I bought a Actron CP9580 AutoScanner Plus a few weeks ago to do some troubleshooting on some other vehicles. I finally hooked it up to my 2004 S2000 yesterday and did a 90 second run at 60MPH. It was 90F degrees outside and the IAT readings were 138-140F for the whole run. It was mostly cloudy overcast, so I can't really attribute these high readings to road surface heat. The IAT was 162F at engine idle just before the test run. That's some pretty hot air entering the throttle body at a dead stop, and doesn't cool down much while driving 60MPH. No wonder we have heat soak issues in the summer!

 

I've noticed the engine bay in my S gets very hot. The temp gauge reads fine, but you really have to let the car cool down a good bit before attempting any kind of engine work. I have had Heat Soak hit me a few times this summer as it has been hotter than usual.

 

That sounds pretty high for those speeds wonder, I wouldn't have expected the temps to be so high at 60 mph, I know at idle it gets crazy hot, but I thought the engine bay was designed better than that for highway speeds. I wonder if it is radiator heat making it's way to the intake opening ?. I think the pcm gets conservative when it sees high temps as well and backs off the ignition timing a bit too, adding to the sluggishness and power loss of the high intake temps.

 

I don't see an issue, I don't think the ECU retards timing until it sees 180-200 IAT temp. 90 second run? Thats not very long considering you have a saturated metal surface. Also, ~162 at idling, how quickly did it drop to the ~140 range? Instantly? I've always wondered if the IAT would read cooler if it wasn't so close to the side of the intake wall.

The fact that intake air heats up at idle is well known, and once moving, the intake air will quickly drop from idle to a cooler temp. Also apparently the IAT reads external temps when its cold out, and I don't know how that works.

 

Will be looking into the hondata heat shield. After being in Texas stop and go traffic for 30 minutes yesterday, it was as if my car was choking on something when it was time to finally go. I had to hold in the clutch and rev the engine a bit to "clear it out" before I could go without the care feeling like it was going to stall.

 

Blipping the throttle before take off is the best way to "clear one's throat" of heat soak after idle. The big issue is asphalt temps are higher than ambient, and the car, especially in traffic, could be sitting in a layer of 150° heat from ambient, multiple other engines, hot exhaust gases, etc. When air is hot its thinner and when in traffic its polluted, so there's just less clean oxygen to be had - it all works against engine power. Usually if you simply apply more gas than you normally do you can compensate for high temps at take off - one thing you can try. Many drivers do not adjust driving style for air quality - common oversight, but easily rectified.

Since the OP is interested in air temps, you might find this interesting - its an old thread where the OP placed temp sensors around the engine bay and in the intake system and tried different intakes and insulations. Bottom line, insulation will slow heat soak, but once its soaked, it will retain heat longer. Its effectiveness is really a matter of timing - drive for 30 min and the insulation is effective, drive for 40 and it no longer is. https://www.s2ki.com/s2000/topic/200...mps-session-2/


Fyi, everything I have ever seen shows about a 12-14° rise in temp from stock airbox/intake filter to the throttle body when the car is moving at at least 30 mph (aftermarket CAIs can half that difference), so I'm not sure how worried I'd be about throttle body temps as it represents a ~1% change in hp. The real question is, is there a better way to cool the intake air? The only thing I can think of is to run the intake out of the top of the hood and shorten the run from intake to filter. Of course, that would make the car undrivable in rain and would add turbulence to the airstream. The other option is what race S2000s have where the intake simply shoots straight forward rather than crossing the bay.

 

I wouldn't put much faith in a Hondata gasket, all the metal eventually heats up from all of the heat around it, it just takes a bit longer, but after a few minutes of driving it eventually ends up at the same temperature as pre-gasket situations. They work really well on a dyno with the hood open, once you close the hood the manifold heats up just as much.

I've been looking for a way to extend my oem air box opening over the radiator, I put on an aftermarket rad and it puts out a lot of heat right where the oem box opening is located. I think just a short extension may work to clear the radiator, I'm not looking for a full snorkel though.

 

I always keep an eye on IATs and water temp. Ambient temp has a big impact on it imo. When cruising at 60ish, the IATs are usually around 50 C with my FIPK.

 

I cannot wait for winter.. My car instantly gains 20 whp on the butt dyno come December.

 

since you got a tool for intake air temps, can you do a idle temp and freeway temp with a shortram and a coldair intake (if you got local s2k buddies)? somebody did this test a while back on a celica gts and at idle cai's run cooler but when moving they are near identical (the issue was if the cai was worth the hydrolock potential with the celica). it'd be interesting if the s2000 is the same or is it just a hot box with no air circulation and we knew it for sure rather than countless intake debates.