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so i know our engines are never going to be power monsters, but i wanted just a lil extra out of it. i started lookin at crank pulleys, and decided to go with the kartboy because it wasnt feather light like most of the pulleys out there. it weighs in at 2.5lb, which drops approx 2lb from the stock pulley. installation was straight forward, and it was definately worht the $90. car seems to rev quicker throughout the rpm range, and shifts are improved cause the rpm's stay up easier in between gears. no bottom end power loss felt, and overall it makes the car easier to drive all around. if your lookin for something small, cheap, and easy for your n/a, check out the kartboy crank pulley, definately worth it ;D
 

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Why was the weight between pulleys a concern for you? I mean why you went with not the lightest one.
 

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1 lb is about the lightest out there. best bang for the buck i could find was the gimmick motorsports pulley @ 1.2 lbs and $95. it is black and so stealth. you can definitely feel the difference it makes. beware though... it is not advised to go with both a lightened crank pulley and a lightweight flywheel @ the same time as it will throw off the crank position sensor / CEL.
 

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Why was the weight between pulleys a concern for you? I mean why you went with not the lightest one.
It's good to kill some of the rotating mass, but getting rid of too much weight is bad too because something has to keep the inertia going...

Just like a lightened flywheel will let it rev faster it will also decelerate faster, due to the fact that there isn't much to keep it going...

A common problem with pulleys and flywheels that are too light, is that the car will actually stall if the RPMs drop too fast or hard...
 

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Discussion Starter #5
Why was the weight between pulleys a concern for you? I mean why you went with not the lightest one.
It's good to kill some of the rotating mass, but getting rid of too much weight is bad too because something has to keep the inertia going...

Just like a lightened flywheel will let it rev faster it will also decelerate faster, due to the fact that there isn't much to keep it going...

A common problem with pulleys and flywheels that are too light, is that the car will actually stall if the RPMs drop too fast or hard...
+1, i wanted to get some weight off, but not too much. i didnt want problems at low speeds with revs and everything. if your going to maximum top end power, go ahead and get the 1lb pulley. i drive my car every day, and i drive it everywhere so i wanted something that would interfere with day to day driving. like i said, i am happy with the purchase overall and am glad i got the one i did
 

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I've heard of some 240sx's stalling suddenly from a lightened crank and flywheel combo....

The guy's girlfriend was driving the car, it stalled when she pushed in the clutch, lost power steering, and she hit a huge wood beam being used as a parking indicator

The front mount intercooler and some uber rare JDM s13 front bumper was completely trashed.

I had a perrin lightweight and fidanza 9lbs flywheel on my 2.5 NA GC8 and I never had a stalling problem, I DID occasionally have the "misfire" CEL caused by the crank position sensor though.
 

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I think alot of problem are caused by lightened crank that also under drive everything to gain a few extra HP.
 

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i luv mine, what up kartboy!!!!!
 

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I wonder if Kartboy Crank Pulley would make any issues for my Automatic 08 as far as low end RPM?
Any one here drives an Auto that did this ?
 

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I wonder if Kartboy Crank Pulley would make any issues for my Automatic 08 as far as low end RPM?
Any one here drives an Auto that did this ?
Well, i've just ordered a Touge Tuning pulley, i'll let you know how it works out...
 

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I wonder if Kartboy Crank Pulley would make any issues for my Automatic 08 as far as low end RPM?
Any one here drives an Auto that did this ?

i have an auto well i havent driven my car with the kartboy one

i did drive it with the cosmo racing one i didnt notice anything at all

i did seem to have a minor lower end power

and as far as a new belt...i had to get a smaller belt with the cosmo one but with katboy one i wa able to use the stock belt
 

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Hi NH8991. How does it work on your auto ?
I wonder if Kartboy Crank Pulley would make any issues for my Automatic 08 as far as low end RPM?
Any one here drives an Auto that did this ?
Well, i've just ordered a Touge Tuning pulley, i'll let you know how it works out...
 

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Sorry, I haven't fitted it yet, i'm a slacker i know :D Just been too busy with work, renovations around the house etc.

I hope to get it fitted in the next few weeks.....he says....
 
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