Underdrive Pulleys, who's got em? Worth the $$??

[Cadeez]

Most sites claim up to 10-11hp gain from a set of underdrive pulleys, is that hp increase legit and actually noticable? At high/low rpm range? And is it worth $200+? I'm trying to squeeze some more power out of my car, this seems like an easy way to get a few extra ponies, simple install at least. I just have a hard time spending over $200 on a couple pulleys, seems ridiculous. The Turner kit actually comes with 3, one for the alternator as well, but it's also $250 plus shipping. Looking for someone who's got a set on their car to fill in the blanks for me, thanks!

Rouge Engineering - $195 +s/h
http://www.rogueengineering.com/mm5/merchant.mvc?

UUC from ECS Tuning - $230 free s/h
http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Pulleys/Performance/ES2777201/

TMS - $250 +s/h
http://www.turnermotorsport.com/showproduct.aspx?ProductID=187020&SEName=turner-motorsport-power-pulley-kit-e46-325i330i

[ryankokesh]

It might be legit technically, but the butt dyno didn't agree. Just my $0.02.


Sent from my iPhone

[Vas]

Rogue are on my list. Plus they are not plastic like the factory ones.

[johnrando]

My experience was that there wasn't much of a difference. Maybe the engine seemed to breathe a little easier at higher speeds at higher revs, but really hard to quantify. Truly worth $200? Meh. Not unhappy I did it though. Plus they are better than plastic.

Sent from mobile

[NoVAphotog]

Most sites claim up to 10-11hp gain from a set of underdrive pulleys, is that hp increase legit and actually noticable? At high/low rpm range? And is it worth $200+? I'm trying to squeeze some more power out of my car, this seems like an easy way to get a few extra ponies, simple install at least. I just have a hard time spending over $200 on a couple pulleys, seems ridiculous. The Turner kit actually comes with 3, one for the alternator as well, but it's also $250 plus shipping. Looking for someone who's got a set on their car to fill in the blanks for me, thanks!

Rouge Engineering - $195 +s/h
http://www.rogueengineering.com/mm5/merchant.mvc?

UUC from ECS Tuning - $230 free s/h
http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Pulleys/Performance/ES2777201/

TMS - $250 +s/h
http://www.turnermotorsport.com/showproduct.aspx?ProductID=187020&SEName=turner-motorsport-power-pulley-kit-e46-325i330i

I had thought about them as well, but decided against it. I noticed a massive difference just refreshing/replacing the worn pulleys/belts on my car with OEM and a aluminum water pump pulley from ECS. I would spend the money on that job instead, the car had noticeably more punch and ran smoother.

[TheFinanceGuy]

I too looked into going this route. My research yielded the same results as the posts above, not much of a difference. So, rather than chance it, I went with new OEM. Stopped my terrible squeak.

[GoGators]

i am running an underdrive set. didn't notice any discernible difference. one additional thought though, when you switch you can no longer run the stock belt. you have to order which ever belt length is required for your set of pulleys.

[3ZHP]

I've got the Turner's and will say it was the best addition I ever made. I've owned my ZHP since 12-23-2006 @ 28,090 miles. The Turner Pulley's were installed on 3/7/2009 @ 64,725 miles. Best mpg before was 29.36069 and after (on the way to the 2013 ZHP reunion) 32.07311. The performance upgrade is significantly noticeable and today @ 137,250+ I have only had one issue with the power steering pump that cured itself and may not be related.

(added) Turner makes 2 sets, one for high end stereo, one for max power. I have max power.

One interesting fact: a few years ago, I took a Dinan ZHP for a test drive from EAG with my Son (27) and Son-in-Law (29). The car had a Dinan CAI, Throttle Body & Stage 3 software. During and after the test drive, it was the general consenses, hands down between the three of us, that mine would have undoubtedly left that thing in the dust, was far more responsive, and had significantly more pull

[slater]

I've got the Turner's and will say it was the best addition I ever made. I've owned my ZHP since 12-23-2006 @ 28,090 miles. The Turner Pulley's were installed on 3/7/2009 @ 64,725 miles. Best mpg before was 29.36069 and after (on the way to the 2013 ZHP reunion) 32,07311. The performance upgrade is significantly noticeable and today @ 137,250+ I have only had one issue with the power steering pump that cured itself and may not be related.

