75mm TB without an adaptor plate.

[HM_Motorsports]

Well after toying around with the idea of an aftermarket Mustang 75mm TB on my 3.5L swap for about a month I finally just did it. The throttle cables will go on top, but aside from looking odd I can't imagine it being a detriment in anyway. You'll have to switch to a mustang TPS, or make an adaptor for the 4th gen TPS.

**Edited**4th gen tps=.5-4kohm '00 4.6L tps=.6-3.8kohm I think they're close enough but they may not be. (They are, not just theory anymore It works. 2 weeks driving on it, haven't seen a problem yet)

The hardware part though, pretty much is confirmed. Here's the pics.

You have to move the throttle cable side holes maybe 4-5mm outboard to make it fit the 3.5L manifold.


On the bottom holes, use the TB as a template and drill and tap two 6x1.0 threaded holes below the factory ones.


That leaves you with this. Obviously some porting is neccesary.


The factory hole with the arrow pointing to it needs plugged it'll be closer to the opening than I would trust to seal.


I haven't finished the port matching yet, however there's plenty of material there. The coolant passage on the bottom will become vacuum, there's no doubt there, you can't get close enough without cutting into the passage. So either plug it or use it for a vacuum source.

[HM_Motorsports]

The (almost) finished product.






I'll update as soon as I figure out the TPS deal.

Did some porting tonight. here's a rough idea of the work required.

The lower outside edge you have to be careful, it won't be completely flat, it's simply too thin. But with a little more work I think I can get it to be of minimal obtrusion. I haven't hit the coolant port either, which I was surprised, the passage must be smaller than I originally thought.

Not finished yet. I only had an hour or so tonight free to mess with it. I haven't done anymore on the cruise control yet other than look, but I've got some ideas now.

[HM_Motorsports]

And the porting is done.

It clears everything, the throttle cable hooks up just fine and is in a great place for a bracket, ride by the top two bolts for the intake neck. Also in the picture below you can see the cruise is right by the extra hookup on the throttle cam. I just need to find one of the ends that hook to that. (probably off a mustang, I'll make a trip to the ford dealer tommorrow to see if you can just buy the end or have to get the whole cable)

And a shot straight through the open TB.

All and all, even if the Ford TPS doesn't work and I have to make an adaptor for the 4th gen TPS, this is relatively simple to do. It does require some time to port it all out but I have about $125 in the TB, TPS, and TPS pigtail all together. I never did hit the coolant port, but I like the idea of those two ends being vacuum so I probably will drill a hole to make them as such. Lemme know your thoughts!

***SIDE NOTE*** This thottle cam is a progressive type. The more you push the pedal the faster it opens. You only get about half the pedal travel you used to, which is either good or bad depending, my car was already touchy, now it'll be REALLY touchy. Plus you might want to make a pedal stop so you don't break the cable during WOT, or change the cable attachment to the pedal to be lower to gain back some travel. We'll see how it drives.

More on the TPS to come. Car should start this weekend. Taking a weeks vacation next week just to enjoy it!

[secondtonone317]

very creative mod

[Tatanko]

Wow, very nice. It's cool that it works with little modification, too. I'm curious as to how stuff matches up, though, as it looks like part of the factory opening will actually be outside the walls of the new throttlebody (and consequently not used) but it seems like it would be a tiny part. I'll reserve that thought until I see the finished product, though.

You mind telling us specifically which throttlebody this is and where you got it from?

[HM_Motorsports]

Originally Posted by Tatanko

Wow, very nice. It's cool that it works with little modification, too. I'm curious as to how stuff matches up, though, as it looks like part of the factory opening will actually be outside the walls of the new throttlebody (and consequently not used) but it seems like it would be a tiny part. I'll reserve that thought until I see the finished product, though.

You mind telling us specifically which throttlebody this is and where you got it from?

I got it off Ebay. Seller is Performance Tuners. 75mm mustang throttle body. The top of the manifold is indeed above the opening, by about 1/4" I planned on angling the edge of the TB where it overlaps to smooth out the airflow. You can't match it completely without having material added to the manifold, but you can definately help its transition.

