I recently installed a new 383 motor in my 94 z28 and am having a dyno tuning session next week. I have heard some great things about e85 tuning on high compression motors as its octane is around 104. i am running a 12:5:1 static, and 9:4:1 dynamic compression setup and contacted the guy that will be tuning my car, he seemed rather reluctant to tune to e85 with my setup, as he stated the lt1 computers don't allow for a great degree of parameter adjustment. Wondering if any of you familar with e85 tuning can comment or give me advice on whether you believe it can be done, I think my injectors may be on the small side but am not sure. Heres my setup:
383 with flat top pistons and 5.7 rods
around 9:4:1 DCR
cam specs 230/236 .544/.555 with 1.6 rrs
ported heads and intake
52mm TB
37 lb injectors
255 lph fuel pump

any help is greatly appreciated as i would really like to convert over

 

if i am not mistaken the big thing would be larger injectors but leave the fuel injector constent set for the smaller injectors the pe tunning would be the hard part

 

I know you will need 20-30% more fuel than with gas, so set your injector constant at current size/1.25 to flow more fuel, and 2-3* more timing across the board.

Other than that, I would be interested to know as well, as I have thought of tuning a 2nd PCM for E85 that i could swap in when I want to run E85.

 

Yea i would like to know whether these injectors are large enough...is there any way of determining this. could increasing fuel pressure help at all?? The tuner said that that injector band width may be maxed out...not entirely sure what this means.

 

i tuned a similar setup with e85, with 36# injectors we had to crank the fuel pressure up to around 50 or so. he's since bought some bigger injectors so i need to retune it... but it did work
had some cold starting issues, not sure if its related to the upped fuel pressure or not.

 

If there's a way to measure the duty cycle of your injectors that's what you need to do. If they stay under 85% duty cycle then you don't need bigger. You can try telling the PCM that it has a smaller injector than it really does, then measure the duty cycle. I've been mixing e85 and gas and it was cold out one day, like 45, and it did take longer to crank to start the motor. So that may be an ethanol characteristic.