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SR Performance Underdrive Pulleys (05-10 GT)

Market Price $186.99 You Save 12% ($22.04)
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  • Item 41131

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    Features, Video & Details

    • Free Up Horsepower
    • Complete Kit
    • Durable, Lightweight Aluminum
    • Brilliant Polished Finish
    • Premium Quality
    • Fits 2005-2010 GT and Bullitt Mustangs

    Review & Installation Video

    Review & Install 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

    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

    CA Residents: Warning: California's Proposition 65

    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?

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    Questions & Answers (24)

    5 Top Rated Questions

    Low accessories power? How much power will this take away from the accessories? Is it a noticable difference or not?

    • I had the same worries, but after the install I checked the output voltage on the alternator and all around the vehicle before and after the installation and there was no power shortage at all, and for the performance the pony revs way more faster......and it looks cool.....

    Helpful (9) Show 2 more answers

    Will the belt remain the same or does the belt have to be shorter or longer?

    • These pulleys allow you to reuse your factory belt.

    Helpful (1)

    Will this work on my 07 roush 427R supercharged Mustang?

    • These pulleys are compatible with the 2007 Roush 427R and will work with your Mustang.

    Helpful (1)

    can i use this for the Mustang 2006 V6??

    • These pulleys will not work for the 2006 V6 Mustangs.

    Helpful (1)

    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.

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

    Helpful (1)
    Post Your Question
    10 More Questions
    What kind of horsepower gain can you expect with these pulleys 1 answer
    Does this require a tune? 1 answer
    Can this install require a new tune update and will that add any additional gains? Compared to just an install without a retune? 1 answer
    is this considered a non piggyback ? 1 answer
    I've had mine in a box for about 2 yrs now. My concerns relative to mostly what I've read online. I'm 52 yrs young, so aftermarket isn't anything new to me. My situation is, our 09GT 5spd is a daily driver for my wife, thankfully she works 2 miles away from home. However, with the changes, both Pro and Con, these pulleys make I see/read the effects with the alternator, but whats the deal with the A/C? We live in FL. so anyone married knows what life is like without A/C in the wife's car. 1 answer
    Will this work with a 150 shot of nitrous set up? 1 answer
    If my car is tuned, will I have to get it tuned again when I install the pulleys? 1 answer
    I don’t see any top dead center mark how can I find top dead center with these? 1 answer
    What's the diameter of the crank pulley? 1 answer
    How much will power steering be reduced? I understand it will lose a bit but like. How bad. If my steering is gonna be hard at low speeds then i wonder if its worth the extra horses. Let me know any downsides anyone notices. Thanks! 1 answer

    People Who Bought This Item Also Bought

    Customer Reviews (100+) Write a Review

    Overall Rating 4.8

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:0-$100

    • Performance Gain 4.31579 4.3
    • Fit 4.854167 4.9



    • 5/5

      Installation Time: Afternoon

      September 11, 2018

      Physics Is On Your Side!

      These pullies work great. You definitely feel some type of power gains from it. Of course they claim it adds an extra 10 horse power and have dyno charts to prove it. Definitely felt the torque. I recommend SR to maybe add an extra instructions on where to find the certain tools. I went to autozone to rent a 3 prong pulley puller. It was a universal and even that did not fit to help on the mustang. It was a real hassle getting that crankshaft pulley off. Definitely recommend a professional to help out in a situation like that since you are messing with your engine in a situation like that.

      RemiB

      Year: 2009 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Afternoon

      August 14, 2018

      PULLeys

      I felt a little extra pull!! Install was decent. Got installation for $200.

