Stock GN tips

Eric Schoewe

New Member
May 16, 2017
Good afternoon fellow Turbo nuts. I have a bone stock 87 GN that I bought 5 years ago that I'm finally doing some upgrades on. I have it in the shop right now and have talked to a bunch of enthusiasts and read damn near everything in this forum looking for answers. I am not looking to run 11 or under qm's, just want the car to run well and have a little more get up. Right now, the suggestions I've gotten is to get the 3" downpipe(internal wastegate, external??? not sure) that will go into my current 2.5" test pipe into the stock 2.5" exhaust. So many people have said going with the bigger 3" cat back exhaust causes rattling, which i'm trying to avoid. Additionally, I'm ordering a new turbotweak chip with 42lb injectors. They've also told me to put a new breather on to help airflow. Any other suggestions are welcome, but I'm trying to keep it as close to stock as possible. Was going to throw in the Scanmaster G as well. Anyone want to help a brother out?

Thanks fellas(and ladies).


Well-Known Member
Feb 15, 2009
Opinions will vary but here is my worthless 2 cents - Start with a scan tool, modern chip (injectors not a bad idea either), and bring your fuel system up to par with a new pump and hotwire. Then get what you have working perfectly by performing all the necessary preventive maintenance stuff, before thinking downpipes and such. If your car is truly bone stock original I think you are wise to try and keep it as close to stock as possible. Values of these cars, especially ones close to factory stock, have sky rocketed. If you absolutely cannot resist the urge to mod the car, sell this one for buku bucks and purchase one already properly modded to your taste. You’ll be dollars ahead.


Escaped mental patient
Jul 5, 2021
Definitely think about upgrading the fuel system. If not for performance, also the safety aspect of it. These cars live on fuel and die without it.
A good pump, hot-wire kit, and an adjustible fuel pressure regulator will be money well spent. As you said, air filter, down-pipe, exhast, chip and injectors. If your car is truly stock? Make sure you keep and store all the factory parts or you will regret it later.
But be forewarned, once you start it becomes an addiction!!!


May 25, 2001
Raise your fuel pressure and boost level but use a Scanmaster tool to monitor everything and make sure you don't lean the motor out.
As for which accessories that'll give you the most "bang-for-your buck", I'd go with a Terry Houston-style downpipe and second, a front-mount intercooler.
Good luck,