How am I doing?

[rauck]

I have been having a blast messing with my tune and driving my swapped 528i. I do not do this for a living, just for fun, so I have been reading like crazy and making tons of changes. Can someone take a look at my tune and let me know where I need to focus my attention? Each time I adjust the tune, things get more fun to drive and the car drives better. I just want to make sure that I am not missing anything obvious. Here are my specs: Stock LM7, Iridium plugs, speed engineering shorty headers, no cats, LS1 (1999 corvette) intake/injectors/fuel rails, LM7 MAF, LM7 throttle body, corvette fuel regulator, 4l80e, higher stall torque converter 2400-2800 rated, new denso 02 sensors, fuel pressure 75 PSI KO and idle, I run 87 octane w/10% ethanol.

Any guidance is appreciated-Ray

BMW.10-1999 ls1 injector full data (68lbs fuel pressure)(raised idle to corvette).hptbmw fuel trim log.hplBMW.10-1999 ls1 injector full data (68lbs fuel pressure)(raised idle to corvette).hptbmw fuel trim log.hpl

[5FDP]

Fuel pressure is too high. The stock injector are designed to run around 58psi and I would not run 75psi on them.

Get a wideband in the exhaust and start tuning the MAF and VE tables to get fueling dialed in. It shouldn't take much with the minimal mods done. Both the secondary and primary VE tables have to be tuned and it's done a certain way on those early computers.

[rauck]

Thank you for the input. I am running a WIX brand corvette filter, and I noticed that my fuel trims were negative and that's why I put a fuel gauge on it. I will start by purchasing an AC Delco filter in the hopes that it will bring the pressure down a bit. Is it not possible to just tune for the higher PSI? I really only work on the car over the winter and drive it 11 miles each way to work during the nice weather. Will the higher PSI hurt anything? Hopefully everything else looks solid in the tune. Thanks!

[5FDP]

Too high of fuel pressure changes how the injector operates, the data is no longer accurate either.

If you have a beefy fuel pump, you need an aftermarket fuel pressure regulator to control pressure. I personally hate corvette filter regulators because they rarely work right with other pumps. It's designed for a corvette with stock everything and not much else.

[rauck]

Is there a better choice for a filter/regulator? I don't mind swapping it over. I am running a stock 1997 BMW 528i fuel pump with the WIX filter.

[blindsquirrel]

A restriction in the return line anywhere between the filter and tank will cause that high pressure too.

[rauck]

I will start by replacing the WIX filter with an AC delco one to see if that makes a difference. While I am under there, i will look at the return lines to make sure nothing looks awry.

[blindsquirrel]

No stock replacement part for that application will have a different return orifice size inside from any other.