Q45 throttle body swap

[stevecorrado88]

So I am gonna do a q45 tb swap on my s13 sr with a Isis intake manifold. I no they make weld on flanges but do they make bolt on adapter to where I could just bore out my intake to match?? Or does anyone know someone that could make one or sells them???

[Kingtal0n]

So I am gonna do a q45 tb swap on my s13 sr with a Isis intake manifold. I no they make weld on flanges but do they make bolt on adapter to where I could just bore out my intake to match?? Or does anyone know someone that could make one or sells them???

First I want to make sure about something - you intend to make over 400 horsepower right? like 450+ Right? Because if you are working with under 40lb/min of airflow, I would suggest you maintain the OEM throttle body.

[stevecorrado88]

Im running 21 psi on a 3071r i should be right around 400 hp maybe more. I keep snapping stock tb

[Kingtal0n]

Im running 21 psi on a 3071r i should be right around 400 hp maybe more. I keep snapping stock tb

what do you mean snapping? You mean its opening too far and breaking? Any TB will do that, keep the cable adjusted properly. Swapping to a larger TB will do two major things for you:

#1: it may allow you to make an extra few horsepower (at the 400HP level) at the very top assuming the OEM throttle body actually causes a pressure differential across the blade due to its physical size as a restriction.

#2: your throttle control may suffer, your drivability may suffer, your fuel economy may suffer, it may become harder to control the finite amount of air entering the engine at idle and overall the custom piece requires fabrication to be installed which can also go sour if you are not accustomed to welding brackets/working with metal.

I would figure out how to keep an OEM throttle body happy. If you are seriously worried about "choking the engine" you can install a boost gauge right before the throttle body and right after, and compare the two. If the throttle body is actually choking the engine, you will see higher boost pressure before the throttle body, which indicates that the mass of air cannot enter the engine fast enough to level the pressure (before and after). IMO You will see less than 1psi difference, and there is always some even on a stock engine (because the TB even when open does represent an actual restriction when compared to an open empty pipe)

[stevecorrado88]

I tried to fix the tb from breaking. I was running 12 psi and never had problems thrn i upped the boost n it breaks now. Dont care if i make any more hp just want to drive the car. At 400hp im not worried about gas lol n i have cams so i understand ideal problem. I understand what may happen when this is installed but i wouldnt do this if it didnt serve a perpose.