Modified Ford Racing 4.6 Mustang Throttle Body

[aldive]

I have been using a Ford Racing 4.6 Mustang throttle body for well over a year (http://www.explorerforum.com/forums/...=throttle+body ) and have been delighted and experienced no problems with it; it produced better gas mileage than the stock throttle body and the “seat of the britches dyno” indicated more HP, albeit not earth shattering.

But yet again, as the norm, I wanted more ….

I had been reading about modifying the throttle body by cutting throttle shaft and screws. Reports from Sport Trac owners using the modified throttle body include 7 RWHP ( dyno proved ) and up to 5 MPG gains; all reports were positive. The modified stock throttle body flows 26 CFM more air than the stock throttle body ( http://www.zabteck.com/tb.htm ). With the mods to the Ford Racing throttle body it will flow well over 600 CFM; more than the 600 CFM the 4.0 SOHC motor needs at 6k RPM.

The potential for mileage gains undeniably peaked my interest and more HP never hurt, as a result I decided to have Todd Zabbia of Zabtech Performance (http://www.zabteck.com ) do the shaft and screw modification to my Ford Racing 4.6 throttle body.

Upon consulting with Todd several times, I decided to have him also enlarge the throttle body bore before the butterfly valve ( which was 65mm ) to as close to 70mm, like the rest of the throttle body, as possible in addition to the screw and shaft modification. Why Ford made that throttle body that way is a mystery to me.

Todd is a good guy, a great communicator and is very easy to deal with. I highly recommend him and his work.

I shipped my 4.6 throttle body to Todd for the mod. While it was gone, I had to return to the stock throttle body ( after I thoroughly cleaned it to a pristine condition prior to installation; I have come to the conclusion that to really clean the throttle body, it must be removed from the vehicle ). And yes, I could perceive a distinct performance decline, especially in the higher RPM ranges. Regrettably I did not have time for a long trip gas mileage evaluation with the stock throttle body.

The total time I was without my throttle body was exactly 3 weeks door to door, including the Thanksgiving holiday. Todd was always upfront with the delivery time; no surprises here.. The cost of the mod was $200.00 to my door.

To my knowledge this was the first mod job on a 4.6 throttle body used on an Explorer. Todd has modded many stock 4.0 throttle bodies.

The actual bore measurement areas follow: in front of the butterfly valve 69.45 mm and behind the valve is 70.07 mm.

Will install and evaluate in the morning. See post # 15.

[briwayjones]

Have you finished evaluating the new ignition pack yet? It's unlike you to start evaluating a new mod before the old evaluation is complete.

[MONMIX]

watching and waiting,,,

[aldive]

Originally Posted by briwayjones

Have you finished evaluating the new ignition pack yet? It's unlike you to start evaluating a new mod before the old evaluation is complete.

Both will be evaluated on a 1500 mile voage to Atlanta this Friday.

Stay tuned ....

[briwayjones]

You won't be able to seperate out the performance each is contributing will you? Or since you'll probably be netting small gains you're not worrying about it?

[aldive]

Originally Posted by briwayjones

You won't be able to seperate out the performance each is contributing will you? Or since you'll probably be netting small gains you're not worrying about it?

Stay tuned and you shall see ...

[Fredness]

O.K., we're staying tuned...

[briwayjones]

Originally Posted by aldive

Stay tuned and you shall see ...

[celly]

Originally Posted by MONMIX

watching and waiting,,,

Did you ever install the TB you bought from me?

[MONMIX]

Originally Posted by celly

Did you ever install the TB you bought from me?

Yup
positive results.
Oddly enough it goes weeeeeeeeeeeeeee at certain RPM's
People keep thinking I have a turbo. No negative results though.

[celly]

Originally Posted by MONMIX

Yup
positive results.
Oddly enough it goes weeeeeeeeeeeeeee at certain RPM's
People keep thinking I have a turbo. No negative results though.

Strange. Mine never sounded different on my '00 Sport. Any issues with cruise control with the new TB? I could never get mine to hold a speed on anything but flat road with both the Ford Racing and BBK TBs. I've heard there are tweaks, but I never solved the problem before I traded in the Sport.

Al asked me recently in another if I'd come up with a solution.

[aldive]

Originally Posted by celly

Any issues with cruise control with the new TB? I could never get mine to hold a speed on anything but flat road with both the Ford Racing and BBK TBs. I've heard there are tweaks, but I never solved the problem before I traded in the Sport.

Al asked me recently in another if I'd come up with a solution.

I have had zero problems with mine.

[celly]

Originally Posted by aldive

I have had zero problems with mine.

The issue with mine seemed related to the length of the throttle and cruise control cables/controls. I had the "throttle cable mod" done before the switch of TBs and had to add more zip ties after. That took care of the slack in the throttle cable but I couldn't find a fix for the cruise which is not controlled by the mechanical linkage. The problem lessened when I ditched the thin, paper based gasket that came with the BBK and replaced with the OEM, plastic gasket (after removing those fins) which is thicker and picked up some of the slack. It still wasn't perfect though.

