SLP Underdrive Pulley? Anyone using the 25%er?

[HEMISFEAR]

What do people say about it? Anyone here? Should this be on our "to-do" list for those running NA?

http://i250.photobucket.com/albums/gg272/hemisfeardesignworks/Modifications/SLPBalancerDyno.jpg

Off of HHP's website:

SLP Harmonic Balancer & Underdrive Pulley, 2005-‘08 5.7L & 6.1L SRT-8 Dodge Magnum/Charger/Challenger/300C (incl. Jeep SRT-8 Grand Cherokee)
SKU: 100235

New 25% underdrive balancer from SLP incorporates a number of high quality features you won't find on any other aftermarket unit and makes up to 9 additional rear wheel horsepower and 10 ft-lbs of rear wheel torque over the stock crankshaft pulley. Pulley features are a pair of extra tall belt retention walls that eliminate the belt slippage issues common with other balancers. Other unique design strengths include a 100% steel construction (other brands use aluminum), integral timing marks and built in puller mounting threads. Includes detailed installation instructions.

Applications:
2006-2008 5.7L Dodge Charger R/T
2005-2008 5.7L Dodge Magnum R/T
2005-2008 5.7L Chrysler 300C
2008-2008 6.1L Dodge Challenger
2006-2008 6.1L Dodge Charger SRT-8
2006-2008 6.1L Dodge Magnum SRT-8
2006-2008 6.1L Chrysler 300C SRT-8
2006-2008 6.1L Jeep Grand Cherokee SRT-8

Features:

* Up to 9 Rear Wheel Horsepower Increase
* Up to 10 ft-lbs. Rear Wheel Torque Increase
* Extra-tall belt-retention "walls"-no more thrown belts!
* 100% steel construction
* Lighter than the stock balancer
* Integral timing marks and puller-mounting threads
* Does not cause false knock ****** or erratic power-curve dips

Note: Requires new belt - See Related Products Below For Link To Replacement Belt.

PRICE: $279.95 $249.95

[markus]

hahaha they censored knock r-e-t-a-r-d...how gay!?!?!?

[Red02WS6]

Unless you're doing a H/C swap with a tune, I wouldn't recommend it. No point in having your car drive like shit just for a pulley. If you're dead set on doing it, I recommend getting bigger gears and or a stall converter instead. Huge seat of the pants difference.

[QBNKID]

I have it, and it looks like a work of art compared to the stock one.
As far as performance gains, they are good for at least 2 tenths, as I've tested it at the track and corrected it came out to 2 tenths.
If you're doing this make sure you have the correct tools as indicated on the instructions.
Hope that helps.

[budoboy]

I have it and you barely notice the difference (in both performance and charging). It is a lot nicer than the rusty iron stock piece (at only 15K miles).

[HEMISFEAR]

Unless you're doing a H/C swap with a tune, I wouldn't recommend it. No point in having your car drive like shit just for a pulley. If you're dead set on doing it, I recommend getting bigger gears and or a stall converter instead. Huge seat of the pants difference.

Thanks Red. I have P&P Heads, Intake and a cam as well as a 2800 stall so I'd need to have my tune refined.


I have it, and it looks like a work of art compared to the stock one.
As far as performance gains, they are good for at least 2 tenths, as I've tested it at the track and corrected it came out to 2 tenths.
If you're doing this make sure you have the correct tools as indicated on the instructions.
Hope that helps.

WOW, that's what I'm looking for! Hell, even a tenth would be worth the money imo.


I have it and you barely notice the difference (in both performance and charging). It is a lot nicer than the rusty iron stock piece (at only 15K miles).

So Jeff, you don't know if it actually helped performance then right? You're saying it drives flawlessly though with no negligible side effects?

[GRRRR8]

Powerbond makes these pullies for SLP and I have 1 on the G8. They do work. They weigh less which is good and not buzzing the alternator with hi-rpms is always good.

[HEMISFEAR]

Ok, added to my list.