(added) Turner makes 2 sets, one for high end stereo, one for max power. I have max power.

One interesting fact: a few years ago, I took a Dinan ZHP for a test drive from EAG with my Son (27) and Son-in-Law (29). The car had a Dinan CAI, Throttle Body & Stage 3 software. During and after the test drive, it was the general condenses, hands down between the three of us, that mine would have undoubtedly left that thing in the dust, was far more responsive, and had significantly more pull

guy, thanks for the feedback. i had been considering this as i don't like the idea of plastic pulleys, although when i refreshed my cooling system last summer i used an aluminum WP pulley. now i want to get that plastic PS pump pulley out of there! i may go for the TMS kit.

peter

[3ZHP]

guy, thanks for the feedback. i had been considering this as i don't like the idea of plastic pulleys, although when i refreshed my cooling system last summer i used an aluminum WP pulley. now i want to get that plastic PS pump pulley out of there! i may go for the TMS kit.

peter

No problem, Peter. I have every tank of gas logged for well over 100,000 miles. When I was in Ohio, I could get a pretty good calculation of before and after however; now that I'm in the back hills of Southern Middle Tennessee, it's way too much fun, to keep my foot out of it, to calculate mileage. Let me know if you need the data I have.

guy

[Cadeez]

I've got the Turner's and will say it was the best addition I ever made. I've owned my ZHP since 12-23-2006 @ 28,090 miles. The Turner Pulley's were installed on 3/7/2009 @ 64,725 miles. Best mpg before was 29.36069 and after (on the way to the 2013 ZHP reunion) 32.07311. The performance upgrade is significantly noticeable and today @ 137,250+ I have only had one issue with the power steering pump that cured itself and may not be related.

(added) Turner makes 2 sets, one for high end stereo, one for max power. I have max power.

One interesting fact: a few years ago, I took a Dinan ZHP for a test drive from EAG with my Son (27) and Son-in-Law (29). The car had a Dinan CAI, Throttle Body & Stage 3 software. During and after the test drive, it was the general consenses, hands down between the three of us, that mine would have undoubtedly left that thing in the dust, was far more responsive, and had significantly more pull

Great info, I appreciate the feedback. Odd how your experience is drastically different than the others, but if it's working on your car then I guess that's money well spent! So you have the 3 pulley "power" kit which comes with the extra alternator pulley correct? Maybe that's the difference? But 32+ mpg?? That's way more than even the factory spec, which we all know is high to begin with. What are you feeding that thing?!

[3ZHP]

Great info, I appreciate the feedback. Odd how your experience is drastically different than the others, but if it's working on your car then I guess that's money well spent! So you have the 3 pulley "power" kit which comes with the extra alternator pulley correct? Maybe that's the difference? But 32+ mpg?? That's way more than even the factory spec, which we all know is high to begin with. What are you feeding that thing?!

Yes, that is correct, I am using this 3 pulley set. http://www.turnermotorsport.com/BMW-E46/c-129-bmw-underdrive-power-pulleys.aspx As for the food: mainly V-Power and the MAX mpg was just after I installed new NGK plugs but, before I changed out the my Dinan CAI filter.

[slater]

No problem, Peter. I have every tank of gas logged for well over 100,000 miles. When I was in Ohio, I could get a pretty good calculation of before and after however; now that I'm in the back hills of Southern Middle Tennessee, it's way too much fun, to keep my foot out of it, to calculate mileage. Let me know if you need the data I have.

guy

thanks, guy! i'm always interested in MPGs but i am constantly calculating what i'm getting so i have a delta point for my car already. my best tank so far has been 33.x mpg, although that was in the summer.



