[bahambart]

Quote: Originally Posted by sam_a156 (original)

There are 10s and 10s of pages in NAM on this topic and no conclusive evidence of the problems related to crank pulleys.

So true - there is no evidence either way.

I was considering one until I drove a car w/ one. The vibration transfer to the interior turned me off completely. Perhaps if I was building a track car but for my taste its a pass for a daily driver.

[sam_a156]

The first real piece of evidence I only saw recently here.

Six failures starts to be statistically significant...assuming that at the same time there were NO failures in cars without crank pulleys (does not say, I was supposed to ask). Also, it does not say how many of these had a raised rev limiter (my understanding is that an oversized crank pulley + raised rev limiter is a bad idea).

Re. vibration transfer - weird, I have not noticed any vibrations (I have a +3% GTT). The only thing I did notice is that if you are engine braking AND switch on the air con you can actually FEEL when the air con starts to load the engine. I also noticed that the air con sounds a bit noisier with the crank pulley. But that's about it as far as the perceivable downsides.

If the crank pulley is not dampened AND it is not very very symmetrical, I presume this could explain the vibrations you felt?

Cheers

[toydestroy]

Cheers for all the replies


Not going to bother with the crank pulley and just going to go for a 15% pulley instead (I'm always revving the nuts off mine and the air con is load enough as it is lol). Probably going to fit it this Sunday or next.

Just pulled out my old die grinder to do a bit of head work in the meantime, sure my neighbors are going to love the sound of a compressor going when the weather is this nice lol. Almost payday so should have funds for a newman cam by the time I'm finished so might get 1320 to dyno it and see how rubbish my engine currently is while I pick one up (any ideas how much for a run?).

Still looking into headers and intercoolers.

[Hyper Active]

Quote: Originally Posted by toydestroy (original)

Cheers for all the replies


Not going to bother with the crank pulley and just going to go for a 15% pulley instead (I'm always revving the nuts off mine and the air con is load enough as it is lol). Probably going to fit it this Sunday or next.

Just pulled out my old die grinder to do a bit of head work in the meantime, sure my neighbors are going to love the sound of a compressor going when the weather is this nice lol. Almost payday so should have funds for a newman cam by the time I'm finished so might get 1320 to dyno it and see how rubbish my engine currently is while I pick one up (any ideas how much for a run?).

Still looking into headers and intercoolers.

£35 for a power run on the rollers .

[Bhozar]

I'm not convinced a small bit of hard rubber partially embedded into the crank pully as a damper is going to be much cop. The OEM crank pully even has holes drilled in it to balance it. At least with a CNC crank pulley you will know that its true and balanced as the CNC machines are so acurate.

[BigShow]

In recent years the weight of the crank shaft in modern engines has been reduced in order to improve fuel consumption and to control torque more accurately, while horse power has been increased. These two factors together increase bending vibration so when you're incresing torque and horse power further still through performance tweaks, the bending vibration also increases. This is why the crankshaft pulley damper was originally invented, to try and stop this bending vibration from travelling to other parts of the car, such as the oil pump for instance, but also to suppress noise in the car body.

I took the following from an article on Engine Technology on Wikipedia to explain better why IMO it's madness to remove the OEM dampened (harmonic) crank pulley:

There has been a trend at times by some "performance enthusiasts" to remove the harmonic balancers on their cars, usually when the balancer is attached to the crank pulley. The argument is that they aren't necessary and their mass reduces the performance of the engine. Others argue that this is not worth it, because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high. Certain cars, however, do not come equipped with an external balancer on the crank pulley, and as such, can have the pulley replaced with a performance oriented product.

While net engine output can be increased without harmonic balancers, in professional race cars harmonic balancers are still commonly equipped, for reasons ranging from safety concerns to regulations. Almost all modern car manufacturers, even "performance" car makers and specialty tuners, include a harmonic balancer on their vehicles, and removal voids vehicle warranty.

[Lucky Dave]

So please tell me what Mods DONT invalidate your warrenty??

Have you seen the so called damper? it does not look anywhere near as large on some on other cars I have seen.

Is a 3mm thick hard rubber rubber ring squeased between two 100mm (approx) heavy metal surfaces.

One way to see if this damper does anything would be to paint its surface with a thin layer of non flexable paint and then if the paint cracks then its flexing and doing something.

[Paul Webster]

Quote: Originally Posted by toydestroy (original)

Cheers for all the replies ;Still looking into headers and intercoolers.

I would wait for a couple of weeks

MINI COOPER :: North American Motoring - Revolution Mini Works New Header for standard catbacks

[Ruskins JCW]

Well after seeing the pics of the RMW prototype manifold...........WOW

The thing just looks powerful, cant wait to see what it makes on the dyno.....