Summit Underdrive Pulleys

[Dixie Design]

I know we've talked about this set in the 04-08 forum, just thought I'd "rate" them over here.

Put about 600 miles on them already (had a couple long trips Sunday and Tuesday). Fuel economy is up, not quite a whole mpg but I've only put a tank and 3/4 on them so far. Could be coincidence, could be the pulleys.

As for performance, I'd like to think I can tell a difference. Not sure how much you can "feel" 15hp on a 3500lb truck, but when I stomp the gas to pass someone on a 2 lane I feel like I get up to speed and around them a little quicker.

Install wasn't difficult, maybe I have a good taste in my mouth because I virtually did the install twice and the last time was a breeze.

Summit's kit takes the stock length belt, Goodyear's website has a part number cross reference tool, use that, find you a Gatorback at stock length and IGNORE summit's recommendations. They don't have a clue what belt goes on an 04 4.6L. They tried 3 times for me, wrong all 3 times.

Price was GREAT at $134.

[88Racing]

Glad they are working out for you!

Now if I can find the time to put mine on! I know it won't be this weekend.

Lars

[Dixie Design]

**UPDATE**

Have put about 800 miles on my truck with the pulleys, and between both city, rural, highway miles, I'm consistently getting 1-1.5 more Miles per gallon. Didn't really want to comment that early, could have been conditions, but 800 miles of an extra MPG+ I think speaks for itself.

Very pleased.

[DOD 4.6]

**UPDATE**

Have put about 800 miles on my truck with the pulleys, and between both city, rural, highway miles, I'm consistently getting 1-1.5 more Miles per gallon. Didn't really want to comment that early, could have been conditions, but 800 miles of an extra MPG+ I think speaks for itself.

Very pleased.

wow. so $134 for an extra 1-1.5 mpg's. this mod sounds like it WOULD actually pay for itself within our lifetime. lol. can you explain again on the how the power gains felt? and also which part number this is. i've been looking at troyer's pulleys but they are about $100 more than the summits.

[88Racing]

**UPDATE**

Have put about 800 miles on my truck with the pulleys, and between both city, rural, highway miles, I'm consistently getting 1-1.5 more Miles per gallon. Didn't really want to comment that early, could have been conditions, but 800 miles of an extra MPG+ I think speaks for itself.

Very pleased.

Are they starting to run summer blend in your area?

Lars

[Dixie Design]

Are they starting to run summer blend in your area?

Lars

Last time I asked my contacts at a couple gas stations no, not yet. I only put gas in my truck from the same Shell Station (unless I'm out of town of course).

I'll double check again tomorrow night at softball.

[DOD 4.6]

Last time I asked my contacts at a couple gas stations no, not yet. I only put gas in my truck from the same Shell Station (unless I'm out of town of course).

I'll double check again tomorrow night at softball.

so are the power gains mostly in the upper rpm range? due to the fact that you can feel it while passing

[Dixie Design]

so are the power gains mostly in the upper rpm range? due to the fact that you can feel it while passing

Correct me guys if I'm wrong, but I'd say it's across the board. You're spinning less for the same speed.

[3StarJ.R.]

Seeing your thread about underdrives reminded me I picked one up a couple of years ago @ a going out of business performance shop sale. I forgot I had it! :doh:

If anyone is interested I'll sell this one for what I paid. 85.00 bucks plus shipping.

http://inlinethumb38.webshots.com/41381/2512883730063931783S600x600Q85.jpg (http://rides.webshots.com/photo/2512883730063931783ZYGnyw)

http://inlinethumb50.webshots.com/30961/2068699200063931783S600x600Q85.jpg (http://rides.webshots.com/photo/2068699200063931783GDRikV)

http://inlinethumb22.webshots.com/43349/2507079540063931783S600x600Q85.jpg (http://rides.webshots.com/photo/2507079540063931783ogBvrv)

http://www.dougherbert.com/underdrivedamperspulleykit-p-25782.html

[Dixie Design]

That's a STEAL! Wish you had found them before I bought mine! :)

[Desert Racer]

I know you have a 4.6 but does Summit make them for the 5.4? Thanks Cody

[88Racing]

I know you have a 4.6 but does Summit make them for the 5.4? Thanks Cody

Pretty much stuck with troyer for the 5.4. That's where I got mine.
Rpm outlet also has them(moto blue) but customer service isn't the greatest.