Great info, I appreciate the feedback. Odd how your experience is drastically different than the others, but if it's working on your car then I guess that's money well spent! So you have the 3 pulley "power" kit which comes with the extra alternator pulley correct? Maybe that's the difference? But 32+ mpg?? That's way more than even the factory spec, which we all know is high to begin with. What are you feeding that thing?!

LOL. i think driving style and roads you are driving play a key part... for example, i live in the sticks, so the majority of my driving is around 50mph, and 75mph when i'm on the highway. i do very little stop 'n go... however i do a lot of trips to 6800rpm. :) i typically average about 30mpg in the summer and 25mpg in the winter.

peter

[Cadeez]

Yes, that is correct, I am using this 3 pulley set. http://www.turnermotorsport.com/BMW-E46/c-129-bmw-underdrive-power-pulleys.aspx As for the food: mainly V-Power and the MAX mpg was just after I installed new NGK plugs but, before I changed out the my Dinan CAI filter.

Rock n Roll, thanks again!

[Hermes]

I have the TMS set. I can't really say if they do anything on the butt dyno since my car has so many other mods, but if you have money burning a hole in your pocket then get them as they actually do give you some power on the real dyno.

[johnrando]

Guy that is awesome. I have the set from Turner as well.

[Cadeez]

I have the TMS set. I can't really say if they do anything on the butt dyno since my car has so many other mods, but if you have money burning a hole in your pocket then get them as they actually do give you some power on the real dyno.

I wouldn't say I have $$ burning holes in anything haha, I'm just looking for a little more oomf on the cheap, better gas mileage wouldn't be bad either. There's not a lot of performance/hp mods to do to these cars without getting serious like cams, full exhaust or superchargers, so I'm trying to squeeze out all the hp I can with the $$ I do have, this seemed like a decent option. General consensus of this thread is no noticeable power increase, which is to be expected I guess. Which puts these pulleys in the same realm as a CAI as far as price and performance goes...parts look great and have proven dyno power, but no noticable power increase.

[johnrando]

That's my whole mod story... bunch of little things that hopefully add up. Pulleys, Intake, Dinan Throttle Body, Exhaust, Tune, eventually Stewart Water Pump (waiting to be installed), etc.

[LivesNearCostco]

My experience is in between. They provided a noticeable, but small difference and the difference is biggest at higher RPMs. The ZHP has the Evosport 3-pulley set (alternator pulley had to be modified to fit Bosch alternator with oval plug) and E36 has UUC 2-pulley set. I dynoed the ZHP before and after. Doing underdrive pulleys plus Shark Injector gave me +9 RWHP (peak WHP, not peak difference). Since the Shark was advertised as delivering +4HP alone, I guess the pulleys offered +5HP.

Later I dynoed with pulleys, intake, Shark, VANOS seal refresh, and lightweight wheels and the total boost was +19 RWHP. The dyno guy had moved his dyno from his shop garage to a truck (portable dyno). He claimed it was the same physical dyno but to me it still makes the before and after results hard to compare. Also my car was a little low on HP when I got it (like 189.5HP when I expected it should have been 195).

So it comes down to whether +5HP is worth $200 to you. If I were doing it all over again, I would do front swaybar, stickier tires, lighter wheels, and some track days or autocross events before getting the pulleys, but I'd still get them.

Edit: Actually I'd get a shorter diff (like 3.46) before getting pulleys. I heard that's a much better bang for the buck and can be found as low as $250 online for a used one. But it will probably your gas mileage worse. And for power/$ I heard (but have not tried) headers are a much better deal than the pulleys. But hard to keep headers on a street-legal E46 in California.

[Cadeez]

That's my whole mod story... bunch of little things that hopefully add up. Pulleys, Intake, Dinan Throttle Body, Exhaust, Tune, eventually Stewart Water Pump (waiting to be installed), etc.

Glad I'm not alone! But I've got quite a ways to go to even get to where you are. How does a different water pump add hp/performance??


