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SR Performance Underdrive Pulleys (05-10 GT)

52 Reviews
Our Price

$164.95

  • Item #41131
  • MPN# 41131

  • Market Price $186.99
  • You Save 12% ($22.04)
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Product Videos Customer Photos
Features
  • Free Up Horsepower
  • Complete Kit
  • Durable, Lightweight Aluminum
  • Brilliant Polished Finish
  • Premium Quality
  • Fits 2005-2010 GT and Bullitt Mustangs
Description
Untap Hidden Horsepower. Don't let your accessories and A/C drain power from your GT or Bullitt Mustang. By replacing your factory pulleys with this SR Performance Underdrive Pulley Kit, you'll free up to 15 horsepower that's currently being drained by your accessories and put it back where it belongs - under your right foot. Best of all, you won't affect your vehicle's charging or cooling capacity in the process.

SFI Certified Design. If you're ready to take it to a track, you'll rest easy knowing these SR Performance Pulleys are SFI Certified.

Premium Quality. Don't settle for inferior parts. These premium quality SR Performance Pulleys are made from lightweight aluminum for durability and performance. Made using precise, state-of-the-art CNC manufacturing, you can count on these pulleys to perform at the highest level.

Easy Installation. This SR Performance Mustang Underdrive Pulley Kit installs quickly and easily in under 2 hours with no modifications required.

Application. These SR Performance Underdrive Pulleys are specifically designed for use on the 2005 to 2010 GT and 2008 to 2009 Bullitt Mustangs.

Fitment: 2005 2006 2007 2008 2009 2010 Details

What's in the Box
  • (1) Crank Pulley
  • (1) Water Pump Pulley
  • (1) Crank Bolt
  • (1) Instruction Sheet
Installation Info
Tech Specs
Underdrive Pulley Specifications
Year/Model: 2005-2010 GT Manufacturer: SR Performance
Material: Aluminum Finish: Polished
Crank Pulley: One Piece Crank SFI Certified: Yes
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09, 10

Most Helpful Reviews

5/5
Great Bang for Your Buck

The pulleys look good,installation was a piece of cake,the only recomendation for the install is to get a M8-1.25x2 bolt to replace the alt stud,instead of cutting the stud for the waterpump pulley to ...

Read More
Helpful (8)

5/5
Horsepower Increase

Awesome Product just as good BBK, without all the price. Just buy a new bolt instaed of cutting the one on your vehicle. Take your time, snap a picture of how your belt diagram, just in case.

Helpful (6)

Read All 52 Reviews
Overall Rating 4.8 out of 5 stars

Video

Hey I’m Justin with AmericanMuscle.com, and I’m breaking down these underdrive pulleys from SR Performance, fitting the 4.6L V8 motor found in all 2005-2010 Mustang GTs. Engine accessories like the AC compressor, water pump and alternator can really rob your car of horsepower, a great example of how much power an accessory can eat up is whenever you turn your cars AC on and instantly it feels a little more sluggish. This is referred to as parasitic drag. The idea of an underdrive pulley is to turn the different accessory pulleys at a different speed, using these different sized pulleys thus requiring less power from the motor to drive each accessory. This reduction in drag on the crank shaft should allow the motor to operate more efficiently, and essentially equate to more power at the rear wheels. The SR Performance kit includes a new water pump pulley along with a brand new crank pulley, and the hardware needed for the install. Both pulleys are SF5 certified and are constructed using lightweight aluminum. As an added bonus, that bright polished finish is sure to look good under the hood as well. As far as the install is concerned, you just want to leave yourself a couple of hours to get both pulleys installed. Ideally, you should have a torque wrench on hand as well as some high temp RTV sealant and a breaker bar for that crank pulley bolt. This isn’t the hardest job in the world, but if you’ve never attempted it before, I really suggest watching the detailed instruction video located on this product page before getting started on the install. So be sure to check out the SR Performance underdrive pulleys right here at AmericanMuscle.com

Customer Photos (28) View All Photos

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9 Questions / 5 Answers

Ask a Question

will these work with a supercharger? i have just put on a ford racing/Whipple supercharger 550 kit on my 08 GT and now i want to dress up the engine and free up some hp. now will these work with a supercharger? lot of the pulleys A/M sell do not work with superchargers.

gdellobuono

  • No. Underdrive pulleys are designed to slow down your accessories. This combined with a supercharger would give you a lower boost. The result is you would make less power than without the pulleys.

    rogercharger

    Good Answer (1) (0)

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Work with on a V6? I've seen on a few forums people were saying to increase HP on a V6 to get an underdrive pulley, but the only ones on here are for GT's. Was just wondering if these would work on a V6.

ZStang07

  • I would only get pulleys that are meant for your specific engine. Could cause problems otherwise and I doubt they'd fit.

    MarkL

    Good Answer (0) (0)

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Will this cause the A/C not to work?

Geoff365

  • A/C still works great in my car and I've had these exact pulleys for years. No drawbacks in my opinion unless you're going supercharged then you don't need them.