Al, it's great that you had no issues because I had heard from a few others who did this mod and had the same problem. The issue is definitely related to the slack created when the new TB is put on, at least in my (and other's) cases. I'm just curious if Kevin as the same problem since he had the same year Explorer as mine. Given that I had the same issue with two different TBs, this was no fluke. The OEM TB definitely goes on and there is less slack at the linkage (accelerator and cruise).

[Jakee]

Originally Posted by celly

The issue with mine seemed related to the length of the throttle and cruise control cables/controls. I had the "throttle cable mod" done before the switch of TBs and had to add more zip ties after. That took care of the slack in the throttle cable but I couldn't find a fix for the cruise which is not controlled by the mechanical linkage. The problem lessened when I ditched the thin, paper based gasket that came with the BBK and replaced with the OEM, plastic gasket (after removing those fins) which is thicker and picked up some of the slack. It still wasn't perfect though.

Al, it's great that you had no issues because I had heard from a few others who did this mod and had the same problem. The issue is definitely related to the slack created when the new TB is put on, at least in my (and other's) cases. I'm just curious if Kevin as the same problem since he had the same year Explorer as mine. Given that I had the same issue with two different TBs, this was no fluke. The OEM TB definitely goes on and there is less slack at the linkage (accelerator and cruise).

The fix is to adjust the cruise control cable after installing the 4.6 TB. Can be done by removing a little metal clip located on the bracket.

Just for the record, I have a modified 4.6 TB on mine right now. I saved the 200 Bucks and did it myself. Not hard at all. The front bore can be done with a 3" flap wheel bought from home depot. Now, if you don't have the ability to measure then I wouldn't suggest this. Those of you that are interested then make sure not to mess with the bore where the butterfly is. Also, A half shafter TB is as good as any.

There is a point where making your TB bigger will doing nothing. Interested to know if this is going to help u Aldive. Good luck.

[aldive]

The install ....

The removal and replacement of the throttle body was a straightforward less than 10 minute job ( see http://www.explorerforum.com/forums/...=throttle+body ). Prior to removal the negative battery cable is disconnected and reconnected after the install.

Prior to the new throttle body install, I conducted several WOT 0 to 80 MPH runs so I would have a comparison to the same with the new throttle body.

Initial impressions on a road test and the 0 to 80 MPH runs were positive; I undeniably felt a difference in throttle response and acceleration at higher RPMs. There were no issues with the cruse control function.

The throttle response alone is worth doing the mod.

I shall be making a 1500 mile road trip ( to the Atlanta area ) this Friday; gas mileage will be evaluated. I plan to swap the modded throttle body with the stock one on one leg of the trip for a direct comparison.

Mileage data will be reported after the trip.

A jaunt to the dyno is also in the works; stay tuned.

NOTE: the pictures of the before and after of the shaft and screws were borrowed from the Sport Trac website. They are of a stock throttle body and are better quality than the ones I took.

[Turdle]

Any audible difference Al?

[Green98XLT]

I can undeniably see the difference the modding makes but can you honestly tell me that a basically stock 4.0 SOHC needs that additional ~30 CFM of air? If the stocker flows 550+cfm I have to think that is more than enough flow for these motors. Now if you were to add an aftermarket upper/lower intake, cam, headers etc. Then maybe, but C'mon... throttle response may pick up but 7rwhp??? Nahhhh I need dyno proof.

[aldive]

Originally Posted by jtsmith

Any audible difference Al?

Yes, at WOT you can really hear it a sucking air. There is no difference at less than WOT.

[aldive]

Originally Posted by Green98XLT

I can undeniably see the difference the modding makes but can you honestly tell me that a basically stock 4.0 SOHC needs that additional ~30 CFM of air? If the stocker flows 550+cfm I have to think that is more than enough flow for these motors.

The motor calls for 600 CFM at WOT.

What do you base yoiur thoughts upon?

Now if you were to add an aftermarket upper/lower intake, cam, headers etc. Then maybe, but C'mon... throttle response may pick up but 7rwhp??? Nahhhh I need dyno proof.

There are no aftermarket upper and lower intakes.

Dyno proff ( charts ) are available on the Sport Trac website.

[Green98XLT]

Al- not doubting your info at all, I just hate type and biased 'facts'. The company thats modding the TB's is the one giving me the dyno data just doesn't do it for me.

I find it hard to beleive this little 4.0 needs 600cfm at wot... I've done tons of mustang testing and dyno work over the years and it was a waste to go above a 65mm TB on all but a totally built 5.0, dyno proved that many many times. The stock mustang TB could flow right around 550-600cfm and that was plenty for a larger, higher revving engine.

I also know there are no upper/lower intakes available for the SOHC, and I'm betting the stock piece cannot flow 600cfm, so my point is why put a 600+cfm TB on an intake that flows >500cfm?? Seems pointless to me.