Any interest in having a run of water pump under drive pulleys made? I've been in chats with Dennis @ HGB Motorsports to get one made for my S2 to test and see if I can alleviate some high temperature concerns on track/autocross while not under driving the A/C & alternator.

If we can get a decent group of folks interested the cost is pretty reasonable

Dennis from HGB quoted the following (subject to change pending design changes from where we're at):

"Oh yeah. Basically cost breaks down like this:
1 = $325
2 = 175
3 = 160
5= 150
So anyone else want to get in on the Ken development and my cad/manufacturing it would help out pricing substantially. I would get one myself but I don't have an S2 car.
Lead time is about 3-4 weeks."

Dennis also had this to say for those wondering about Series 1 cars, "S1 could be done as well for basically the same(ish) costing break down. The bolt pattern is different and a diameter adjustment "

The reason I'm going down this path was ~220F coolant temps in a lap or two of VIR, but more concerning was 217F coolant temps in a single 60 second autocross run from my radiator fan set point of 194F on the starting line. I'd really like to under drive the water pump and keep temps under control to not risk the engine.

So far it sounds like we have at least one other Series 2 owner interested.

 

isn’t it a bit risky to ask people to buy into it untested; what if it makes it worse?

the appropriate thing to do is make several different diameters and test them to see what works best, if at all.
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So you're sure this is what the problem is?

 

couldn’t help but notice the delrin control arm bushings he’s selling, seems like they’d be binding up by not allowing multi-axis rotational motion.

I could send in a set of Speedsource S1 underdrive pulleys to duplicate since those are NLA now.
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Not 100% sure yet, but we're testing on my car now.

It would definitely be interesting to duplicate the Speedsource pulleys, especially since they're S1 & S2 compatible.

 

They don't bind the most usable suspension ranges. I have built them and tested them. Currently running them on the car and I could not be happier with the rear end performance. Also people are concerned about it they can keep OEM in that one arm or put spherical in.
Most people just purchase an entire poly kit. So it would be silly of me not to offer all the bushing components in superior Delrin. It really makes the rear end more consistent by eliminating a lot of the rotational spring force the rubber bushings put in the system. I desgned and built these before sphericals were allowed in SP.

I'm building the pulley based on docwalts request. I have no skin in the game other than doing the CAD work and having them made. The potential customer did all the testing and has solid logic for this pulley.

 

S2 water pump is already under driven compared to the S1. I found out pretty recently the s2 pump bolt pattern doesn't match the s1 though.

I'd be interested in a solution to underdrive the s1 water pump & alternator if it is reliable and the cost is reasonable. Doesn't need to support AC.

 

There's already a solution for S1 engines, and as Team said, if you can find a set of Speedsource pulleys then you can easily just do that on an S1 or S2

 

the Speedsource pulleys aren’t a solution unless you can find a used set somewhere, or at least I’m not aware if somebody else started remaking them

I offered to send a set in for that purpose and I guess he declined to pursue it
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Got the underdrive pulley installed easily, just bolted on like stock. I've done some logging too, good temps while cruising around (180F stable with AC on, as usual) and temps so far are better at autocross. They still recover super quickly too and I'm not seeing as wild high temps. I used to see 217F at the end of autocross runs, I've done one event and I'm only seeing 205F as a peak on course even with a lot more rev limiter action at 9800 RPM. No more autocross events planned this year for me, sadly. Might get to do a track day or autocross, unsure though!

Big thanks to Dennis at HGB Motorsports for the pulley and hand delivery at nats!

 

Probably going to take into the mid-summer next year to see how effective this really is. At least that's my initial thoughts after my own giant water pump pulley install a little over a month ago, and a few autocrosses. Though, like you, my results so far also seem extremely promising.

Damn 9800rpm! Just thinking of the speed that translates to in second gear makes it clear I am too slow.

 

It was like 80 degrees at the last autocross at Warminster, so not too cold. I have data from all year from ~50 degrees to ~100 degrees. Outside temps never seemed to make too much of a difference in peak temps, I was almost always seeing 210-217F. I am definitely curious how it will go on track, at the WDCR TT I had zero temp issues but it was 45 degrees at best, haha.

Different course, no way was I hitting limiter at the Ripken event, haha. I did the pulley install after Ripken. I had to disconnect the battery to swap the trans so I just went ahead and installed the HGB pulley.