Underhood temps

[Bill in MN]

I installed a charge air sensor the other day and found my boost temps to be pretty high at 195 (12-15psi). I did the obvious and found nothing to be amiss with the IC system and, in fact, the IC water was quite warm.

My motor's always been quite hot after operation but I figured that was normal. For kicks I took a spare sensor and rigged it up along side the AFM and took it for 3 full boost runs with cool down runs in between. Charge air hit 195 again and the underhood temp was 408. I did 5 mile sections of normal off boost highway driving to see if the charge air temps would come down but I never saw below 100 after the first run. Underhood temps stayed about the same.

Temps. during and after the runs were as such : Coolant 185, oil 190, EGT 1400 at full boost, 1000-1100 off boost, oil pressure 45, vacuum 15-18 off boost. AFR's were right in the ballpark as well. This rules out something afoul with the motor I'd think. All vitals are well within spec. range.

It's been over 30 minutes since I shut it down after letting it idle for several minutes for a "cool down" and the valve cover's still quite hot to the touch.. As a comparison my 735, while warm after use is nowhere close to the temp of the S2.

I'm starting to think it may be possible the early "shark" spoiler I have on the front has altered the airflow enough to cause this to happen. There is no mechanical reasoning for this so it's got to be something wierd.

Any ideas, guys?

btw, nothing is blocking the airflow in front of the radiator nor anywhere else in the front of the car.

[russc]

I typo'd the underhood temp. It was 408.

Im confused,
All your underhood temps are ~200F, yet your "underhood" temp is 408F? Thats a 200F rise over ambient. While that may be true, it seems high. Where are you taking the reading from specifically for the "underhood" temp?

195F at full boost doens't seem abinormal. A better measurement would be intake air temp to charge air temp. Then you know the efficiency of the system. From there then you can narrow down your culprits that cause all the heat rise.

RussC

[Bill in MN]

Russ

I had the sensor zip tied to the old air box mounting bracket.

I've recieved several PMs suggesting the under hood temps of that magnatude are not all that uncommon for a FI car and that it ought not be worried about, especially on the exhaust side.

The goal now is better insulation for the intake plumbing and a better heat shield for the air cleaner. Obviously what I had done was not adequate.

[Shawn D.]

... abinormal...

Do you watch "Young Frankenstein" much?

[russc]

Russ

I had the sensor zip tied to the old air box mounting bracket.

I've recieved several PMs suggesting the under hood temps of that magnatude are not all that uncommon for a FI car and that it ought not be worried about, especially on the exhaust side.

The goal now is better insulation for the intake plumbing and a better heat shield for the air cleaner. Obviously what I had done was not adequate.

Was this measurement while the car was moving faster than 15mph? Gosh, 400F seems high. I know the manifold can get hot in these cars, If you pop the hood after running on boost and put your hand say 10" from the manifold, it'll melt the skin off in no time.

The intake air temp would still be a good measurement to take, as Im not sure weve seen where the S2 falls in that regard?
Maybe we did and I forgot.

And Ya, that is a good movie....

RussC

[cwl4m5]

is there an intercooler on this car? what will these temps do to an engine

[Shawn D.]

is there an intercooler on this car?

Yes. That's what he's referring to when he says "IC system" and "IC water."

[cwl4m5]

it seems to be doing same thing as yours. how hot are these things supposed to get? it seems like this will be heat soaked in no time.

[Bill in MN]

I've got 6 inputs on my EGT readout and have ordered several more sensors.

I think an experiment is in order. I'll be able to read from 3 or 4 different areas at the same time and this ought to give a better idea as to what is really going on in there.

Stay tuned!

[Jeremy]

Bill, do you have ceramic coating on your manifold, turbo exhaust housing, or exhaust downpipe? I think a cold air box around your air filter might help, it's one of the things that bothers me about my own setup. At present I think my car breathes a lot of hot air when I'm stuck in traffic.

Jeremy

[Bill in MN]

Everything is coated and I have a box around the air cleaner. Admittedly it sucked and I've built another one. That made a difference in intake temps from 195 to around 165 under boost. Still high but a lot lower than before.

I'm considering wrapping the turbo and downpipe in a thermal blanket but I need to do some research as to whether or not this is a good idea. It may not have any effect whatsoever.

[Boru]

Bill, I'd check the flow of coolant through the IC system. I'd guess something is amiss. Skeen's max intake temps after the IC are around 150F while flogging the car on track. Todd, though he has a slightly larger intercooler core has seen highs of 120ish on an 80 degree day.
Make sure the system is properly bled and you have a strong flow of coolant. Run the pump with the cap off the intercooler fill port so you can see the flow. Make sure the pump is running in the correct direction, etc.
Also, confirm that your gauging is acurate. Drop the probes in ice water to confirm 32F and (just) boiling water for 212F.

[Skeen]

Yeah, if I go out and do just a couple WOT runs, I won't break 130. Last month, I logged a run where I did probably 30 WOT runs (WOT, brake hard, WOT, brake hard, etc) and I was just getting to 160-170ish after about 15 minutes. That is with everything coated, but zero air box.

[Bill in MN]

Hey John

The temp. probe and readout are reading accurately. I did the ice and boiling warter test before I installed the probe into the intake and everything was accurate.

As far as I can tell the IC is flowing properly. To make sure, I took a section of clear tube and replaced the IC return line with it. I put in some blue food coloring into the filler on the IC to see what would happen. It didn't take more than a few seconds for the blue to make its way back up.

Any idea as to the flow rate for that pump? It's entirely possible it may not be pumping correctly.