e85 update

I felt the same thing when I was running higher timing last year. Now I am leery about running higher timing at 24psi.
 
I really wouldnt go much over 24-25 degrees no matter what the scenario just cause Im more concerned with preignition than detonation with ethanol....torched a head gasket in half a second with a tune hiccup on my other car on the corn....that fuel will make you feel like superman and take anything you throw at it...but cross the line and its a quick rod in the ass...
 
Rafs-T-Type said:
You're not making sense here. You said "Now if under, you want to shoot for a gas AF of 9.37 = 7.35 E85" To me that sentence reads under boost you want to aim for a 9.37 on the gas scale which comes out to a 7.35 on the E85 scale. Is that not what you meant? I said that 9.37 seems rich which I thought was obvious that I was talking about the gas scale, as you were just talking about that number on the gas scale. Now if you are talking about running boost at 9.37 on the E85 scale, then yes it would be lean as that translates to about a 14:1 on the gas scale. And again 9.37 on the gas scale will not equal 7.35 on the E85 scale. 9.37 would be more like 6.2 on the E85 scale, which is rich as all hell. However going the other way 7.35 on the E85 scale come to about 11.1 on the gas scale which I think is a little rich, but perfectly acceptable AFR.

I also disagree with you about the injector sizing. I would say you need about 50% larger to make the same power...so 60lb injectors, for example, would become 90lb as 60 x 1.5= 90
Click to expand...


I let me fingers do the talking and proof read. What I was saying, that with the SD Chip and the classic fast, you want to have your WOT Target AF around 7.35 (E85) /9.37(gas) scale. 9.9 E85 is equivalent to 14.7 gas AF. I will disagree with you again on 7.35 (give or take a little) as to being to rich. These cars love the E85 and at WOT...... This is why you are allow to run more timing and boost........

Ethanol is a pure chemical substance with the formula C2H5OH (or empirically C2H6O), with a formula weight of 46.06. Its gravimetric lower heating value (LHV) is 11,604 BTU/lbm, and its stoichiometric (perfectly-balanced mixture) ratio A/F is 9.003 lbm (14.7 AF on gas scale) of dry air per lbm of ethanol. So the 46.06 formula weight is half of gas. That is why you need to double your injector size. As your combo, you have 120s to do the same job as 50s would do on C116. Put 80# INJECTORS back in your car and prove your statement. You will not get the performance. Your duty cycle will be shot, you will loose boost, and be running out of fuel........

Although the formula varies, it is close to C7.4H13.7 with a formula weight in the neighborhood of 100 to 105. Its gravimetric LHV varies, but is usually close to 18,700 BTU/lbm. Its stoichiometric ratio also varies, but is usually close to 14.9.
 

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gtfrede said:
I really wouldnt go much over 24-25 degrees no matter what the scenario just cause Im more concerned with preignition than detonation with ethanol....torched a head gasket in half a second with a tune hiccup on my other car on the corn....that fuel will make you feel like superman and take anything you throw at it...but cross the line and its a quick rod in the ass...
Click to expand...

I agree that you can run more timing. I would even step out and say, that you could run around 27* on 24#. But your tune has to be right.... Spark/ignition is the cooling factor of the motor. There are tuners out there that have experimented with detonation and egt. As they started to get detonation, their egt started to drop. Hense the cooling factor. Now the fuel is where we start to see our heat. The excess/extra of fuel on the cylinder walls and ring lands are where and why we get that burnt piston, rings, and head gaskets.
 
CGASTON said:
I agree that you can run more timing. I would even step out and say, that you could run around 27* on 24#. But your tune has to be right.... Spark/ignition is the cooling factor of the motor. There are tuners out there that have experimented with detonation and egt. As they started to get detonation, their egt started to drop. Hense the cooling factor. Now the fuel is where we start to see our heat. The excess/extra of fuel on the cylinder walls and ring lands are where and why we get that burnt piston, rings, and head gaskets.
Click to expand...

