what are the advantages of the pully yopu guys talk about?

 

1. the pulley is smaller so it drives the alternator and other accesories slower therefore using less horsepower

 

2.Its much lighter than stock and reducing rotating mass from the crank leaves more horsepower to drive the wheels just like lightening a flywheel.

 

See the tech section on TT.net about the pulley it explains it quite well.Its supposed to make quite a difference to acceleration I here..

See ya

Paul

 

thanks for the tip sounds cool if there are group buys out there im in

 

i heard that this can affect the performance

of the ac ???

 

i think it will affect the performance of all ancillaries that are run from it, if the driving pulley is smaller than the original.

 

As it has multiple drive wheels on it (3 i think [1]), i'm not sure if any are kept the same size or not.

 

DaveW ? can you confirm if all of them are smaller, or just one or two.

 

It means that everything driven by belt from a smaller pulley will run at a lower speed than normal.

 

So, being pessimistic, worst case scenario is :-

less efficient engine cooling;

lower hydraulic pressure for steering;

less efficient aircon.

 

However, i dont know how much smaller the pulley is than standard, and i think most of the performance gain is from the fact that the pulley is lighter than standard, so less force required to drive it.

Refer to Paulg's post earlier to find technical articles on it.

 

[1]

1) water pump and alternator

2) power steering pump

3) aircon compressor

 

I have the Auto Specialities pulley and it must weigh in at about 1/3 of the stock pulley weight.

 

I have not noticed any difference in the cooling efficiency of the engine and the air conditioning still works very well.

 

The performance is very noticeable with the AS pulley and the engine has a very nice growl at the higher rev range.

 

Highly recommended!!

 

Steve

 

i have spoken to a guy at www.mphunlimited.com and he recons it is proven not to upset the aircon and the likes, so i recon i am going to find out about it.

maby a group buy as there is even a fitment article on twinturbo.net.

chat to you later warren

 

I've not noticed any problems with the aircon/power steering/charging system. Apparently the voltage drop has been measured by someone and is only in the region of 0.1v. Not even enough to worry hifi's of Bob/Tooley proportions!

And as Steve said, the performance gain is noticeable- so is the engine growl at about 3.5k rpm :o)

Dave

 

heheh... i did mean to add that plenty of people have done the mod, and no problems have been reported.

 

i was just being objective and mentioning what the worst case problems would be.

 

I just got carried away and forgot the upside :)

 

sorry....

 

just my bloody luck. i had a major service done on mine as it was imported two months ago and i wanted to make sure it was ok and so had the cam belt done as you do and now you guys all tell me this pulley is better than a four hour blow job. i take it its as big a job to put this pulley on as it is to change a cam belt

 

Tooley,

 

The underdrive pulley isn't such a big deal!

 

I think it only takes about 1/2hr - 1hr for someone who know what they are doing.

 

The three belts need to be removed for the power steering, air con and alternator and then the pulley needs swapped over.

 

You will also need some different size belts to fit because the pulley is a smaller diamaeter than stock.

 

Go for it!!

 

the belts come with the kit that i enquired about. so now the big question is who will do the job? and what do they charge in labour?

last one what are the import duties from the usa to the uk?

 

I also have the underdrive pully and I'm very pleased with it!

 

No A/C or power problems.

 

At first you don't notice much difference, then you put your foot down on the moterway and grin as the engine gives you a different note and starts pulling harder!