jangy

Do it bro!! Nice, I can't wait to see if this is a go. I am loving the idea of modding both pulleys so that I can get boost without such a huge crank one.

dyno

down 3mm means 6mm smaller diameter ..

if the material left in our 55K pulley is more than C32's, it would be great
.. if it is the same, maybe it s a bit too much

joe w211

I have been thinking about making my own s/c pulley too, and will now be prompted into action with a visit to the nurburgring next month coming up.

Just a question aside though - to remove the pulley as the clutch is disengaged when the engine is off, it is necessary to engage the clutch to undo the retaining bolt. To do this, looking fron the front of the car on the left side of the charger at the front there is a plug with 2 pins, this is undone and a 12volt charge connected, engaging the clutch.

When I first got the car it suffered fron s/c shut down as the ic pump was dead - i fitted a johnson 90 (damm tight fit) I expect the shutdown is activated through this plug, if i wired it up for permenant feed to lock it all the time it would make boost from launch - do you guys think this would be of benefit - it might stop belt slip at the moment of engagement too if i am going to make the pulley smaller.

Has any one made their s/c clutch run permenantly on ?

bobgodd

Looking at that pic, you think that 3mm would be too much??

bobgodd

I can't comment on the rest of your post because I don't know the answers, but taking off the S/C pulley was surprisingly easy. I didn't have to have anything engaged or tied down, just a 15/16" socket, a one foot 1/2" drive extension, a little spray of penetrating liquid (seafoam deep creep) and an impact gun and the bolt came right out. Easiest part of the job actually lol.

dyno

took a rough measurement of my pulley:



seems total thick is about 8.5mm, ONLY !

- the groove is about 3.5+ deep
- that elastomere inside is maybe 1.5-2mm

..remains only 3-3.5 total . You can save about 1mm making the groove less deep, with a more flat edge on the bottom.
so, you have total 4-4.5 ... and I would leave at least 2,5mm

therefore, down 2mm max (after making the groove 1mm less deep).. and you get a 91-4= 87mm pulley that is a 4.6% gearing increase.

Not much but not so bad: like having a 158mm crank pulley instead of 151mm
stock... or a 183mm instead of 175

but it's only a very rough measurement !

Exotic-metal55

I saw this reply from Finny in a search .. This was a reply to Jangy on another pulley thread back a while ago.. Times have changes, since Jangy was only looking for 170mm back then..

Here is where he states heavier is better. Thoughts????

jangy

I'm assuming that somehow the momentum of the pulley helps to make it a good buffer for energy absorption? I dunno but that has been all I can come up with. I keep thinking what would happen if a part locked. The pulley being heavy would help it to shred through whatever the block was and avoid damage to the crank (twist). I dunno.

splinter

Any luck?

bobgodd

I told the guy he could take some time if he needed it. I was planning on going back in there once my grill gets back from paint. I'm thinking about another week though. I'll definitely update!!

splinter

Were they able to successfully machine it?

bobgodd

Unfortunately I won't know if they would have been able to do it or not. After having the pulley for what seemed like months, I finally just went and got it back, I was tired of not driving the car lol.

The engineer said they were just too swamped with work to take on any side projects. Oh well.

bobgodd

Oh and to add to that.. He said he could turn the pulley with relative ease, but his biggest concern was the correct way to detach and refasten the pulley to the clutch and keep everything in balance. He said he could not use the clutch when turning the pulley because there was no way to tell if the pulley was true to the clutch.

positronicC32

Hi Splinter. I've been discussing the C32 stock SC Pulley on a few other threads (and SRT6/crossfire forum) and wanted to ask if this pic was a cross section of a stock C32? It looks like it.

I'm trying to ascertain by how much I can turn it down. Looking to go to 68mm from 74.2mm. Is this realistic though? I've read of fears that - given the apparent inside groove (where the bearing sits) adjacent to the belt grooves- 65mm is not achievable.

From this image, it doesn't look it. Not much room to play with.

Any guidance would be welcome.

Regards,
James

Snogard

Just for the record; i just managed (after a month of research, laser measurments, laser welding and CNC machining) to customize our OEM SC (91mm diam.) pulley to Fi 84 mm Dia. (eqvivalent to OEM SC pulley and Fi 164mm crank pulley combo). Clutch remains intact.
If someone is interested, i can post pics (pre and after), but i can not get them (pics)to server.... Si if in can send them to someones mail and then he post them here...If interest.

shardul

iTrader: (1)

nice work!

Snogard

Just send you pics and some description of the project....


I guess now, after all my measurments and -been there-done that-there should be no problem for someone else to make fi 84 SC pulley.
But i am still telling you guys that this project is no easy task; you HAVE to laser weld (16 hours of laser welding!!!) inner groove (other wise our stock SC stainless steel pulley will deform because of TIG welding heat and your SC pulley will be destroyed - trust me-i have alraedy destroyed one SC pulley that way before, and after that i decided to laser weld next SC pulley). Be carefull-you have to have proper EXACT dimensions of OEM SC pulley!!! Lucky for me that i have laser measurment 3D machine in our company (and all other CNC and laser welding
machines, so no cost for me). Then you have to make machine knife with proper contour shape (to make pulley grooves for belt)!! And most important- you have to have REALLY GOOD master man for machinning.
I guess for someone who have no ability to make all this machine work for free there is no benefit for doing that mod price wise(rather buy crank pulley), because just laser welding (cca 16 hours just for that inner groove!!!) is about 700 $ (16hours x 50$), not to mention at least 3 hours for CNC laser measurments (and making blue print) and at least another 3 hours to CNC machined and not forget cca 1 hour to make machine knife (with belt grooves contour). So all in all there is 1000$ + price for someone who have to pay for all that (and do it PROPER exact way). Lucky me-i work in company (i am quality man) which have all that machines, so its free for me...:-)
I am also planning to do underdrive pulley set for M113k (water pump, alternator and servo pump UD pulleys).


P.S. I have already done that same mod 5 years ago on my SLK 230kompressor (which have exact same system SC pulley).
And SC pulley is still good after almost 80.000 km and after 5 years
of daily abuse! Also underdrive pulley set for 230k is still good and working loike a charm on my SLK:-)

Pics: Look at the finished product at belt grooves....we intentionaly made rough belt grooves so belt will not slip...

OEM SC pulley with visible inner groove


Laser velded inner groove with rough outer machinning


Finished product


Finished product