IPSCO U D pulley worth it

[WA 2 FST]

The title didn't format like I wanted it to... is the U/D pulley worth it?

For those who have installed this unit, what are your impressions after the fact? I'm guessing the net gain, in and of itself, isn't that great, but combined with other bolt-ons maybe it is worth it... ? Any noticeable issues/negative effects on a street-driven car?

TIA

[Fatboy 18]

I only swapped out to one because it added Bling, Not noticed any difference to be honest. Temp still goes up and down etc.
You do need a different length Belt.


Sorry Just realised you are asking about a Gen V, pic above is of my Gen 2.

Cant advise on Gen V sorry.

[Lawineer]

There’s a reason the pullies are the size they are. A lot of engineering went into picking the right size. I assure you they are well aware that oversized pullies waste power and gas.

[Steve M]

There’s a reason the pullies are the size they are. A lot of engineering went into picking the right size. I assure you they are well aware that oversized pullies waste power and gas.

There's also apparently water pump cavitation at high RPMs: https://driveviper.com/forums/thread...l=1#post164821

I didn't mind installing one on my Gen 4 because I knew I could bump up the idle RPM to compensate for any potential charging issues (I run a decent stereo system). I probably wouldn't have done it otherwise.

[ViperTony]

I have the underdrive crank pulley from Doug Shelby as it's supposed to help to prevent the collapse of coolant hose on the track. I honestly don't know if it makes any difference but incredibly easy to install on the Gen5 FWIW.

[Aevus]

There's also apparently water pump cavitation at high RPMs: https://driveviper.com/forums/thread...l=1#post164821

I didn't mind installing one on my Gen 4 because I knew I could bump up the idle RPM to compensate for any potential charging issues (I run a decent stereo system). I probably wouldn't have done it otherwise.

As in, you aren't spinning the alternator as fast, so there is less drag (the faster you spin it, the more drag there is), but at the possible expense of the alternator not charging properly at idle. Same goes for the water pump - you are spinning it slower, so it isn't pumping as much water, therefore creating less drag. This was a win-win for the Gen 4 ACR-X, because not only did the underdrive pulley lower the accessory drag, it also reduced pump cavitation at higher RPMs.

https://driveviper.com/forums/thread...l=1#post164962

[Old School]

50k+ miles on my Gen3 with one, no adverse effects - cooling, battery charging, power steering, air conditioning all good.

[JGK95]

Easiest install ever. If you need help, just holler and I'll get on the phone with you to assist.

Essentially you're going from a six-inch diameter to a five-inch diameter. You can either reuse the same belt or get a smaller belt.

Don't know about power claims though as I haven't dynoed it yet.

[Voice of Reason]

Yes it works great, I had 8k miles on my 13 and 23k miles on my 14 and no performance or cooling issues. I used the factory belt as well, the only issue I had there was the tensioner on my 13 must have been a little weaker because if I let rpm’s drop too low when starting from a stop I’d get a chirp (belt slip) on the 13. I’ve never gotten that chirp on my 14.

[SilveRT8]

Got the UD pulley installed on mine 4 years ago along with 3.91 gears and other bolt-ons. No issues so far.
It's much lighter thasn stock. New Belt is 1'' shorter, but some keep the OE one.

[Steve M]

FWIW, I've seen essentially no increase in my quarter mile trap speeds after installing one, but my data set is pretty limited.

[Old School]

The reason I installed one was the same reason I did on previous cars, everything on the front of the engine is now turning 15% slower. Being a daily driver, maybe it will last longer. That and a guy on ebay had a couple of new ones for $50 each.

[TBSH]

No issues here 1,000 miles later.

underdrive pulleys have been used for years on multiple cars.

[ViperGeorge]

I believe Mark Johnson told me that IPSCO's pulley is the same diameter as the one SRT used on the ACR-X.

[Aevus]

The title didn't format like I wanted it to... is the U/D pulley worth it?

For those who have installed this unit, what are your impressions after the fact? I'm guessing the net gain, in and of itself, isn't that great, but combined with other bolt-ons maybe it is worth it... ? Any noticeable issues/negative effects on a street-driven car?

TIA

slightly more responsive (on my gen3) probably not more than a 4-5 whp gain but per dollar spent it's a no brainer, unless you need your alternator to spin at full normal speed

[Arizona Vipers]

Sure, why not? A few ponies, plus it's exactly half the weight