under drive pulleys

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by 00chevy53, Oct 31, 2010.

  1. stephan

    stephan Rockstar 4 Years 5000 Posts

    Try looking at the "March" kits. I can't say they make one for the 5.3 but they are real quality sets. They also come with the aluminum water pump pulley where a lot of the kits only come with crank & alt pulleys.
  2. chevybulldog6

    chevybulldog6 Rockstar ROTM Winner 100 Posts

    Ijust looked up March pullys and they do not make any pullys for anything newer than a 2003 Chevy, so I am still looking.
  3. stephan

    stephan Rockstar 4 Years 5000 Posts

    I don't get it. I just cruised through my Summit catalog & nobody seems to make them for the 5.3 either. What changed from '03 to '04 & beyond, & why nothing for the 5.3 engines?? They make them for every other engine, (4.3, 5.0, 5.7, & 7.4) why not the 5.3?
  4. 00chevy53

    00chevy53 Rockstar 100 Posts

    take it from me i have a pulley kit on my truck and there is no noticeable difference in power gains.... i am a fan of every little bit helps but the pulley kit has been worth it... i should have bought headers and a y-pipe... basically i have had alot of issues with them so far
  5. stephan

    stephan Rockstar 4 Years 5000 Posts

    25%-35% less parasitic drag from your water pump, alternator, power steering pump, & a.c, plus accelerating aluminum pulleys that are 1/3 the weight of steel, has to be worth something on your engine even though you might not have noticed it.
    It was worth 3/4 - 1 mpg on mine & I can actually feel it accelerates a little easier from 800 up to about 2,000 rpms. Beyond 2k rpms it gets lost in the shuffle. I agree you would have gotten more return with headers & a Y pipe, since the exhaust is the weakest point on Chevy small blocks & is usually the first thing replaced. I would not recommend underdrive pulleys for anyone who has had overheating problems or a zillion watt stereo, or as a first mod, but as a final mod after everything else has been done to improve performance & mpg. Some people can live with them & some can't. What issues have you had with yours other than the low voltage at idle?? Are yours the aluminum pulleys or steel?

    I have noticed 8Volts @ idle on mine but have not experienced any low charging of the battery as I don't spend much time ar idle. Do you do a lot of stop & go driving or get stuck in traffic jams a lot?
    Last edited: Nov 9, 2010
  6. Big75

    Big75 Rockstar 4 Years 500 Posts

  7. Do underdrive pulley's increase MPGs?
  8. stephan

    stephan Rockstar 4 Years 5000 Posts

    Welcome to the GM truck club Arin.
    Yes, according to the laws of physics, they have to improve mpg, but you can do something else to your engine at the same time that takes mpgs' away & you'd never know. That is why you only want to change one thing at a time for testing purposes.
  9. 00chevy53

    00chevy53 Rockstar 100 Posts

    I try to stay away from the city, most of my driving is done on the highway. I just feel that I could have spent the money on something with more power gains. But as far as the volts go im running about the same at an idle.
  10. Thanks Stephan!

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