Under drive pulley kit

[gprgeorge]

Hey guys

I am getting a dinan exhaust later this month. I was also Checking out the under drive pulley kit. Anyone have one on their m3? Something worth considering? Labor cost?

[Tracyis300]

I have the Evo sport PP, and it's a great product. Easy to install if you know what your doing?!
But the difference isn't that much! Unless you get a tune?
But ether way?! You well notice a increase in the lower RPM band... Well for me that is.. Not sure if it's the same for the other products :

[buffstocover]

Looking forward to the responses here as well. Is there a point where you'd want to replace these preventatively or otherwise and would choose an upgrade at that time?

[yangin]

Is an underdrive pulley kit the same as a power pulley kit? If so, I have the MS one installed. Car doesnt feel any different to be honest. Plus it cost a bucketload to fit. I wouldnt recommend....

Car may rev a little more freely, but I think its placebo.

[maloo]

Originally Posted by Dr. George

Hey guys

I am getting a dinan exhaust later this month. I was also Checking out the under drive pulley kit. Anyone have one on their m3? Something worth considering? Labor cost?

I recommend it. You're not going to feel a ton more power but the car just feels like it wants to rev up a lot more freely and you're not fighting as much resistance or engine strain. Most of the improvement is felt above 6000 rpms.

[maloo]

Originally Posted by buffstocover

Looking forward to the responses here as well. Is there a point where you'd want to replace these preventatively or otherwise and would choose an upgrade at that time?

It's not a bad idea to change the 2 belts every 80k-100k miles but the pulley itself you would never change as preventive measure.

[duk]

Not worth to do this mod imo

[bradleyland]

The harmonic damper on the S65 is a separate component, so this post is irrelevant.

Most underdrive pulley kits eliminate the harmonic damper. I don't know if the S65 has one, but I would not ditch it. The harmonic damper is there to counter harmonic vibrations inherent to the engine. Removing it can cause damage to... wait for it... the main bearings. Given the mystery of the S65's main bearing durability, there's no way I'd remove the harmonic damper on this engine. Too much risk; not enough reward.

[maloo]

Originally Posted by bradleyland

Most underdrive pulley kits eliminate the harmonic damper. I don't know if the S65 has one, but I would not ditch it. The harmonic damper is there to counter harmonic vibrations inherent to the engine. Removing it can cause damage to... wait for it... the main bearings. Given the mystery of the S65's main bearing durability, there's no way I'd remove the harmonic damper on this engine. Too much risk; not enough reward.

That's just flat out wrong and erroneous advice on the S65 engine. We can argue about whether the gains are worth it but there is zero risk. Do a simple search...there are dozens and dozens (maybe even 100s?) of forum guys not running the factory pulley.

From the Dinan website:

Dinan’s underdrive pulley is designed to increase power by reducing parasitic drag on the engine from spinning the alternator, water pump and AC compressor. This is accomplished by slowing down the speed of these accessory drives that rob power from your engine. Dinan® has done extensive hot weather testing so you can be assured that your engine is safe. The Dinan underdrive pulley is made of aircraft quality 6061 alloy, is anodized black and does not modify your harmonic damper as some underdrive pulley kits do which can be harmful to your engine.

This product is backed by our industry leading 4 year/50,000 mile warranty so you can rest assured that you are purchasing the best quality product for your BMW.

[X5-User]

Originally Posted by maloo

That's just flat out wrong and erroneous advice on the S65 engine. We can argue about whether the gains are worth it but there is zero risk. Do a simple search...there are dozens and dozens (maybe even 100s?) of forum guys not running the factory pulley.

From the Dinan website:

Dinan’s underdrive pulley is designed to increase power by reducing parasitic drag on the engine from spinning the alternator, water pump and AC compressor. This is accomplished by slowing down the speed of these accessory drives that rob power from your engine. Dinan® has done extensive hot weather testing so you can be assured that your engine is safe. The Dinan underdrive pulley is made of aircraft quality 6061 alloy, is anodized black and does not modify your harmonic damper as some underdrive pulley kits do which can be harmful to your engine.

This product is backed by our industry leading 4 year/50,000 mile warranty so you can rest assured that you are purchasing the best quality product for your BMW.

Dinan is not a good source to make a decision based on. While ago they were not recommending to install underdrive pulley...search the forum for that thread.

[maloo]

Originally Posted by Bimmer-M3

Dinan is not a good source to make a decision based on. While ago they were not recommending to install underdrive pulley...search the forum for that thread.

I've run it for almost 20k miles with zero problems.


http://www.m3post.com/forums/showthread.php?t=705136


From the Macht Schnell website:

Macht Schnell Performance Underdrive Pulleys have no negative effect on accessory operation and come fully equipped with new belts.

