Thread: Normal operating temperature w/ lead-in story

Had a bad day at the dyno yesterday...

If you dont know/remember I had to replace the alternator on June 5th after i got done at Carolina Motorsports Parkway during a HPDE. Which i left with a blown headgasket. And just changed about 3 weeks ago.

Well yesterday I went to have my AEM tune adjusted since i finally added in a wideband.

It was a 90 mile drive to the dyno.

Well about 4 pulls in, voltage started dropping and having misfires. When he told me voltage was about 11V i knew it was the alternator. So after many phone calls. I was able to find a B15 alternator in stock locally.

They put a charger on it so they could keep making a run or two at a time while i went to get the alt. Since there were some guys scheduled after me and I was on the dyno longer than planned. They took my car off, and That gave me a chance to change the alt.

He pulled up a couple of the data logs and showed me the coolant temp ...with the hood open and shop fans blowing*

Coolant was rock steady at 170F. Ambient temp was around 96F. This was before I changed the alty.

Couple hours later, when he was able to get back to my car. (raining like crazy by now) He sat in my car for about 10-15 min before his road test, still around 92F ambient, And the coolant still only got up to 172-173F. And gave it to me after he got back. He didnt look at the intake temps while he was there sitting, just the coolant temp.

I changed the thermostat while i was changing the headgasket. OEM 76*C thermostat.

Is that normal...? I thought temps got up to 190ish.
(havent had a chance to put in the digital coolant temp gauge yet, planned on doing it yesterday, but started having loose wiring issues (fuel pump cutting in and out) on the way home. So i had to be towed about 35 miles)

/rant

Was the tuning shop air conditioned? Where you running an air/water intercooler w/ the reservoir filled w/ ice? Just trying to figure out how the intake temps dropped below ambient temps. If you air/air intercooled, intake temps always approach ambient or settle at a range above ambient temps depending on the setup.

No its not.
Air to air
Not sure how they got that low, besides the fans blowing on it.
He didnt remember to look at the intake temps while the hood was closed,

What were you using to check the temperature? Connection to the ECU? Aftermarket water temp gauge ?

Thats what was shown from the sensors on the AEM EMS during a log.
I will have an aftermarket gauge installed in the next few days to confirm the coolant temp.

and when i can get a serial to usb adapter, i can take some logs of my own to see the temps.

Where is the sensor for the AEM EMS located (or does it use the factory sensor) ? Reason i ask is that location of the sensor will read possibly higher or possibly lower than the water temp. I've seen sensors in silly places before. Worst place is to have it located in the radiator hose that goes to the thermostat housing.

it uses the factory coolant temp sensor. (2 wire)

the intake temp sensor about ~7 inches from the throttle body.

and when i get the aftermarket gauge installed the sensor for it will be put where the factory sensor is for the dash cluster gauge.
http://i211.photobucket.com/albums/bb110/nx2000det/car/SSL29933.jpg

Hmmm, somethings not right...thermodynamically, it's impossible for the IATs to go below ambient without adding work e.g. ice, air conditioning, etc so it might be a sensor issue. I'm not to familiar with the AEM software but here are few ideas. I think they have some sort of "sensor wizard". Can you select the type different types of sensors in the calibration software or input sensor resistance values based on temps? First thing I would do is too double check ECT and IAT selections.

Double check that you have the correct iat selected and the correct scale.

Unless you have an oil cooler or an unusually large radiator, I would imagine you should have seen more than a couple of degrees rise in water temp.

I noticed a long time back that with my oil cooler installed the water temp was a LOT more stable as the oil would cool the water and vice versa when the temps go above one another.