Hic Rhodus, hic salta. I hate to clutter Colin's new shift points thread, so here it is guys. Let's talk engine cooling, and stock fans.
Let's first all agree with the following statements:
- No two engines are alike; tolerances, configurations, and state of tune.
- Variable timing, and distributor wear, coils, etc and advance differences.
- Fuel configurations, AFM settings, fuel maps, etc.
With that out of the way, let's not talk what we know and our experience, but let's show what we have observed, and lets support it with some data...
I'm fortunate enough to have digital logging capabilities, and somewhat accurate temperature probes on the air intake and head-surface of the #3 cylinder.
For this experiment I "pre-heated" my engine, and went for a 60 minute ride. I purposley emposed "13.0:1" across my entire fuel map, including steady idle at "13.0:1".
Here are somewhat relevant tid-bits:
- Idle: 900RPM at close to 11 BTDC . Max mechanical advance: 28 BTDC @ 3000 RPM.
- Fuel: 2 squirts per two crank revolutions; or 1 engine cycle. (same or similar pulse as stock L-Jetronic as if you tuned your idle for 13.0:1 AFR)
- Engine: stock cam, 42mm intake x 36mm exhaust valves.
- Stock Fan.
- Stock Heater Boxes.
- Working thermostat.
- Conditions: 70F ambient, city driving, some hills.
Here is somewhat raw data....
CLT - #3 cylinder head surface temperature - TempII Sensor location - in Fahrenheit (F).
MAT - Manifold air temperature (Intake AIR Temperature) - in Fahrenheit (F).
RPM - Revolutions Per Minute
AFR - AIR to FUEL RATIO
Hits - The number of times that event was observed
Let's break that down a bit...
First filter, 800-1000 RPM; Second filter, 1000-2000 RPM; Third filter, 2000-3000RPM;
Fourth Filter, 3000-4000 RPM, Fifth Filter, 4000-5000RPM.
Cooling shenanigans
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- Old School!
- Location: Little Rock, AR
- Status: Offline
Cooling shenanigans
1981 Volkswagen Vanagon Westfalia - air-cooled Type4 1970cc CV (hydraulic lifters, 42x36 valves, stock cam, microSquirt FI with wasted spark ignition)
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI
1993 Ford F-250 XL LWB Extended Cab 7.3L IDI
- Xelmon
- Sedna of VW lovers
- Location: LA or Portland, OR
- Status: Offline
Re: Cooling shenanigans
Very interesting data... I'll assume that Left scale is degrees C.
Looking at your sig though I see that you have larger valves... Could larger valves make that big of a difference?
Looking at your sig though I see that you have larger valves... Could larger valves make that big of a difference?