Downpipe questions 2007-GPGT L32

[intrigueing]

Getting a new flex welded into a used 3" catted downpipe I purchased - finally! Got a few questions before I get it put in.

1) Anyone have the part number Advance Auto would use for the gasket between the cat and exhaust pipe (resonator side)? I got the one for the cat to manifold, but the one advance gave me was way too big for the other end.

2) Any tricks to getting it put in? Will I snap bolts? I've been hitting it with PB blaster a few times.

3) I need to extend the O2 line. Should I buy an extension or just add in wire? Anyone have an extra they would like to sell?

4) How much difference will I notice?

5) I have an wizaired intake. What should my next mods be? I've been thinking 1.9 modified rockers. Would I need to do springs? It is very unlikely I'll up the rpm limit - it looks like 07 PCMs are a pain to mod. I don't want to get too crazy with the car it is my DD. Wish I had a scanner.....maybe that should be next.

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[rocket69GTP]

You need to scan the car before you go any further. These model year grand prix's are notorious for having knock retard straight from the factory. Installation should be relatively easy unless the shop is doing the work for you and just get an extension from someone here or zzp. You should be able to go with a smaller pulley on the s/c but it needs to be tuned after that happens or it could end up being a bad day for the motor and your wallet.

 

[1quick]

I havnt looked around at the tuning stuff for a long time but last I herd 06' and newer pcm's couldnt be tuned, I used an 05 in mine but I dont know if it works with 07's for shure or not, some codes are different from 05-06 so the check engine light will be on for ever if you switch computers to an older one

 

[smug]

Just get the gaskets from the dealer because they are not to expensive and they will get you the right ones. The downpipe to catback bolts will probably break so be perpaired to replace them. Buy a O2 extension because if you do a crappy job extending the wires it will throw the readings from that sensor off.

Rockers are a very good mod and stock springs usually work just fine and I would not even consider a pulley on the car until it is scanned to see how much KR you have. The best mods I have ever done to a supercharged gp is full Intercooler, headers, rockers or cam, tune, and lastly pulley.

 

[intrigueing]

Thanks guys. I'll order the extension. Will I tell a SOTP difference? Car runs noticeably faster when cold out. Should I get a 180 tstat?

 

[rocket69GTP]

This came out last month from Overkill Will

Hello everyone. I've been hard at work lately on 2006-2008 3800 Grand Prix computer tuning

As most who own an 06+ 3800 Grand Prix know, you have non reprogrammable PCMs. At least, you did.

I'm very excited and pleased to post that I'll be offering a proper tuning solution for 06-08 GPs using your original PCM modules. What this means is:
-no more searching for 2005 PCM modules
-no more non-returnable computer cores
-no more extra expense just to make your vehicle tuneable.

You'll be able to purchase an Overkill PCM tune, receive a 06+ PCM module that's been reprogrammed, and send back your old module for the core charge refund.

Also, 2007-2008 owners, you'll be pleased to know that I've been able to correct the operation of the fuel gauge on your vehicles with an aftermarket tune, so when you purchase an Overkill PCM for your 07-08 you'll receive a PCM that won't cause your fuel gauge to read backwards.

All of this announcement is exclusive to Overkill Motorsports. I've worked very hard lately for 06+ owners to provide better tuning solutions.

If you've purchased a 2005 based Overkill PCM for your 2006+ vehicle in past, stay tuned, I'm going to see what I can work out to allow you to return your 2006 computers for at least a partial core charge refund regardless of when you purchased. Please email me [email protected] if you'd be interested in this.

My website will be updated shortly with the changes! :: Overkill Motorsports ::

Any questions please post or email. As always, I appreciate the business from fellow W-Body owners!

Best Regards
- Will

 

[intrigueing]

Is overkill any good? Anyone used them?

 

[rocket69GTP]

I have his PCM in my car now and the best part is the transmission pressures that he uses to shift the car are pretty decent.

 

[boostedguy05]

from what i have read on other sites overkill is second only to personal tuning.