Underdrive pulley question gen 3 & 4

[FLATOUT]

Hey guys I have a question, I know of at least one local gen 4 car that ran an under drive pulley.

My question is, is the gen 4 pulley pulley any different or is it the same one from the gen 3's?

Thanks for your help.

Andy

[345s-bspinnin]

Now that you have received confirmation that the pulleys are interchangeable, here are a few facts/pics of my install.

Size:
-OEM: 5.72"
- UD: 4.61"

Weight:
-OEM: 2.2 lbs
-UD: 1.0 lbs

Belt Replacement: Mopar P4510224

Remember that you don't have to remove the crankbolt to install this pulley. Its just 6 bolts that come with the kit.

Pics:

[Getnlwr]

I asked this question on the "other" forum. I was told straight up they are different pulleys and are not interchangeable. Was this confirmed otherwise? If it was, this will be next on the list.

[FLATOUT]

I asked this question on the "other" forum. I was told straight up they are different pulleys and are not interchangeable. Was this confirmed otherwise? If it was, this will be next on the list.

I spoke with Arrow today and they told me the one from the comp coupes was the same one used the X's. I have one of the comp coupe versions coming but I will go out to the garage and look again to verify. I also spoke to Tom Francis at Viper Race Headquarters and he said the same thing.

[FLATOUT]

I just looked at my 08 and it appears to be the same setup as from the comp coupe. I know of another local gen IV car that ran one and he bought it from Tom Francis from an ACRX. If it doesn't fit I will let you guys know.

[Getnlwr]

Cool! If it is the same as the Gen 3, I'm stoked.

[ACRucrazy]

I asked the same question on the other forum a while back, I recall something about the computer. Always researched and never really found one for the IV. Would be cool if it's an option..

[FLATOUT]

I'll let you guys know if there is any issue but if they ran them on the X's I would think they should work on the street cars with a Mopar ECU.

[SSGNRDZ_28]

Are these pulleys available from Arrow or where can I learn more about them? What are the expected gains and are there any negative side effects?

[FLATOUT]

Same benefits and effects that they had on the gen 3's, roughly 10rwhp, less rotating mass. I should have it in a couple days and I'll see if it bolts up. It's the mopar unit, from the comp coupes.

[ACRucrazy]

Dyno?

[FLATOUT]

Dyno?

I'll make a pull with it when I get the new headers and cat back installed.

[ACRucrazy]

I should move to Texas. All these Viper owners down there and mine sits in the garage for 6 months of the year.

[FLATOUT]

I should move to Texas. All these Viper owners down there and mine sits in the garage for 6 months of the year.

Major reason why I moved back

[slowhatch]

Here are some dyno numbers, before/after on a UD pulley on a gen 3 coupe that i found on the other forum;

My 06 Viper has the following mods: 3.55 gears, k+n cai, and a sct tune. I was debating if it would be worth purchasing and underdrive crank pulley. Research on this forum indicated most people were saying it would offer zero to a few hp at most and was probably not worth the time or effort. With that assumption and a low budget I thought I would try it anyway. Besides it kind of looks pretty. (justification bling-bling).

My results:

Baseline mods:
3.55 gears
SCT tuned (canned) by Todd A&C performance thanks.
k+n cai
441 hp and 468 ft lb's of torque.

Addition of UDP only with above mods: 451 hp and 484 ft lb's torque.

For what its worth I looked at the corrections factor and the atmospheric conditions from the first time I dynoed and found the conditions were very similiar (1.19). Some of you guys will find my numbers low. However, I live at a mile high location and the numbers appear to read lower than what i've seen throughout this forum. Viper's with full exhausts on this dyno have only resulted in the high 450 to 460 range.

[FLATOUT]

Cool so roughly 10rwhp with a little more torque. Thats a good chunk per dollar spent on this mod.

[ACRucrazy]

Are we going to see several 650 rwhp Gen IVs in 2014?

[FLATOUT]

Are we going to see several 650 rwhp Gen IVs in 2014?

Maybe if guys start getting some heads ported.

[Troublemaker]

Maybe if guys start getting some heads ported.

I know the stock heads have great cfm flow numbers and read there isn't a lot to be gained from porting, 20-30hp doesn't seam out of reach, but where does the flow become limited by the cam?

[FLATOUT]

I know the stock heads have great cfm flow numbers and read there isn't a lot to be gained from porting, 20-30hp doesn't seam out of reach, but where does the flow become limited by the cam?

Guys have already seen gains from porting them, not exactly sure how much but I would say 20rwhp off the top of my head. I was just saying if people are wanting to get to 650 it would take that.

There are also some new big primary header designs hitting the market that might help make a difference. I have a new set coming shortly and will see what it makes, along with a 3 1/2 inch catback. 650 maybe out of reach thats ACRUCrazy's number not mine

[The_Greg]

Are there known concerns about future durability of the system with this component? I don't think under-driving an alternator is harmful but how about any pumps that are also belt driven? The oil pump or the water pump?

I have seen where UD pulleys have caused durability issues, but this was mostly on engines that integrated the harmonic balancer into the pulley.

[Black Pearl]

Where did you buy them and what was the cost?

Now that you have received confirmation that the pulleys are interchangeable, here are a few facts/pics of my install.

Size:
-OEM: 5.72"
- UD: 4.61"

Weight:
-OEM: 2.2 lbs
-UD: 1.0 lbs

Belt Replacement: Mopar P4510224

Remember that you don't have to remove the crankbolt to install this pulley. Its just 6 bolts that come with the kit.

Pics:

[ACRucrazy]

There are also some new big primary header designs hitting the market that might help make a difference. I have a new set coming shortly and will see what it makes, along with a 3 1/2 inch catback. 650 maybe out of reach thats ACRUCrazy's number not mine

Guess we will see I too have some big primary headers on order. Let's see how close we can come without porting the heads

[FLATOUT]

Are there known concerns about future durability of the system with this component? I don't think under-driving an alternator is harmful but how about any pumps that are also belt driven? The oil pump or the water pump?

I have seen where UD pulleys have caused durability issues, but this was mostly on engines that integrated the harmonic balancer into the pulley.

Well they were designed for the comp coupes, and then run on the ACRX's so I figured if it was good enough for them it was good enough for mine. That might be flawed logic but I'm not putting 100K miles on my car so that's not really a major concern of mine.

[ACRucrazy]

I'm not putting 100K miles on my car

And why the hell not?!