turbo did underdrive pulley help increase spool up

euromaxima · 07-14-2008, 09:24 PM

For the price of one is it worth the gain, thanks

Brandon

*The Wizard* · 07-15-2008, 02:26 PM

IMO, it's not worth it for the price. I believe any gains with the UDP will go un-noticed and spool will not change enough to even notice.

I have no experience with this, but some have stated that ceramic coating or header wrapping the tubing will allow the turbo spool up a little sooner. Keep in mind though, that header wrap will eat away and kill the piping over time.

**nismology** · 07-15-2008, 02:46 PM

UDP's are pretty much useless in any application.

khantalha · 07-15-2008, 05:21 PM

lets put it this way auto 4th gen with intake and udp < bone stock 5 speed at 1/4 mile

**Nealoc187** · 07-15-2008, 10:05 PM

UDPs are damn near worthless in any capacity, even less than worthless in a boosted application, if there is such a thing. it certainly wouldn't do a thing for spool up - that's not how they work.

96blkonblkse · 07-15-2008, 10:55 PM

Meh when i put my UDP on i noticed the car seemed to rev a little quicker but thats just the but dyno. I dont think it would make any difference in spool time at all. I got mine used for cheap, so i thought what the hell.

**nismology** · 07-15-2008, 10:58 PM

Quote:

Originally Posted by 96blkonblkse

Meh when i put my UDP on i noticed the car seemed to rev a little quicker but thats just the but dyno. I dont think it would make any difference in spool time at all. I got mine used for cheap, so i thought what the hell.

Sure...it revs up quicker in neutral, not while in gear.

khantalha · 07-15-2008, 11:22 PM

Quote:

Originally Posted by 96blkonblkse

Meh when i put my UDP on i noticed the car seemed to rev a little quicker but thats just the but dyno. I dont think it would make any difference in spool time at all. I got mine used for cheap, so i thought what the hell.

i did see it revving up a little faster but again i had crap load of other mods to go with it too but lightened flywheel and udp combo does help u rev quicker... but it doesnt have anything to do with ur turbo spooling

*JonBlz* · 07-15-2008, 11:50 PM

the good thing about it is less stress at the crankshaft but other than that your wasting money that can be use for something way better

khantalha · 07-16-2008, 12:16 AM

^ i agree

96blkonblkse · 07-16-2008, 01:06 AM

Yeah, personally id put the money towards something thats difference is more noticable..lighter flywheel if you were so inclined to reduce rotating mass..a set of light weight wheels would be better spent as fidanza's arent exactly cheap. I noticed a small difference in neutral, nothing while moving, but i noticed a significant difference in first gear with the flywheel and even more in neutral.

Nothing beats a set of light wheels though. Dropping 4lbs per rim made the biggest difference.

**Nealoc187** · 07-16-2008, 10:21 AM

UDPs are undamped (as far as I know, I've never had one) so if anything it could actually be more harmful to your crank. when the rotating assembly is properly balanced, VQ cranks have been used into the 2000hp range (performance motorsports). if you get one unbalanced though, it could easily tear itself apart. without an balancer, you run that risk. i wouldn't run one on my car.

the physics say that, just like a lightweight flywheel, the gains diminish with each successive gear. it'll be most noticeable in neutral, then 1st, then 2nd, by the time you hit 3rd or 4th gear the gains are so small as to be not worth mentioning.

**nismology** · 07-16-2008, 11:26 AM

I'm careful not to lump a lightweight flywheel and an UDP into the same category.

TurboA32 · 07-16-2008, 12:56 PM

ud pulley is just another go fast mod. if you got the money buy it if not dont. i know race cars have them and i dont think they use them for no reason.

**nismology** · 07-16-2008, 01:45 PM

Got some ocean-front property in Montana to show ya too.

streetzlegend · 07-16-2008, 06:56 PM

i got an UDP with in mine, and let me say. Its the only mod i regret doing, all its good for is to dim your lights, make your a/c not work at its best while in idle. its a useless mod. dont do it.

euromaxima · 07-16-2008, 07:17 PM

thanks for the advice, just trying to get the turbo to spool a bit faster, i have heat wraped every pipe, and it seamed to help a bit, I know it will be hard to get it to spool faster since it is kind of a big turbo. thanks

Brandon

*choray911* · 07-16-2008, 10:50 PM

Quote:

Originally Posted by streetzlegend

i got an UDP with in mine, and let me say. Its the only mod i regret doing, all its good for is to dim your lights, make your a/c not work at its best while in idle. its a useless mod. dont do it.

I concur! If you like to drive your car at night and listen to the radio, pass on the UDP. The only time I ever lost a motor, the set screw that holds the timing ring on the back of the UDP, backed out and milled a hole through timing cover. All the oil drained out and the motor locked up. Before ya'll start talking crap, I did use thread lock and the UDP was on for 2 years before it let go.
I ran a 200 dry shot for 20 bottles of hose and she still ran like a champ! Pass on the UDP.

*liqidvenom* · 07-17-2008, 11:56 AM

Quote:

Originally Posted by Nealoc187

UDPs are undamped (as far as I know, I've never had one) so if anything it could actually be more harmful to your crank. when the rotating assembly is properly balanced, VQ cranks have been used into the 2000hp range (performance motorsports). if you get one unbalanced though, it could easily tear itself apart. without an balancer, you run that risk. i wouldn't run one on my car.

the physics say that, just like a lightweight flywheel, the gains diminish with each successive gear. it'll be most noticeable in neutral, then 1st, then 2nd, by the time you hit 3rd or 4th gear the gains are so small as to be not worth mentioning.

this is the most correct post in this whole thread, once out of the shorter gears its effect is lost.

Quote:

Originally Posted by nismology

I'm careful not to lump a lightweight flywheel and an UDP into the same category.

why not? they both do the same thing at just different ends. granted the effects are felt more from the flywheel mod.

**nismology** · 07-17-2008, 12:18 PM

Quote:

Originally Posted by liqidvenom

this is the most correct post in this whole thread, once out of the shorter gears its effect is lost.

Strictly speaking, the effect of a lightweight flywheel (or the crankshaft itself or anything attached to it) is only directly related to the rate of acceleration of the crankshaft, and only indirectly related to gear selection. Depending on the HP levels, the effect could extend into the higher gears as well if the crank accelerates fast enough despite the longer gearing.

Quote:

why not? they both do the same thing at just different ends. granted the effects are felt more from the flywheel mod.

Because one makes a difference in accleration once in gear and the other doesn't (only in neutral). You couldn't actually think I didn't know they operated on the same principle......

*doc2278* · 07-29-2008, 06:18 AM

Quote:

Originally Posted by The Wizard

IMO, it's not worth it for the price. I believe any gains with the UDP will go un-noticed and spool will not change enough to even notice.

I have no experience with this, but some have stated that ceramic coating or header wrapping the tubing will allow the turbo spool up a little sooner. Keep in mind though, that header wrap will eat away and kill the piping over time.

Gotta agree with the wizard on this one. I had a UDP with my trubo set up. The only thing that it did was give a healther feel to the engine. no MPG increase.

Torgus · 07-29-2008, 12:35 PM

OT: fwiw a lw flywheel isn't always the best. especially when launching...

oh and i doubt the lw pully made your spool any faster.