Larger throttle body?

[Colossus]

I was browsing dss-racing.com. I saw a larger throttle body on the site, but it says it's for 89-99 All Turbo. Now, would this fit my 420A engine? Or just the turbo models? What kinda performance gain would a larger throttle body help me with? It's a 70mm btw, and I'm not sure what the stock size is.

 

[dr1665]

Your engine is a 420A. All turbos are 4g63. Nothing is interchangable there. You need a TB for the 420A. Sorry. There are 60mm available, but to see the most gains from one, you need the CAI, complete exhaust and some headwork.

Modern Performance sells the 60mm.
You can also find a lot of good 2GNT parts at Howell Automotive.

 

[Colossus]

Thanks. I wasnt sure about the TB, I did know that the 2 engine components arent interchangable, but the way the website had it discribed made it a bit difficult to fully understand.

But still, what kind of performance gains would I notice with a larger TB? I have a CAI, exhaust, etc etc, but I dont have any head work or bottom end work done yet. Haven't had the time to pull out my engine, let alone another car to use while it's out.

 

[Kirby]

You can expect good gains from it, but to see the full advantage of it you will need to port your intake mani and head so the air can get into the motor. Think of it this way:If you take a big straw and tape it to a smaller straw end to end, you will have an example of a large throttle body on a stock manifold. If you pull liquid through the straws you will only get the amount of liquid that will flow through the small straw at any given pressure. So basicly the throttle body (big straw) will be capable of pulling in more air, but the intake mani (small straw) will still only let a certain amount of that air into the engine. So yes it will help a little, if you do the porting it will help more.

 

[dr1665]

I recently did a hi-comp rebuild on mine and while it was all out, I ported my OEM TB and opened up the ports on the mani at every location I could. I still have a bone stock head on there, but the car pulls a lot harder imo. I think with some minor suporting mods like the CAI and full exhaust, you could maybe see 5-8hp from a larger TB.

NOTE: While porting and polishing w/ a Dremel like I did is certainly CHEAPER, you might get idle issues when you're done. You will have less problems with a bored unit.

Have fun. You WILL like it either way. It's a mod that should be done regardless which direction you're heading mod-wise.

 

[Colossus]

Yeah, I'm trying to save enough to get a turbo kit installed, but I recently rear ended some1, so a new (carbon fiber) hood and getting a few painting details done has sent me back a few hundred...