Mercedes-Benz Forum banner

More on the big pulley from ASP

1084 Views 9 Replies 5 Participants Last post by  Buellwinkle
I think that I have read about every post in this forum regarding big pulleys. I appreciate all of the information that Buellwinkle and Linh have shared. I still have a couple of questions; the #1 question being: How was the size of ASP's pulley decided upon?

I believe that I read somewhere that the ASP pulley is 15% overdrive. If I'm correct on this figure, why not 12%, 18%, or even 20% over? Were there any trials done with other sizes?

Any engine studies done that showed a size to be too big?

Any boost pressure data, before and after the pulley? (I saw that Deathy posted that the new pulley should give a 4 pound increase in boost, but that's the only reference to pressure I've found.)

I almost stopped by ASP Racing today to see if someone in-house could answer these questions, but then decided it may be best to post here first and see what response I get.
1 - 2 of 10 Posts
You can't beat the ends on the stock intercooler, very smooth and well designed. For best dyno results it's always best to remove the IC altogether and use a straight pipe as the pressure loss from the IC will always show up as less HP on a cold car. Not that that's the best solution but tuners can make anything look good on the surface, the testing we did showed that it wasn't for me but that doesn't mean that under the right circumstance it may work for someone else, specially if you autocross at low speeds in the desert. We also tried IC misters and they work OK and helped by about 5 HP under extreme conditions, nothing that you would notice in spirited driving.

As for the ASP pulley, I believe that Lee only makes one size for your car, the 2001. Don't know the percentage but it's close enough to the largest you can make it because the belt can rub slightly on the waterpump pulley. There is a way to make the pulley larger by either redesigning the waterpump pulley or make the idler pulley larger as to push the belt away a little from the waterpump pulley. You can't go to big with the idler as it sits about 1/2" from the tensioner pulley below it. I know one car that did this and we ran many dynos side by side and even though he had 1/2 PSI more boost, the HP/Torque numbers were very close, once in a while I was slightly higher, once in a while he was slightly higher. I don't beleive that pulley was ever sold in the U.S., it was a Mexican tuner's product. The boost increase with the ASP pulley for the 2001+ is 4 PSI as you go from 6 1/2 to 10 1/2 PSI. Dyno is on my website.
See less See more
The easiest way to test the results of changing the end tanks would be to see what the max boost is in comparison to the old tanks. Afterall, the reason for changing the tanks was to increase flow and thereby reduce the pressure loss of the IC. For example, when I went from the stock IC to the Renntech IC (using the ASP pulley) I lost about .7 PSI so that accounted for the 12HP drop when cold, about a 5HP drop when hot. All it takes is a $15 boost gauge.
1 - 2 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.