craig001

I am thinking about getting one of these. I know some of you all ready have them out there so I was wondering what came in the kit. Is there a special pulley assembly or did you just reuse part of the original set-up.

TIA.

Bill Gregory

Craig,

This is the Carrera RS part you're talking about:



And here's what it looks like, installed



All you're doing is replacing the hub, as in this drawing:



You can also remove the fan belt warning wheel at the left base of the fan belt (The alternatator warning light then provides that function). After unplugging the sensor, you'll need to jumper the two contacts in the wiring harness, to complete the circuit, lest the computer get upset. Tie wrap the wire that's left so it's not flopping around near the fan blades.

The least expensive source for the part is from a discounting Porsche dealer. There's at least one catalog that has the part for alot more money.

PC2

Sorry for my ignorance, but what are the benefits for converting to a single pulley?

Bill Gregory

Here's a post by Cupcar in 2001 (found using the Rennlist search function):

The theory behind the single fan drive for the Euro RS and American "Carrera Cup Edition" cars is that since these cars have no A/C, radio,cruise control, power seats etc. there is less requirement for electrical output from the alternator. The engine fan on a C2 turns at 1.6 times engine speed and the alternator turns at something faster than this, I can't find a factory number but it looks like maybe 2 times engine speed. When you convert to single belt everything turns at 1.6 times engine speed, i.e. the alternator turns slower. So, if you go to the single belt system less average output from the alternator will be available and you may run into a weak battery situation if you usually drive the car with A/C, etc. running all the time. A nice side benefit of going to single belt is the elimination of the fan belt monitor since the alternator light can now perform this function. There may also be a very minor power increase from the engine. Conversion to single belt a no brainer for a track car, somewhat dicy in an electrically "loaded" street car IMHO

PC2

Thank you Bill!

Jeff Curtis

I have one, you re-use (unless you order new or find some at a hardware store, etc.) the three studs that hold the outer pulley half on your original setup.

Bill, interesting, the one you have pictured has the studs protruding from both sides?? ...unless I'm looking at it wrong? I find this interesting as my pulley is held in place by the pressure provided on the large nut (24mm??) at the end of the shaft, if it wasn't real tight my hub could slip...hasn't yet...two years and running.

The conversion is a difficulty level 7, that because most of the time it's DIFFICULT to remove the old pulley/hub assembly without dinking up your fan or the shaft...but it's "doable" fer sure...after all, I made it through.

WHAT would be the purpose of making this conversion?? ...just to have a "neat" setup or performance gains, etc.?? If I had it to do all over again, I wouldn't.

FWIW, I still have my fan belt sensor operating, the belt that remains intact is the one that rides on the sensor, no changes or adjustments were necessary...the new single-belt setup uses the larger pulley, closest to the fan assembly, as a matter of fact half of that pulley setup uses the hub of the actual fan assembly, so the alternator is now underdriven - offering a VERY slight HP advantage.

Bill Gregory

Jeff,

Maybe this view helps (sorry for the scary size!):

Johan K

The engine revs more freely, not having to turn all that (unneccesary) stuff like A/C etc?

GP964

I've had this conversion done for 3 years now, no problem.....GP

914und993

The only time that the reduced alternator operating speed makes any real difference is at idle. Once you get above 1000 rpm, the alternator will put out plenty of current to power all your factory subsystems and accessories.

I did some testing with my 993, both before and after conversion to the RS pulley system and posted the results in this thread:

RS Pulley mod & charging system

Chip

Christer

Actually, maybe I should do this as I don't have aircon and my car idles at around 975rpm now anyway...

Could I ask price...in the UK?

Jeff Curtis

These can be had for under $100 - I bought mine from someone that reproduced them in high-grade aluminum with a CNC machine...he doesn't have anymore, doesn't plan to make them last time I corresponded with him.

Bill, yup, yours looks EXACTLY like mine, I was looking at it backwards. Only the tightness of the nut ensures the assembly rotates with the shaft, this bothered me a bit - but no troubles so far!

craig001

MS Road & Race has them for a few cents short of a c-note. I know others on the board have had issues with them, but my personal experience has been good.

Does anyone know if you could use the outer (larger?) pulley halves with this set up. Would that solve the lower alternator output issue? I don't use my AC that much (only enough to lube the o-rings) so that isn't really an issue.

Of course for me it's a fading issue as I have just picked up a 1992 Turbo suspension to put in along with some other things that have pretty much wiped out the improvements fund for this year. After going through my PET it looks like the Turbo suspension is the M030 set-up for the other cars.

viperbob

These are real simple to install, and they have a couple of benefits. One less belt to break, and each belt takes about 4-6 HP to drive. Not a big improvement, but reasonable for the cost.

Craig - Don't worry about the power output. I have sold and installed MANY of these and no one has every had a charging issue.

Bill Gregory

If I remember correctly, the hub adaptor was $65-$75 from a discounting Porsche dealer.