I'm still running the stock pulleys - spoke with Paul @ Gruvenparts (Thx to Josh for the lead). Their findings are that an underdrive pulley set causes over-heating which makes sense. I've heard about water pump impellers slipping - usually it's the plastic ones but this car has been doing that on this car for a long time. I think it was the same before I changed the pump BUT I have a spare at home and may just do that.
I don't have the OE shields - I built some ducting late last year and am prepared to build more as this is driving me absolutely insane (as if I wasn't beforehand for racing a VW). ----- Original Message ---- > From: darner <[email protected]> > To: Volkswagen a2 16v discussion list <[email protected]> > Sent: Wed, August 11, 2010 12:59:57 AM > Subject: Re: [a2-16v-list] Overheating > > Do you have an underdrive pulley set? It might be worth trying to > "push" the coolant pump a bit more. If the crank pulley is smaller than > stock, try a return to full size (opposite at pump: if it's oversized, > go down a size or two so that it has to go around more times for a given > belt length passing by). I've seen a water pump that had a shrink-fit > aluminum impeller on a steel shaft; when hot, it slipped. No idea > whether it did it from new, though, and that was an older car. Another > thought: try running a fully normal thermostat once, letting it act as a > constriction that slows flow, giving more dwell time in the radiator. > Are all of your shields and airflow control pieces in place around the > radiator? Air that bypasses doesn't cool. > > Matthew Yip wrote: > > I've been fighting this issue for an eternity - with all new hardware and > > a > > gutted thermostat, my car runs HOT during a race - right at the hot-line > > on >the > > > OE gauge with oil temps around 250-260. My former crew and now fellow > > competitor doesn't have this problem and most everyone else with a VW >(albeit 8v > > > cars) doesn't have any issue. > > > > As noted, all the components are new and the t-stat is gutted so, in > > theory, >I'm > > > absolutely befuddled. The radiator is a 16v rad for an a/c car so, > > theoretically, it's the largest 16v radiator available. > > > > > > One comment from a buddy who races and tunes Hondas is that the timing is >too > > > aggressive and it's building too much heat. I wonder if it could be that >the > > > car is running too lean, creating too much heat. > > > > > > Any suggestions on a more efficient radiator? > > > > Ugh...Matthew > > > > > > > > > > _______________________________________________ > > a2-16v-list mailing list > > [email protected] > > http://mail.a2-16v.com/mailman/listinfo/a2-16v-list > > For list archives, see listinfo link above. > > > > > _______________________________________________ > a2-16v-list mailing list > [email protected] > http://mail.a2-16v.com/mailman/listinfo/a2-16v-list > For list archives, see listinfo link above. >