      GabeL

      Year: 2008 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Afternoon

      August 11, 2018

      mustang horse power gains

      the SR underpully kit a long with new idlers really helped let the horses go . the SR underpully kit. along with cold air intake. and.exhaust .and tuned .was the perfect fit . eliminated stalls when A/C cycled at stops . pushing 400hp now thanks

      RobertC

      Year: 2007 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      July 27, 2018

      Great

      A/C is still cool. Great if your looking to pick up some more horsepower and looks good under the hood

      Snowman28

      Year: 2006 Submodel: GT

      Helpful (0)

    • 5/5

      Installation Time: Afternoon

      July 07, 2018

      SR Performance Underdrive Pulleys (05-10 GT)

      Definitely a noticeable gain. Only problem with the install was getting the right pulley puller. Should've listened to my instincts and told the guy at auto zone I do, in-fact, need a Chrysler 3-prong pulley puller to remove a Fords crankshaft balancer.

      AdamM

      Year: 2005 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      June 23, 2018

      GOOD PULLEYS FOR A GREAT PRICE!

      I’ve been on the edge about which pulleys to get and I finally decided on the SR Performance Pulleys. All I can say is that if your planning on getting the BBK UDPs save yourself some cash and get the SR UDPs. Install was pretty fair just make sure to have a 3 jaw crank pulley.

      DylanK

      Year: 2007 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      June 21, 2018

      They do exactly as promised

      Great lil upgrade, no loss of power w/ AC on. Decent price compared to other brands

      MichaelP

      Year: 2008 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      June 11, 2018

      Definite power gain

      Recived pulley quickly. Had shop instal for a few bucks. Seats of the pants dyno can feel a definite increase in power.

      BenjaminA

      Year: 2009 Submodel: GT

      Helpful (2)

    • 5/5

      May 19, 2018

      Worth the price

      Nothing too noticeable, but the difference is still there. You can tell it does something.

      LeviM

      Year: 2005 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      April 29, 2018

      SR UDP

      Product has a great finish.....the pulleys also work great .....in my opinion the only reason not to install udp is a s/c

      Moe

      Year: 2005 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      April 09, 2018

      Worth it

      Minus not being supplied an alternator bolt and having to grind down the stock alternator bolt, this is a pretty good kit, installation instructions are straight forward and with the right tools, install is a breeze. Noticeable gains in the mid power and range.

      Easy

      Year: 2006 Submodel: GT

      Helpful (2)

    • 4/5

      March 08, 2018

      great quality

      Have not installed yet, to cold out, lol but the quality of the pulleys looks great, instuctions are included and arfe very easy to follow

      jasons

      Year: 2006 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      March 05, 2018

      Great Buy

      Fast shipping from AM! Install took me and a buddy about 3-4 hours with every tool needed from instructions. Looks clean in the engine bay and noticed a slight increase in the lower rpms as well as a deeper exhaust note (quite surprised). Most importantly I do not feel that drain the AC takes anymore and car runs a lot smoother.

      EBoss

      Year: 2010 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      March 03, 2018

      Pullllls

      Worth every penny req retune if your mustang been tune gain 35hp 13 trq

      JacoryC

      Year: 2010 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      February 16, 2018

      Big difference

      Looks great. Definitely can tell a difference. Love it! Lil modding had to be done. Looks good with an add on mod. Moroso coolant tank!

      Jd

      Year: 2007 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      January 03, 2018

      Underdrive pulley

      Easy to install and could tell a difference in power

      GarretR

      Year: 2008 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      December 10, 2017

      Add a little more

      Great fit, easy install. I have read bad reviews about not charging the battery proper or a/c now working properly. I have had NO issues with this.

      JeffC

      Year: 2007 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      October 31, 2017

      Definitely a must have or at least

      After my local shop finished installing these pulleys. It definitely looks better than the stock pulleyes and I notice a difference in when I put it in drive. Because when I had the stock ones I had to put my foot on the gas a little bit to make go but now it just wants to go!

      AdamR

      Year: 2007 Submodel: GT

      Helpful (3)

    • 5/5

      October 21, 2017

      Cool beans!!

      Not a bad purchase. Could tell the difference from before.

      JuanC

      Year: 2007 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      October 11, 2017

      SR Pulleys

      Great Price, Great Quality, and I felt some power gains!

      RubenC

      Year: 2010 Submodel: GT

      Helpful (2)

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