DIY Turbo Discussion greddy on a 1.8? homebrew kit?

what makes your air temps hit 60C on a 20C day.

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Old 05-10-2007, 10:43 AM
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Default what makes your air temps hit 60C on a 20C day.

I been datalogging the **** out of my car and I notice my post intercooler temps are like four billion degrees. The logs show about 60C / 140F. That's insane!

Here's the thing... I have zero knock; can't hear any, nothing on the datalog. You'd think I mistakenly put my heat gun on instead of the turbo....

the car runs great except for the mild tming retard from the coolant and air temp spark trims (probably lose 5 degrees of timing).

Could it be that having my air temp sensor right behind the radiator is causing it to read super high.... conducting heat from the hot pipe and hot air out of the radiator?

Make no sense.
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Old 05-10-2007, 10:49 AM
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maybe build a little heat shield for it? but i wouldn't expect a sensor to heatsoak....is the sensor hydra specific or can the resistance values be altered to show crazy readings? or maybe you're boosting 25psi?

fwiw, i was only hitting 33.8C at 13.5psi this morning, seeing 20C at cruise...

https://www.miataturbo.net/braineack...3psi_2_3_4.jpg

im no help am i?
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Old 05-10-2007, 10:49 AM
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Sorry dude, this is way off topic and I know I got you excited expecting a good suggestion to help you with your problem, but everytime I read or answer one of your posts, I feel like I'm talking to that *** on your avatar. I'm sitting here passing time between classes at school and am trying not to laugh and have everyone stare at me.

Seriously though, not sure why your IAT's are so high, don't think 5 degree retard every now and then should be giving you constant high temps like that, and I sort of doubt that your whole intake tract is heat soaking that bad from a section of it being close to a radiator hose, but stranger things have happened. Good luck man. Hope you get it figured out or find a good deal on water injection....
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Old 05-10-2007, 11:23 AM
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Is that at the end of a boost run?

For comparison- I've got a small IC (spearco core = 17x6x3). With everything fully heated up, 29c ambient, the IAT shows 32c rising to 52c at 7k rpm on a 14-15psi boosted run from 2k rpm. My IC is up against the a/c condensor.

My coldside pipe runs right past the edge of the rad, tho the fan doesn't blow on it.

Heat soak has radical effects on just about any temp you'll see from underhood. My coolant temp is 88c all day long, under boost, doesn't matter - until the car stops moving, then it rises to 97c in about 15 seconds. See if you can plot your IAT to what the car is doing at the time. If it's 60c all the time, something IS wrong.

DL below: rpm=dark green, dashed=boost, darkblue=IAT
Attached Thumbnails what makes your air temps hit 60C on a 20C day.-dlait.gif  

Last edited by m2cupcar; 05-10-2007 at 01:22 PM.
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Old 05-10-2007, 11:33 AM
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already have WI... just not installed.

I'll wrap the **** in foil faced fiberglass and do more runs.
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Old 05-10-2007, 11:34 AM
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Originally Posted by m2cupcar
Is that at the end of a boost run?

For comparison- I've got a small IC (spearco core = 17x6x2). With everything full heated up, 29c ambient, the IAT shows 32c rising to 52c at 7k rpm on a 14-15psi boosted run from 2k rpm.

My coldside pipe runs right past the edge of the rad, tho the fan doesn't blow on it.

Heat soak has radical effects on just about any temp you'll see from underhood. My coolant temp is 88c all day long, under boost, doesn't matter - until the car stops moving, then it rises to 97c in about 15 seconds. See if you can plot your IAT to what the car is doing at the time. If it's 60c all the time, something IS wrong.

