Tuning fuel maps with E85

[Mahonroy]

Hello, just a quick overview this is an 04 Hyundai Elantra, 2.0l, 7.9:1 compression, 4x 290cc's and 4x 460cc's, TD05H big16g boosting 24psi.

I recently changed all my fuel maps to add aproxemetly 30% more fuel, and added about 3 degrees of timing across the board, and have been filling up with the E85 fuel. I had a question though...

When I was using 91 octane gas, driving around on light throttle I would get 14.7:1 air/fuel ratio. Under wide open throttle and full boost I tuned it for 12.5:1 air/fuel ratio (which is 0.85 lamda), mostly because I've heard that under boost this is a good ratio to shoot for (safe and you still get good power). Basically I want the best performance I don't care about fuel consumption. So now with E85, I'm getting 1 lamda when I'm cruising around on light throttle, but what is the best air/fuel ratio to shoot for for best performance? I was assuming I would want to go for the same 0.85 lamda again, but whats best?

Any help is greatly appreaciated, thanks!

[60-1teg]

On all my e85 cars 0.85 works good and is safe

[HONDA GHANDI]

The best would be to shoot for a Lambda value that produces the best torque without sacrificing EGT or reaching the lean burn crossover. Your engine setup and turbo setup have a lot to do with this but .85 L is a good starting point. I have found that dyno tuning E-85 using a load bearing dyno can really get some amazing results when fine tuning the ignition curve and fuel curve. My vehicle actually made more power when I ran it slightly richer due to the efficiency of the burn. With E-85 some of the fuel is wasted in quench area and that it stores less energy. I made the BMT between .78 and .80 Lambda. (approx 11.4-11.8 afr) Of course timing has a lot to do with these numbers but as oxygen is depleted in the cylinders during the burn it is more likely to detonate. The extra fuel helps this in three ways, the E-85 carries some extra oxygen with it, the extra fuel helps cool the cylinder quench areas after the burn cycle, and of course, it burns much cooler. This alone will allow some very high timing numbers and that is where the torque is hiding. As I approached the 12.0-12.5 mark my ignition became more unstable as cylinder pressures began to skyrocket (due to knock) as well as my EGts. This made my torque plummet as well.

Vehicle: honda Element- T3T0E-.57 trim. 389whp 391 tq uncorrected @14 psi (stock engine)
Hope this helps.