[Hunter399]

I spoke to Joel over at Bavarian Hyper Sports todays about pulleys for the e90


He said if I could get a list of 10 people to sign up and pay upfront, he could custom fabricate under drive pulleys for our e90 for only $150!


This is one of the most well known shops in North America

They are known for turning out M3s with 600+ hp to the wheels....

The wait should be about 2 months after the last is full

1.Hunter399
2.Aw330i

[BMW_E90]

show me a dyno ill be on it ...

[Ryan@Motorwerks]

Cool, I've heard nothing but great things about this shop, and I also know Joel(Head of shop) is knowledgable and honest, and he never does things just to make a quick buck. I would highly recommend these to anyone who wants some easy hp.

[aapriadi]

1.Hunter399
2.Aw330i
3.aapriadi

[IDENTITY_MOTORSPORTS]

ME.

[Ryan@Motorwerks]

1. Hunter399
2. AW330i
3. aapriadi
4. Identity Motorsports

[uhaulball]

1. Hunter399
2. AW330i
3. aapriadi
4. Identity Motorsports
5. uhaulball

im in if the dyno gains are consistent (evot*ch)

[BMW_E90]

1. Hunter399
2. AW330i
3. aapriadi
4. Identity Motorsports
5. uhaulball
6. bmw_e90 (only after dyno and gains are good)

[18LLC]

what's the gainning hp number that we looking for?

[lux.sh]

Pullies? or Pulley? how many are we talking for exactly which ones?

[ksfrogman]

Add me in as a maybe; I'd like to research this a bit.

[Pretender]

How can the "pullies" (below) give extra hp in e90?

[ChineseGuy]

1. Hunter399
2. AW330i
3. aapriadi
4. Identity Motorsports
5. uhaulball
6. bmw_e90 (only after dyno and gains are good)
7. ChineseGuy (only after dyno and gains are good)

[bavarian19]

Originally Posted by Pretender

How can the "pullies" (below) give extra hp in e90?

In any car, making your pullies lighter will allow the engine to rotate faster. Its a similar concept to lightweight wheels.

I dont know if pullies have historically given any decent gains, but I might be interested depending on the possible gains...

[lux.sh]

Yep. underdrive pullies usually gives you decent amount of hp/tq improvement when done right. Basically you are replacing stock pullies with aftermarket pullies that are usually lighter and smaller in diameter. It reduces parasitic drag. Depending on which pullies you get, alternator ones are known to cause malfunctioning alternator down the road. You might also run into problems if you have a huge sound system because of less accessary voltage caused by the underdrive pullies. Sometimes there are aftermarket pullies in same diameter but in lightweight that gives you good compromise between performance and safety.

Usually, when pullies are made correctly and installed right, it doesn't cause much problem at all. Yet gives you decent power increase with relatively small money.

[RichP]

Pulleys are going to do very little, if anything, on an E90.

There are two ways to change pulleys; either change the crank pulley, or all the accessory pulleys. The crank pulley is heavy, and for a reason: its the harmonic balancer to the engine. Its what keeps our I6 so smooth, and keeps the crankshaft from vibrating itself apart over time.

The other way, changing the accessory pulleys, is the preferred way. HOWEVER, in the E46 and E36, the pulleys that are changed are the waterpump and powersteering; no reason to do AC, and its bad to underdrive the alternator, as our cars need every bit of power they can get (and beside, that pulley is VERY hard to change out)

We have an electric waterpump, so in the E90, the only pulley we can change is the powersteering. So, if you underdrove that pulley, we are talking 1 or 2 hp at most. The aftermarket one will be heavier, our pulleys are made of thermoset (bakelite-like) plastic, and dont get much lighter than that.

[Hunter399]

Awesome guys

Since this is a custom job a dyno can not be done before...

[Hunter399]

This is from Joel over at BHS

Hunter,

To do this I will need at least 10~15 guys that are willing to pay in full
($150.00 each kit. These will sell for $200.00 after the initial run)... up
front. Then they will have to wait about 2~3 months to get them developed. I
cannot say for sure what the power gains will be because we have not built
them yet. I can tell you that they usually give about 4~6 wheel horse power.
However, I cannot guarantee that they will make this much. They will be
built like our other pulley sets and be constructed from T6061 aluminum and
hard anodized black. Kit will include water pump pulley, power steering
pulley and a longer serpentine drive belt.

[ksfrogman]

It might be helpful if someone wants to visit e46fanatics.com and do some research on the past experiences of e46 owners with the underdrive pulley mod.

[///Matt]

He's full of it now! He just said the kit has a waterpump pulley! N52 (our engine) doesn't have a belt driven waterpump!

[Hunter399]

Ya
I forgot to post about that

He looked at my engine and said that bmw put an electronic water pump in our engines so pullies are a waste of time for us and he will not be making them