i think i might be confused on this whole pulley upgrade business. you guys are increasing the diameter of the pulley, right? so then you are changing the crank pulley, right? what about getting a smaller supercharger pulley? do you know of anybody that makes them specifically for the coupe. bc the supercharger is an Eaton i believe and i know that on Eatons, you can get smaller charger pullies to increase the boost like people do on an SSEi or GTP. any help clearing this up would be appreciated.

 

without getting too technical you cant decrease the size of the SC pulley and more cause it will put too much of a bend in the belt. Plus I think the pulley is pressed on the SC as well.

 

The S/C pulley seems already as small as can be. No room to play here. If this could be done, it would have been done on SLK, C230K sedan and on the C Coupe long time ago.

 

If you understand the pulleys for the SSEi and GTP then you'll appreciate that ASP Racing carries pulleys for the Pontiac as well as your coupe with the same quality and low price.

Actually a forum member, Benzy230 made a smaller S/C pulley for his car but him and his mechanic never decided to pursue it.The crank pulley is an easy 1 hour DIY job, Search the forum for my install instructions or e-mail me and I'll forward them to you.

 

You have to remove to whole s/c to change it's pulley. Crank pulley is a lot easier. Go with a Kleeman and save 6 pounds

 

Why would you save 6 pounds, over what? If you do the math, the ASP pulley costs 221.1 pounds and the Kleemann costs 567.9 pounds. You save 346.80 pounds with ASP, that's enough for a few nights stay in London. And the ASP pulley is sturdier, it weighs only a 1/2 kilo more.

Did I confuse everyone yet, late night humor, sorry

 

Vadim,

But it been done by Dynospotracing on the Slk 230. They made the S/Culley (not crank pulley) smaller. But you lose the S/C clutch.

 

There's no S/C clutch on the new 230K anyway, but my comment was actually based on the picture of the M111 engine. I'm retracting it hereby, now that I know that there IS some room to decrease its diameter even more. I guess the reason is simplcity of installation of the crankshaft pulley vs. S/C pulley.

 

thanx for the info guys, i really appreciate it. do any of you by chance know what the diameter of the s/c pulley is? also do u know what model Eaton is on the coupe? is it an M45 4th generation? thanx again.

 

Just because you CAN make the pulley smaller doesn't mean you SHOULD. There is a practical limit to the size, which isn't the same as the physical limit...

 

Spykes right, if the s/c pulley is too small the belt goes through a really harsh angle that will put a lot of wear and strain on it.

 

Worse yet is you reduce the surface area of the pulley available to transmit power- the faster you spin it the more HP required to turn it. At some point you cross the line and belt slip occurs!

 

My opinion, i would go with making the S/C pulley smaller instead of making the crank pulley bigger because you want to keep the 'harmonic balancer" on the factory pulley.

 

I know many of you are probably wondering, what does this magic smaller S/C pulley from DSR look like...

 

Then you might even ask, how does it look from the side;

 

Now you're asking, why the DSR pulley, is it really better. Yes, it generates more boost than crank pulleys on the coupe and it does preserve the harmonic balancer as intended by the factory and not with a heavy ring attached to it's outer edge or made out of solid metal.

Don't get too excited, it won't fit the coupe or newer SLKs. I think the biggest obsticle for the coupe is that the pulley is pressed on. I don't think you can get it off without damaging it and it would be difficult if not impossible to go back to stock.

 

That was my understanding of the matter, too. However, statements like this, although seemingly correct based on common sense, need to be proven. In reality, someone has made a smaller S/C pulley. Is it "small enough" to provide the same boost as a 20% larger crancshaft pulley, is a different question. Or - how it affects the belt lifetime.

 

OK, let's say that you are correct and a the S/C pulley I've shown above from DSR is too small at 3" and the radius is too sharp, then why do you think the belt doesn't totally explode and self destruct in your car with the 2 3/8" altenator pulley?

 

Good question! There's been a lot of speculation about this, but Buellwinkle is the first to provide numeric comparison. Indeed, the alternator pulley is much smaller (the lowest in the picture), and the belt makes a full 180 degrees around it, unlike the S/C pulley (the one on the left).

 

I don't want to sound like a know it all but I did spend a lot of time staring, measuring, taking pictures, just short of making love to those pulleys. If the DSR S/C pulley has been around for so long and I've heard no complaints about it on the W202 or R170 forums, then I don't expect that you would have a problem if it was feasible to install on the Coupe. Say the belt lasted half its life at 30K miles instead of 60K miles, is that so bad, they cost under $20 and take 15 minutes to replace. The problem for me was that it's pressed on, that would mean cutting it off and then you are at the point of no return. The boost potential is greater, the DSR pulley gets more boost than most crank pulleys. You need Benzy230's mechanic to open up and take pics of his creation, it's the only one I've ever heard of.

 

I know of three people that has installed S/C pulley from Dynospotracing. Two guys from mbnz.org forum. They love it cause it come with custom GIAC chip. Dynospotracing pulley max boost is at 11.5 psi vs Kleemann max boost is at 9.5 psi. With crank pulley, you can not make it any bigger to get more boost then 9.5 psi cause it will rub the water pump pulley. That's the down side to crank pulley.

 

The amount of force required to turn the supercharger at any given rpm (but especially at high rpm) is going to be quite a bit higher than what is required to turn an alternator. So comparing the 2 is not really valid. Belt slippage might be a problem, but I bet the real reason is the compexity of changing the SC pulley compared to the relative ease of changing the crank pulley.

 

Why are you guys keep asking about belt slippage when there have not has one case of belt slippaged yet. As for installation, nothing complexity about it.Remove the S/C pulley then drill out the clutch. This procedure would be much easier on the C32 because of the S/C is on the top. On the 2000-2001 Slk, there's no S/C clutch, so nothing to drill.

 

You are right about this and that maybe the reason why Dynosporacing keep it at 11.5 psi and not 12.0 psi or higher. Jackson Racing S/C pulley for Honda is the same size at DSR S/C pulley. I'm sure if they have belt slippage problem, then they wouldn't go that route.

 

Linh, on the new SLK230 and C-Coupe the S/C pulley is a solid pulley that is pressed on the shaft, you can only remove it by destroying it. There is no clutch like on your car.