70mm or 75mm Throttle Body???

69clark · Dec 19, 2005

Some of you know my setup but for others, by next spring I will be making about 500 hp to the flywheel. Thats with 6lbs of boost for now but I may up it to 8-9lbs. Should I run a 75mm or a 70mm. By the way I am switching to a Fox tb setup so I will be using a fox style throttle body. Right now I use a 70mm on the 94-95 cobra intake but I don't know if I should go to a 75mm tb w/ over 500hp to the flywheel.

I wasn't really even questioning going to the 75mm but I saw a fox in a mustang mag that made over 600hp to the wheels and he was using a 70mm and he was supercharged. I have seen several times when a bigger tb has lost power on the dyno but always thought it was because the tb was too big for the mods done.

Also what is the best fox tb to buy. I have been looking at accufab which I know is probably good but I see the Professional Products tb are cheap and polished but am I sacrificing quality or is that not an issue with a tb (I mean I know that a cam or heads, quality is important, but with a tb it only has to open when the throttle is depressed, so would there be a problem with either).

Thanks guys

Grn92LX · Dec 19, 2005

A bigger tb won't hurt at all. Either way you look at it, you'll make plenty of power you won't hook anyway. The cobra opening is 70mm so if you use a 75mm, you need to open it up with a dremel.

Tb's aren't rocket science, they're a circular piece of metal with a blade that opens. Ask Ernie on here what happend when he swapped from a stock tb to a 75mm tb on his n/a 302 heres a hint, he DIDN'T lose power

Black95GTS · Dec 19, 2005

Grn92LX said:
A bigger tb won't hurt at all. Either way you look at it, you'll make plenty of power you won't hook anyway. The cobra opening is 70mm so if you use a 75mm, you need to open it up with a dremel.

Tb's aren't rocket science, they're a circular piece of metal with a blade that opens. Ask Ernie on here what happend when he swapped from a stock tb to a 75mm tb on his n/a 302 heres a hint, he DIDN'T lose power

TB NAZI!!!!!

Unless you're gonna port your cobra, the 70mm will be fine for you. I know I'll get flamed for this because of articles previously read in MM&FF and such, but in a forced induction application like yours TB size isn't crucial. Head on over to turbomustangs.com and see guys with 65mm TBs on 10 second cars.

If I were you I'd get a 70MM Accufab TB, because they have good user reviews and it matches your intake opening. If you ever decide to lose the S/C, then this will be the correct TB for you in N/A trim.

- Adam

VibrantRedGT · Dec 19, 2005

I agree with Mike. With forced induction there is no way a 75MM will hurt, it could only help. Like mentioned you'll have to punch open the opening on the intake.

4Jenna · Dec 19, 2005

70mm makes plenty powa...not a restriction at all, good to well over 600rw

But a 75 is fine also if u open the int..no gain at all between the two imop

4Jenna · Dec 19, 2005

Just match it up to the int...all that matters

95COBRA241 · Dec 19, 2005

What intake will you be using when you convert to fox style? IMO match the throttle opening to the TB. If the intake is 70mm use 70 if its 75mm use 75. Either way they should make gobs of power. Accufab is probably the best TB on the market.

69clark · Dec 20, 2005

Sorry guys. I posted in the talk section that I just bought a new BBK ssi which I believe has a 75mm opening. Now I know that someone will say why didn't you use a Systemax or TFS track heat? Well, I was planning on using the TFS but at the last minute I went with the BBK because of the looks, no one on here is using it (originality), and I figure in the future if I do like it I could have it extrude honed to bring the level of performance to more of a TFS track heat or Systemax level (hopefully). Not to mention the other advantages such as easy removal of valve covers and bigger fuel rails.

YEAHLOH95 · Dec 20, 2005

don't forget holley makes some really nice throttle bodys too as far as size if that intake has a 75 opening then thats what tb to run did you read the test in 5.0 on that intake ?

Carollo734 · Mar 16, 2021

Hello all, first timer her on the site and wanted to ask all you professionals a question. I have a 95 GT with the 5.0/ 5- speed. I’m wanting to build it just a tad bit. It’ll be mainly used on the weekends and down here in Louisiana, everybody wants to race on the streets. So just want something kinda competitive. Am I off to a good start. I have the following: 3:55 gears, MSD pro billet distributor with coil, MSD 9mm wires, MSD 6AL, GT40 heads and a GT40 upper from a 95 Cobra. Currently waiting for them to be ported. BBK long tube headers, off-road H, Pypes M80 mufflers. A comp cam, not sure of the specs, 24# injectors from a 95 Cobra. BBK air intake with a 76mm MAF. Just trying to figure out what size throttle body to go with. And waiting on a Holley terminator X ecu to come in to tune everything up. Am I off to a hood start for now?

Carollo734 · Mar 16, 2021

Carollo734 said:
Hello all, first timer her on the site and wanted to ask all you professionals a question. I have a 95 GT with the 5.0/ 5- speed. I’m wanting to build it just a tad bit. It’ll be mainly used on the weekends and down here in Louisiana, everybody wants to race on the streets. So just want something kinda competitive. Am I off to a good start. I have the following: 3:55 gears, MSD pro billet distributor with coil, MSD 9mm wires, MSD 6AL, GT40 heads and a GT40 upper from a 95 Cobra. Currently waiting for them to be ported. BBK long tube headers, off-road H, Pypes M80 mufflers. A comp cam, not sure of the specs, 24# injectors from a 95 Cobra. BBK air intake with a 76mm MAF. Just trying to figure out what size throttle body to go with. And waiting on a Holley terminator X ecu to come in to tune everything up. Am I off to a hood start for now?

Also forgot to mention that it’s currently bored over to a 306

General karthief · Mar 16, 2021

Go for the bigger one.
Sounds like you have a good start.

revhead347 · Mar 24, 2021

Thanks for using the search feature.

70mm throttle body will be fine for that combo. Probably won't be much more than the stock throttle body, but no harm. The 75mm makes it hard to get the inlet tube on for no useful reason.

MSD is not known for reliability, particularly the billet distributor, those are famous for failing within 1000 miles, and it doesn't perform any better than the stock one in any way. You don't need any of that stuff. It's just going to break down at an inconvenient time. The factory ignition system will support over 1000hp, don't mess with it. Getting gasoline to combust isn't really that complicated. Return all that MSD stuff. You don't need a Terminator X either, that's just going to be another reliability issue. You are going to lose 9 out of 10 street races because that damn Terminator is doing something you weren't expecting. You are using mostly factory parts, and the factory ECU will be far more reliable. You are much better off spending $1000 having a professional tune your car on the factory ECU on the dyno than blowing $1000 on a Terminator X and spending the next 3 years sucking on your thumb trying to figure out how it works. If you are in Louisiana, then you are within driving distance of JMS Performance in Mississippi. They invented the SCT chip. Get the hard parts on the car, and take it to them. They will sort it out on the dyno, and you will be much better off.

Welcome to StangNet,
Kurt

70mm or 75mm Throttle Body???

69clark

Grn92LX

Fidanza Man!

Black95GTS

Active Member

VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

4Jenna

4Jenna

95COBRA241

New Member

69clark

YEAHLOH95

Carollo734

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Carollo734

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General karthief

wonder how much it would cost to ship you a pair

revhead347

Apparently my ex-husband made that mistake.

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70mm or 75mm Throttle Body???

Fidanza Man!

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"STANGNET'S PENGUIN SMACKER"

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New Member

wonder how much it would cost to ship you a pair

Apparently my ex-husband made that mistake.

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