is a 75mm t/b too big for my setup?

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Its fine, once you have good 'breathing' mods, match your TB to your inlet opening. An internet myth is that you need "lots of boost" or "a big stroker" or a "high rpm car", but the truth is that couldn't be anymore Wrong!!
 
I think i remember reading somewhere you could get 600hp with a 60mm TB and not be hindered. but i may be incorrect.
I personally wouldnt buy anything bigger than a 65 unless i had the Kenne Bell blower which loves big Parts In its Air path.
 
Grn92LX said:
Its fine, once you have good 'breathing' mods, match your TB to your inlet opening. An internet myth is that you need "lots of boost" or "a big stroker" or a "high rpm car", but the truth is that couldn't be anymore Wrong!!

I must need to go out and get a bigger throttle body, I can't believe I bought into the internet myth. :rolleyes:

Yeah, I know a 75mm t.b will work and you dont NEED gobs of power to see gains, but I've seen them used on a 600+rwhp car...I just think with E7's they aren't neccesary. Isn't there people using 65mm's running 12's. I just don't see what myth you are talking about.I understand that there are arguements over this topic,but seriously.
 
i kind of want a 75 because it will match closer with my 3" intake pipe. 3" is 76.2 mm. if it doesn't hurt performance, i think i'll go with that. eventually, i'll get better heads. i only want to have to upgrade the throttle body once.

a 75mm throttle body won't actually HURT performance, will it?
 
What size is the opening when the TB mates up to the intake (or elbow)? I know most aftermarkets are 70mm, anything biggger is a waste...unless you port it.
 
eades5.0 said:
What size is the opening when the TB mates up to the intake (or elbow)? I know most aftermarkets are 70mm, anything biggger is a waste...unless you port it.
the intake pipe is (will be soon) a 3" PVC pipe, i assume 3" is the inner diameter, but it may be the outer ... i'll check at lunch.
 
I used the 75mm TB with stock E7 heads and the car ran well. I used that same TB when I had TF heads and the car still ran well. IMO you should use the larger TB’s and work other things to get what you want. The way I see it more restriction on either side of the engine is a bad idea. Open the intake and exhaust up (within reason) and you will have the ability to make more power.

When I raced NMRA Factory Stock we were limited to a 70mm TB but had we the option to us a 75mm unit I would have. That motor had unported Explorer heads and intake with a stock cam and I still feel that the larger TB would have been a benefit.

The idea that boosted engines need a larger TB is also kind of weird to me. Why does an engine that is being force fed air need a larger opening than an N/A engine that is depending on natural air pressure to push air into the motor? Without doubt you can make more power with a larger TB on force fed engines…but I feel that the same is true with N/A motors.
 
TMC said:
I used the 75mm TB with stock E7 heads and the car ran well. I used that same TB when I had TF heads and the car still ran well. IMO you should use the larger TB’s and work other things to get what you want. The way I see it more restriction on either side of the engine is a bad idea. Open the intake and exhaust up (within reason) and you will have the ability to make more power.

When I raced NMRA Factory Stock we were limited to a 70mm TB but had we the option to us a 75mm unit I would have. That motor had unported Explorer heads and intake with a stock cam and I still feel that the larger TB would have been a benefit.

The idea that boosted engines need a larger TB is also kind of weird to me. Why does an engine that is being force fed air need a larger opening than an N/A engine that is depending on natural air pressure to push air into the motor? Without doubt you can make more power with a larger TB on force fed engines…but I feel that the same is true with N/A motors.
that settles it, i'm going with a 75mm unit! now i just have to find one ...
 
Good choice, don't listen to anyone who tells you otherwise ;) On your car 70mm vs 75mm probably won't be noticable, but go for it anyway. It will help as you do more mods down the road.
 
Black96VertGT said:
that settles it, i'm going with a 75mm unit! now i just have to find one ...

I vote 70mm . Like eades asked, what size is the opening of the intake MANIFOLD/elbow?

If the intake is only 70mm, what benifit would there be to have a 75mm tbody when its bigger then the intake opening?? Doesnt make any sense to me.