Installed Underdrive Pulleys - a review

Blair · 10-26-2009, 05:40 PM

This past weekend I installed some Steeda Underdrive pulleys on my 2010 GT. The install wasn't too bad. The hardest part is getting the stock balancer off with a rented Autozone puller that has seen too much action. Other than that it was a breeze. I had a set of these pulleys on my '06 GT and it was only natural to put them on the new 2010.

The pulleys make the car accelerate a little quicker and throttle inputs are a little more responsive. Not a huge difference but it is noticeable especially if you do a lot of city driving. The difference in power seems to be about the same as when I added the headers. Not a huge increase, but noticeable. So far I have noticed two things that I especially like:

1) The car gets off the line a lot easier. After I added the headers it seemed like it was easier to bog the engine if you didn't give it enough gas off the line. That is gone and it seems like it would be very difficult to bog the engine now.
2) You don't get that loss of power sensation when the AC kicks on. I live in Florida and the AC is almost always on, but now it doesn't seem to hold the car back as much. If you are sensative enough to feel the difference in power between running with no AC and AC on, you'll feel this mod. If not, you might not think anything has changed.

This is one of the few mods that in my opinion has no obvious downsides. It doesn't make the car louder, it doesn't make the car whine or vibrate, and it doesn't ride harder or scrape on driveways like some other mods.

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Kona6Stang10 · 10-26-2009, 05:49 PM

very nice
i'm thinkin about pickin up some of these for the 6.
As far as the 2010's go I can BARELY feel a difference between air on and off when compared to the sn95....I did a dyno with air on and with air off for ****s and giggles when I was tuning the H/C/I silver 6er.....I made 176 with air off and I made 158.7 with air on!!!
Now maybe my car was a factory ****ter but I hated that I couldn't get outta my own way in that car with the air on (or off for that matter

lol )

crescent_wrench · 10-26-2009, 05:57 PM

Any ill effects with the air conditioning performance or electrical? Also, does the motor rev down faster when bliping the throttle (with no load of course)?

BL00DSH0T · 10-26-2009, 06:17 PM

Nice review. I have been thinking of doing these next and getting back on the dyno.

Blair · 10-26-2009, 07:25 PM

Quote:

Originally Posted by crescent_wrench

Any ill effects with the air conditioning performance or electrical? Also, does the motor rev down faster when bliping the throttle (with no load of course)?

I had an '06 GT and used the same pulleys on that car and never had a problem with AC or electrical. I had aftermarket HIDs in that car and an amplifier and never had any electrical problems, no lights dimming and no battery problems either.

As far as AC, in the heat of the summer before the UDPs you could sit and idle in traffic and stay cool with the fan at position 2. After the UDPs you had to crank the fan up a little to 3 to keep it cool. Once the car got moving there was no difference, but if you sat in traffic not moving idling for any long period of time you needed to kick the fan up a notch to keep the car cool. I didn't really consider that a drawback, because you could just turn up the fan.

Honestly, I haven't noticed if the car revs down faster. That would probably be more apparent with an aluminum driveshaft or aluminum flywheel. The crank pully is really only a little bit smaller and is pretty heavy like the stock one... I did not weigh the new one though.