Supercharged IAT location
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Supercharged IAT location
Roots supercharged Chevy with Enderle throttle body/hat, 8 injectors above blower.
What is the consensus on the IAT location, Above or below the blower?
Pros and cons of each?
What is the consensus on the IAT location, Above or below the blower?
Pros and cons of each?
Re: Supercharged IAT location
The IAT has to report the air temperature actually entering the cylinders. In a situation like this, with or without coolers, you want it to be after the last heat-transferring device.
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Re: Supercharged IAT location
That would be the logical location I agree.
I have also seen several similar setups with the IAT above the blower with the injectors.
These usually were tied into some kind of plug and play non tunable ecu.
Wonder what their thinking was as to why that location?
Was it just to make a "package" or was there a tuning reason?
I have also seen several similar setups with the IAT above the blower with the injectors.
These usually were tied into some kind of plug and play non tunable ecu.
Wonder what their thinking was as to why that location?
Was it just to make a "package" or was there a tuning reason?
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Re: Supercharged IAT location
If it was a MAF (mass air flow) based system the IAT placement is much less critical, once you know the mass of air moving through you're no longer using the ideal gas law to make fuel calculations.
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I build, repair, install and tune Megasquirt systems in North Dakota and beyond!
I build, repair, install and tune Megasquirt systems in North Dakota and beyond!
Re: Supercharged IAT location
Not a MAF application. The best example I can think of is here.
http://www.force-efi.com/specials.htm
http://www.force-efi.com/specials.htm
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Re: Supercharged IAT location
Hmmm, I'd guess it is a packaging issue, meaning they can package it there and you don't have to be drilling holes on the pressure side of the manifold.
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Re: Supercharged IAT location
They probably just don't want to/ can't deal with heat soak start up issues. If you have the sensor down there in the oven then you will have heat soak but under boost you do need to know the true temperature of that intake charge. I have seen guys run a second ambient IAT temp sensor for start up and change to the MAT sensor after start. Mine being N/A, I just fudge the curve. lol.
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Re: Supercharged IAT location
That sounds like a good possibility of what probably happens there.
Any idea of how one would go about getting an MS2 extra to see the 2 different IATs? 1 at start/warmup and the other at Run.
Any idea of how one would go about getting an MS2 extra to see the 2 different IATs? 1 at start/warmup and the other at Run.
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Re: Supercharged IAT location
IIRC the guy had a change over relay driven by a programmable output. Probably used the "seconds" output channel to switch over after a given elapsed time. That's probably what I would try if I needed it.
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Re: Supercharged IAT location
This isn't a bad idea, however I reckon it could be implemented a bit better.slow_hemi6 wrote:They probably just don't want to/ can't deal with heat soak start up issues. If you have the sensor down there in the oven then you will have heat soak but under boost you do need to know the true temperature of that intake charge. I have seen guys run a second ambient IAT temp sensor for start up and change to the MAT sensor after start. Mine being N/A, I just fudge the curve. lol.
Run two temp sensors, one as a Intake Air Temp (IAT) sensor and another as a Manifold Air Temp (MAT) sensor.
Always use the IAT sensor until you exceed 100kpa (or based on a curve) then begin using the MAT sensor.
This would allow you to avoid any heat soak issues and still be able to run Speed Density correctly.
As a bonus, you would also have the ability to see the difference between the IAT and MAT temps side by side in logs.
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Re: Supercharged IAT location
I have been looking around TS to see how to implement this dual temp scheme and am failing to see the light.
Is this possible to pull off?
Is this possible to pull off?
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Re: Supercharged IAT location
As mentioned, use a programmable output to drive a relay that switches from one sensor to the other. Go to "Boost/Advanced" and then down to "Programmable On/Off outputs".
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I build, repair, install and tune Megasquirt systems in North Dakota and beyond!
I build, repair, install and tune Megasquirt systems in North Dakota and beyond!
Re: Supercharged IAT location
This sounds like it might be a great (but complicated) solution to my problem.
http://www.msextra.com/forums/viewtopic ... 34&t=56915
@fueler...pros and cons of IAT location from my perspective are in that post
http://www.msextra.com/forums/viewtopic ... 34&t=56915
@fueler...pros and cons of IAT location from my perspective are in that post
Re: Supercharged IAT location
knightrous,
you had mentioned that you posted some Eagle files for the megasquirt. I cannot find them anywhere. can you repost or send a link to them? Thanks.
you had mentioned that you posted some Eagle files for the megasquirt. I cannot find them anywhere. can you repost or send a link to them? Thanks.