My experience is in between. They provided a noticeable, but small difference and the difference is biggest at higher RPMs. The ZHP has the Evosport 3-pulley set (alternator pulley had to be modified to fit Bosch alternator with oval plug) and E36 has UUC 2-pulley set. I dynoed the ZHP before and after. Doing underdrive pulleys plus Shark Injector gave me +9 RWHP (peak WHP, not peak difference). Since the Shark was advertised as delivering +4HP alone, I guess the pulleys offered +5HP.

Later I dynoed with pulleys, intake, Shark, VANOS seal refresh, and lightweight wheels and the total boost was +19 RWHP. The dyno guy had moved his dyno from his shop garage to a truck (portable dyno). He claimed it was the same physical dyno but to me it still makes the before and after results hard to compare. Also my car was a little low on HP when I got it (like 189.5HP when I expected it should have been 195).

So it comes down to whether +5HP is worth $200 to you. If I were doing it all over again, I would do front swaybar, stickier tires, lighter wheels, and some track days or autocross events before getting the pulleys, but I'd still get them.

Edit: Actually I'd get a shorter diff (like 3.46) before getting pulleys. I heard that's a much better bang for the buck and can be found as low as $250 online for a used one. But it will probably your gas mileage worse. And for power/$ I heard (but have not tried) headers are a much better deal than the pulleys. But hard to keep headers on a street-legal E46 in California.

Great info, thanks Costco! I in fact live very close to a Costco myself haha

[3ZHP]

FYI; I installed my Dinan CAI nine months after the Turner Power Pulleys and didn't see the dramatic change I did with the Power Pulleys. The sound and look is great but, little change in the performance.


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[johnrando]

Glad I'm not alone! But I've got quite a ways to go to even get to where you are. How does a different water pump add hp/performance??



Great info, thanks Costco! I in fact live very close to a Costco myself haha

In and of itself, nothing. But, it's like the pulley idea, less strain on the system - lighter, more free flowing. Maybe more similar to the mechanical fan delete which I did too.

[az3579]

I don't like the thought of underdriving the electrical system (alternator). I doubt anyone has done any studies on the long term effects of underdrive pulleys and its effect on the electrical system...

[wsmeyer]

I don't like the thought of underdriving the electrical system (alternator). I doubt anyone has done any studies on the long term effects of underdrive pulleys and its effect on the electrical system...


I wouldn't worry about it. The alternator was designed to put out ample current in any scenario the car might encounter plus a buffer to account for variances and or an alternator getting near the end of it's life. And it's designed to do this at idle.

It's the same with underdriving the water pump. In it's stock configuration our cars could idle all day long in the middle of summer with the air conditioning on and not self destruct. With pulleys maybe it can no longer do that but as long as you're paying attention it shouldn't pose a problem.

[rkneeshaw]

I have the turner set. Don't go installing these thinking huge changes, but I did notice a change. And would I do it again? Yeah, probably would. Car feels "peppier" to me with them on.

[Hornung418]

It's all about the steering feel. I dont care about anything else that you may or may not gain...the thing that was most noticeable on both of my BMWs was the difference in slow speed steering feel.

[az3579]

It's all about the steering feel. I dont care about anything else that you may or may not gain...the thing that was most noticeable on both of my BMWs was the difference in slow speed steering feel.

What exactly do you mean by slower steering feel? The ratio doesn't change, so what is it that feels different? Less power assist?

[Hornung418]

What exactly do you mean by slower steering feel? The ratio doesn't change, so what is it that feels different? Less power assist?
When the revs are low and the steering input is high. The feel is heavier and you get a meaningful response from the road surface.

[Cadeez]

Noob question! I got the TMS pulley kit which I'm going to install tomorrow, I also picked up an idler pulley and the alternator tensioner roller as well. I figured, since I was in there... Question is, since the pulleys are going to want to spin, do you loosen up all the pulley nuts while the belt is still on and tensioned? Or is there a special trick? Also, are they all threaded standard? I looked around for some DIY's but didn't come up with anything good.

[danewilson77]

Just untension it. Do you currently have mechanical or hydraulic tension.

