Couple of questions regarding fuel and tuning

[horizontalkev]

I bought my car 4 months ago after it sat in storage since 2007.. I bought the car without any knowledge about it, the seller knew nothing about it either (relative of the original owner) my questions are:

How can I know for sure what fuel the car was originally tuned for? I want to say E85, how would the car run if I ran 91 and it was tuned for E85?

Today I confirmed the car had a walboro 255 installed.

Also has 6 bolt swap, aeromotive fpr, complete fuel system upgraded with walboro 255 rewired, T28 turbo, AEM fuel rail and intake, MAFT, motor internals unknown, fuel injector sizes unknown.
Thanks DSMers

 

[Cdc1221]

How could it be tuned for e85 with a maft? Does it not have a wideband? I seriously doubt its been tuned for e85 based on your info. Best possible solution is to pull your fuel rail and see exactly what injectors you have. Check your maft settings too. See how much of a percentage its compensating for.

 

[horizontalkev]

No wideband, just a crappy narrowband. I've gotten terrible gas mileage, even worst than my girlfriends 05 Tiburon GT (V6). The tibby used to be my DD and its much better on gas... Im ordering a wideband soon

 

[Cdc1221]

If it does in fact have an e85 tune, and you're using pump gas, it will inject more fuel than needed. If you have a logger, check your fuel trims. If not, there's not much else you can do.

 

[horizontalkev]

My long term fuel trim was around 8.5% I don't remember how my short term acted. Double digits are to worry about right? If so, Im uncomfortably close to those double digits