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Measuring heatsoak vs actual AIT?

Old Mar 16, 2016 | 09:30 AM
  #21  
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Originally Posted by slmhofy
Really though, is 180F not feasible for a heat soaked intercooler, on track @ 20psi?

I feel like that could be possible especially if ambient temp is 80-90 outside.

Or still would that just implicate a crappy intercooler?

It's feasible, ez, go slap on a MSM IC.

but if those temps are accurate, I think it's time to look into a more efficient core/system for that particular setup. I wouldn't be quite happy with a core that can get so heatsoaked that it loses that much cooling efficiency.
Old Mar 16, 2016 | 10:48 AM
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Attached Thumbnails Measuring heatsoak vs actual AIT?-80-subaruiat4_0f69c54e6b1927979d9fc2281811ca58629726b3.png  
Old Mar 16, 2016 | 11:00 AM
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Vlad,

That's great and all and does look like a super efficient intercooler setup. But just going by the picture, that looks like it could have just been a simple 1-2-3 gear pull on a nice cooler 78f day.

Put that car on the track for a 20 minutes session and then the results would be more applicable.
Old Mar 16, 2016 | 11:04 AM
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Originally Posted by nitrodann
It was 95f, 22psi.

I can't answer any of your questions but id like to.
Last time I measured my IAT at the track, I got it up to 160f @ 14psi and it was also probably 90f ambient air temp. Temp sensor end of my larger crappy ebay intercooler.

This was at AutoClub Speedway where there's a front straight you can go full throttle for probably 10 seconds in 5th or 6th gear. That builds a lot of heat in every system (turbo, coolant, oil, etc). My IAT was highest consistently at the end of this straight.

At the time I had my oil cooler in front of my intercooler and have since moved it.

Didn't get around to logging last time I was out, but I'm sure it's better.
Old Mar 16, 2016 | 12:39 PM
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Originally Posted by slmhofy
Vlad,

That's great and all and does look like a super efficient intercooler setup. But just going by the picture, that looks like it could have just been a simple 1-2-3 gear pull on a nice cooler 78f day.

Put that car on the track for a 20 minutes session and then the results would be more applicable.
I'll find more relevant logs, but IMO the post IC AIT's should not be hovering at 180+ with a proper (non-ebay) core and sufficient (properly ducted) airflow.

But I'm no trackday bro so I'm not 100% sure what is normal on track. Just sharing data
Old Mar 16, 2016 | 12:40 PM
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We need @Savington in here with Theseus logs.
Old Mar 16, 2016 | 12:41 PM
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he had a precision core with decent ducting so yeah
Old Mar 16, 2016 | 12:51 PM
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Theseus ran max IATs of maybe 30*F over ambient doing 20 minutes of 4-5-6 pulls in 100*F weather. I doubt your IATs are actually 180*F.

I'm with Braineack, though. Putting your IAT sensor in the coldside pipe behind the radiator is an awful idea and I don't understand why anyone does it. Move it to the coldside IC endtank where it belongs.
Old Mar 16, 2016 | 12:58 PM
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Originally Posted by 18psi

Old Mar 16, 2016 | 01:00 PM
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Originally Posted by Savington
Theseus ran max IATs of maybe 30*F over ambient doing 20 minutes of 4-5-6 pulls in 100*F weather. I doubt your IATs are actually 180*F.

I'm with Braineack, though. Putting your IAT sensor in the coldside pipe behind the radiator is an awful idea and I don't understand why anyone does it. Move it to the coldside IC endtank where it belongs.


Got that same intercooler headed my way.
Old Mar 16, 2016 | 01:07 PM
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Originally Posted by Savington
Theseus ran max IATs of maybe 30*F over ambient doing 20 minutes of 4-5-6 pulls in 100*F weather.
I've asked before, but will you post a datalog showing this?
Old Mar 16, 2016 | 01:12 PM
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I think I still have a datalog of Splitime's 1/4 drag pull.

as he goes through the gears his AITs get cooler than when he started.
Old Mar 16, 2016 | 01:15 PM
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Originally Posted by Braineack
I think I still have a datalog of Splitime's 1/4 drag pull.

as he goes through the gears his AITs get cooler than when he started.
That's not possible (the air getting colder when you go in boost). That would mean his intercooler is over 100% effective.

But I've seen this before on my car. Heat soak raised the temps of my air going into the intake manifold at low speed (charge pipe between intercooler and intake manifold heat soaked bad) so AITs dropped when going into boost. This is why I run my AIT sensor close to the intake manifold, so it actually measures the temperature of the air going into the engine. Sticking it in the intercooler exit tells you the air temp exiting the intercooler, sure.
Old Mar 16, 2016 | 01:27 PM
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well it just means his ait was a little hot in staging.

iirc his ait was screwed into his IM.


here's one:
Attached Files
File Type: xls
datalog200809211714.xls (397.8 KB, 85 views)
Old Mar 16, 2016 | 01:50 PM
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Originally Posted by patsmx5
I've asked before, but will you post a datalog showing this?
Sure, just as soon as you dyno your car.
Old Mar 16, 2016 | 02:06 PM
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well played
Old Mar 16, 2016 | 03:01 PM
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Originally Posted by Savington
Sure, just as soon as you dyno your car.
Old Mar 16, 2016 | 04:17 PM
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Its a slow corner big straight track with an average speed of 80mph and a top speed of 150 in this particular car.

It really sounds like the right place for iat sensor is in the inlet manifold.

The end tank location is to prevent heatsoak?

Comments?
Old Mar 16, 2016 | 04:19 PM
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end tank is best for everything
Old Mar 16, 2016 | 04:32 PM
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Originally Posted by nitrodann
Its a slow corner big straight track with an average speed of 80mph and a top speed of 150 in this particular car.

It really sounds like the right place for iat sensor is in the inlet manifold.

The end tank location is to prevent heatsoak?

Comments?
Do you want to know the air temp coming out of the intercooler? If so, absolutely put sensor in end tank of intercooler to measure that.

Moving a sensor does not actually prevent the charge pipes/intake manifold from heat soak. That's going to happen no matter where the sensor is.

The sensor location will change what temperature you measure (air temp pre-turbo, post turbo, air temp exiting intercooler, air temp exiting charge pipe, air temp in intake manifold plenum, etc).

If the sensor body temperature skews the air temp sensor's reading, then you need a better sensor since it's not doing its job (measuring the air temp it's designed to measure).

Test sensor, if heat soaking the body does not change its reading at the element, the sensor is good. Place it wherever you want to measure air temperature.

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