Performance Underdrive Pulleys Features:
- DualDrive design allows maximum performance, with minor affect on accessory speed
- Proper cooling temperatures are retained at proper levels on or off the track
- Maintains proper alternator speed, allowing sustained levels to sensitive control modules
- Machined from 6061-T6 aerospace aluminum
- T3 Hard-Anodized for maximum strength and corrosion/wear resistance
- No affects to crankshaft dampening or harmonics
- Simple bolt-on installation

[maloo]

From the Turner Motorsport site:

"As the S65 M3 V8 engine doesn't use a traditional harmonic balancer, all factory harmonics and dampening are fully and properly retained."


http://www.turnermotorsport.com/p-18...e92e93-m3.aspx

[bradleyland]

Originally Posted by fhaze3

Anything after the bolded comments is complete bullshit. Why waste the time to post and attempt to erroneously influence an untold number of naive members? It is irresponsible and borders on, wait for it..it IS fear mongering. Congrats to you. Perfectly played.

It's rod bearings, NOT main bearings.

Simmer down, chief. I'm first at bat to calm the over-hyping bearing-fearing minions. I offered a clearly qualified opinion coupled with what is an open question in the community.

If the S65 has no harmonic balance, then it's a moot point. Go grab yourself an under-drive pulley and have at it.

[bradleyland]

Originally Posted by fhaze3

It's rod bearings, NOT main bearings.

Leaving aside the question of whether or not the concerns are valid, those who believe there is a problem do not believe it is limited only to rod bearings. Rod bearings usually fail first, but the mains are affected. The infamous Gintani video makes this clear.

www.youtube.com/watch?v=O90RArIFRyk&t=03m45s

I really don't want to get in to another pissing match over this. Especially not in the direction of supporting claims that it's an issue (because I too believe it to be over-hyped). The only people with enough data to say whether it's a "real" issue are BMW. I was just trying to share the full picture with a forum member without coloring it with my own feelings on the matter.

[bradleyland]

I edited my first post to make sure that the OP isn't led astray by any concerns about a nonexistent harmonic damper on the S65. Mea culpa.

[bradleyland]

Originally Posted by fhaze3

You are clearly not in a position to give advice, yet you do. STOP PLEASE.

What is your deal?

A) Removing a harmonic damper (if one is present) from an engine does, in fact, have downsides.

B) I posted information that flat out shows you're talking out your ass about the "it's not the mains" comment.

Like I said, I believe it's over-hyped, but you're wrong about what the other side has to say on the matter. It's not a matter of debate. Go watch the video and have a beer.

[bradleyland]

Originally Posted by Bimmer-M3

Dinan is not a good source to make a decision based on. While ago they were not recommending to install underdrive pulley...search the forum for that thread.

Looked in to this because I was curious why Dinan would recommend against it. I found what appears to be the article. Steve was warning against removing the harmonic damper, which isn't an issue with the S65, because, as I discovered with a little more digging, is separate from the crank pulley on the S65. See link below for parts diagram.

http://mfans2.com/parts/catalog/E93/...bration_damper

So the S65 does have a harmonic damper, it's just separate from the crank pulley.

[yangin]

Originally Posted by Dr. George

Hey guys

I am getting a dinan exhaust later this month. I was also Checking out the under drive pulley kit. Anyone have one on their m3? Something worth considering? Labor cost?

Dr george I think people are divided on the benefits. If you have spare $$ go for it otherwise trust me it is pretty pointless...

[FogCityM3]

I think that running an under drive pulley at least in CA weather is very low risk and coolant temps increase may 1-3 degrees when really gunning the engine ( I have the e-perfomance steering wheel and the difference isn't very large). Dinan has the most aggressive pulley but the chief complaint is that the belt they supply (which is really a Napa auto parts belt) is super tight. I had an issue with the belt tensioners after about 40k miles on the Dinan pulley. I took to BMW and they covered under CPO warranty as it was unclear if this problem was caused by the tight belt or the tensioners going bad (leaking) as they said that happens with other BMW models. But BMW did mention they such a hard time getting the belts around (I got replacement Dinan belts). In contrast, at the Dinan dealer, they must have some sort of trick tool because they install those things with 1/2 hour labor max. Anyway, the BMW did emphasize that the tensioners going bad may have been a spurious occurrence. If you're worried about it, would go with Evosport, Rogue, or Turner as the belts aren't super tight. I went ahead and kept the Dinan pulley on as I do like it, it definitely makes the engine run smoother, even at start up and idle. Dinan told me there have been no issues with tensioners and several people I know have also run without issue, FWIW.

[Mvy]

I know others have had success with running new pulleys, but my take is that underpowering accessories to get just a couple extra hp might have unintended consequences to your alt, AC etc. Id look for power gains through other means.

[Patrón]

great mod for the $, pulley, tune and main cat deletes change this car in a very good way.

[pbonsalb]

I did the pulley about 3 years ago. Mine is a Rogue. Bought it used. If you are chasing power there aren't a whole lot of options. Pulley, cat deletes, filter, intake, tune, supercharger. And if going supercharger skip the pulley since superchargers use a special pulley.