[KRRZ350]

Oh **** yeah! This is awesome innovation!!! I'm psyched right now!! Also the side benefit of getting two more vacuum lines is awesome! One of them is perfect local' and size for Evap, and allthough small, the other one provides a nice alternative to drilling & tapping a 5/8"s hole in the back of the manifold for EGR. Oooh, this is awesome. I swear to god if you can get cruise on that puppy that would top it all off.

Re: tps. Does the stang one turn the other way? Mreaning, you need to be careful, I once foolishly mounted the max tps on the other side of the tb (because it's SOOOO much easier) even though I KNEW you couldn't do that. Boy did I feel like a tool when I had wot @ idle and vice versa.

FYI I have a tps off of an SN95 collecting dust, it's yours if you want it no shipping.

[maximariceboi]

very nice

[HM_Motorsports]

Originally Posted by KRRZ350

Oh **** yeah! This is awesome innovation!!! I'm psyched right now!! Also the side benefit of getting two more vacuum lines is awesome! One of them is perfect local' and size for Evap, and allthough small, the other one provides a nice alternative to drilling & tapping a 5/8"s hole in the back of the manifold for EGR. Oooh, this is awesome. I swear to god if you can get cruise on that puppy that would top it all off.

Re: tps. Does the stang one turn the other way? Mreaning, you need to be careful, I once foolishly mounted the max tps on the other side of the tb (because it's SOOOO much easier) even though I KNEW you couldn't do that. Boy did I feel like a tool when I had wot @ idle and vice versa.

FYI I have a tps off of an SN95 collecting dust, it's yours if you want it no shipping.

EVAP exactly. On a side note, for you 3.5L swappers, if you enlongate the holes on the evap solenoid, it fits perfectly on the two bosses on the side of the head where the EGR used to be. (I'm not using the external EGR on my swap, if you are they may not be accessable.) Anyways, my Evap is directly below the TB so that port becomes handy. And cruise? DEFINATELY will get it working. I have a welder. and about 5 or 6 spare random throttle bodies, Something will work lol. I was ticked when my cruise didn't work after my 5 spd swap, and never had the time to track it down. When I removed the wiring harness for the engine swap, I saw I forgot to plug in the connector I had removed to get to the clutch master cylinder! Felt like an idiot. drove 12 hours last summer to NC on vacation without cruise because of a connector I forgot to plug in.

Back on topic lol. The TPS situation... the mustang TB actually does work backwards from the 4th gen TB, but my theory is this; if you take Ohm readings of the three wires, there's a power wire, signal, and ground. The resistance between power and signal act directly opposite of the resistance between signal and ground. For instance, when the resistance between power and signal is .5 kOhms the resistance between ground and signal will be 4kOhms and vice versa, so if the throttle body opens opposite of factory, just switch the power and ground wire. Voila! In theory. Anyone please feel free to correct my thinking. If my understanding is correct a TPS is a glorified Potentiometer so it doesn't care which side the power comes from. Once I actually am able to start the car (which hopefully will be tommorrow night or the next) I can verify or nullify these theories.

Thank you BTW for the offer on the TPS, however a brand new one at the local parts store is only 26 bucks, which is another benefit because if IIRC a 4th gen TPS is over $100, incidently the Ford TPS pigtail I got from the Ferd dealer to replace the 4th gen pigtail is $26 as well(which I stashed after I cut off in case this doesn't work).

I'll not be able to finish up tonight, but hopefully tommorrow night I'll have more complete pictures and a better idea of how to make the cruise work.

[KRRZ350]

Originally Posted by HM_Motorsports

The resistance between power and signal act directly opposite of the resistance between signal and ground.

Speechless. Hope this works.

[HM_Motorsports]

Originally Posted by KRRZ350

Speechless. Hope this works.

You and me both!!!! lol I miss my car.

[HM_Motorsports]

Updated and added pictures to the top.

[KRRZ350]

Originally Posted by HM_Motorsports

I never did hit the coolant port, but I like the idea of those two ends being vacuum so I probably will drill a hole to make them as such. Lemme know your thoughts!

