LS7 (441 CID) with Light Boost in 1998 Trans Am (Need MAF advice)

[Black LS1 T/A]

OK ... I've taken the 422 Iron block out, moved the the 4.125 crank over to the LS7, purchased Diamond Pistions, three-angle valve job LS7 Heads with stainless steel valves, etc, etc ... and just got an LS7 intake. Upgrading the injectors to 80# (from the Siemens 55#'ers) and now I'm at the decision-making time on throttle body and MAF.

For centrifugal FI, does it matter a lot beteen the 90mm and 100mm MAF? Particularly since the stock intake and throttlebody are 90mm?

Also, since my tune is for the 75 mm MAF that came with my Trans Am (actually, an 80mm MAF on it right now), are there any tunes I can start from or import MAF for if I cnage from my stock MAF? Are there still huge hurdles to jump for a 1998 computer when changing to a larger MAF?

I've been out of the loop for quite a while and would appreciate any help, including .tun's to look at.

Thanks!

[Rhino79]

Id just go speed density. Your maf table will max at 512 g/sec. If you are dead set on going with a maf setup, order a maf sensor boss from gmpp and run the new style car maf. The maf tablel will have to be setup for it, but it is a much better setup. But my vote is for sd.

[Black LS1 T/A]

Thanks for the advice; I will consider that. Can you possibly post a link to a good thread about the basics and setting up for SD?

And what about turbulence of the intake from the Supercharger? How is that generally handled? Is the MAF still physically in place, just not connected? I feel like such a newbie at the moment. :doh2:

[Rhino79]

Leave the maf out, leave your iat sensor in and tune only with the ve tables. I would upgrade to an efilve custom operating system that will allow you to tune beyond the 1 bar limits of the stock ve table (if available for the 98 pcm). There is a nice writeup in the tutorial section in the help tab of the tune tool. Basically speed density is only using the map sensor, iat, and tps for fueling calculations (well and all the obvious injector tables normally used). It takes the maf out of the loop and you set your tune up based of manifold pressure.

[minytrker]

No cos for 98. If it were my car I would re-pin harness and swap to 411 PCM then run cos 3.

[joecar]

+1 run a 0411 PCM (repin the harness), then you can run COS3 (boost, nitrous) or COS5 (boost, nitrous, throttle VE)...

you won't regret it :)

[joecar]

SD is easy:
- disable/remove the MAF;
- disable COTS, DFCO;
- make sure OLFA and PE are sufficiently rich;
- correct the VE table in OL using a wideband;
- decide if you're going to run COTS, DFCO;
- decide if you're going to run OL or CL.

[Black LS1 T/A]

Ok ... cool. Thanks for the simplified run-down, joecar.

I can't find any thread about how to do the re-pin. from joecar post over on LS1Tech:

1998: require 411 PCM
swap, PCM connector re-pin, fuel segment swap

I'm having trouble finding a clear, concise description on the re-pin and PCM swap
I did find this:

1998 PCM Pin Assignments
http://www.ls2.com/boggs/torques/98pinpcm.htm

Am I understanding correctly that 411 PC is simply 2001/2002 Camaro/Trans Am PCM?

I'm sorry I'm so ignorant of all this at the moment. I got very adept at tuning my own car, but have no experience with the PCM swap and re-pin, modification to SD or tuning SD.

Thanks!

[Black LS1 T/A]

Is this a good route to go for a PCM?

Flash Masters: 2001-2002 Camaro, Z/28 Engine computer 12200411 Programmed to your VIN. PCM ECM
http://www.ebay.com/itm/2001-2002-Camaro-Z-28-Engine-computer-12200411-Programmed-to-your-VIN-PCM-ECM-/170885730424?pt=Motors_Car_Truck_Parts_Accessories&hash=item27c9955078&vxp=mtr

[joecar]

Follow this thread, it links to the pinouts:


showthread.php?11000-97-PCM-to-cos (http://forum.efilive.com/showthread.php?11000-97-PCM-to-cos&p=109238&viewfull=1#post109238)

That ^ post contains these links:

showthread.php?t=10066 (http://forum.efilive.com/showthread.php?t=10066)
showthread.php?t=7992 (http://forum.efilive.com/showthread.php?t=7992)
showthread.php?t=6870 (http://forum.efilive.com/showthread.php?t=6870)
showthread.php?t=5739 (http://forum.efilive.com/showthread.php?t=5739)
showthread.php?t=5281 (http://forum.efilive.com/showthread.php?t=5281)
showthread.php?t=3306 (http://forum.efilive.com/showthread.php?t=3306)
showthread.php?t=5948 (http://forum.efilive.com/showthread.php?t=5948)
showthread.php?t=6011 (http://forum.efilive.com/showthread.php?t=6011)
showthread.php?t=4964 (http://forum.efilive.com/showthread.php?t=4964)
showthread.php?t=9195 (http://forum.efilive.com/showthread.php?t=9195)

[Black LS1 T/A]

As always, you are a lifesaver! 13631

[ScarabEpic22]

Thats the correct PCM you want to run, I dont know what the going price of them is these days but that sounds about right.

[Black LS1 T/A]

Thanks!