Heads+ cam+ intake+nitrous is it time to upgrade tb yet?

 

I did figured it couldn't hurt, I got the TPIS 58mm, only thing is you have to get the intake port matched to the TB.

 

get pcm tuned for the larger TB...

 

Absolutely, tpis says the 52mm tb is good for 325-480hp range. If you have the stock 48mm you will definitely gain some hp and throttle response.

 

Don't worry about what TPIS says.

Far as throttle response that changes because 5% open on a larger bore is just more air than 5% on the 48mm.

If content with 52mm I would have a stocker opened up, if going 58mm understand most,require some mods to make the IAC circuit work right.

 

Heck with making it right....

 

Yup And this can be a pain in the A$$ tuning wise, trying to make it idle if the mod isnt done....

 

If he has an A4, the pressure tables should be adjusted or the pcm might not command the pressure it needs at a certain power level since pressure tables look at the throttle angle and there is less throttle angle for the same amount of air flow. Especially with a 58 mm TB.

 

OP

any larger TB will require PCM tuning...you will need scan tool to read IAC counts as you chase your idle issues. The "drill" mod is often required with aftermarket TB's as they don't have the air inlet hole or same passage as stock 48. Another way is crack blades open some and slot TPS holes to move TPS back. I don't subscribe to that method but some do it to get larger aftermarket TB's to idle right.

if you are in need of a larger TB, get the stock one re-bored to 52...