I would be all over that, it will definitly simplify things.

[vernk]

Just a thought for the cruise, you could see if you can find a set up like what my 85 has.

[HM_Motorsports]

Originally Posted by vernk

Just a thought for the cruise, you could see if you can find a set up like what my 85 has.

Now that would work too! One of my friends at the Ferd dealer is getting me a couple cable ends in that may work to just hook directly to the 4.6 TB but if that doesn't work, the 85 setup may be the ticket.

I have a pretty full schedual tonight and tommorrow but I'm gonna try my best to fire her up on Sunday so we'll know more about the TPS. That's the only big question now.

[wagesgt903]

I dont want to sound like a dick but 75mm is too big even for a stock 4.6 mustang. We have done dyno's at school and seen drops in horsepower and torque because and an engine needs a certain amount of restriction to keep the air velocity up. Other than that I hope everything works. Just "food for thought" anyway.

[AnDyMaN]

Originally Posted by wagesgt903

I dont want to sound like a dick but 75mm is too big even for a stock 4.6 mustang. We have done dyno's at school and seen drops in horsepower and torque because and an engine needs a certain amount of restriction to keep the air velocity up. Other than that I hope everything works. Just "food for thought" anyway.

i don't think we have enough information about his goals to determine if it will or will not adversely affect (effect??) his performance.

[HM_Motorsports]

Originally Posted by wagesgt903

I dont want to sound like a dick but 75mm is too big even for a stock 4.6 mustang. We have done dyno's at school and seen drops in horsepower and torque because and an engine needs a certain amount of restriction to keep the air velocity up. Other than that I hope everything works. Just "food for thought" anyway.

I chose a 4.6L TB because of its simplicity, not because of its size neccesarily. the stock 3.5L TB is 70 mm, and there seem to be plenty of people running 70mm Pathy TB's in both a 4th gen and 4.5 gen application and at least on the 3.0L that's been dyno proven IIRC. Problem is, you need an adaptor plate, or with a 3.5 swap converting the factory DBW TB to cable. That entails a bracket for the TPS, and loss of cruise control. I started investigating the pathy TB and the cheapest one I found was $150. Slap an adaptor plate on there ( I have the means to make my own, but many do not) you've got $250+ in that. Which it works fine. Not knocking the PF TB setups at all, they work. And so do the converted DBW's. This is simply another option I am exploring. The porting is not perfect, it is NOT a true 75mm inside at least not straight. Which I kinda had an idea it would not be but I was hoping for a little closer. I only have $125 in it. some time. I'll still have cruise, and it looks clean (albeit a little weird with the cables on top). I know that air velocity does count, however, I also know that restriction in the intake path is not the way to improve upon it.

I'd like to see those dynos though. I know quite a few running around with 75's that seem to perform quite well.

[NiZMo1o1]

ahh damn my 6th gen with DBW

[KRRZ350]

Originally Posted by HM_Motorsports

I'd like to see those dynos though. I know quite a few running around with 75's that seem to perform quite well.

On top of that they aren't a VQ either.

HM, I'm hoping that you have done a decent SSIM on this upper and that you'e be willing to do a little something.......

I'd be willing to send you an SSIM'd upper with modified DBW to cable, to borrow, and swap it out at the dyno to see what just 5mm on the TB add's to an SSIM'd hybrid?

[HM_Motorsports]

I may take you up on that KRRZ, I'd be interested to see, although not my intended purpose, I don't doubt it might add a little bit of top end. However, I did NOT do the ARP rod bolts so no extended Rev limit yet, plus Emanage has yet to be installed. The intake is SSIM'd(you can critique it, the pics are in my build thread) no port matching. So I don't know if we'd get the full potential without the extended rev limit, but I'm sure there's potential.

[wagesgt903]

I'd like to see those dynos though. I know quite a few running around with 75's that seem to perform quite well.[/quote]


Ill see what I can find, I already finished the class but it was just really weird to see a 4.6 mustang lose a pretty significant amount of hp and torque to throttle body sizing. It was something like 15 hp and 20 torque we lost at the wheels.

[Weimar Ben]

Seems to me tha