Easy and cheap way to retrieve 11hp

[Susie520]

I stumbled onto this on Turner Motor Sport's website. Here's the product description for the Underdrive Power Pullies:

Power Pulley Upgrade Kits
Part #: EVO-PP1
Applications: 1992 - 2004 E36, E39, E46, Z4 (325, 328, E36 M3, 323, 330, Z4)

As used on our racecars and steet cars, these are engineered not only to be the best pulley kits on the market but also to provide the best compromise between performance and reliability. Specifically, we have designed them to underdrive the water pump, power steering pump and alternator*. Adding these is like getting FREE HORSEPOWER - there are no downsides and underdriving each of these accessories has been proven safe through years of on and off-track use. We do not believe it is safe to change the crankshaft pulley due to the potential harm to the crankshaft. These kits provide 10%-20% overall reduction in driving your car's systems and have been dyno tested with a gain of up to 11hp.

Kit includes water pump, power steering, alternator pulleys and belt. The T-6061 hard anodized aluminum pulleys account for a 10 to 20-percent decrease in accessory speeds, reducing the load on the engine. Installation involves removing the fan for easy access to the front of the engine. The main drive belt comes off easy and each pulley is mounted with Allen head bolts. Typical installation time is 3 hours. New main drive belt included. The pulleys were good for 10.7 wheel hp at 6960 rpm and 8.1 lb-ft of torque at 5550 on the 1995 M3.

*Alternator pulleys - we offer two kits, one for the performance minded individual and one for the serious audiophile. If you have a significant additional load on the alternator, from aftermarket audio amplifiers, you will not want to underdrive the alternator. Thus, we simply lighten that pulley rather then underdrive it. For E36 kits we now ship both BOSCH and VALEO alternator pullies! We include a postage paid box to send the one back that you don't need. You will get a $70 refund once we get it back.


Price: $399.95
Sale Price: $299.95
Savings: $100.00


What are your opinions? I feel as though it sounds like an easy mod, and cheap to add back 11 hp! It also doesn't sound as though it will have many repercussions on other parts of the engine, thus affecting the warranty. Sounds safe, but has anybody tried this yet? I think I will ... if I do I will certainly update this thread!

 

[Tom]

Replacing the pulleys are an affordable upgrade on most cars and will give you a pretty good return on your investment.

The only two drawbacks is that it will affect your alternator and in some instances reduce your car's cooling ability. However lots of people perform this mod and many are happy with their results.

 

[epj3]

Another problem is it could potentially wreak havoc on devices like your power steering that require a certain amount of pressure. I know you do not have to replace ALL pulleys... but just a thought.

 

[Section_8]

Most safe/good pulley kits only replace 2 of the 5, water pump and power steering if I recall correctly. Anything else can cause problems.

Heres a link from Rouge Engineering describing their kit and the 5 pulleys.
http://www.rogueengineering.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RE&Category_Code=PP


I dunno about the 11hp gain, I've seen reports of anywhere from 3-7, but it could be possible. I'd throw in a CAI or Shark your car before I went for pulleys (or both) but it's another few hp and a good mod if you're doing alot of modifying.

 

[Susie520]

Will CAI or Shark void my warranty?

 

[Blue]

frying your engine after dropping in a tiny water pump pulley to gain 3 hp sure as hell will void that warranty

 

[Blue]

P.S. the physical concept behind "performance upgrades" like this may be scientifically sound, but someone in your shoes (brand new 330) shouldn't be shopping for this stuff. If you have a dedicated track car and you're pulling out all the stops to gain an edge, then you start tinkering with stuff like this. Don't you think BMW designed your model year 2004 pulleys to be the way they are for a reason? There's also a reason stuff like this is advertised on the internet to everyone: Sale Price: $299.95

 

[Bmw 325i 7803]

I wouldn't screw with my car for 11hp.......Sounds like something a riced out highschool civic driver would do, not a new e46 owner.

