porsche mania

Ive had the rs hub on my car for over 15000 miles now with no issues. Always plenty of charge in the battery, no lights on the dash that havent had another reason for being there. No power loss down low and no poor running at low rpm either. My car will pull off hot or cold without any throttle and i can get it all the way up to 5th gear without touching the gas once which to me would mean there must be running well with the rs hub. My car is also fitted with the most agressive cams you can have while still being 3.6 which if anything i would have thought would have highlighted a weak running engine below 3k. My car is my daily driver and track car so does everything from crawling in traffic for half an hour at a time to getting ragged round the track for the day. The rs hub is something i would have recomended to anyone based on my experience.

jpar

Same here, zero issues with my RS hub.

elbeee964

Concur, and still quite happy six years on.

Goughary

No argues...but guys- lots of guys have used the RS pulley with no issues for years- so did I. Except that the issue is there if you look closer.

You won't kill anything using the RS pulley - but if you are curious - stick a tester on the battery and measure volts and amps at various rpm. Over 3k matches 1:1 with and without the single belt conversion. Down below, not so much. But it'll run fine to the normal "butt dyno"...no worries. For me the difference was enough to change back...

JasonAndreas

PAG ended up increasing the idle speed by ~300RPM for cars delivered with the single belt pulley.

Maxi_z

Is the "low voltage at idle" issue with the single pulley belt also there on a standard 964 RS from the factory or are there other differences on the RS that makes the low rpm voltage not an issue?

What is the OEM RS idle speed from factory?

I have a 964 carrera that was built as a 964 RS 3.8 replica and is fitted with a basically new 3.8 built engine that use a 993 engine block and electronics as a base and Individual throttle bodies.

At Idle speed there is some ( ! ) dash error light many times and the idle is rough ( probably to be expected with ITB and single pulley etc ) and as soon as I accelerate a little more to about 2000 rpm the dash error light turns off by itself.

I think that probably as others reported the alternator makes a too low voltage at low idle with single pulley and apart from fitting back a standard pulley setup I d like to know if there are any other things or mods to improve the low idle voltage without reverting back to standard.

Thanks

Ubipa

I have the single pulley setup on a C2 without any warning lights. What is your current idle (880-890)? Cut in issue?

Does your battery stay charged, or do you know the draw at idle with whatever electronics you are normally running? Amp issue?

Maxi_z

My Idle was about 850 to 890 rpm and I noticed that I had to give a slight throttle input for the engine to start well and that when idling especially when cold it was a little rough and low and the ( ! ) warning light was turning on and then off as soon as I accelerate above 1500 rpm...

I adjusted the idle mechanically to around 1100 rpm and it seems to be much better starts without throttle and no error on dash etc...

I think that especially with my eninge buit 3.8 engine setup with ITB, cams, single pulley, etc... the alternator does not give enough voltage at just 850 rpm...

But still I d like to know the OEM RS ( and eventually RSR ) recommended idle, and if there are any other mods ( or eventually an aftermarket alternator ) that would improve the spark between idle and 3000 rpm with the single pulley setup

I don't know the actual draw at idle but I do not have particular problems with the battery charge ( but I disconnect it when not in use and charge it so not sure about that )

Ubipa

I can’t help with the RS/RSR RPM values, but the cut in for the stock alternator, I believe, is ~850. So if your idle is below the cut in, the alt is providing zero amp.

Is it the RS/RSR idle rpm or the power requirements at idle for those cars? Weren’t those really stripped down? The alt doesn’t provide full amp@idle.

There is a 6 phase alternator out there by Classic Retrofit that provides more amp at idle.

Ubipa

Just remembered I had this… same idle speed