I've got a 96 T/A I just put a weiand 142 roots blower on and I'm trying to get it somewhat tuned and driveable before I take it to the dyno. I have the OBD1 conversion ecm on it and was wondering if I need a different map sensor other than the stock one, like a 2 or 3 bar sensor? I don't know very much about tuning these cars but from what I have read the LS1 guys have to have a custom OS for the ecm in order to run boost with a 2 or 3 bar map sensor, is that true for LT1's too? The car wants to spit and sputter and backfire and shake like crazy when you hit the throttle (this is all happening while sitting in the garage) followed by a big black puff of smoke out the back like it's pig rich, but the O2's don't show it being rich. If you ease on the throttle it won't do any of that. Basically I need to know if I need a different map sensor before I attempt to put it on a dyno. Got any ideas?

 

Are you sure???

Anyway. . . your issue is not tuning. Unless you changed the injectors out and didn't modify the computer, there's something else wrong with the car.

FYI, some of the LS1 guys have converted to a 2/3 bar MAP, but with custom programming. Very few have been successful doing this with an LT1.

 

lol Yes I'm sure, here's a link to a crappy vid of it. This was before it started all the popping and backfiring.

http://ls1tech.com/forums/showthread.php?t=545595

So what are the LT1 forced induction guys doing, just using the stock map sensor??

 

Yes, most people use the stock MAP sensor. The fuel is managed above 1 bar by using the top row of the (100kPa) PE v. RPM table. A 2 bar sensor can be used but requires a lot of editing of the PCM tables and no one has ever shown to my satisfaction that it works any better.

Rich

 

Most of the guys over here use a stock Map sensor or go to a Fast, BS3 etc. Mine runs great on a stock Map sensor. On the stock lt1 you will need to reduce the timing in the 95-100 KPA area to about 26 degrees or it will go Kaboom. Also try to get your AFR to approx 11.8. You need tunercat or Lt1 edit to change your timing and PE vs RPM table or you could take it to Jeff Creech at Carolina automasters. He tunes all kinds of exotic setups.

That is amazing that you got it to fit under the hood and came up with a belt routing system. I wonder how the bearings in your alternater are going to hold up?

I can't believe you've only got four posts over here at CamaroZ28.com. This forced induction forum is very useful for 93-97 LT1's. Welcome.

 

Well I really have no clue about tuning these cars but yesterday I backed the timing waaaaay off everywhere and it quit spittin and popping but it would just bog when I hit the throttle, sorta like it wasn't getting any gas. Is there any way to give it a bigger "pump shot" and see if that helps?

 

Thought I'd post a pic of a roots blower Camaro that was at the CC Summer Nats this year. Can't remember if it was an LT1 - you can see it has perimeter valve covers. He had to cut his windshield a little bit to fit this in there.

 

Are you still able to run a Mass Air Flow meter? If not you need to get someone to tune your computer for speed density. Also I assume your running bigger injectors so you need to program for bigger injectors. You could get a mail order tune from PCM for less to get you started until you can get all the bugs sorted out for the dyno. $75 for unlimited mail order tunes.

 

Yes I'm still running MAF and yes I programmed it for bigger injectors. I pulled it apart today and found some small problems/leaks I need to fix.