Lars

[Desert Racer]

Thanks man, damn mod bug! lol

[BlackSTX]

Quick question for you.... Do you experience any charging issues at lower RPM's? Coworker had a kit on his Mustang and said that was the only negative he experienced.

[Power Hungry]

Undercharging at idle is a common problem, especially with E-Fans. The only thing you need to do is raise the idle 50-75 RPM w/o fans or about 100-125 RPM with fans and you're good to go.

[BlackSTX]

Thanks Bill. It's much lower RPM increase than I expected. I wasn't sure if most of the kits changed the alternator pulley too, but I see none of them really do.

[88Racing]

I know you have a 4.6 but does Summit make them for the 5.4? Thanks Cody

The 4.6 ud pullies are all over out there. The 5.4 ud pullies are hard to find and if you do find them they run $75 to $100 more. Troyer performance is where I got mine from for the 5.4. There is a couple of more places but they have horrible customer service. Watch out when you search for them online some retailers mix up the products or don't give good numbers. You might order a set for a 5.4 and end up with a 4.6 set. So my advice go with a performance shop who has used them and are selling them.

Lars

[88Racing]

Thanks Bill. It's much lower RPM increase than I expected. I wasn't sure if most of the kits changed the alternator pulley too, but I see none of them really do.

Some kits out there are still three pulley kits. Just depends on who the mfgr is and what they thought was best! Majority of pulley kits are only 2 pulley kits.

Lars

[Desert Racer]

The 4.6 ud pullies are all over out there. The 5.4 ud pullies are hard to find and if you do find them they run $75 to $100 more. Troyer performance is where I got mine from for the 5.4. There is a couple of more places but they have horrible customer service. Watch out when you search for them online some retailers mix up the products or don't give good numbers. You might order a set for a 5.4 and end up with a 4.6 set. So my advice go with a performance shop who has used them and are selling them.

Lars

I plan on ordering a set from Troyer here in the next month or two. Need to give the card a break with mods lately. :smiley_roll1:

[BlackSTX]

All said and done, I'm glad this mod makes a noticable difference; it's one of the cheaper ones you can make. As far as the belt goes, do you know what the length of the stock belt is, or the part number for the Goodyear belt is?

If anyone can chime in on this, I'd appreciate it... Thanks!

[SinCityFX4]

Here is the part number that Troyer has listed.

"This kit requires a 1 inch shorter serpentine belt, and we recommend the Goodyear Gatorback serpentine belt as it's much higher quality, and are no more expensive than the factory belt. This will also stop the serpentine belt "squeal" that is heard many times during heavy-throttle upshifts in these vehicles, especially if a performance tune is being used. We carry these Goodyear Gatorback belts, for 2002 & 2003 F-150's, order our Part# 4060980, and for 2004 & up F-150's with the new 3-valve 5.4 engine, order Part# 4061010. All of these belts are listed at the bottom of this page, as well as in the "Belts" section of our Store here. For 2003 F-250 SuperDuty Trucks, the correct belt to order is our Part# 406990. "

It is their part number but they have it listed as 1" shorter. I am sure the guys at the parts counters could pull that out.

[88Racing]

All said and done, I'm glad this mod makes a noticable difference; it's one of the cheaper ones you can make. As far as the belt goes, do you know what the length of the stock belt is, or the part number for the Goodyear belt is?

If anyone can chime in on this, I'd appreciate it... Thanks!

Here's the interesting thing the kit Dixie got was still able to use the stock length belt. The shorter one he ordered didn't fit. His was from summit and for the 4.6L.
So to this day I'm still scratching my head on that one?

Lars

[BlackSTX]

Yeah, I scratched my head at that too; they list that theirs uses the original size belt.

[Dixie Design]

Yup, still running the stock length belt. I know my RPMs dropped once the kit was installed so it did what it promised. Now if I could only find the time to install my efans!