 

[Akakubi]

I'd recommend to take the car at least once to a good driving school, especially if you start feeling the car is getting slow and not fun anymore.

Not only the experience will make you a much better and safer driver, but you'll gain so much more respect for the car as well. You'd be very surprised how many other more powerful and expensive machines you can put to shame with it. [driving2]

Then, if the bug bites you, you can decide what you might need/want to upgrade.

 

[M3 motorwerks]

There's some good and some bad advice in this thread. The good advice is to track your car. Spending money to learn your vehicle's limits and get a feel for what the car will and won't do is a wonderful experience. And, you'll be shocked just how incredible a machine you have!

That said, underdrive pulleys (aka power pulleys), if done properly, are a totally safe, simple mod with no long-term repercussions or issues. Underdriving the water pump and power steering poses no problems whatsoever. However, underdriving the alternator or crank pulleys can be dangerous and damaging.

Here's the most recent issue of the M3 motorwerks e-Magazine that deals with just this issue. It's a long read, but it's very informative. I'll let you draw your own conclusions. (If you'd like to sign up, just head to www.m3motorwerks.com/products/newsletter.php)

 

[Akakubi]

Great article! Thanks for sharing!

 

[Section_8]

lol M3, YOUR article was the one I was recalling, showing the 5 pulleys in color.. I was searching all my favs going 'which darn site did I see that great explanation!!'.

I'd always suggest a driving class before getting into modding. Know your cars stock limitations before you decide to 'extend' them..

 

[M3 motorwerks]

Shhh, don't tell anybody, but I'm a mind reader!

By the way, there's no reason to go for the Turner kit at $299. We offer the Rogue Engineering Pulleys at $174.95 w/ Free shipping for all E46 non-M3 vehicles. Here's a link:

http://www.m3motorwerks.com/products/description.php?II=145

 

[Blue]

That said, underdrive pulleys (aka power pulleys), if done properly, are a totally safe, simple mod with no long-term repercussions or issues. Underdriving the water pump and power steering poses no problems whatsoever.

That's all well and good, but I'm still left wondering......why didn't they (pulleys) come from the factory that way? No disrespect meant whatsoever, I hope you understand.

 

[M3 motorwerks]

Blue, I understand your concern and hesitation. As I'm sure you know, the design requirements and goals for a BMW are often different than what an enthusiast may want. For example, underdriving the power steering pump will increase steering effort marginally in low speed driving (parking lots, etc.) If BMW used a pulley similar to these underdrive pulleys, they'd probably have the soccer moms who often drive these vehicles moaning about how hard the steering wheel is to turn at low speed.

This is a problem for BMW, because it prevents them from selling as many vehicles as they otherwise would be able to. For an enthusiast, this small trade off in steering effort for increased power may be worth it. In short, the reason BMW didn't design their pulleys like aftermarket underdrive pulleys from the factory is because they have different design considerations and the need to accomodate a much wider buyer group than just enthusiasts.

I hope I've done a good job explaining and clarifying a bit. If there are any other questions/concerns you have, let me know so I can help.

 

[VANCE]

http://www.unorthodoxracing.com/faq_pulleys.html

 

[HornyHornet]

Now that I have come back to this thread, I guess it is a valid mod for your vehicle. But I see that it is also somewhat debated too. From what I have read it seems that only the water pump and power steering pulleys are the only ones that should be switched.

 

[VANCE]

From what I have read it seems that only the water pump and power steering pulleys are the only ones that should be switched.

depends on who you ask. the only time you will run int trouble with the alt pulley is if you have a large aftermarket sound system. as far as the crank pulley goes you cant have it and a light weight flywheel.

 

[HornyHornet]

According to M3's article, changing the alt pulley can cause trouble even with a factory alarm and disrupt idle voltage; not to mention recharging of the battery as well.

 

[VANCE]

do a search at www.bimmerforums.com....this has been debated many times.