[paxton]

Well, nonone has really talked about the effects on the electrical system with a smaller diameter pulley, especially the alternator. I remember having pullies on a 5.0 Mustang many,many years ago and I kept going through alternators. Lost about 3 of them before I said fuck it and took the pullies off. Are todays pullies designed better than the ones from the past or are our alternators better built to handle lower charging loads from a smaller pulley? This mod isn't on my list until I see that people don't have any problems with the charging system on the LX cars.

[QBNKID]

Well, nonone has really talked about the effects on the electrical system with a smaller diameter pulley, especially the alternator. I remember having pullies on a 5.0 Mustang many,many years ago and I kept going through alternators. Lost about 3 of them before I said fuck it and took the pullies off. Are todays pullies designed better than the ones from the past or are our alternators better built to handle lower charging loads from a smaller pulley? This mod isn't on my list until I see that people don't have any problems with the charging system on the LX cars.I was skeptical too about that but I read from others with jeep SRT8s running it and no issues so I got it and I've been running it for around 2K miles now and no issues whatsoever, and I run all the time with my headlights and foglights on, radio pumping pretty loud, charging my cell, and everything else you can think of and nothing :thumbsup:. I think it should be the same for the LX's right... I mean I think we have the same set up as alternators go right?

[paxton]

I was skeptical too about that but I read from others with jeep SRT8s running it and no issues so I got it and I've been running it for around 2K miles now and no issues whatsoever, and I run all the time with my headlights and foglights on, radio pumping pretty loud, charging my cell, and everything else you can think of and nothing :thumbsup:. I think it should be the same for the LX's right... I mean I think we have the same set up as alternators go right?

I would guess the Jeeps and the LX cars have the same charging system(alternator), but I don't know for sure.

[GRRRR8]

The older mustangs usually used a very small pulley with a 65 amp alt. Our cars now use a balancer assembly and have 95-130 amp alternators that the ecm controls the voltage, so you dont have those issues any longer.

[paxton]

The older mustangs usually used a very small pulley with a 65 amp alt. Our cars now use a balancer assembly and have 95-130 amp alternators that the ecm controls the voltage, so you dont have those issues any longer.

That's the kind of info I was looking for...Thanks!

[GRRRR8]

Anytime. Just incase I didnt tell you guys I am Master Certified and have over 25 years experience. So if you have a question just PM or post.

[Red02WS6]

I forgot to mention that the smaller pulleys cause engine surging and even with a dead on tune it'll still surge but just not as bad without a proper tune :thumbsup:

[HEMISFEAR]

I forgot to mention that the smaller pulleys cause engine surging and even with a dead on tune it'll still surge but just not as bad without a proper tune :thumbsup:

I hate surging but I guess there's no way around it then correct? I'm pretty sure I can get the tune nailed down perfectly.

[Red02WS6]

I hate surging but I guess there's no way around it then correct? I'm pretty sure I can get the tune nailed down perfectly.

Yes Sir, you are correct.

[budoboy]

So Jeff, you don't know if it actually helped performance then right? You're saying it drives flawlessly though with no negligible side effects?

I got it at the same time my cam/heads went in so I can't say what it did or didn't do. I know the charging seems fine. If I had a bunch of auxilliary stuff (halos, aftermarket audio visual stuff, etc) I might think twice about it though.

I do get some surging around 1500-2000 rpm at a medium load. Barely noticeable. First I've heard that this might be a byproduct of an underdrive pulley. My tuner thought it might be due to the torque converter locking and unlocking.

Why would an underdrive pulley cause surging at 1500-2000 rpms?

[paxton]

I got it at the same time my cam/heads went in so I can't say what it did or didn't do. I know the charging seems fine. If I had a bunch of auxilliary stuff (halos, aftermarket audio visual stuff, etc) I might think twice about it though.

So do you have any surging issues with the pulley?

[GRRRR8]

I have installed 100s of pulley systems on all makes and NEVER seen a surge. If you did this at the same time as the cam your cam is making it surge. Spinning accessories at a slower rate can not effect idle/vacuum in any way.