Throttle body questions

[ivan12]

I had a 70mm bbk/edelbrock TB laying around that I put on my car when I installed my shorties. I put it on to see if I would feel a difference and I did. But It felt like I lost a lot of low end power and gained it back after around 2500 rpm, what I didn't like was that the rpms would drop really fast while in between shifts. what I Also noticed was that my rpm would stay at 1500-1700 while at idle with the throttle screw all the way out (butterfly completely closed). I thought my idle issues were due to the egr elimination. So today I swapped my stock tb back on and it now idles great. What would cause this to happen? BTW the bbk tb came with ford electronics when I got it and they look brand new.

 

[rz5.0]

did you check the votage on your tps.

 

[BlkoutGT]

I have head that, when your throttle screw is all the way out, and your idle is still not right, you may have to drill a small hole in the butterfly to get it to idle properly. Hopefully someone else can chime in who has had that problem. I put a summit 70mm on and had no problems.

 

[ivan12]

I haven't checked the tps yet

 

[ProKiller]

didn't have the problem with the same throttle body i had but i switched to a stack racing from AM and am now having this issue periodically.

EDIT: oh and i did have a small hole drilled through the plate which i redrilled on this new one.

 

[ivan12]

So the hole in the plate brings the idle down?

 

[toyman]

So the hole in the plate brings the idle down?

I suppose it allows for more air to flow through in the closed position. However, that's what the IAC valve is supposed to do so I don't see the advantage to drilling a hole in the throttle plate. If the idle did improve it was probably because the IAC wasn't working to spec.