Fox TB Conversion

[final5-0]

Its been a while since anybody has asked so .............................

Does anybody have factual or hard data to back up the claims of gains

I know peeps say it is more responsive but I suspect most of that is due to the difference in how the throttle blade is opened between the two.

Anyway, has anybody come up with some proof?

Later
Grady

 

[final5-0]

ttt

Later
Grady

 

[wytstang]

I have yet to see any on any board.

 

[Rootus]

Not proof, ... but I went from 276 to 297 with the TB/MAF change (65mm 94/95 to 75mm Fox, and 75mm MAF to 80mm MAF), and then I TwEECed up to 310 (entirely through timing). So there's a couple of variables there...

 

[My95.0L]

I think I may be the only one that went slower from the swap. But I did the swap earlier this year when my 70mm bbk took a dump on me. Found a good deal on a used 70mm accufab, went to the bone yard & gathered up all the necessary parts. Long story short, I lost 2 mph & 2 tenths at the track ( I don't care what the dyno says, only what the time slip says). I know there are a lot of factors (temp., humidity, etc) but the conditions from my 12.89 @ 106.X mph night were actually a little worse than the night I went after the swap. To verify I went a week later (after the 1st trip to the track following the swap) & the car ran exactly the same. Put the SN95 set up back on & I picked up my 2 tenths & 2 mph again. Not saying the swap isn't a good idea, but what works on one car doesn't mean it works for another.

 

[final5-0]

I think I may be the only one that went slower from the swap. But I did the swap earlier this year when my 70mm bbk took a dump on me. Found a good deal on a used 70mm accufab, went to the bone yard & gathered up all the necessary parts. Long story short, I lost 2 mph & 2 tenths at the track ( I don't care what the dyno says, only what the time slip says). I know there are a lot of factors (temp., humidity, etc) but the conditions from my 12.89 @ 106.X mph night were actually a little worse than the night I went after the swap. To verify I went a week later (after the 1st trip to the track following the swap) & the car ran exactly the same. Put the SN95 set up back on & I picked up my 2 tenths & 2 mph again. Not saying the swap isn't a good idea, but what works on one car doesn't mean it works for another.

Thanks for the info and it is very interesting to say the least

Later
Grady

 

[V8SHME8]

It seems no one mentions this, but is it possible to fit a strut tower brace after the conversion? The intake piping looks like it would cause a problem.

 

[final5-0]

It seems no one mentions this, but is it possible to fit a strut tower brace after the conversion? The intake piping looks like it would cause a problem.

Not really sure!

I took mine off years ago and have not thought about it since then, lol

Later
Grady

 

[5.0_GT_kid]

I think I may be the only one that went slower from the swap. But I did the swap earlier this year when my 70mm bbk took a dump on me. Found a good deal on a used 70mm accufab, went to the bone yard & gathered up all the necessary parts. Long story short, I lost 2 mph & 2 tenths at the track ( I don't care what the dyno says, only what the time slip says). I know there are a lot of factors (temp., humidity, etc) but the conditions from my 12.89 @ 106.X mph night were actually a little worse than the night I went after the swap. To verify I went a week later (after the 1st trip to the track following the swap) & the car ran exactly the same. Put the SN95 set up back on & I picked up my 2 tenths & 2 mph again. Not saying the swap isn't a good idea, but what works on one car doesn't mean it works for another.

Wow, that sucks man. At least you got it back to the way it was.

 

[My95.0L]

Yeah it did suck. I was really happy with how well the swap cleaned up the engine bay. It really looked sweat. Only thing I can figure is with the SN95 set up the bend in the intake piping is more gradual rather than the abrupt 90* bend on the fox set up. The butt-o-meter felt like the car was a bit crisper & quicker, but the time slips showed otherwise.

Oh well, if I ever want to get a vortech aftercooler I'll have all the parts I need to swap back over to the fox set up. Provided I get a blower one day.

 

[kck6894]

I had some decent gains from doing my Fox swap. It's been long enough ago since I did it I am not sure how much I gained. I also think I did headers at the same time though.

The major gain from swapping IMO is that you get rid of those crappy adapters they make for the 94-95's. I had an Edelbrock adapter that I spent tons of time porting. I believe the 75mm Pro-M AFM, Mac cold air kit, 75mm BBK THB, and the Edlebrock elbow only flowed 500 cfm's as an assy. After finding that out I switched to a fox set up with a Pro-M 80mm shorty, Power pipe and a 90mm THB.

 

[Stangfreak95]

Does anybody have factual or hard data to back up the claims of gains

Anyway, has anybody come up with some proof?

Yeah.
oh no..not again...

 

[BlackVert]

Not really sure!

I took mine off years ago and have not thought about it since then, lol

Later
Grady

i just put one on after a year of not having one, and let me tell you, and it made a huge difference in the way the car drives. much less wobbly up front and just tighter all around. try putting it back on just to see if you notice a difference.

then again, i have a vert ...

 

[final5-0]

I started the thread to see if anybody had done the swap with no other mods included which would show the gain from the swap only.

I've been looking for such a post for quite some time now. I myself can't see how the fox method is more efficent as far as air flow is concerned. My best friend is an engineer in the AC industry who deals with air flow from time to time and he told me that the fox setup looks more restrictive to him also.

I compared our throttle cable setup to a friends fox and I can see how peeps who do the swap would say the car is more crisp feeling due to how the fox setup opens up the throttle body blade.