DL below: rpm=dark green, dashed=boost, darkblue=IAT
I suspect it is heat soak. You've seen where my filter is. I found some old datalogs and it hangs out between 35-40. the later datalogs show it hanging around the high 50s. definitely wrong.
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Old 05-10-2007, 11:40 AM
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Originally Posted by y8s
I suspect it is heat soak. You've seen where my filter is. I found some old datalogs and it hangs out between 35-40. the later datalogs show it hanging around the high 50s. definitely wrong.

you didnt need that driverside headlight anyways...
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Old 05-10-2007, 11:57 AM
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I don't doubt it. I was amazed at the hot air that comes out around my headlight gaps with the fan cuts on. I need to get the undertray back on to see if that helps channel air back and out when the car is stopped.

I'm surprised that it's not cooler though. The NBs have a cold air path built in from Mazda. There's a small "splitter" in the mouth that channels air into a path that runs over the driver's side fender liner and through a hole under the driver's side headlight. You might consider a proto type fab'd box to isolate the filter from the hotside- maybe even extend it to the headlight.

IMO - one of the biggest problems is your filter has a cap on the end, the end aimed at the cold air source. So it's forced to suck all the air around the sides- the air from the turbo, header and rad. That was part of the reason I went for the mushroom style foam filter - it allowed me to get more filter area for the space used, which also allowed me to get it over to the headlight away from the turbo.

Check and see if the air temp rises dramatically when the car stops.
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Old 05-10-2007, 01:32 PM
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that "splitter" is gone.... it was replaced with a front mounted IC. I'll have to see if I can whip up a little dryer tube that goes from the mouth to the hole behind the headlight.
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Old 05-10-2007, 10:39 PM
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sooooooooo thermocouple confirmed that the ambient air under my hood is MFing hot. with the car warm and idling.... about 55-60C. Even behind the headlight.

stuck the probe in the intake pipe before the throttle body.... 60C.

Nutty.
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Old 05-11-2007, 05:21 AM
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You should take your filter 2 inches front and 3 inches down. Where the power steering should be at. Not sure if you have PS though...
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Old 05-11-2007, 08:54 AM
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Damn! that is hot. Yeah- get the filter as far away from the compressor as possible. If you can put a curve on it so the filter material is picking up some of the air from the that hole it should help once you get pulling air in. What about your undertray- installed? Word is that the undertray is crucial for getting the air out of the engine bay at speed or stopped. Otherwise it does alot of circling around the engine bay, rather than exiting.
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Old 05-11-2007, 09:14 AM
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my pre-turbo intake temps are like 70c
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Old 05-11-2007, 09:43 AM
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what are they post IC?
I don't know what mine are pre, but post after a boosted run they're less than y8s starting point- and at 20f less ambient. He's got an oven in there.
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Old 05-11-2007, 10:21 AM
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no idea, my ATS is in my inlet pipe.

I know it's supposed to be post turbo, but i'm lazy.
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Old 05-11-2007, 11:34 AM
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Originally Posted by m2cupcar
Damn! that is hot. Yeah- get the filter as far away from the compressor as possible. If you can put a curve on it so the filter material is picking up some of the air from the that hole it should help once you get pulling air in. What about your undertray- installed? Word is that the undertray is crucial for getting the air out of the engine bay at speed or stopped. Otherwise it does alot of circling around the engine bay, rather than exiting.
I made a new undertray... tried to seal the bottom of the IC to it but the foam went missing....

I also tried to move the filter over using some random piping but..... the area behind the headlight is still 60C. I will leave it as is and F with it after the dyno day when I have some time to take it apart.
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Old 05-11-2007, 12:30 PM
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be sure to bring a bag of ice to the dyno
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Old 05-11-2007, 01:09 PM
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well I've never seen it go above 70 ever

i posted this in your datalog thread but do you have any pictures of your air intake setup? I'm curious...
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Old 05-11-2007, 02:31 PM
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Any of you guys running the hondata intake manifold gasket?
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Old 05-11-2007, 02:33 PM
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it's just one of those nitrile rubber elbows

don't have a hondata gasket on mine BUT they are a proven asset to reducing heat soak from the head to the mani.
Attached Thumbnails what makes your air temps hit 60C on a 20C day.-engine01.jpg   what makes your air temps hit 60C on a 20C day.-engine02.jpg  
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