U-Luze

iTrader: (4)

My new stroker is up and going now but I have a question about it running rich. It has 30# SVO's and its running rich at an idle. It also has a stock Maf sensor too. Ed Wright has it tuned for the injectors but is also tuned for a 85 mm Maf that I had on my H/C/I setup. But the TNT power ring wouldnt fit so i Put the Stocker back on there. Im also running a Autolite 103 a cold plug. Can I get some opinions on this running rich problem. Thanks Justin Hagerman

VINCE

iTrader: (1)

Nice setup.. Have you drove around for a while yet.. Mine ran rich immediately and then it ran normal after about 100 miles..

99WhiteSS

Awesome engine choice! I had Ed Wright do my tuning too, then I installed the same injectors you are using (30# SVO). I called him up to discuss the cost of retuning for the new injectors. He told me he didn't do that. (I'm saying, be wary of what he told you. He may not have tuned for the bigger injectors at all, hence you are idling very rich.) Same with my car. Very rich at idle and a little leaner as the RPMs increase. It's not a linear response across the whole engine range because a simple calculational offset in the PCM table would skew one side of the numbers high and another side low. (Insead of moving a whole line up or down think of it more like rotating a line about a fixed middle point...) Anyway, it's more difficult to tune for these injectors than one would think, partially because of the fact that they are rated at a different fuel line pressure and have a completely different offset. Here is something I copied down from another post, and I quote, maybe it can help you too: (I would suggest buying LS1 Edit and doing this yourself)

The lean mess, I believe is caused by differences in the SVO injector offset compared to our stock table.
The stock table works fine, but some of the LTerms are pretty crappy at times (ie when you first hit it,
and also coming off of the gas).

To properly scale your injectors, use the following formula.

Injector Flow = Rated Flow * SQRT((Your psi + Intake psi) / Rated psi)

Injector Flow: How much your injectors will really flow for that given pressure (intake pressure)

Your PSI: How much fuel pressure your car has. For a stock car this is 58.015 psi or 4 BAR

Intake PSI: How much pressure in the intake. This value is represented by Kpa (kilopascals) on your injector
scaling table.

Rated Flow: The flow that the injectors were rated at. For your case it would be 30 lb/hr.

Rated PSI: The pressure that the injectors were rated at. For SVO 30#'s this pressure is 39.16 or 2.7 BAR.

Sooooooo.....

Convert Inlet Pressure Kpa to PSI.
KPa * .14503 = PSI

Here is an example of the calculation for first cell in your Injector Scaling table.

Injector Flow = 30 lb/hr * SQRT((58.015 psi + 0 PSI) / 39.16)
Injector Flow = 36.51 lb/hr

Our PCM tables are in Gram/Sec, so we have to convert the 36.51 lb/hr to gram/sec.

36.51 lb/hr / 3600 sec = .01014 lb/sec
.01014 lb/sec * 453.6 g/lb = 4.6007 g/sec

Or you can just go to http://ls1edit.slowcar.net/faq.html and use ChrisB's table if you aren't a numbers guy.

-Kris

U-Luze

iTrader: (4)

-Vince I have no miles on the motor yet as it is getting an alignment from where i changned the K-member and A-arms out. So maybe ill get to drive it a little bit this weekend.
-99WhiteSS The computer is tuned for the injectors on the file sticker he puts on the PCM it says 30lb injectors. But also would it be that the computer hasnt done the idle relearn an when it does would it lean out to bout right? Thanks