    MarkL

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Customer Reviews (52) Write a Review

Overall Rating 4.8

out of 5 stars




  • 5/5

    Installation Time: Afternoon

    April 03, 2012

    Great Bang for Your Buck

    The pulleys look good,installation was a piece of cake,the only recomendation for the install is to get a M8-1.25x2 bolt to replace the alt stud,instead of cutting the stud for the waterpump pulley to clear. Noticed a slight power gain. Great product for the price.

    drmustang

    Year: 2006 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 3 N. Myrtle Beach SC

    Helpful (8) (0)

  • 5/5

    Installation Time: Afternoon

    February 27, 2012

    Horsepower Increase

    Awesome Product just as good BBK, without all the price. Just buy a new bolt instaed of cutting the one on your vehicle. Take your time, snap a picture of how your belt diagram, just in case.

    IndigoBlue

    Year: 2008 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 2 Agoura Hills, CA

    Helpful (6) (0)

  • 5/5

    Installation Time: Afternoon

    January 27, 2012

    Fuel Millage

    The day after the install of the new pulleys, I took the car for a trip. I got 26- 28 mpg! I have never seen that before, so it clearly made a difference. I have since done a few more bolt-ons and together they have turned the car into a real handful! When I speed shift into second, hold on becouse she is going to pull sideways and then bark a hard 3rd! The pulleys were easy to install. I have already recommended that my friends to do the same. Cannot wait until the track opens to see the new times. Fastest pass has been 13.7 totally stock.

    supercross

    Year: 2010 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 4 Anderson Texas

    Helpful (9) (3)

  • 5/5

    Installation Time: Afternoon

    February 23, 2012

    Pulley = Epic Win

    Hardest part about getting these installed was finding a friend with all the parts. It was a helluva lot of fun putting these on, the instructions were right on point. Note: this WILL require removing some hoses so you will want to be aware of some possible dripping. I'd have to say the car is a bit more peppy, I'm able to do wonderful things in 1st gear with no gas... Great fun!

    AustinJim

    Year: 2008 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 2 Austin, Tx

    Helpful (3) (0)

  • 3/5

    Installation Time: Less than 1 Hour

    March 05, 2012

    Price wise, better then other pulleys, power is ok

    I work at Mustang Specialties, I purchase this set for my personal 09 GT did a before and after dyno. made 316rwhp before the install. Install went smooth and everything fit no problem and looks great. went ahead and dyno'd the car after the install same day just an hour later. car made 320rwhp with the pulley install. So with no other changes at all on the car what so ever this car will give a dyno proven 4rwhp. For me its not worth it, the car on nitrous still ran the same time and mph 11.5X@118-119

    KOTSCHRIS

    Year: 2009 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 2

    Helpful (9) (5)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    September 26, 2013

    Smooths out performance a bit, but don't expect miracles

    I recently had these UD pulleys installed alongside a set of FRPP 3.73 gears. They seem to have offset the slight (1-2 mpg) drop expected by jumping from 3.31 to 3.73 rear end, and overall the car feels like it runs a little smoother. The engine feels as though it revs a little freer as well. Install cost for the pulleys was $75. A solid mod and I would buy them again.

    TitanJC

    Year: 2007 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 The Woodlands, TX

    Helpful (2) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    June 29, 2012

    SR Performance Underdrive Pulleys (05-10 GT)

    This was a simple install about 1+ hours to do, It looks great and there is a very noticable HP gain.

    BobD

    Year: 2008 Model: GT Driving Style: Show 'Stangs I have owned: 1 Selinsgrove, PA.

    Helpful (2) (0)

  • 3/5

    Installation Time: Less than 1 Hour

    December 01, 2011

    Great just a few things to watch out for..

    Pros- great power gain and is identical to the BBK pulleys..pretty easy install Cons- the bolt that is provided needs to be shorter or a has to have a spacer... (the bolt as is will run out of threads leave the crank pulley only half pressed on).. by adding a washer it allows the bolt to pull in the pulley more.... Other thing is I have to switch to a smaller serpentine belt because my tensioner was maxed out and was causing the belt to slip...

    DaminB

    Year: 2007 Model: GT Driving Style: Race 'Stangs I have owned: 3 OC

    Helpful (8) (5)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    May 18, 2012

    Power when you want with fuel savings

    The stang definitely feels quicker on it's feet and the lighter pulleys help deliver better gas mileage when you're not gunning it. Best of both worlds. I got this installed at a shop, total labor cost $190 for a 2 hour job but it was worth it because they had to shave off a certain stud because one of the pulleys sits too deep. I think this is a great bang for your buck. With increased gas mileage, the pulley will pay for itself in about 2 years. Not bad.

    Nitin

    Year: 2005 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Fremont, CA

    Helpful (2) (1)

  • 5/5

    Installation Time: Afternoon

    March 08, 2012

    The best!

    I installed these on my 08 Shelby GT CS. It took about 2 hours and the results are amazing! They look great and install perfectly. I was so amazed at the horsepower, torque, and throttle response these achieved. If it wasn't for my racing lower control arms, it would be hard to keep traction on the road! I highly recommend!

    Tdavis

    Year: 2008 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 2 Longview, Texas

    Helpful (2) (1)

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