"No flamesuit required"

[Cadeez]

Just untension it. Do you currently have mechanical or hydraulic tension.

"No flamesuit required"

Umm, I have no idea, how can I tell? When you say "untension it", what's "it", the serpentine belt? If I take the tension off, then the pulleys are going to want to spin when I'm trying to take them off, which sounds counterproductive. I guess my question is mainly regarding the water pump pulley, it's the only one that doesn't have a single hub centric bolt

[danewilson77]

The pulleys will spin, but the bolt shouldn't. You're freaking me out dude. Just take that shit apart! :)

"No flamesuit required"

[Cadeez]

Haha alright, I'll shut up, I'll let you know how it goes afterwards!

[danewilson77]

I would do it in this order though I've never just replaced the pulley (except for defection pulley).

Release tension and remove serpentine belt.

Then remove pulley.

You are replacing the tensioners (AC and Serp) correct?

"No flamesuit required"

[wsmeyer]

I loosen the water pump pulley bolts then remove serpentine

[Cadeez]

Dane, I'm installing the TMS power pulley kit (water pump, power steering, alternator), along with the idler pulley and the alternator tensioner pulley, links below

http://www.ecstuning.com/ES2534805/
http://www.ecstuning.com/ES2534799/

[danewilson77]

You should be replacing the serp belt tensioner as well, honestly.

"No flamesuit required"

[Cadeez]

Jeez, all this yelling... Part#? Are we talking about this bad boy?

http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Pulleys/Tensioner/ES21813/

[3ZHP]

If I remember correctly, the alternator pulley was a real PITA. I think I had to remove the alternator and there was a spacer collar that needed to be moved to get it back in place before you could get it back in the correct location for the lower bolt alignment.

Good luck.

[Cadeez]

If I remember correctly, the alternator pulley was a real PITA. I think I had to remove the alternator and there was a spacer collar that needed to be moved to get it back in place before you could get it back in the correct location for the lower bolt alignment.

Good luck.

Haha, awesome, just what I was hoping for..! Thanks for the heads up, I'll keep a few cold ones by my side to "help" with the frustrations of the job.

[LivesNearCostco]

Loosen the power steering pump and water pump pulley bolts before removing the serpentine belt, but do not remove those bolts until the belt is off. For the alternator pulley, I had to remove my alternator to swap it. Except when I visited Evosport to have them grind down their alternator pulley, they had a special home-made tool that let me remove and install the alternator pulley bolt with the alternator still in the car.

[Vas]

You should be replacing the serp belt tensioner as well, honestly.

"No flamesuit required"
How come ? Do they usually go bad ?

[danewilson77]

Yes....its 100k maintenance. If it fails, obvious overheat and trashed head gasket is plausible.

"No flamesuit required"

[Vas]

How common are failures?

[danewilson77]

Not sure. How does one define common? I've heard of it a few times. Mainly the pulleys wear out, but damn, while you're in there....

"No flamesuit required"

[Vas]

Those tensioners are not cheap.

[Vas]

Wonder if this part can just be replaced

http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Pulleys/Tensioner/ES21655/

[ClimRox]

Jeez, all this yelling... Part#? Are we talking about this bad boy?

http://www.ecstuning.com/BMW-E46-330i-M54_3.0L/Engine/Pulleys/Tensioner/ES21813/

From what I understand, the OEM BMW pulley parts are/were made by INA. When I did my belts and tensioners, it was the older style mechanical predecessor of the item linked in your post that was causing all the noise for me.

I bought this one:
http://www.ebay.com/itm/INA-Brand-Mechanical-to-Hydraulic-Belt-Tensioner-Conversion-Kit-BMW-/151524487747?pt=Motors_Car_Truck_Parts_Accessories&hash=item2347903243&vxp=mtr

[Johnmadd]

Serpentine belt failure is not as bad as timing belt failure...

[danewilson77]

I've never heard of timing chain failure on normal e46. Really John?

I went with the INA hydraulic tensioner conversion kit when I did my pulley overhaul.

