Back to back fox versus 94-95 TB dyno results inside!!!

[Killercanary]

Yes, I finally did back to back dyno pulls comparing a fox style TB setup to a 94-95 setup. We've all wanted to see the results of such a comparison and I did it today. I tried to minimize the differences between the two pulls as much as I could. The only change between each pull is the TB and inlet elbow, I used the same air filter and inlet tube on both setups. The fox TB was a 75mm and the 94-95 setup was a 65mm. I would have liked to do 75 on both but I didn't have a larger 94-95 one to do it with. testing was done on an AWD dynojet dyno. Obviously the engine has loosened up a little since the last time I dyno'd it as I have more miles on it now. It was virtually brand new when I dyno'd it last. I will be dynoing the car again in a few weeks after I put on my new AFR 185 comp heads, probe shaft mount rockers, MAC 1-3/4 ceramic coated headers, and Dr. gas 3 to 2.5" X pipe that I just bought from a member here.

On the dyno:

Here's what everyone wanted to see... I'm convinced that the fox is worth more power, even with the difference in size between the TB's. The car was run at FULL temperature (190*) with 90* inlet air temps on both setups, no ice or shortbelts were used. These are true unaltered results. Run 2 was the fox TB, run 3 was the 94-95 style. The car made 355/365 STD last year with the 94-95 setup. The graph is hard to see, I'll try and get better scans later.


SAE

STD

I can't wait to see how much power I see with the new heads and exhaust.

I have to say thanks to the great students and staff at Wyotech in Blairsville where the car was dyno'd.

 

[94v6GT]

so with a TB 2 sizes smaller the sn95 was only down 2%. My sn95 snout aint going NOWHERE!!!

 

[YEAHLOH95]

thats it... mine is hitting the shelf on goes the fox set up, mine will be a little different as i am super charged and i hope to see even bigger gains

 

[Yobi1Kanobi]

thats it... mine is hitting the shelf on goes the fox set up, mine will be a little different as i am super charged and i hope to see even bigger gains

they are virtually equal

 

[Pokageek]

Yea but how do you shut the hood!?

 

[YEAHLOH95]

what you can't see and feel over the internet is the throttle reponce is sooooo much better, that i would do it with less gains for the better looks and chance i might be able to make somemore boost

 

[Stopsign32v]

This comparison is about like comparing Fox body headers to SN95 headers, but oh yea the Fox body headers are long tubes and the SN95 ones are only shorties. I don't even see why this was done unless you are doing the swap and just wanted to make a thread.

Also if someone is doing this mod (sn95 TB to Fox TB) in hopes of going faster then they have alot to learn...

 

[blksn955.o]

Damn good post. Thanks for doing the comparo. It would have been really nice to see an = size t-body to = size t-body but it is at least a back to back of a non-stock size sn95 style to fox style...too bad no one had a 65 fox one laying around.

If your looking to get every ounce of HP 8.6-ish hp is not bad. Its not earth shattering to the point your stupid for not making the switch...but some people spend several hundred more to gain the same amount or less (ie. non PI cam swap in a 96-98 for instance).

The biggest factor if I was to make the swap is the fact it is so much cleaner under the hood with the much less "in your face" t-body.

 

[Yobi1Kanobi]

If your looking to get every ounce of HP 8.6-ish hp is not bad.

The biggest factor if I was to make the swap is the fact it is so much cleaner under the hood with the much less "in your face" t-body.

I agree with this train

 

[wytstang]

so with a TB 2 sizes smaller the sn95 was only down 2%. My sn95 snout aint going NOWHERE!!!

More importantly it shows how little power 75mm make over the ''tiny'' 65mm TB's. Proof 65mm are NOT "holding" back h/c/i 302 down like once "preached". I'm really loving this back to back dyno run, and thank you for doing this.

 

[FastFord]

Excellent! Good to be informed. Thanks!

 

[95WhiteVenom]

I'm leaving my 94-95 70mm bbk on cause there is no difference to me after seeing the results it ain't worth the time to remove mine.

 

[gmkillr]

what you can't see and feel over the internet is the throttle reponce is sooooo much better, that i would do it with less gains for the better looks and chance i might be able to make somemore boost

Less restriction = less back pressure = less boost

 

[Venom351R]

Charlie was telling me about this at the track last night. As far as if its worth it or not I guess it comes down individually and what you deem worth it or not

 

[ProKiller]

interesting results. I'm thinking the same thing Rob. Troy if you do it, it would be awesome to get back to back supercharged pulls, you know for posterities sake

 

[Bullitt95]

This just shows that a 65mm TB doesn't hold back even a built stroker as much as you might think. The extra 8-9hp and better throttle response that a 75mm TB provide are welcome though. Considering that a 75mm TB costs about the same as a 65mm TB, it's probably better to buy the 75mm TB from the outset if you're planning H/C/I or stroker later on.

 

[YEAHLOH95]

rob i would think that too, but the guys that have done this with a blower seem to make more boost for some reason . i'm still running the stock vortech discharge which is more of a joke than the elbow for the intake.where is charlie? he did this swap already

 

[95opal]

Less restriction = less back pressure = less boost

I must agree with rob here.

rob i would think that too, but the guys that have done this with a blower seem to make more boost for some reason . i'm still running the stock vortech discharge which is more of a joke than the elbow for the intake.where is charlie? he did this swap already

Troy not to rain on your parade but as Rob already pointed out, boost is just a measuremaent of restriction when you really break it down. Now if your telling me some guys are seeing more boost with the swap, than guess what? that would lead me to beleave that the fox conversion is more of a restriction and the only real benifit is the increased throttle responce brought on by the different arc and ramp rate of the throttle arm. I still think the dyno #s show nothing as the different size T-body could be responcible for the minimal gain. Untill I see a better comparo I will stick with the sn set up.

 

[final5-0]

that would lead me to beleave that the fox conversion is more of a restriction and the only real benifit is the increased throttle responce brought on by the different arc and ramp rate of the throttle arm..

Good thread here

You usually see the "throttle response" phrase used in these threads

Like 95 opal ... I've always thought the different rate of opening of the
throttle body blade has a lot to do with that

Just a thought

Grady

 

[Touring23]

Thanks for sharing.
Diggin' the clean engine
How is the 75mm TB at ~2,000 rpm?