trabots

I tried a search to no avail. I have my pulley off my SC as it threw a finger. I am still scratching my head at how it engages. The part is mounts to has been called "magnetic". I can find nothing magnetic anywhere. If it is electromagnetic how does it get its current supply? I can see no wires and being a rotating part it would need a commutator to continuously have an electricity supply. Do the 3 leaves get pulled inward to lock the pulley on the shaft? Thanks.

tw2

The large black spinning thing is the electromagnet. It has two wires which engage it and pull in the pulley.

trabots

I had another look and found the wires into the back. I take it that the electromagnet holds the the friction faces apart (together?)until the ECU at a certain rpm (3000?) releases (pushes?) it to engage the pulley. The 3 'fingers' are in fact just shock absorbers to ease the engagement.

I found the friction ring cracked as shown in the image. I have been told I need to buy the whole deal at around $1600. Has anyone else had to fix this issue without the expense noted?

Tavs

Looks to me that it would be as good of a reason as any to just get a fixed pulley and a tune.

tw2

It always engages above 3500rpm or earlier if enough throttle is applied. Some have had great results but people have had issues with fixed pulleys. I would do a search.

trabots

Jerry at EC advised that the ECU looks for the clutch electronically and as such he wouldn't do a clutch-less tune for me. That has got me thinking that the ECU could maybe be fooled by measuring the impedance of the clutch electromagnet and then just connect a resistor of the same impedance to the wires leading to the clutch. The ECU would then see that impedance when it should happen. The tune would need to be altered for un-blown situations I would think. What say?

cnterline

Your whole other outer friction ring is gone, that piece is 600 from the dealer
Just the piece pictured on the left.

trabots

I can see that now. The friction rings are not available without the metal part they fit into I take it. That $600 in the US would quickly double in Oz unfortunately. I will check with the dealer tomorrow. Do know the name the part goes by? Thanks for your help guys.

I am wondering what would happen if I sandwiched a layer in between the two halves creating a fixed pulley with the electromagnet still in place but with the armature now immobile but still letting the ECU think all is well. Or does it sense the actual movement of the armature?

new55

i have thought about this as well and think it would work but you will still need a tune for fixed pulley via another tuner. just an additional thought is the fixed pulley in the states is only about $200 and removing the electro magnet would free up a lot of heavy spinning mass for better response... the things i have read is that you are more likely to have issues if you do the fixed pulley AND s larger throttle body.... other members chime in here please for FSP issues

JoeJErnst

You could try to find an industrial friction supply house that can cut you new friction rings that you could then glue into the grooves of the hub. I've tried going that route but I can't find anyone around me that can do it. You may have better luck in your area.

trabots

I have ordered a spacer ring to be lathed to lock the bare pulley to the magnetic drum. The ECU should still think the clutch is ok I hope. The car only has an 83mm pulley, belt wrap and EC tune.

new55

i believe the ECU will think the electro magnet is good but it in reality you will have higher boost from low rpms and will need additional fuel down low as you will be lean > i like the idea but think you still need a tune to compensate, keep us posted

Redwood415

there is a positive to the unit being clutched. the s/c puts a lot of parasitic drag on the motor that equates to more fuel consumption. Motor only needs s/c on demand under loads. It's nice that it isn't permanently engaged! Factory did this for a reason. My 2 cents..

Notdke9fdkfjekrjrkj123

If you want a tune for a fixed pulley that works get in contact with Raceiq (Anthony Lawshee)i have the usual mods incl 82mm tb and it runs perfect!

trabots

Thanks for all the input. According to a conversation I had with a Bosch engineer these cars have 2 ECU maps, one which references the various sensors and gives variable fuel delivery for most driving situations which are low load, part throttle. This map is left alone. The other map is fixed and this is the map which gets altered by tuners. The fuel delivery is fixed and assumes large throttle/loads. As I never floor the car from below when the SC clutch engages, there should be no difference really. I will advise.