"No flamesuit required"

[danewilson77]

http://www.zhpmafia.com/forums/showthread.php?t=62

"No flamesuit required"

[Johnmadd]

Just saying if the serp belt rips it doesn't bend valves, that's all. :)

[Vas]

From what I understand, the OEM BMW pulley parts are/were made by INA. When I did my belts and tensioners, it was the older style mechanical predecessor of the item linked in your post that was causing all the noise for me.

I bought this one:
http://www.ebay.com/itm/INA-Brand-Mechanical-to-Hydraulic-Belt-Tensioner-Conversion-Kit-BMW-/151524487747?pt=Motors_Car_Truck_Parts_Accessories&hash=item2347903243&vxp=mtr
So this kit comes with everything pictured ? If it does then I'm going to buy one instead of spending $200 on a bmw part like I did last time.

Picture below of a factory part that I had removed from my car when I did the tensioner assembly.

Says INA and has a bmw logo on it.

http://tapatalk.imageshack.com/v2/15/02/13/1f497e5f1c3cc9a012cfc0f0b86f39e6.jpg

[danewilson77]

Yep. You have hydraulic tensioner.

"No flamesuit required"

[ClimRox]

So this kit comes with everything pictured ? If it does then I'm going to buy one instead of spending $200 on a bmw part like I did last time.

Picture below of a factory part that I had removed from my car when I did the tensioner assembly.

Says INA and has a bmw logo on it.

http://tapatalk.imageshack.com/v2/15/02/13/1f497e5f1c3cc9a012cfc0f0b86f39e6.jpg

Yep, what Dane said. Everything in the picture (only without the BMW logo).

Since you have to remove the idler pulley to get to it...

http://www.ebay.com/itm/BMW-E36-E39-E46-M6-Accessory-Belt-Idler-Pulley-OEM-INA-11-28-1-738-605-New-/350623801862?pt=Motors_Car_Truck_Parts_Accessories&hash=item51a2cea206&vxp=mtr

[danewilson77]

Absolutely.

"No flamesuit required"

[Hornung418]

I wouldn't spend the money on a new Hydraulic Tensioner unless you know it's trashed. The only reason to buy one is if you were convert from a mechanical unit. I've never heard of or seen one of these tensioners fail. The oil is all self contained and the unit is sealed. No need to worry IMO. Consistent belt change intervals are key though to engine longevity.

[Vas]

I think so too. Unless it's broken or leaking fluid the worst that can happen is that there would be less tension. When that happens you might get a belt squeal noise.

[Cadeez]

Loosen the power steering pump and water pump pulley bolts before removing the serpentine belt, but do not remove those bolts until the belt is off. For the alternator pulley, I had to remove my alternator to swap it. Except when I visited Evosport to have them grind down their alternator pulley, they had a special home-made tool that let me remove and install the alternator pulley bolt with the alternator still in the car.

I did the underdrive pulley job over the weekend, it was probably the easiest job I've done...with the exception of the alternator pulley. I couldn't figure out how to get it off? I didn't remove the alternator from the car, because I knew I didn't have the right tools to remove the pulley hardware. I think I need a 24mm socket? I found the below link showing some tools, but I'm not sure how accurate it is. Any tips, or verification of the tools I need and best way to do it? Right now I'm just running the PS & water pump pulleys, I'd really like to get the alternator pulley on asap. Thanks!

http://forum.e46fanatics.com/showthread.php?t=690055

[danewilson77]

What belt are you utilizing?

"No flamesuit required"

[3ZHP]

I did the underdrive pulley job over the weekend, it was probably the easiest job I've done...with the exception of the alternator pulley. I could've figure out how to get it off? I didn't remove the alternator from the car, because I knew I didn't have the right tools to remove the pulley hardware. I think I need a 24mm socket? I found the below link showing some tools, but I'm not sure how accurate it is. Any tips, or verification of the tools I need and best way to do it? Right now I'm just running the PS & water pump pulleys, I'd really like to get the alternator pulley on asap. Thanks!

http://forum.e46fanatics.com/showthread.php?t=690055

I may have used my impact to get the nut off and that would be why I pulled the alternator.

