LQ4-E39

iTrader: (7)

I’m nearly done with the build portion of my car and am going to be firing it up for the first time. Few questions regarding tuning and driveability.

First off, the specs:

Stock bottom end 6.0 LQ4 out of a 2003 Express Van
317 heads milled .026” for a 66cc chamber
Stock cam out of a 2005 LS2 Corvette
LS6 Yellow valve springs
LS6 intake manifold and throttle body
Stock LS6 fuel rail, 42#/hr Ford Greentop injectors
Exhaust is stock CTS-V iron manifolds paired with the OEM BMW exhaust
4” intake pipe to a cone filter

My biggest concern right off the bat is that the 42# injectors will run super pig rich as the car isn’t tuned for them. It’s obviously a completely stock 2003 Express PCM. I’m hoping that the added airflow from the LS6 intake will help offset the extra fuel, but I don’t know if that’ll help. It will obviously need to be tuned for the injectors, and all the other parts. This leads me to my next thought:

PCM is stock and I’m assuming it still has VATS. I’d like to have VATS removed along with the rear O2 sensors, and any other emissions related codes that would cause a CEL.

Finally, the question: How crappy will the car run until I get it tuned? The closest good tuner that I have chosen is just about 1 hour away from me, so will I be able to drive the untuned car there to have VATS and etc removed as well as have it tuned (get it all done at once), or do I need to ship out the PCM for tuning just to get it driveable?

Any input helps, thanks.

minytrker

iTrader: (13)

Your going to have to get it flashed first. It will not run without vats disabled. It would also be very rich and probably kill they plugs trying to drive it with the 42 injectors. Alot of the time whoever is doing the tuning will cut you a deal on a mail order if your bringing the vehicle to them to tune in person.

LQ4-E39

iTrader: (7)

What seems silly to me is that I’ll need to have the car flashed to remove VATS and etc, as well as flashed to have it run decently enough to be driveable. Then, I’ll have to take the car there anyways to have it properly tuned in person.

Just trying to kill 2 birds with one stone rather than going back and forth.

sweet-94z28

iTrader: (30)

That car really shouldn't need much more than the VATS, injector changes, some VE changes, and maybe some small timing changes to start and run pretty good. If it was an aggressive cam or forced induction, I could see the concern. A good tuner should be able to get you close by mail I would think.

minytrker

iTrader: (13)

The VATS has to be removed inorder for it to run in an engine conversion, no big deal. It would run on a stock tune with just VATS turned off if you didnt installed the big injectors, it would have ran on stock injectors. A good tuner can get it really close on a mail order tune for your setup. A lot of tuners will credit you back either all or a portion of the price of the mail order tune when you come to get the tune finished in person. Thats about your only options with your combo.

LQ4-E39

iTrader: (7)

Thanks for the heads up. Good to know that it’ll be close via mail order tune. Unfortunately the tuner closest to me does not do mail order tunes or have a bench setup—they only do tuning via OBD2 port, so I’d have to finish the car, trailer it 1.5 hrs away, and have them do their stuff. Theoretically the first fire up would be at the shop…which is assuming all my wiring will be correct. Certainly don’t want to go down that road.