Calibrate trip Comp??

[racer1989]

Can any help as I am new at tuning...I am running a 99 GTP. I got my fuel trims perfect with e85 and 42.5lb injectors but my trip computer is way off on mileage? its reading adv. 32mpg when I am only getting 22mpg? can this be calibrated? if it can be, please let me know how I can do it.

Thank you in advance
Mark

[BlackGS]

You are getting 22mpg on e85? Is that all highway? I'm lucky if I get 17 most of the time, but I have done just under 20 on a long highway trip.

I have the same problem with the mileage calculator in my Regal. It seems to be calibrated for gas only somehow.

[racer1989]

BlackGS, yes that is solid hwy mileage... i am not sure if it helped or not but i had a 3.25" sc pulley on and the HP scanner was reading adv. 4-5psi at idle a little more crusing and 21+psi at 3400rpm under boost? seems too high to be true? also was running about 34 deg adv. timing at cruse as well so maybe that helps... Once I get more exp. tuning I would like to try to lean out cruse a little to add to the mpg.... It would be nice to get the dic mpg cal. to make it easier to see what helps mileage.

Thanks
Mark

[Phantom]

Check out http://www.clubgp.com/newforum/tm.as...mode=1&smode=1 this should be what you want.

[Phantom]

Note I assume by mileage you meant MPG and mileage as in 10mi.

[racer1989]

Check out http://www.clubgp.com/newforum/tm.as...mode=1&smode=1 this should be what you want.

I will have to give that a try, but it says it will not work with E85... i wonder why that wont work? as that is my goal. if I can get that close with E85 then I can start playing with the timing to get the most mpg.

thanks
mark

[E85GP]

Assuming you adjusted the IFR to add the extra 30% fuel needed by E85, then your trip computer will be off by around 30%.... you have told your car the injectors flow much slower than the really do (so it leaves them open longer to get the extra fuel you need for E85).

But if it thinks the injectors are flowing like 36lb injectors and they are really 60lb injectors, then it thinks it's using a lot less fuel.

It is possible to tune for E85 without messing with the IFR table. My E85 tune is set up with the IFR just about perfectly set to match 60lb injectors, and the car is using 9.7AFR for closed loop, and around 7-8AFR for WOT.

It takes a lot more work to tune for E85 this way, but in the end my trip computer is always within .5 gallons used of the actual fill-up amount.

I don't think there is any other real advantage to my way vs just adjusting the IFR, I just wanted to do it this way because a bunch of people said it wouldn't work. I also like seeing the true E85 AFR on my scans and my fueling tables.

The one critical part of my tune is that I needed access to some tables that aren't normally accessible. Without TinyTuner I couldn't have made it work.