what kind of power do you get out of this upgrade?

 

wrong section....this is for power adders like nitrous, superchargers, and turbos.

To answer your question....and plenum and throttle body combo will probably gain you 5-8rwhp.

 

moving to 4.6 tech...


The TB/Plenum combo like he said is worth arouand 5-8rwhp on a stock cam,heads, car. A few more if you have those upgraded.

 

What you relly get with that upgrade is better throttle response, at least I did

 

iight thanx

 

i noticed little if any gain from the upper plenum. I'd just as soon spend that 150 bucks on brakes or subframe connectors or save it for nitrous. bolt on's are ok but they NEVER make enough power to be worth the money.

 

I never ran an aftermarket plenum on my car but I did port my stock one along with the stock throttle body. It made a nice SOTP differance and did help me clock my best ever ET and MPH. Only cost about $25.

 

What size is the bore on the stock plenum?

I was thinking of getting a 70mm Accufab TB, porting the stock plenum to match the 70mm TB.

Good idea?
Bad idea?

 

The stock TB is 65mm.

It depends on what you wanna do with your car and what kind of deal you can get. On a mostly stock or bolt on car I dont think the Accufab is worth its price.
If you step up to a blower,Trickflow intake or cams your gonna want the 75mm.
My 99 GT had only 4.10's, exhaust and a chip. I ran my ported stock stuff for 4 years and my best ET was 13.31 @103

 

if you're going to waste money on a tb/plen then get a 75 mm, no point in getting a 70

 

other way around... 75mm is too big for anything but a ragged edge NA car or a blower car. you don't buy bigger parts just because the stock one is fine... that's called insanity.