Selecting the right Throttle Body

[Sgt.5point0]

I am finally getting started on my engine and I'm not sure what size of throttle body to go with.

I plan on having:
AFR 165(61cc) Heads
TFS Track Heat/ Edelbrock Perf. II/Holley Systemax II(whichever I get cheaper)
FTI Cam

I already have:
75mm Pro-M MAM
24lb Inj.

Any suggestions? I've heard a few ppl say a 65mm is enough but I want to make sure.

 

[willys1]

With your combo,Id go 70mm

 

[90_Red_LX]

What about for just a cat-backed one for now? A new throttle body, CAI and prochamber and SFC's are on my list. 65mm? Do I need the EGR spacer?

 

[sn9550]

I wouldn't spend the the money on a TB until you replace the intake. Then you can do them together.

 

[Sgt.5point0]

Yeah I plan on doing the heads, cam, new timing chain, injectors, fuel press. reg., intake, throttle body, and mam all in one teardown.

 

[houstonstangguy]

lol this is a touchy subject. half the people here will tell you 65mm and the other half will tell you 70mm.

do a search and you will see how many times this comes up without resolve and how worked up people get that cannot agree.

I would probably stay 65mm myself if i were you but then if you know a few people with both then borrow each and stick with the one that feels the best. either that or dyno both and then decide. whatever you do just make sure you are happy with your choice.

good luck.

 

[90_Red_LX]

It's gonna be a while before I do an intake . I was going to do a CAI, TB, prochamber, headers, and then a little bit of suspension work and a rear disk conversion. Then I was going to go on the lines of a H/C/I and n20. But thats at least a year off before n20.

 

[1992blkGT]

The Trick Flow intakes have a 75mm throttle body opening, so I went with a 75mm throttle body and EGR spacer. Everyone said I would lose low end, but I drove it for awhile with the stock throttle body, then installed the 75mm and noticed no loss in torque but a huge gain in horsepower. Everyone will disagree with me on this but it's working for me. Oh and I plan to later get a supercharger so the 75 will see even more use then

 

[L8 MUSL]

sgt5point0,
I would match the TB to what ever the TB opening is on the particular intake that you end up buying.
90_red_lx, don't bother with the TB untill you do the other mods.
1992blkGT, MM&FF's mag did a comparison test between 65,70 and 75mm TB's on a supercharged and NA motor and with the blower the 65mm made the most power due to increased air velocity under boost. Bigger is NOT alway's better.
I went with a 70MM TB because that is what the opening was on my Typhoon intake.