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Rob 930 Rob 930 is offline
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Join Date: Dec 2002
Location: Seattle
Posts: 659
Someone in this thread said they thought it was geeky to have an IC in/out temp gauge. I disagree. It's one of the only gauges I focus on when I'm on the track on a hot day. On the street, it's highly unlikely that you'll ever reach a dangerous IC outlet temp, so maybe it's not necessary. But on the track, under long periods of sustained boost with limited cooldown, I think it's critical. I was told long ago that if the IC outlet reaches 130 deg or more, it's time to back off or risk high combustion chamber temperatures that may be damaging (i.e., may promote detonation). For those who log and review the IAT sensor from their engine management systems, that's fine. But unless you have a readout for instant feedback, I think it's risky to do a retrospective look at such critical information. Last year, we had a track day in Seattle on the hottest day ever on record; air temps were 103 F and track temps were 150 F. I found that after 7 or 8 laps, even with a massive IC, I'd see IC outlet temps climb above 130 F. By backing down to 7/10 for half a lap every so often, I could bring those temps down very quickly. On normal "hot" days here, I rarely exceed 130, but I can get pretty close.

I use a Davtron in/out gauge, model 307FD. The sensors have been installed in the IC inlet and outlet. On the outlet side, the IAT sensor is right next to it. (BTW, I tapped the IC for the sensor threads; I don't like the idea of a nut on the inside that may get loose.) I can log and review the IAT data as well on my DTA system, but by then it's too late! It's like logging your oil temperature and later finding that you exceeded the limit. The Davtron readout is mounted in a little aluminum box that's placed where the ashtray used to be. In that same box, I have an AFR readout and a couple of electrical switches (one for an oil cooler fan and one to turn on the DTA data logging).

BTW, I happen to have a spare Davtron readout and sensor pair, which I'm willing to sell reasonably. Please PM me if you're interested.

Rob

Here's an early incarnation of my gauge box, when I was running CIS and a 915 transmission. At that time, I was more concerned about frying the transmission than the engine, so I had transmission cooling and a transmission temp gauge.




Then later, I converted to EFI and a 930 transmisson, so I now cared more about frying the engine rather than the transmission, so I put an AFR gauge in the place of the transmission temp gauge. The red switch is for the fan, the black one for logging data to the DTA ECU. Sorry about the glare; it's the only photo I have.

Old 03-18-2010, 10:04 AM
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