It’s been a month since my last entry, and things have been interesting.
After the meltdown at Birmingham, I thought I had licked the transmission issues with an additional cooler, and I had replaced all the melted MAP lines and covered them in heat-resistant sleeve. I also found a turbocharger gasket that had burned through, and replaced it along with all new hardware.
But all was not good. I traveled to Peru, Indiana for the CAM Challenge. On my third run of the day, the car caught fire. Oops.
Quick thinking by corner workers had the fire out, and after a tow back to the pits and a couple hours spent cleaning up my mess, I had the car on the trailer and ready to go home. When I got home, the transmission came out.
What I found wasn’t pleasant.
Scoring and chatter marks indicated the torque converter was moving in unwanted ways. The heat had melted a nylon spacer in the pump and made a mess. There may have been other issues, too. In any case, the transmission went back to to the shop and the torque converter went back to PTC for diagnosis.
The verdict from PTC was the thing got hot. They freshened the converter and sent it back with a recommendation: use thicker transmission fluid. Apparently the thinner stuff will cavitate inside the converter and that creates a lot of heat.
So that led off into some research into transmission fluids. I had been using Mobil1, becaue it has a really high temperature tolerance. But it turns out Mobil1 is really thin. I charted all the major varieties of cluid I could find information on and came up with this:
The brands are sorted by viscosity index. The Red Line high temp is the heaviest, but has a rather low flashpoint. The Motul Dexron III is slight thinner but with a much higher flashpoint. But the Motul costs $17 a quart.
Moving over one more, the Castrol Transmax Dex/Merc gives me almost as much viscosity as the Motul. The flashpoint is lower than all the Motul products, but higher than everything else. And it’s $14 a GALLON. Winner
Additionally, I addressed the cooling issues:
This new cooler is more than twice the size of the old one. It nearly fills the grill apterture.
Around the radiator you’ll see the new radiator box in kit from GNS Performance. This kit replaces some rubber baffles that had seen better days. It forces all air entering the grill opening through the radiator opening. Nothing leaks out or around.
I got some dope headlight covers from my friends at TR Custom Parts. No pics because I haven’t installed them yet, but back in the day I had a set. They were worth over 1mph in the quarter mile. I figure with the car being much faster and going on race tracks, they couldn’t hurt.
And to top it all off, I replaced the suspension… again. New 250 pound springs in the rear, and new Afco shocks all around, with the fronts being custom valved 70 series. Hopefully the wallowing we saw in Birmingham will be resolved.
All I’m waiting on now is the transmission itself to get back. Fingers crossed it happens soon. My next local event is an autocross here in town on the 16th, followed by the SCCA Time Trials Nationals at the end of the month.