If it does work I plan to lock the clutch on my SL55 77mm pulley. This car has a KC and a larger TB and corresponding mods.

trabots

I had a pulley machined without the bearing or the clutch portion. The back half of the clutch was left in place with the wires still connected. The good news is that it worked fine with no CEL and felt the same under full throttle. The bad news is that now that it turns at idle it exposed the horrible sounds of the SC bearings being worn out. When releasing the tension on the belt there is some play felt when moving the pulley and the stethoscope puts the noise as coming from within the SC housing. If someone with a FSP could advise what theirs sounds like at idle I would be grateful. I find that there are no kits for rebuilding '55' superchargers. What does a Weistec cost and does it have a better intercooler, better performance??

trabots

The Wiestec costs $9k but at 3.0 L is bound to give more boost and the bigger IC would surely help keep IATs down

seanol

I have a fixed pulley and you will gear the gear set backlash in the front of the supercharger. It rattles. Not the greatest sound but considering how much fun my pulley and RaceIQ tune are I don't care. There will always be backlash in a gear set. This is to ensure proper engagement and allow for growth when they get hot. That is the play you feel going left to right and back again. With a proper tune it is like driving a whole new car, power everywhere and torque for days.

trabots

That is great news. I thought the bearings were making the noise. I released the tension on the belt on my other SL55 and it has the same side to side movement. Can you advise where the oil goes? I have never checked either car.

seanol

There is a plug on drivers side housing that takes a 5mm Allen wrench. I did mine when I had my charger out. There is a supercharger oil change thread in here that details the procedure with charger on car.

ryanhere

Question for @Trabots.... Have you considered removing the Supercharger Magent structure itself?
Since you are no longer using the Magnet(Due to the Fixed pulley), why hang on to all that additional rotating mass ?
This is something that I never understood from the numerous FSP installations I have seen

hayseed

iTrader: (2)

same question here -- these cars may still go down in value some but I don't think they are going up - are you going to try to put it all back to stock and sell it like it was never modified ,, I would think the SC would last longer also not spinning that weight along with the quick spin up --

trabots

I left the back half of the engagement magnet installed with the electrics still connected. I felt that if the ECU sees the electromagnet still actuating it will assume all is good. Many FSP installs put in a resistor to imitate what I have left on. Now that I understand the rattle at idle is normal I have been out giving it a thrashing and it works just fine. There is a slight stumble occasionally when just giving slight throttle but then it did that before. It is 'jumpier' now of course but that is fixed with your foot. I however am waiting on a RaceIQ tune just to be safe. Overall the FSP with the back half of the clutch is still much lighter than the full clutched pulley.

trabots

I have had both my 55s' clutched pulleys changed to fixed pulleys which I had machined for Oz$200 each. My E55 had an 84mm clutched pulley and a Eurocharged tune and it was great, easily 50hp seat of the pants improvement. That was all good until the pulley failed and cut through a few hoses and pipes. I had an 84mm pulley machined and with no other change I can find no fault. It is just as quick as before but feels more responsive down low.

My SL55 had a 77mm clutched pulley with shorty headers, bigger TB, bigger injectors, K&N filters, no cats, Killer Chiller with 2.5 gal under hood tank, Pierburg 50 pump, modified belt wrap kit and a EC tune after supplying AFRs to Jerry. I decided to try a fixed pulley so had a 74mm pulley machined and put that on. I always had a slight stumble on throttle application down low. This has totally disappeared now and the car feels so much more responsive. It is a blast to drive now, especially in manual mode. This is a pic of the 74mm pulley.

Flydutch

Look at the below video and it explains.
A static Electromagnetic ring (locked onto the SC body) magnetizes the Steel ring clutch which runs around it after the ECU has energized that magnet ring. Then that Electromagnetic ring pulls the pulley against it. that magnetized clutch ring. The pulley is driven by a belt going around the Water pump and the Crank Shaft. The ECU energizes the Electromagnetic ring after the engine reaches between 2000 and 3000 RMP so the boosting starts. at lower RMP the engine is virtually idling so it does not need boosting.