Pulley kits

[sumdeus]

I was curious if anyone had any pulley kits on their 8? I have read of some significant power gains (Granted they come from the manufacturer), but are those number realistic? 10hp+ from a pulley kit?

[Phoenix7]

I never understood how a pulley can give you HP. I can see how it would free up some of the parasitic power loss but I don't see how you'd GAIN power.

Also, are these underdrive pulleys? Don't underdrive pulleys do JUST that? Underdrive some components so the parasitic loss is minimized. Is the water pump one of those items? , what pulleys are you talking about?

[sumdeus]

Yeah, I guess I should have said that differently, freeing up power instead of increasing power. The kit I am looking at is a set for alternator, waterpump and drive crank.

[Phoenix7]

well, I don't know about the new rotary water pumps but the older pumps can cavitate at high RPMS (but it's because they're spinning too fast?).

If you underdrive it then you MAY not experience this problem but what happens at low RPMS? The pulleys will be spinning the alternator and water pump at a much slower speed, right? How many problems, if any, would this cause?

[Herblenny]

If mainly driven daily and occasional pulls on the Hwy. I would just stick with stock pulleys.

I say this to FD guys all the time... If you are just pudding around, no real reason to get all these under drive belts.. Reason for underdrive belts are so that at high RPM you don't over drive your alternator and your water pump (which at high RPM cavitation occurs). If you drive at low RPM most of the time, benefit is minor and negative effect is also minor as you are not in high load area...

Some say these aluminum under drive pulleys are light and hence you might gain responsiveness of the engine.. which could be true.. But I also noticed better response by just plugging in HKS twin power I guess if you start adding all the minimum HP gains, it will eventually worth something.. But as an FD owner, Its nowhere what you could gain from just turning up the boost a little on an FD..

I just feel that some people are spending WAY too much money to gain 50-60HP on renesis and at the same time reducing the reliability of the engine. Its almost better to buy a used FD as a spare car when some people are dropping 5-8K on a turbo system... or just putting 13B REW with stock twins, you'll make more than some of these turbo kits available for Renesis... My 2 cents.

[rx8man]

Originally Posted by Herblenny

If mainly driven daily and occasional pulls on the Hwy. I would just stick with stock pulleys.

I say this to FD guys all the time... If you are just pudding around, no real reason to get all these under drive belts.. Reason for underdrive belts are so that at high RPM you don't over drive your alternator and your water pump (which at high RPM cavitation occurs). If you drive at low RPM most of the time, benefit is minor and negative effect is also minor as you are not in high load area...

Some say these aluminum under drive pulleys are light and hence you might gain responsiveness of the engine.. which could be true.. But I also noticed better response by just plugging in HKS twin power I guess if you start adding all the minimum HP gains, it will eventually worth something.. But as an FD owner, Its nowhere what you could gain from just turning up the boost a little on an FD..

I just feel that some people are spending WAY too much money to gain 50-60HP on renesis and at the same time reducing the reliability of the engine. Its almost better to buy a used FD as a spare car when some people are dropping 5-8K on a turbo system... or just putting 13B REW with stock twins, you'll make more than some of these turbo kits available for Renesis... My 2 cents.

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I agree..

The Alloy pulleys I have (not under drive) are a lot lighter than the std pulleys, very slight gain responsiveness , but to anyone who is not tracking/ racing there 8, .... Not worth the money spent.
And the under drive pulleys, which were $100 USD more than one pulleys I bought, .... Unless you are pull 7000 rpm and upwards ... all the time.
Totally waste of money.
My 2 cents worth, which in NZ cents... is worth less........lol

[sumdeus]

Sounds good, no pulleys for me. DD with some sprinklings of track time.

[Phoenix7]

what are your current mods?

[sumdeus]

Intake, catback, and springs and shocks. I am trying to figure out what next. With pulleys out, I am thinking the next will be a set of sway bars (RB or Tanabe).

[wite out]

if nobody else ever gets aftermarket accessory pulleys, I guess that will just make mine all the more unique.

no, there's not a big gain to be found at the wheels, but what CAN you do to make big gains on an Rx8? SR Motorsports said their project car gained 12hp from the pulley swap alone, but that's not believeable to me. I don't expect to see a lot of jaws dropping at the dragstrip performance of my car...that's for somebody else. I just enjoy knowing that my newer, shinier alternator pulley weighs ~60grams, compared to the ~160gram stock pulley. I didn't have the opportunity, but if that ratio holds for the other pulleys, then the 2.0lb shipping weight of the new parts is a lot lighter than the approximate 5.3lb combined stockers. That makes me happy enough to live with myself