[Hermes]

I may have used my impact to get the nut off and that would be why I pulled the alternator.

This

Take your alternator and the pulley down to a shop and have them change it for you, it will take all of 5 minutes

[Cadeez]

What belt are you utilizing?

"No flamesuit required"


The new Conti one that came with the overdrive kit. It's only slightly bigger than the OEM one, I'm fine running it like this until I get the 3rd pulley on. Trust me, before I did anything I checked the difference in the two in case of this very issue. The tensioner has enough love in it to pull it tight, it's not all flopping around or anything haha

[Cadeez]

This

Take your alternator and the pulley down to a shop and have them change it for you, it will take all of 5 minutes

Haha, genius...! Not sure why I didn't think of that?? That's what I've done for my CAB's in the past as well, I've got an indy about 2 miles from my house

[johnrando]

Impressions so far?

[Cadeez]

Impressions so far?

As far as the new pulleys are concerned? It's pretty hard to tell actually, not to mention I'm obviously still one (alternator) pulley short. I've done so much to my car in the last two weeks that I can't really tell which mods/maint made the differences, but I'm blown away by the results! My car...runs absolutely freaking amazing now!! My hard work really paid off, the difference/feel is simply unreal, night & day for sure, best it's ever ran. I've got way more bottom end torque, better throttle response, smooth acceleration all the way through the revs, better top end, nice little burly grumble from the CAI...basically every possible aspect is better. Recent mods/maint: K&N CAI, TMS underdrive pulleys plus new idler & tensioner pulleys, cleaned ICV, DISA & throttle body, and a can of seafoam into the gas tank. I also added an ECS strut brace and H&R 27mm sway bar. So now not only does it get up and go like crazy, but the handling is way more balanced as well, super flat in the corners. It's like driving a new car, it's fabulous. I also detailed it, which we all know adds at least 10-15 ponies on the open road:roundel

[johnrando]

As far as the new pulleys are concerned? It's pretty hard to tell actually, not to mention I'm obviously still one (alternator) pulley short. I've done so much to my car in the last two weeks that I can't really tell which mods/maint made the differences, but I'm blown away by the results! My car...runs absolutely freaking amazing now!! My hard work really paid off, the difference/feel is simply unreal, night & day for sure, best it's ever ran. I've got way more bottom end torque, better throttle response, smooth acceleration all the way through the revs, better top end, nice little burly grumble from the CAI...basically every possible aspect is better. Recent mods/maint: K&N CAI, TMS underdrive pulleys plus new idler & tensioner pulleys, cleaned ICV, DISA & throttle body, and a can of seafoam into the gas tank. I also added an ECS strut brace and H&R 27mm sway bar. So now not only does it get up and go like crazy, but the handling is way more balanced as well, super flat in the corners. It's like driving a new car, it's fabulous. I also detailed it, which we all know adds at least 10-15 ponies on the open road:roundel

Awesome. And, at LEAST! :)

[Alikessu]

Thanks for the nice write up, i think i will be doing the underdrive pulleys as well.

[JPMo]

Well its been awhile since this thread was updated. Any updates 3 years later?

[BMWCurves]

I have Turner’s underdrive pulleys, including the alternator. I noticed a very mild power bump. Not much. Worth it for me because I got it on sale.


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[Reasoned1]

Aside from the placebo effect, it's tough to detect a lot of these mods, but my theory has been they'll all add up to something significant and help counter the natural deterioration of performance over time, and my experience--like the OP's--has been clearly positive in this respect. That said, there are some mods that scientifically guarantee improved performance (no matter how small)--like under-driven pulleys and lighter wheels--and others that are debatable as to whether they help or hurt--like CAI. I try to do the former and avoid the latter...

[johnrando]

Agree. And, I still stand by my earlier comments. Slight improvement.

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[Newjack]

I loved my Rogue pulleys. I definitely noticed a slight power bump and the car seemed more eager to rev. I would definitely recommend getting them over an intake

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