Dinan Stage II pulley size

[MOTRSPRT]

Well, at 82K miles I had to send my supercharger into Vortech for rebuilding. They said also to replace the s/c pulley; my wife took the call and so I have no information on WHY.

Anyway, the markings on the pulley are: D315-0306.

What do these mean? I measured the diameter of the pulley to get 86.5mm. Translated = 3.4055". On this website http://www.superchargersonline.com/product_listing_2M.asp?Cat2=accessories%5Fpulley&offset=40, there are no pulleys with that size. Does anyone know what the proper size pulley is for the Dinan kits? I'm guessing the markings are for Dinan only so most are forced to get the pulleys from Dinan.

[Croak]

It's a custom sized pulley, not part of the standard Vortech pulley size.

It's not so Dinan can specifically make more money, it's because a 3.41" SC pulley combined with their 5.25" crank pulley keeps boost in what they deemed a safe level AND provides good belt wrap (reduced slipping).

So, the proper sized pulley with Dinan tuning is the one that was on the SC. The markings on the pulley are just Dinan internal part numbers.

You could drop down to a 3.33" Vortech pulley fairly safely, but that does raise your max boost ~1.5 PSI and belt slip at higher RPM will be worse.

[MOTRSPRT]

Well, it looks like I'll have to live with the belt slip at higher rpm's and get the 3.33. I don't usually hit really high rpm's frequently (I've never hit my rev limiter), so maybe I won't even notice the slippage...

[paul e]

It's a custom sized pulley, not part of the standard Vortech pulley size.

It's not so Dinan can specifically make more money, it's because a 3.41" SC pulley combined with their 5.25" crank pulley keeps boost in what they deemed a safe level AND provides good belt wrap (reduced slipping).

So, the proper sized pulley with Dinan tuning is the one that was on the SC. The markings on the pulley are just Dinan internal part numbers.

You could drop down to a 3.33" Vortech pulley fairly safely, but that does raise your max boost ~1.5 PSI and belt slip at higher RPM will be worse.


Dinan, apparently, played pretty fast and loose with their 'stock' pulley size. My 'Stage II' Dinan kit back in '99 made 8 psi boost because the sc pulley on my kit was the 3.33" pulley, in conjunction with their standard 5.25" pulley. At the same time I was measuring 8 psi on my VDO column mounted gauge, confirmed by the dealer who I questioned about it, and by two handheld boostgauges of my own, I was reading others' results who almost all were reporting either 6 or 7 psi. My point here, relative to the OP's pulley questions, is that Dinan's software should support the 3.33" pulley with no problems if he chooses to go with it.

BTW, Motrsport, any particular reason youre having it rebuilt? I had mine done a while back , and it turned out to be a good idea.. IN my case, it silenced some noises it had started to make, and is now so silent you can barely hear it at idle even. AT that time I had logged about 50k miles on it. How many miles have you put on yours?

[MOTRSPRT]

I had it rebuilt due to leaky seals. I could remove the intake plumbing and have a stream of oil drip from out of the s/c. Of course, until I discovered that, the oil was going straight into the motor...:mad Total mileage on the s/c is ~62K miles. Total cost to reuild was only $381 which includes shipping, and I had it done while we were on vacation to Montana so driving without the s/c on the M3 has been minimal. BTW, my M3 still pulled really hard on the freeway from 80 mph. :D I was pleasantly surprised.

Thanks for the info about the 3.33" pulley. My car is a 98 so it should have the identical software setup that yours had in 99. It makes me more comfortable knowing that my setup will support this pulley.

[Croak]

Well, it looks like I'll have to live with the belt slip at higher rpm's and get the 3.33. I don't usually hit really high rpm's frequently (I've never hit my rev limiter), so maybe I won't even notice the slippage...

It'll just wear the belt a bit faster if you do stand on the fun pedal. Slip can start to happen around 6k.

I ran a 3.33" for a couple months on an otherwise stock Dinan OBD1 setup before I switched to different software and a 6" crank pulley, no issues other than the slip, which I did notice (though I thrashed hell out of mine every chance I got).

Paul has the only reported 3.33" Dinan V2 setup known to man, by the way, and I'm more inclined to think his installer did the swap than it coming from Dinan that way.

[paul e]

It'll just wear the belt a bit faster if you do stand on the fun pedal. Slip can start to happen around 6k.

I ran a 3.33" for a couple months on an otherwise stock Dinan OBD1 setup before I switched to different software and a 6" crank pulley, no issues other than the slip, which I did notice (though I thrashed hell out of mine every chance I got).

Paul has the only reported 3.33" Dinan V2 setup known to man, by the way, and I'm more inclined to think his installer did the swap than it coming from Dinan that way.

Love the sarcasm.. Sure, you could be right. The installer could have done the swap.. But the installer was the BMW dealer in Greenwich, and I was one of the first SCs that they installed.. They were the only Dinan dealer in the area, and from talking to them, I dont think they would have had the 'balls' to do the swap! They were a real 'stick to the book' kind of outfit, and hadnt done many blowers before me. Regardless, doesnt really matter how the pulley got there. The main thing is my experience with it.. Which BTW, included no noticeable belt slip on either the boost gauge or over many dyno runs, where it usually would show up.

Motrsport will be fine with it.

[guc32]

Has anyone done their own rebuild on this board?

http://www.corral.net/forums/showthread.php?t=780865

[MOTRSPRT]

Has anyone done their own rebuild on this board?

http://www.corral.net/forums/showthread.php?t=780865

I was going to attempt it, but the rebuild kit I had found on the Net was only a few dollars less than having Vortech do it properly. Plus, my wife reminded me of the lack of time I would have for something like that and she wanted the s/c rebuilt quicker and back on the car. Couldn't argue with that...

Would moving to a 6" crank pulley and a 3.33" s/c pulley be the better route to go for the slipping belt issue? I guess if I did that, I probably wouldn't want to go with a 3.33" s/c pulley, but rather the next smaller one?

[marc1119]

I was going to attempt it, but the rebuild kit I had found on the Net was only a few dollars less than having Vortech do it properly. Plus, my wife reminded me of the lack of time I would have for something like that and she wanted the s/c rebuilt quicker and back on the car. Couldn't argue with that...

Would moving to a 6" crank pulley and a 3.33" s/c pulley be the better route to go for the slipping belt issue? I guess if I did that, I probably wouldn't want to go with a 3.33" s/c pulley, but rather the next smaller one?

moving to a LARGER blower pulley....not smaller:)

Moving to a 6 inch crank pulley would definitely increase your belt wrap but also add mucho boost to your setup..
right now a 5.25 crank pulley with a 3.33 spins @ 7000 RPM spins your blower @ 39700 RPM.
Going to a 6 inch crank pulley with the 3.33 will spin @ 45405.....6000 RPM increase ..OR equates to an ADDITIONAL 3 lb boost over what you are making now...the tune..the injectors and the HFM cannot handle that..


Going to a 6 inch crank with a 3.60 blower pulley, will yield you 42000 RPM, or ~ a 1 lb increase over what you have now...

So more belt wrap with a 6 inch crank pulley and a 3.60 blower pulley , and a possible 1 lb increase in boost...not bad...

Marco

[MOTRSPRT]

Okay, good information to know. I wonder if this setup will give me belt clearance issues? I may just go ahead and stick with my plan of getting a 3.33" s/c pulley...

[DADx2]

Shameless plug to sell my 6 inch crank pulley.:D

$250 shipped