How can I increase fuel in relationship to MPH (IE more fuel down track)

[Snowman1987]

Hey guys!

We are working on a couple builds that have 700 RWHP or more (over 1000 on one) and of course as MPH increases down track the car leans out, obliviously due to the higher load on the engine because of wind resistance, weight, effective gear ratio, etc.

My question is, on the E38 ECU the cars are using how can I keep the same fueling the same down low and richen the mixture up top to match the AFR I can achieve in 1st and second gear, without it being TOO rich down low.

Thank you in advance!

[Lakegoat]

Are you reading a wideband to determine that it is lean?
Add fuel to the maf and vve in the areas that it is needed.
Make sure that you are not running out of injector or fuel pump capacity.

[Snowman1987]

Yes. I can add fuel, but that in turn richen's it up down low. It responds well to that, but then its fat in 1st and 2nd. (5 GPM pump and 1600CC injectors.)


One example is a Procharged car. It loads the car at 6500 and 18 psi for the 2nd 1/8 mile (TH400 trans with a Cameron's converter that maintains the load in high gear). Adding fuel where needed makes 1st gear and second gear richer than I'd like, it may just be something we have to deal with on these builds? It's not the end of the world, but would like it to be able to add fuel in high gear and not in the first 2.

I only have a log from narrow bands at this point, but we are currently putting a new WB in the car to log with hptuners

[Lakegoat]

If you add fuel to the overall maf and vve, it is not going to be correct. When you get your wideband and hptuners channels and graphs setup, you will see that you can add or subtract fuel at different areas. Narrow bands don't work at wot. Your converter setup may make it harder to tune, but it seems like the load is going to change the faster/higher gear that you run. Are you even running a maf?

[Snowman1987]

If you add fuel to the overall maf and vve, it is not going to be correct. When you get your wideband and hptuners channels and graphs setup, you will see that you can add or subtract fuel at different areas. Narrow bands don't work at wot. Your converter setup may make it harder to tune, but it seems like the load is going to change the faster/higher gear that you run. Are you even running a maf?

Yes, I understand what you are saying. It is a MAF based setup.

[Snowman1987]

Another note* On the nitrous car, the MAF and MAP actually read lower during a nitrous pass than an all motor pass. I am assuming its the turbulence around those sensors when nitrous is spraying from the plate.

This only exacerbates the fueling issue. I am jetting up the fuel side to compensate for this issue.