for you 2.0 liter s2000 guys:
original url here--> http://www.autoxforum.com

not saying it will make us 2.0 guys in 100 degree weather win, just saying it'll make our 2nd/3rd runs normal.

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I imagine every national level 2.0 liter s2000 driver has given up about 1 second on their 2nd & 3rd runs when it

 

Also, if you read very closely between the lines, this link is what gave me the idea of the cold on the sensor.

http://www.s2000.org/mods/insulator/

 

no good for stock class. You can also do the same w/ an ems.

 

Anyone ever try cooling their fuel just before injection? You could run the fuel lines through a bottle of icey water, in theory... it should work but not sure if it is worth the effort.

 

 

pouring water/air on the intake is legal because you're not replacing, rewiring, modifying anything.

If water is ok tho, what about using nitrous or co2 to really cool the intake and radiator between runs?

 

i'm retesting this with that cool bottle of spray air that cleans your keyboard. i'll report what it does.

 

How did you set your hot and cold conditions? What was the process, and how scientific was it? Please show us your x-scale. How does cool water on the IAT help to fool the ECU? The thermistor junction is at least 20 mm inside the manifold, unless you're saying to remove the screws and pull the IAT from the manifold and pour water over its tip.

I totally agree that there is a heat soak issue with the S2000, but I don't believe for a moment that it is 1 sec worth on an auto-x run. I think I get around the heat soak issue by leaving my engine idle between runs, with the AC on and fan on high. This keeps air moving through the manifold and runs the fan(s) to keep the coolant temp well under the normal fan turn on temp.

Steve

 

If I understand what you wrote, you compared acceleration after the car was started to acceleration immediately after an acceleration test.

Did you test the acceleration after pouring water on the intake temperature sensor?

 

Sorry guys i'm famous for expecting ppl to read my mind. here's more info that may help. (Ortho - yes run0-hot no water botttle, run1 - hot no water bottle, run2 - hot water bottle).

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(Observation) Ob#1
My 1st autox runs felt as if they pulled way better than my next runs. found this 90degree weather. it "felt" like the difference between a 5.5 0-60 and a 6.5 second 0-60.

counter - tire temps may inversely related to starts especially with wheel slips.

Thought - Heat soak

Ob#2
On a test/tune event 3 guys ran my car. It was 90F+ , and i got tons of MaxQData points. All runs at start hit say 39mph up to
a point where you have to turn, but 1 guy got a cold car run and i purposely rembered what run it was (between heats). He was at 46mph. Don't quote me on the mph but i know the difference was 6 mph. Then compared difference of another dozen runs while hot and all speeds went back down to 39mph.

counter - GPS may not be that accurate and got "lucky" on the only cold run recorded.

thought - HEAt soak again.. so how do i cool it down most effectively?

Ob#3
Look up results of a dozen or so National Finale's and national tours for 00-03 s2000's and see if I can determine that there 2/3 runs were slower than the other guys in really all classes (like stock cars like Cstock, of course Astock.. even SS). I was going to pull it all in Excel until i saw "unscientifically" what I thought was plain as day. These guys (relative to competitoin) may be giving up .5 to 1 seconds. I payed closer attention to hotter regions and recalled a few topeka events about how hot it was.

counter - not statistically sound but again, I saw it with clear in the data I checked.nyone is welcomed to put this data deeper under the microscope - please let me know.

Thought - i was convinced for really good drivers. A


Ob#4 -
read this article top to bottom and it made me want to start experiment. http://www.s2000.org/mods/insulator/ . Of course I knew insulators weren't legal in Astock.

thought- s2000 heat soaks too much between block and intake manifold (thus "infecting" the sensor with false reading of "Very hot".



Experiment#1
Idle car in driveway for 15 minutes with obd2 plugged in with hood closed. outside temp was 85F (ish). come back to car. car water temp about 170F and intake air temp(IAT) was about 168F. Leave obd2 in and have wife watch the temp of the IAT. Pour a little water from the garden hose on the top of the air box. wait about 30 seconds - no change in IAT temp. put more water on top of the air box.. still no change. pour little.. then wait then alot on the hose between the airbox and the manifold. I was actually surprised to see no change in obd2 temp. waited a little longer just in case.. no change. then poured garden hose water on far side of manifold.. no change... got closer to the temp sensor and got 1 degree drop.. ok, now here the great part.. poured a little bitty drops on top of the IAT sensor... dropped about 10 degrees. bingo - just like i predicted. then poured slowly right on top of sensor and got the temp down to 121 degrees. More than i was expecting.. but really great news.

conclusion - i knew now how to trick the IAT sensor but didn't know if that translated into more HP. I knew that cold or more dense air was a component too. still I had a feeling that the air in the chamber really wasn't 170 degrees, I thought the sensor was getting a false reading from the block temperature.


Experiment#2
Same one I posted at top... but there were 3 runs (run0, run1, run2). run0 was to prove that run 1 was accurate. I had the car idle for 10 minutes.. ran run0 and got data from MaxQdata in 3rd gear. Then to keep the fact that the car just cooled itself, came back, I waited about 30 second. reran run1. (turns out run0 and run 1 were statistically the same. i did all the "t-test" thingy's and really just looked at means and median accelerations and they were the same. I didn't pull or unscrew the IAT sensor btw.
Run2 was the real test. i came in after run1 and opened hood quick.. poured a 16 ounze of ice cold water right on top the sensor. then i ran the same exact run. what you are seeing in the graph is the difference in acceleration between run1 and run2. run0 wasn't posted as it gave me confidence that my data was valid.

conclusion - read above.
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i'm getting a little tired about writing this - so ask your questions and tell me what you think.