After consulting Jason (the trendsetter Twinskrewd), I decided to install a 90MM Ford racing throttle Body (part #M-9926-M5090) on my 2004 F150 FX4 Roushcharged Truck. The stock TB is 75MM so this was 20% larger. Many of you recall Jason did this to his Whipple. Many of you have read some of my recent posts regarding my Yellow FX4. It is Really starting to run good!

The main issue is making the Roush Plenum big enough to accept the 90 MM TB. I considered fabbing up my own Plenum but due to the complete LACK OF ROOM under and near the firewall of the truck I didn't think I could improve on the Roush Design. I looked at several Mustang GT designs, Lightning plenums and others but there is NO WAY to make them fit even if I re-fabbed them. The Mustang setup is much better than the F150 on the Roush Kits.

I had to remove the supercharger to get my plenum removed due to the lack of clearance under the firewall of the F150. (this takes about 45 minutes).

I decided to port the stock Roush plenum as "open" as I could. After about 3 hours of port work (damn good too!) I finally removed enough aluminum to match up the somewhat wedged shaped 80MM x 90MM Throttle body spacer that came with my TB. I basically opened it up from 75mm to 80MM and believe me...that was all I could do without going through the plenum with the cutting tool.

Obviously the 90MM side of the spacer connects to the TB and the 80MM side connects to the Roush Plenum. (the spacer kit is extra $49ish part number (m-9474-m50). You have to have this spacer with the stock Roush F150 kit. Without the spacer the TB WILL NOT MATCH UP with the stock or ported plenum. You will have to make a paper gasket or use liquid gasket maker on the Roush Plenum because the porting will remove the rubber "O ring" in the plenum.

The beauty of this mod is that the new 90MM TB is plug n play. You simply take out and unplug your old TB and use the same plugs (2 of them) to plug in to the new TB. NO WIRING!

You need to buy K&N part number 08050 ($10) 4x3.5" Rubber coupling to mate the TB with the Roush plastic Intake tube if you plan to keep the intake. I am looking into a 3.5" or 4" ID intake. Maybe I can make one out of tubing like Jason did or fab something up from a Mustang GT? I would love to get a 4" Roush plastic Tube to work with.

The results are "butt dyno" impressive. Throttle response is much quicker, the 90 MM sucks more air and even whistles a bit. I think the fact these 90 MM are designed for "blown Mustangs" makes the throttle position sensor more responsive. They must be tuned that way for supercharged Mustangs because I don't have to use as much pedal to accelerate.

I bought my TB used on ebay (barely used) and it came with the spacer kit for $360. It was a steal. New they are $575 plus the spacer.

I took some pics and would be glad to email them to someone who knows how to post them..I can NEVER figure it out.

This is a mod worth making for those of you looking for more HP.

Edit: Went for a long drive today and really noticed a lot more low end snap. It just takes off even with very light throttle. This mod really works well with my package.

 

VERY nice!

where did u find one for $575.? I was looking and found best of $629.

 

Fordracingparts123.com

 

Pm sent regarding better price source.

 

Pics as requested Jeff.

 

Really glad to see this worked out for you Jeff. Can't wait to see the final install pics.

 

whats the HP gain?

 

The guess is 20-25 under 10PSI. Probably higher with more boost. I can REALLY feel the low end throttle response. The TPS for this is tuned much better. It is very responsive. I am very happy with it.

 

Nice one Jeff. Glad you got it on and are showing encouraging results.

Now lets see some pics of the install.

 

Has anyone done throttle body upgrades on newer model trucks? Mine is a 2012 and I've been thinking about doing a throttle body upgrade, plus intake and custom long tube headers. If anyone has experience with this stuff I'd love to hear about it!