Underdrive pulleys [ merged 1/6/07]

[larryd]

Worth it or not? I'm thinking of going with the AEM tru-power pulley kit. Anyone used them?

 

[spades_gsx]

is an after market udp reliable in the long run as far as daily drivers go? I was told by a shop that after market udp pulleys without a damper would only work on a balanced crank and strictly for race. an udp without a damper would really affect a daily driver in the long run as per my understanding. will someone with expierience please share any info.

 

[miamieclipse]

I've had it on for a good 8 months now....nothing major to report...

 

[speedy13]

our crankshafts are balanced already so you have nothing to worry about.however it is very important that the pulley be perfectly balanced,hence the not goimg cheap that people are talking about.go with the afx,i've had it for about a year and after the intake its the best mod iv'e done.

 

[oldman]

our crankshafts are balanced already so you have nothing to worry about.however it is very important that the pulley be perfectly balanced,hence the not goimg cheap that people are talking about.go with the afx,i've had it for about a year and after the intake its the best mod iv'e done.

Not true. Do a little search on harmonic balancer, most wil tell you it's not a good idea if you want your motor to last. Buschur makes one with damper built in for $350, I'm sure there are others but it would be in the same price range. In my opion, it's the only safe way to underdrive.

 

[speedy13]

it was my understanding that since our crankshafts are balenced internally there was no need for a rubber dampener in the pulley,not the case with the 4g63 wich doesn't have a balanced cranckshaft so it relies on the harmonic balance to balance the engine.

 

[oldman]

it was my understanding that since our crankshafts are balenced internally there was no need for a rubber dampener in the pulley,not the case with the 4g63 wich doesn't have a balanced cranckshaft so it relies on the harmonic balance to balance the engine.

Didn't know that about the 420a. I will learn more before I comment again in the nt section. Thanks for the clarification.

 

[rampridersrider]

Thanks for the input. I wasn't even in the market for one and probably wont be for a while. I just seen 10 on every page there so I figured I would ask.

 

[9D9 MITSU RS]

AFX is definitely the best bolt-on. The car pulls so much better now.

 

[gsx951]

it was my understanding that since our crankshafts are balenced internally there was no need for a rubber dampener in the pulley,not the case with the 4g63 wich doesn't have a balanced cranckshaft so it relies on the harmonic balance to balance the engine.

The function of the damper has nothing to do with engine balance.
Impulses transfered to the crank when a cylinder fires, and since the rod journal acts as a lever against the main journals of the crank, the crank twists. The crank will wind up and then spring back in an oscillation: it actually will flutter.
The crank damper is designed to cancel this rotational oscillation.

 

[speedy13]

The function of the damper has nothing to do with engine balance.
Impulses transfered to the crank when a cylinder fires, and since the rod journal acts as a lever against the main journals of the crank, the crank twists. The crank will wind up and then spring back in an oscillation: it actually will flutter.
The crank damper is designed to cancel this rotational oscillation.

what I meant by balanced is that the cranckshaft is balanced so it will not ocsilate and the crankshaft itself will not twist becouse of it's form and design.I can't explain it in detail,but I saw it on a hot rod show on speedchanel and they had 2 engines one that had a balanced crank and one without it,and they could'nt do a pulley mod to the engine without the balanced crankshaft beacouse it needed the damper from the pulley. If I'm wrong or anyone can explain this in more detail,please do so as it will be valuable info for all of us.

 

[GSGoinFast]

Didn't know that about the 420a. I will learn more before I comment again in the nt section. Thanks for the clarification.

its alright, the guy above that asked about it was talking about his GSX im assuming, which makes no sense why he was in here to begin with.

 

[Itzallstock]

Is the Bomz pully that is on ebay any good? Does anybody have this????? I am thinking of buying one but not sure if the 60 dollars is worth it. If i have a large sound system will it hinder that at all?
-Thanks
Ben

 

[gsx951]

Is the Bomz pully that is on ebay any good? Does anybody have this????? I am thinking of buying one but not sure if the 60 dollars is worth it. If i have a large sound system will it hinder that at all?
-Thanks
Ben

Underdrive pullies for 4G63 motors are bad voodoo.... Don't do it

 

[speedy13]

yeah your engine won't last long after that mod.4g63 do not have an internally balanced cranckshaft and is balnced by a damper pulley.since the udp does'nt have a dampener in it the pulley will not be able to dampen your engines vibration and something could go wrong.i'm a tell you like i tell all 1st gen nters.since you already got a 4g63,slap on a turbo and run lower boost.

 

[Itzallstock]

Actually i decided that since i have a NT and i have higher compressiont than a turbo engine that i am playing with nitrous for a little while. I have only talked to 1 or 2 people that had minimal problems after doing a turbo swap. IF i did do a turbo swap i would want a stage 2 setup and thats gonna run 5000 in parts.
-Ben
Thanks though, i will NOT put one on!

 

[speedy13]

hey nitrous will get you goin,there's no arguin that

 

[Itzallstock]

If you ever think about doing it PM me, I did TONS of research and found the best/safest kit and such. Its not that scary of a project. I will be able to get up to about 220HP, Barley enough to hang with the turbos.......
-Ben

 

[98FWDSM]

just as the title states, i am going to be replacing my belts and i figured that this would be a inexpensive mod to do and see a little increase in power if i swapped the factory pulley with a lighter one

Thanks

 

[yankees1919]

I have an unorthodox racing pulley...no complaints i like it

 

[98turbo]

ebay pulley......that's what I would do.....pulley is a pulley

 

[Tallen]

ebay pulley......that's what I would do.....pulley is a pulley

Umm, no. Afraid not.
You NEED one with a harmonic dampener...your crank will thank you.

 

[boostineclipse]

ONE of the best is prolly the one Buscher Sells.. pricey.. but its dampened.

 

[Jeff91AWD]

Umm, no. Afraid not.
You NEED one with a harmonic dampener...your crank will thank you.

Agreed

 

[98FWDSM]

is there any other one for like $100 to $150 bucks that is dampened?? what kind of performance increase will i get from the buschur pulley....is it very noticable???

 

[boostineclipse]

IMO, for a dampaned Pulley, not stock, the money can be better spent elsewhere.. I would just go out and buy a brank new stock crank pulley from the dealer. With the discount they can be hard for around $100.