Podium

Hey guys. About to finish my winter build. Its a ls6 with a stock bottom end. It has a tick blower cam, full exhaust and A&A Ti v3 with 3.6 pulley. It will be tuned on e85. My question is on WOT Lambda. What should I shoot for to be extra safe with the stock bottom end? Im hoping to build a forged set up this winter but need this set up to last this year. Just looking for advice on tuning ideas on keeping the set up alive for a year.

I have been told .75 Lambda would be good along with timing around 12-13 for gasoline. Also to keep it under 6.5k

I also have been told that with E85, I can just tune it at .75 lambda and let it eat with the timing.

I know I could just tune it for power and see what it likes and it could live for years like that but Id rather be extra safe. Especially considering I want the car for my wedding this summer.

BLOWNBLUEZ06@RKT Performance

.75 is too rich for my taste. I've seen cars nose over up top with that kind of lambda but you could start with that and see how it does. I've got a SBE car running around making 850whp on E85 and it pulls straight to 7200 without even beginning to nose over. Play with it on the dyno or the track. Read the plugs at the track and see where you end up.

Podium

Well 75 is about 11 AFR. Maybe Ill start at 78 lambda or so.

Im not so much wondering about best lambda for power, but more so to play it safe to make the motor last.


If you're suggesting that I just tune it on the dyno on go with the WOT lambda based on plug readings Im good with that.

Rkreigh

Read what Brent said and have the tuner do a hook test to sneak up on timing. basically there is a cross over point where the engine doesn't make more power as timing is advance and shows about the same power with the timing backed down puts the timing where you need to be. The e85 will "tolerate" more timing and not detonate but don't get greedy here as it won't buy you anything.

too little timing on the slower burning e85 without much boost can make the car feel pretty sluggish. don't worry about the stock bottom end on e85 with a safe tune, it's a great choice. just change the oil more often.

Podium

I'm tuning it. I was just looking fortips on how to make the stock bottom end last longer until the new motor is built.

SVT_Z06

E85 burns faster.

kromberg

I thought E85 brunt slow and cooler.

neutron82

Bret tuned my car, it might be the one he referenced in his post but he has tuned a lot of high power stock bottom cars so it could be another one... depending on the weather and ethanol % you might see the afr swing either way a bit but it probably won't be an issue unless you deviate from what you were tuned on by a large amount... I always check what I'm putting in my car and the station I use has never checked out less than 85% even in the cold months, during the summer it's usually in the high 90% range

Turpid porpoise

E85 has a lower burn temperature and luminosity. E85 burns slower than 93 OCT pump gas but quicker than Methanol.

BLOWNBLUEZ06

E85 burns slower than gasoline and faster than methanol.
This reference chart shows burn rates at stoich amongst various fuels. I wish it had the burn rates at WOT under boost shown too. If the fuel burned faster, you would need to pull timing/spark advance back when changing to E85 and that's not the case.

BLOWNBLUEZ06

Yes, you're the one I referenced. Your SBE motor pulls until you let off the gas and I love it!

neutron82

me too

algZO6

be careful, mine SBE use to do the same.

Podium

We are generally low as 60 percent in the winter and close 90 here in MN.

I plan to keep in eye on the wideband with every fillip. Hoping to go Holley or Halltech flex fuep through Brett this winter.


What's the best way to do the spark hook when not using a dyno? I read somewhere that the spark hook test only works in a controlled environment such as a dyno. I wont ne able to hit the dyno for a few months.

Toys4Life C5

According the one of the best minds in tuning - Greg Banish, E85 burns faster.

"No, ethanol has a faster burn rate than gasoline. It just has a much higher AKI (knock index) so you are rarely limited by knock at WOT which allows you to run more timing at high load."

PS, I just tested pump E85 today and it came in at 70% which is what I would expect for this time of year in MN.

BLOWNBLUEZ06@RKT Performance

This is true. Took more work to figure it out, but he's right.

Toys4Life C5

I believe you are correct, there is no way to do part throttle spark hook test without a dyno. At part throttle I suggest a little less than OEM timing with E85 because it burns a smidge faster. For WOT and no dyno, E10 will knock before MBT under boost so go to slight knock and back her down a couple degrees for safety will give you your highest torque. For E85 and WOT, it will typically not knock even as you go past MBT and power drops off so I would suggest looking at your MPH at the track and slowly increasing timing at WOT until MPH starts to fall off - then back it off a smidge. I am what you call a non-professional tuner so use my suggestions at your own risk! Remember 2 things kill these engines. 1. knock will snap the upper piston area. Scan and avoid knock always! 2. Running under boost too long causing too much heat where the rings expand to fill in the gap and then break the piston. Best solution is to build the engine with wider gaps for supercharged. I take the risk and only run 1/4 mile at a time. I would not do the texas mile though as I am pretty certain that would be a disaster without widening my ring gaps.

Good luck!