Trick Flow Street Heat intake TB question

The 70mm will be just fine. A 65mm will flow enough air for a 302. I have a 70mm on my 95. Got a good deal on it, but it's bigger than I need. I can't answer about the EGR spacer though, I haven't had a Fox in 8 years, and honestly don't know the answer to that question.

what he said

I have a 70mm but it's more than I need, again there was a good deal to be had so I got it.

70mm here too with the EGR spacer. 65 will work fine for a 302 though
Kevin

Go with the 75mm if you haven't bought one yet. I ran a 75mm on my street heat with my 302 and I used the 75mm on my 347 as well. I ran a 75mm on the 302 b/c my custom cam grinder ed curtis recommended it

caseyjsegraves said:

Are you running an EGR spacer?

Click to expand...

Nope.

A 65 or 70 will flow plenty for you

If you look into the intake, it necks down way below 75mm. Even the Systemax is 'opened' to 75mm from Holley, but it necks down to around a 65mm. So what good does a 75mm+ give, especially since it flows literally 2x the amount of 302.

Besides a touchier gas pedal, you will not gain performance.

Read this if your interested in some more information:

http://forums.stangnet.com/showthread.php?t=692441

I have a 70mm now on mine but will be going with a 75mm at some point. From all the information I have seen a 75mm won't hurt you at all. I do know bigger isn't always better but from the few dyno's I've seen this isn't the case plus I like the idea of it being port matched to the intake even if it is only 5mm difference.

That doesn't solve anything They just match it to the intake 'hole'

Edelbrock told me 70mm.

BBK told me 70mm.

Holley told me 65mm.

Etc...

You know what they all told me when I asked about if a 65mm is enough flow for a 302. They said "yes, they flow enough," but in order to be consistent they say match the intake inlet.

Talk to George Klass over at Accufab, a head engineer/designer for the best aftermarket throttle bodys. Or better yet, check out their tech section on selecting a proper throttle body.

It is easy to go with a bigger throttle body. For the most part, a big throttle body will not hurt straightline performance at all. The larger the blade, the touchier the gas pedal under part throttle and tip-in situations.

Good choice going 75mm. I have no problems with driveability with mine, not touchy at all.

Hey Casey,

I have been involved in a few throttle body and/or intake swaps, and in each case that the throttle body measurements increased, the pedal got a little bit touchier. Of course I wouldn't care if I had a street car like Grn92LX. He has a nice accufab. For a daily driven car, I would think otherwise though if you plan on being lots of stop and go traffic, it gets a little annoying showing off the inability to mediate the gas pedal smoothly Here is some more information on throttle body sizing:

Accufab:

65 MM - 664 CFM
70 MM - 787 CFM
70 MM - 896 CFM (Race version)
75 MM - 924 CFM
75 MM - 1045 CFM (Race version)
80 MM - 1142 CFM
85 MM - 1322 CFM
90 MM - 1369 CFM
105 MM - 1550 CFM

Holley:

65 MM - 750 CFM*
70 MM - 790 CFM*
75 MM - 840 CFM*
80 MM - 892 CFM*

*Information given by Tech Rep.

BBK:

70 MM - 726 CFM

Edelbrock, Ford Racing and Proffessional Products have no cfm information after calls/emails.

Information to keep in mind when picking out a throttle body for your application:

A 300 cubic inch engine (302 c.i.) flows 521 cfm at 6,000 rpm.
A 330 cubic inch engine (331 c.i.) flows 573 cfm at 6,000 rpm.
A 350 cubic inch engine (347 c.i.) flows 600 cfm at 6,000 rpm.

With the above information from Accufab's website, you can see that the aftermarket throttle bodies offered flow much more than your engine can breath (302-347). Those cfm ratings are even given with NO restrictions and of course our engines all have restrictions, via our heads, cam, intake packaging. An actual running engine flows somewhere in the neighborhood of 200-400 cfm with some rough math. The aftermarket throttle bodies flow two times this amount.

In short, be careful on picking 'too big' of a throttle body for your car. An application with boost (forcing air) allows for you to efficienty select a bigger throttle body, although N/A engines do not.

If you've got a throttle body that delivers 100% of the peak air requirements of your engine when the throttle plate is fully open, you have control of the air throughout 100% of the throttle position range. If you go to an oversized TB that delivers 100% of the air that your engine can consume while the throttle plate is only 60% open, you have given up usable throttle-control range for no advantage.

Good Luck!

I wonder if things changed over the years. Although this info is several years old it slightly different than above. This is off a page posted in here.

MAF AIR FLOW DATA (In CFM):

1.Stock 5.0L 58MM (89-93 Mustangs), 606 CFM
2.Stock 5.0L 70MM (94-95 GT/Cobra Mustangs), 815 CFM
3.Pro-M Bullet (75MM), 964 CFM
4.Ford 80MM (Lightnings), 1017 CFM
5.C&L 73MM, 1171 CFM
6.Modified 80MM (Flow Bar Removed), 1368 CFM
7.C&L 80MM, 1415 CFM
8.Pro-M 77MM (Shorty/Supercharged Version), 1543 CFM
9.Pro-M 77MM (Standard Version), 1562 CFM
10.Pro-M 83MM, 1598 CFM
11.Pro-M 80MM, 1612 CFM

THROTTLE BODY AIR FLOW DATA (In CFM):

1.Ford Stock 5.0L 60MM, 526 CFM
2.Accufab 65MM, 616 CFM
3.BBK 70MM, 726 CFM
4.Accufab 75MM, 845 CFM
5.Accufab 90MM, 1225 CFM

5spd GT said:

You know what they all told me when I asked about if a 65mm is enough flow for a 302. They said "yes, they flow enough," but in order to be consistent they say match the intake inlet.

Click to expand...

So with a TFS top end kit on a 302 stock block, port matching the throttle body to the intake is best then? Say for this setup: 75mm throttle body & egr spacer in the 75mm TFS Street Heat intake opening and a Pro-M 75mm MAF.

Otherwise, a 65mm or 70mm throttle body in the 75mm opening would cause turbulence/vacuum due to the 5-10mm difference, creating a loss in power right?

that intake is such a restriction i doubt a stock TB would hurt power much.