I know nothign about turbos. I have a 420a i want to rebuild and turbo. When i go to get it rebuilt, how much pressure should i tell them i want out of this. I assume the lower the pressure the cheaper it will be. And i just want to pull atleast 250 horses out of it. I have around 200 now. I was also hearing a supercharger maybe better?

 

What do you have done to it, that you have 200 hp already? Just curious so we can help you get to 250... I personally would go with a turbo.. And you can push about 6-8 psi from a stock motor, but if your goin with a rebuild you would be able to get more... You could be over 300 hp if you stick money into the motor also... I don't think you could get 250 to the wheels with the 420a without going with forced induction(turbo, supercharger). 200 hp already seems good tho for a GS, what kind of mods are you running already?

 

Custom Borla exhaust, Electric supercharger, new headers, upgraded tb. Supposidly that all pushs me around 200. I have 155,000 miles on my car. I'm worried it wouldn't handle a turbo. So i'm gonna hafta rebuild her i guess.