Temp Sensor Spacers, Where can I get 'em Options

[76-914]

Sorry guys I just read a thread on these spacers where a guy has them for $24 ea. but I can't find thread and I'm a dumb shit with search features. (IMG:style_emoticons/default/chair.gif)

[detoxcowboy]

"The heads must heat up and cool off quite rapidly. What do people who have a VDO head temperature guage see on their cars?"

Yes they (cylinder heads) heat up first and cool first both much faster when looking at the gauges oil temp. vs. cylinder head temp. especially heating up on a cold start.

[pbanders]

"The heads must heat up and cool off quite rapidly. What do people who have a VDO head temperature guage see on their cars?"

Yes they (cylinder heads) heat up first and cool first both much faster when looking at the gauges oil temp. vs. cylinder head temp. especially heating up on a cold start.

That's what I thought, because I was concerned that since the spacer doesn't have any initial effect (at start, same temp as the cold head), I thought the car would still act lean during the first couple of minutes (i.e. off-throttle surging). However, that's not what I see, it acts great through the whole warm-up transition. I figured that was because the heads must be heating up quickly, and by the spacer delaying that heat transfer to the sensor right from the start, the mixture is kept where it should be.

The quick cooling leads to the warm staring problem we discussed in another thread. This issue is avoided in water-cooled D-Jet implementations, as the engine temperature is sensed from the block. Hmm. You have to wonder if an oil temperature sensor instead of a head temperature sensor would have been a better choice for air-cooled implementations of D-Jet...

The rapid change in head temperatures also points out why avoiding ballast resistance is a good thing, too. If head temps are swinging over a significant range where the CHT resistance is going between 50 to 200 ohms, corresponding roughly to head temps of 300 to 200 degrees, then as little as 200 ohms of ballast would result in the ECU richening the mixture, introducting mixture instability, wasting fuel, and increasing emissions. The spacer helps smooth out those operating-induced swings (that don't actually reflect the cylinder/piston temperature conditions, which dominate the mixture requirements), an eliminate those effects.