Best Dual Pulley Ever Gain 50hp
#26
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Originally posted by Wankelguy
Yes, two belts give an added measure of security in case one breaks, and they make more contact with the water pump pulley. That does not change the fact that it takes more power (albeit slight) to drive them, and since this thread was about belts and horsepower, I figured I'd address that issue specifically. FWIW, I've run a single belt for many years and never had a problem. I use quality belts made by Gates, or Mazda factory belts made by Mitsuboshi and keep them tight.
The biggest mechanical advantage is gained by using a lightweight, smaller diameter main pulley and a single narrow belt, though.
Yes, two belts give an added measure of security in case one breaks, and they make more contact with the water pump pulley. That does not change the fact that it takes more power (albeit slight) to drive them, and since this thread was about belts and horsepower, I figured I'd address that issue specifically. FWIW, I've run a single belt for many years and never had a problem. I use quality belts made by Gates, or Mazda factory belts made by Mitsuboshi and keep them tight.
The biggest mechanical advantage is gained by using a lightweight, smaller diameter main pulley and a single narrow belt, though.
Wankleguy,
In your defense though, we have dynoed a motor with alternator and without. Without alternator, we gained 8hp!!!!!!! The problem without running the alternator, you run the risk of not starting when it is your run and missing the race........I speak from experience.
#28
Originally posted by 1st7heaven
Wankleguy,
In your defense though, we have dynoed a motor with alternator and without. Without alternator, we gained 8hp!!!!!!! The problem without running the alternator, you run the risk of not starting when it is your run and missing the race........I speak from experience.
Wankleguy,
In your defense though, we have dynoed a motor with alternator and without. Without alternator, we gained 8hp!!!!!!! The problem without running the alternator, you run the risk of not starting when it is your run and missing the race........I speak from experience.
#30
Yoohoo belt
If you want to buy dual sheave pulleys for the looks, that's fine, but they are a waste of money if you are simply going for function. Yes, a single belt will slip if you remove the air pump (due to the incredibly small contact area), but you can add something called a "yoohoo" belt between the water pump and main pulleys that provides about 10-times the contact area and costs nothing more than the price of the belt itself (~$5-10). It is a 3L220 -- that translates to 3/8th inch wide, 22.0 inch long standard V-belt, available at many fine autoparts and hardware stores. You just put it over one pulley and start it on the other one, then turn the engine over by hand (or wrench) to "walk" it into the groove. Perfect tension. I use one on my peripheral port 13B GRM Challenge car, which revs to over 11,000 rpm, with absolutely no problems in the 8,000+ miles I have driven it. Thank Rob Golden at Pineapple Racing for cluing me in to the "yoohoo" belt.
BTW, the real problem with dual sheave pullies is the impossibility to equalize tension between the belts due to slight flexing of the alt shaft, as well as the accessory mount. To keep the outside belt from slipping, you have to overtighten the inside belt, leading to wear and tear. Not a big deal, but why spend the money for an inferior solution (unless you like the look)?
--
Blake Qualley
BTW, the real problem with dual sheave pullies is the impossibility to equalize tension between the belts due to slight flexing of the alt shaft, as well as the accessory mount. To keep the outside belt from slipping, you have to overtighten the inside belt, leading to wear and tear. Not a big deal, but why spend the money for an inferior solution (unless you like the look)?
--
Blake Qualley
#31
Great idea! I had heard the term "yoohoo" belt, but was not clear on it until seeing your pic, thank you. Rob has helped me out with information many times over the years, also. I hadn't considered the possibility of uneven belt tension, but that's a good point. I suppose I should also point out that the extra length imparted by the dual belt pulley could cause more alternator shaft runout, placing more stress on the bearing.
But yeah, they do look cool.
But yeah, they do look cool.