What are good base line parameters for SD2 on E85?

#1
Hello all,

Lets start from the beginning. Switched over to SD2 and I'm a little overwhelmed. I guess I don't know what my target air fuel ratio is suppose to be at WOT, idle, cruise etc. etc. I have my wideband setup to show in lambda scale. It just makes it easier I think. I also realize every car is different and there is no magic number to be shooting for (or maybe there is). Also if I ask 10 different people I'll get 10 different answers. So what numbers are in the safe zone and what numbers are not? What about the spark tables? As always any help is great appreciated, Thanks guys!
 

BEATAV8

The Engine Whisperer
#2
Using gasoline scale....
For E85. Idle 13.0-13.5 unless you have 160’s then go for 12.5
WOT shoot for 11.2 at 15psi to 25psi
Cruising try 13.5 to 14.5

Timing start with 18-19 degrees at WOT. 19 deg around 20psi and 18 deg at 25psi. Maybe a little less if you have high compression ratio
 

VooDoo

New Member
#4
Ya I just installed a Holley Dominator and was wondering the same thing. If anybody knows where I could find an ignition table as a reference I would surly appreciate it.:)
 

Nick Micale

Tech Advisor
Staff member
#5
Using gasoline scale....
For E85. Idle 13.0-13.5 unless you have 160’s then go for 12.5
WOT shoot for 11.2 at 15psi to 25psi
Cruising try 13.5 to 14.5

Timing start with 18-19 degrees at WOT. 19 deg around 20psi and 18 deg at 25psi. Maybe a little less if you have high compression ratio
After doing many e-85 conversions including my race car, the above information/data is what we have found best! :)

Another comment is we set base fuel pressure at least 50 psi, and have gone to 60 psi with a 500 RWHP build.
 

VtheGNMan

Active Member
#7
After doing many e-85 conversions including my race car, the above information/data is what we have found best! :)

Another comment is we set base fuel pressure at least 50 psi, and have gone to 60 psi with a 500 RWHP build.
Nick- I'm wondering why you set the base fuel pressure that high? I know you know your stuff and I'm not questioning that but I'm curious as the reasoning.
Do you set the fuel pressure that high with all injectors on E85? For example running 80#s - 120# injectors same recommendation? Does this high of base fuel pressure mess with a chip's tune (or an aftermarket ECM's tune FAST)?

Thanks for any more info and insight you might give on this.
 

Nick Micale

Tech Advisor
Staff member
#8
Nick- I'm wondering why you set the base fuel pressure that high? ........
Years ago when I converted my street car to e-85, it had a slight hesitation at throttle tip-in?

After checking many possibilities, I upped the fuel pressure and the hesitation went away!

Since then, not only e-85 cars, some GN customers had similar issues with gasoline, and increased fuel pressure helped as well.

My thinking is to have more pressure and fuel available at the injector, rather than not enough.

Stock or mild builds may be ok at a base pressure of 44 psi, but when lots of mod are done, the added base pressure is good insurance, especially if idle or cruise in not affected.

Another tuning factor is setting the cam sensor.

Being from the old school with distributors, we would set them at factory specs, but then adjust it ti where the engine is "happy".

I know cam sensors control fueling, not spark, but with an upgrade cam, a change with fuel timing is usually in order for idle and WOT as well.
 

dank GN

BlackArts Automotive (661)993-8277
#9
I would switch your wide band back to the gas scale as the sd2 uses that scale. I just think it would be one less step for you to do . And set your fuel pressure where your car likes it .