nothing to prove.

http://en.wikipedia.org/wiki/E85_in_standard_engines

 

[Toolman]

I actually did not see any cut and pasting, at least not from the wiki article you posted.


E85 will not make you faster than me alex!!!

 

[leerocketmike]

wow that was not a very interesting read. 13.5:1 and 8psi would more than suprise you. E85 will support it with no problem. And if you ask why go read a book.


I believe everything I read on the internet...

 

[Toolman]

wow that was not a very interesting read. 13.5:1 and 8psi would more than suprise you. E85 will support it with no problem. And if you ask why go read a book.


I believe everything I read on the internet...

mike, drinking tonight? haha! Got me some high octane friendly injectors heading my way?!?

 

[yamahaSHO]

I actually did not see any cut and pasting, at least not from the wiki article you posted.


E85 will not make you faster than me alex!!!

You read into it too much as I was just posting more information straight from source

 

[somedude_001]

I actually did not see any cut and pasting, at least not from the wiki article you posted.


E85 will not make you faster than me alex!!!

tim this is all you are going to be seeing

just don't stand too close or my turbo will suck you in.

on a serous note this is a 25psi + build I really don't want to mess this one up. At least if it all does go wrong I will get that spectacular failure I have been after. All I have broke so far is 2 diff pins (1 atx, 1 mtx) 2 clutch packs, 1 sprag gear, 1 planetary gear, 1 converter failure (due to metal filled oil filter), stripped transmission oil pump gear, 1 cracked piston, 1 failed headgasket, 1 cam seal (which caused a fire) 1 tranny seal (which also caused a fire) 2 broken engine mounts, and a pile of strut rod bushings that split.

I have to take one thing at a time though. getting pistons ordered is my current priority, then the new K member is getting ordered. by then the weather will be warm enough to make some sparks fly and burn some fuel.

 

[rubydist]

Good cut and paste Pretty much what I said.... Just with nothing to prove.

Cute, but wrong.

 

[yamahaSHO]

Judging by how everything you said in the first post was wrong, I'd venture to say that I'm not far off on my assumption

 

[rubydist]

The only thing wrong in my first post was the stoich a/f for E85.

You should read more carefully. And it wouldn't hurt to be nice either.

 

[SuperchargedSHOguy]

wow that was not a very interesting read. 13.5:1 and 8psi would more than suprise you. E85 will support it with no problem. And if you ask why go read a book.


I believe everything I read on the internet...

Yeah 13.5:1 even on E85 is very hard to swallow with a turbocharger or supercharger...even with straight boost juice and methonal injection. At this juncture I would not run anything 10:1 or higher with a supercharger or turbocharger, regardless of the grade of gasoline. It can be done but longevity suffers greatly. E85 is not easy to find in FL, atleast on the east coast so personally I would only set up the motor for 93 octane or 100 max accounting for meth. injection. If you really want to be safe go under 9:1 compression and boost the crap out of the motor.

Alex...may the best man win to the 11's...I plan to keep the Taurus SHO body though. Don't worry about Tim, he is just exhaust fumes
RWD setup SHO engine in any chassis>any FWD SHO
































J/K, I am not looking for 11's~!

 

[yamahaSHO]

The only thing wrong in my first post was the stoich a/f for E85.

You should read more carefully. And it wouldn't hurt to be nice either.

Sure d00d... If it makes you feel better.

I'm not being nice or mean. I just don't dance around BS.

As far as 11's. With a boosted E85 SHO motor in a RWD car, I wouldn't stop until you hit the 10's... And then keep running them.

 

[Toolman]

Don't worry about Tim, he is just exhaust fumes
RWD setup SHO engine in any chassis>any FWD SHO

True true! Without exhaust, the turbo thingy doesnt spin!!

And Alex posted the right pic. That is the angle I wll be seeing his car from!