e85

[hcox10]

hi
i have a 84 t type stock except for a red armstrong 93 oct. chip.
can i mix e85 and 87oct with out any problems.
thanks harold

 

[EyesofThunder]

Be very careful running E85, even in mixed with gas, you can still go lean. Don't do it without larger injectors or a WB and watch it closely.

hi
i have a 84 t type stock except for a red armstrong 93 oct. chip.
can i mix e85 and 87oct with out any problems.
thanks harold

 

[novaderrik]

my experience has been that, yes, you can do it without any problems. of course, as far as i know, i have a stock chip and injectors and what not. but it does run much better with half of the fuel being E85 and the rest being 87 octane.

 

[EyesofThunder]

Datalog it, watch the O2's, but NB O2's are NOT trustworthy for jack <>0.45v.

You really need a WB on there to know. I don't know how much extra bandwidth in the stock injectors on the 3.8L Turbo, but on my 3800, there is NOT enough, and it does go lean. With 100% E85, mine went lean around 14:1 under boost, >100 mph, not a good time to go lean.

With 50% E85, it isn't as critical, likely won't go as lean, but still, if you don't have a lot of bandwidth already, aka, mods that need more fuel than stock, you shouldn't play with it until you have a way to know what the actual A/F is.

Holes in pistons just plain suck.... And I would bet your EGT's are SOARING running a mix of E85 and not a chip.

 

[MrMNTTA]

Holes in pistons just plain suck.... And I would bet your EGT's are SOARING running a mix of E85 and not a chip.

Interesting - don't engines typically run cooler with more ethanol in the fuel system? Or am I thinking of something else?

 

[EyesofThunder]

Interesting - don't engines typically run cooler with more ethanol in the fuel system? Or am I thinking of something else?

Intake side yes, not exhaust side. If it ran cooler on the exhaust side guys with Turbos would hate E85. Intake side, sure, way cooler.

What little I am learning on EGTs (if you are in the know, PLEASE post!):
The more inefficient the combustion event, the higher EGT, as fuel is burning outside the chamber and in the exhaust ports. May be good for turbo boost, but bad place to be burning fuel.

Lower timing = higher EGT (Events are poor, so unburned fuel gets out into ports, and will ignite, piston not getting extra push down)
Higher timing = lower EGT (more complete burn, fuel is burned and pushes piston down efficiently)
More fuel = lower EGT, to a point... (ensures complete burn, but too much is a bad thing too)
Less fuel = higher EGT (leaner is going to start causing incomplete combustion so the fuel that didn't get burned burns in the port)

Info is sketchy on EGT tuning, but you gotta be careful messing with mixed fuels or other fuels, you can hurt things. GM has (at least on OBD2 cars/trucks) a lot of routines to manage cat convert temps, which is calculated, but what it does is dumps fuel to cool things off. Like 12:1 or richer. I found my LT1 running E85 went into Cat Temp OverProtect a LOT, even very early from a col start.

My advice, run it, but use a WB and if you can, EGT, but for sure, get a chip on it, run the higher timing you most likely need, E85 burns slower, so that is one of the biggest reasons you need to bump up timing.