I sure do like how the fox setup looks that is for sure.

Bottom line is I've yet to find anybody who has done the swap only ..........

however

What do all of you have to say about My95.0L's conversion experience?

It is true that he used a different tb but it was the same size.

He claims a loss of 2 tenths & 2 mph from the swap.

I really would like to hear your thoughts, opinions, or discussion about My95.0L's conversion experience because he is the ONLY person I've seen so far who has done the swap in such a way that might lead you to think it is a fair compairson to look at.

Later
Grady

 

[Rootus]

What do all of you have to say about My95.0L's conversion experience?

It is true that he used a different tb but it was the same size.

He claims a loss of 2 tenths & 2 mph from the swap.

I can't see the Fox being any -less- efficient than the 94/95 setup, so I'd chalk up his experience to coincidence. Or perhaps something about the swap screwed up the tune. A 2 mph loss is like 20 horsepower, which would imply quite a restriction...

For what it's worth, I improved my ET by 3 tenths and my trap speed by 2 mph when I did my swap, so I guess I cancel out his experience . But I was going from the Edelbrock elbow, which looks to be quite restrictive (it isn't the 45* bend, it's the 1-inch gain in height that constricts airflow). The TFS elbow is rumored to be less restrictive. The 70* bend I used to do my Fox setup definitely had no change in cross-section.

Dave

 

[kck6894]

I don't see how a aftermarket 94-95 set up with the edelbrock adapter could possably flow nearly as well as the Fox style. If you have a mild or med built motor they might work just fine. On a larger CID higher reving engine I don't think you could go wrong with the fox swap. I have never seen the TFS adapter but the edelbrock ones suck and flow crapy.

 

[final5-0]

I can't see the Fox being any -less- efficient than the 94/95 setup, so I'd chalk up his experience to coincidence. Or perhaps something about the swap screwed up the tune. A 2 mph loss is like 20 horsepower, which would imply quite a restriction...

Your mention of 20 hp was the first thing that popped into my mind when I read his post.

For what it's worth, I improved my ET by 3 tenths and my trap speed by 2 mph when I did my swap, so I guess I cancel out his experience . But I was going from the Edelbrock elbow, which looks to be quite restrictive (it isn't the 45* bend, it's the 1-inch gain in height that constricts airflow). The TFS elbow is rumored to be less restrictive. The 70* bend I used to do my Fox setup definitely had no change in cross-section.

Dave

Dave

Would you please give a sentence or two to explain things in a bit more detail about the 1 inch gain in height thing you talked about. I am now using the Edel elbow and things don't look too restrictive to me but maybe I just did not see what you are talking about.

I also have seen peeps say the TFS elbow has the least restriction and I think WhiteDevil told me he saw an increase in air flow in his data logs from switching to that elbow.

Later
Grady

 

[WhiteDevil]

I also have seen peeps say the TFS elbow has the least restriction and I think WhiteDevil told me he saw an increase in air flow in his data logs from switching to that elbow.

Later
Grady

Yeah i have the TFS 75mm elbow and a BBK 75mm throttle body and then i ported the opening of my EDel to match the 75mm. I went form the edel elbow and a 65mm to this set up. I saw a good gain in Kg/hr from my old set up when i did it. As for dyno numbers i dont have any, lol of course. But it seems to work fine this way.

 

[Rootus]

Would you please give a sentence or two to explain things in a bit more detail about the 1 inch gain in height thing you talked about. I am now using the Edel elbow and things don't look too restrictive to me but maybe I just did not see what you are talking about.

I'll use pictures to illustrate what I think the restriction is. No comments from the peanut gallery about the dirty elbow ... I never bothered to clean it up after taking it off.

What bothers me is the "slide" the airway takes upward to match the opening of the intake. I say slide because it looks like what would happen if you took a slinky and slid the ends in different directions rather than letting it bend. It's like Edelbrock decided they didn't have enough room to make a constant radius bend.

Maybe this'll help. Look at how much the opening moves upwards (the intake end of the elbow is on the left, throttle side on the right).

Here is a shot with the intake side of the elbow laying flat on the counter, and the camera is exactly perpendicular to the counter. There is quite an altitude change between the two openings, in a very small distance.

I think that a lot of people only take into consideration the 45* bend you see if you look from the top. Using that logic, it would seem the 94/95 setup would be better. But when I see the side-view, I think that the 70* bend on the Fox body, especially if you do it aftermarket, is much less restrictive. To be honest, I don't think it matters much how many bends there are in the path, I think the most important factor is whether or not the cross sectional area is maintained throughout the entire intake tract.

Or perhaps I'm smokin' crack and this isn't an issue at all. I had a definite improvement when I went to the Accufab 75mm ... one other person had opposite results. Who the heck knows. I will say one thing, however -- knowing what I know now, I would probably opt for trying to correct the 94/95 elbow if I were faced with this situation again. I like the 94/95 throttle response much better -- the Fox setup is too touchy IMO.

Dave

 

[final5-0]

OK Dave

The pics really do help me to see the things you are saying and thanks for taking the time to share.

I've looked for restrictions like things not matching but the way your pics show things ...... as I said before, I missed the bigger picture I guess, lol.

Are you saying that If you were me, you would go for the better flowing TFS elbow rather than the fox conversion?

Later
Grady