I personally havent been able to find much of a knock threshold when using ethanol but agree egt would be very usable for this scenario....that is where the tuning dance begins when you need to consider how rich is safe / detrimental while having enough advance to keep the flame front where it needs to be....On a sidenote I have seen catastrophic failure when not using ENOUGH advance while burning ethanol fuels....pull too much timing and add too much fuel and things will melt with nearly no sign of a problem (without an egt gauge of course) which in that case monitoring egt would have saved the engine above any other tuning tool...which lines up with what you stated about the excess fuel left in the chamber
 
CGASTON said:
I let me fingers do the talking and proof read. What I was saying, that with the SD Chip and the classic fast, you want to have your WOT Target AF around 7.35 (E85) /9.37(gas) scale. 9.9 E85 is equivalent to 14.7 gas AF. I will disagree with you again on 7.35 (give or take a little) as to being to rich. These cars love the E85 and at WOT...... This is why you are allow to run more timing and boost........
Click to expand...

For the third time 7.35 on e85 is not 9.37 on the gas scale. And for the second time 7.35 is acceptable on the e85 scale. I think it's slightly rich, but a ton better then it would be at a 9.37 on the gas scale.

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gtfrede said:
I personally havent been able to find much of a knock threshold when using ethanol but agree egt would be very usable for this scenario....that is where the tuning dance begins when you need to consider how rich is safe / detrimental while having enough advance to keep the flame front where it needs to be....On a sidenote I have seen catastrophic failure when not using ENOUGH advance while burning ethanol fuels....pull too much timing and add too much fuel and things will melt with nearly no sign of a problem (without an egt gauge of course) which in that case monitoring egt would have saved the engine above any other tuning tool...which lines up with what you stated about the excess fuel left in the chamber
Click to expand...

Pulling timing caused issues...as in retarding caused issues? How far retarded? I wouldn't think that would raise egt's. How far advanced are you setting your timing?

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Rafs-T-Type said:
For the third time 7.35 on e85 is not 9.37 on the gas scale. And for the second time 7.35 is acceptable on the e85 scale. I think it's slightly rich, but a ton better then it would be at a 9.37 on the gas scale.

Posted from the TurboBuick.Com mobile app
Click to expand...

Not once did I say that 7.35 WAS NOT ACCEPTABLE....... And for your third time...... I just wanted you to say it again. If was kinda funny. Lastly, Depending on your boost and timing, 9.37 gas scale is not to rich.... Some members run their WOT on E85 with a 6.3 to 6.6......
 
CGASTON said:
Not once did I say that 7.35 WAS NOT ACCEPTABLE....... And for your third time...... I just wanted you to say it again. If was kinda funny. Lastly, Depending on your boost and timing, 9.37 gas scale is not to rich.... Some members run their WOT on E85 with a 6.3 to 6.6......
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I didn't say you said 7.35 was not acceptable. I, for the fourth time, say that 7.35 E85 scale does not equal 9.37 on the gas scale. Again you said " Now if under, you want to shoot for a gas AF of 9.37 = 7.35 E85", which is not true. I would like you to provide one example of anyone running a decent ET with a 6.3 to 6.6. That is waaayyyy too fat. That is in the 9's on the gas scale. Somewhere in the 11's is where most want to be.
 
Update: It seems this has turned into a tech thread but had the car out last night

Made 3 passes,

2 of which the boost was 30psi and I had to abort, car was all over the track at 300ft

Boost at 27lbs
ramp rate 7 lbs per sec.
1.42 60 ft
6.00 1/8th
9.34@145 new best

loving the power its making on the 85 :)
 
Congrats on the new Personal Best with the new combo and on the E85 too. What did it run to the 1/8?

Regards,
Shev
 
Wow! U ran just what i ran on my 109 on E85 pal. Which i know for sure it had a high 8sec. in it after i got done with it. Never took it back to put it on paper lol. But congrats!


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Thanks... I wish I had a successful update but its been a summer of testing and tuning witch ended last weekend at the track after I sheared the crank key and wiped out the valvetrain
1410736874316.jpg
 
ULOSE2A6 said:
Sorry to see this happen. What causes something like that to happen?

Regards,
Shev
Click to expand...
From what I understand the balancer wasn't tight enough or came loose...the crank is a older Crower casting with a single keyway that extends into the timing gear slot only 3/16 of a inch and if the balancer comes loose at all this is what happens.

Newer castings have three keyways which seems to be much better design.

the carnage is pretty bad ...bent every valve ,some pushrods, maybe wiped camshaft ,still assessing the damage :(
 
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