Interesting manifold temp sensor data

[LC2NLS6]

8F outside Sunday, took a cruise out to fill some gas can for the toys, and on the way back the MAT delta temp at 55 mph on the way back after it heat soaked getting gas, wasn't as high as I had thought. I think a cold air intake isn't as great when it is cold outside compared to when temperatures approach 100F, as it is closer in temp to the engine temp? 180F in my case. Now, if I shut the engine down and wait 5 minutes, temps see 210F, which is the actual temp, not 180F. I run an 2 inch open element air filter. I'll make the same drive when temps get warmer and see the delta difference.

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[L31MaxExpress]

8F outside Sunday, took a cruise out to fill some gas can for the toys, and on the way back the MAT delta temp at 55 mph on the way back after it heat soaked getting gas, wasn't as high as I had thought. I think a cold air intake isn't as great when it is cold outside compared to when temperatures approach 100F, as it is closer in temp to the engine temp? 180F in my case. Now, if I shut the engine down and wait 5 minutes, temps see 210F, which is the actual temp, not 180F. I run an 2 inch open element air filter. I'll make the same drive when temps get warmer and see the delta difference.

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Preheating the air works well for atomization with a wetflow intake manifold. I logged the MATs under a stock TBI on an airgap style single plane. Was not uncommon to see the MAT 40-50°F cooler than the IAT.

 

[LC2NLS6]

The Holley has 4 100#/hr injectors at 58 psi. I'd have to think they have better atomization than the stock 2 bbl TBI, even though its all a wet dual plane manifold.

 

[Supercharged111]

A sudden drop in air pressure will cause a corresponding drop in air temps. Works both ways. I'm curious what it would have dropped back to after soaking up to 210.

 

[LC2NLS6]

That's kind of what I did, drove to get gas (first pic cold just off throttle coasting in the neighborhood) MAT still at 8F-10F with throttle almost closed. Let it sit at temp, but I guess it was so cold that there was no heat soak out to the engine bay, but the engine was warm. But once back at 55mph, coolant cooled right off to 175F with the 180F thermostat barely opening, MAT in the lower 30's at speed. I'll redo the test when it warms up next.

 

[LC2NLS6]

It was 65F yesterday, drove to town, on the way back coolant was at 182F and MAT hovered 82 F at cruise and also in the neighborhood at light throttle. So, two tests. Interesting. Was probably more humid yesterday that the middle of a cold snap.

34F MAT - 8F ambient = delta of 26F
83F MAT - 65F ambient = delta of 18F

 

[LC2NLS6]

Towed the boat around, MAT seemed to consistently be +30F from ambient on the interstate at 65-70mph. Outside was sunny and 85F. Coolant was 190-200. MAT was 105-118 at the highest, towing up a long set of hills. Back at 55 mph it all cooled down a bit MAT was 99-105F. After shutdown back at the house, let it sit off for a few minutes, MAT was 145 and coolant was showing 235, even the fenders were hot. I was probably throwing too much timing and too much fuel, I'll have to do some more towing tuning in those cells.

 

[Supercharged111]

More timing makes it run cooler, less timing adds heat.

 

[LC2NLS6]

Going up hills at say 30% tps 2800 rpm the holley was running 40-45* advance at it and 10-11 AFR, sometimes 12-12.5, injector total fuel saying it was using 100 lbs/hr or so IIRC. I was thinking it should have been 36* with that much throttle and bring fueling back to 12.8-13.2 if I can.

 

[JSlezak83]

Stock tune in my L29 gives me about 7* at similar throttle and rpm. No knock counts. I really need HPTuners so I can do the ‘411 pcm.