Building an engine designed for E85

Another thought has crossed my mind.

First things first, I have never run E85 and am operating on many assumptions here.

My understanding is that the primary reason for switching to E85 is to avoid pre-ignition (spark knock).

What I'm unclear on is if E85 will make more power than gas on the same boost level and good tuning, and whether there is a line that can be crossed where even the E85 will self ignite.

I am thinking about this because it would seem logical (if E85 won't suffer from pre-ignition) that one would be able to build a high compression motor (like 11 or 12:1) and then throw 15-16 psi on top of that and really make good power. This would increase the off boost power curve, should increase the off boost fuel efficiency, and would alleviate alot of lag associated with big turbos. But I don't know enough about E85 to know if this is even possible.

 

[Diego]

One day I want to sit in your brain.

That is all.
/ubbthreads/images/graemlins/wink.gif

Diego

 

[onesickcrx]

Your thinking is on point with the compression. You also need to think about where and what turbo is most efficient at that boost level. If I were to do it again 10:1 would be my choice great spool and still plenty of room to turn the boost way way up /ubbthreads/images/graemlins/devil.gif

 

[Boost4U]

^What he said, 10:1, e85, high boost = wet dream.

 

Quoting Diego:
One day I want to sit in your brain.

That is all.
/ubbthreads/images/graemlins/wink.gif

Diego



Thank you sir.

I do believe that is one of the highest compliments I could ever receive.

 

[Boost4U]

what piston/rod combo are you thinking would be best suited for what you're trying to achieve? 2.0, 2.3, 2.4? Very interesting topic sir.

 

[boostx]

The 10:1 CR is wicked. I have see this car run and it was a beast..
click me

 

Quoting Boost4U:
what piston/rod combo are you thinking would be best suited for what you're trying to achieve? 2.0, 2.3, 2.4? Very interesting topic sir.



That would be based more on the needs of the vehicle I think, rather than just the E85 factor. My thoughts right now are occupied with a RWD S-10 application. The truck would see daily duty, would have an auto trans, and it would still be a truck. It would pull toys to the lake, it will have god knows what thrown in the bed, and it would need to be able to have the GF drive it if I've had too many beers.

So either a 2.0 or a 2.4. But probably a 2.0, and here's why.

It needs to be reliable and it needs to be simple. A 2.0 needs rods, pistons, and ARP hardware to be nearly bulletproof. A 2.3 needs rods pistons, crank, clearancing work, and ARP stuff. A 2.4 needs rods, pistons, special block work for the DOHC head, ARP stuff, and you end up with a timing cover that doesn't fit right. A 2.0 makes plenty of powwa, and can be made to be better down low with a CR increase. It is simple, easy, and reliable.

 

[Dark_Horse]

E85 suppresses knock so much that by the time you realize something is wrong, your engine will be a goner.

As for power level - check this link out. Bone stock Chevy HHR on gasoline & E85. click

E85 made more HP and Torque throughout the entire RPM range.

 

[Boost4U]

Quoting galant1517:
Quoting Boost4U:
what piston/rod combo are you thinking would be best suited for what you're trying to achieve? 2.0, 2.3, 2.4? Very interesting topic sir.



That would be based more on the needs of the vehicle I think, rather than just the E85 factor. My thoughts right now are occupied with a RWD S-10 application. The truck would see daily duty, would have an auto trans, and it would still be a truck. It would pull toys to the lake, it will have god knows what thrown in the bed, and it would need to be able to have the GF drive it if I've had too many beers.

So either a 2.0 or a 2.4. But probably a 2.0, and here's why.

It needs to be reliable and it needs to be simple. A 2.0 needs rods, pistons, and ARP hardware to be nearly bulletproof. A 2.3 needs rods pistons, crank, clearancing work, and ARP stuff. A 2.4 needs rods, pistons, special block work for the DOHC head, ARP stuff, and you end up with a timing cover that doesn't fit right. A 2.0 makes plenty of powwa, and can be made to be better down low with a CR increase. It is simple, easy, and reliable.


That was more or less what I was asking. 4g s10 would be so much fun.

 

Quoting Dark_Horse:
E85 suppresses knock so much that by the time you realize something is wrong, your engine will be a goner.

As for power level - check this link out. Bone stock Chevy HHR on gasoline & E85. click

E85 made more HP and Torque throughout the entire RPM range.



This is good to know.

The plus for me is that for my needs the engine might only need 10 psi to be sufficient. I'd think that it would be difficult to nuke a solid motor, even with 11:1 CR, on that low of boost. Plus, I could pull the turbo off if it was too much and still have a peppy four banger.

 

[4thStroke]

With the same timing, AFR, boost, and only adding your ~30% to compensate for ethanol, the horsepower level will be very similar, within a few horsepower.

10psi means very little. An evo 3 16g on ethanol will make over 400whp with a properly built motor. At 400whp, that motor won't skip a beat. The thing is though, if you want to build a high compression motor, you will need to spend some good money on forged pistons and then you won't even be utilizing them if you do end up running such low boost. A stock motor will handle a turned up 16g on ethanol all day long, you just won't have the out of boost response... which with a small turbo, it usually isn't a problem anyways.

 

[thecman02]

My friend messed around putting a 16g back on his ~10.1 2.3l. It pulled hard in every gear as long as you kept it over 2500rpm and under about 6500rpm. The boost would tapper pretty bad. At max torque it would spin 245 proxes ra1's a little. If your going to stick with a small turbo then I wouldn't feel bad going 11:1 when running ethanol. Would be a torque bastige.