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Inlet Air Temp ?

Crankme69

Crankme69

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About 80 degrees here today, had the puter GMTDScan with me monitoring a few things, running at 70 cruise on, ac on, 4~5 psi boost Inlet air temp running between 140~150F.

Is that about normal or what are the rest of ya all seeing out there?
 
I have an intercooler and its around 70. Im going to mount a fan on the backside and see the difference its makes from there.
 
Those temps seem about normal, IAT doesn't really start to climb until you get above 10 psi boost, and then the gradual slope going IAT up with higher boost, turns into a pronounced elevated rate of rise doesn't go straight up but if you didn't have high IAT defuels I see where it could start to resemble a straight line up.

OAT (ambient) has a lot to do with the rate of rise & peaks as well.

When I was running the ATA IC generally IAT ran no more than 30*F higher than OAT on a 10+ psi boost condition
 
I had a thread I started a while ago on the other forum, and before my intercooler on a 100 degree day towing our 9000lb trailer at 55mph I would be just over 200 degrees IAT, when we would get to any incline it would climb to 304 on long grades. After the intercooler I saw 105 or so on a 100 degree day pulling same trailer, same section of freeway, and 140 IAT towing same grades that put me at 304 before.
 
Crankme69 said:
Wow that's mighty hot. A 200F drop has gotta to help a lot of things.

The IC is prolly gonna get added to my things ta DO list

I'll have to search the other place for it, thanks!
Click to expand...

Those readings were from a GM-X turbo?

Not very efficient turbo. TD had I/C aND ATT and while he needed the I/C with the GM-X, removed it with the ATT as it was cool enough IAT's.

For what it costs for both, I'd try the ATT first, then if you still need the IC, at least you alraedy have a way better turbo.
 
The numbers I posted "running at 70 cruise on, ac on, 4~5 psi boost Inlet air temp running between 140~150F." are running my stock OEM GM4 turbo, but with my OEM airbox was cracked & fudged up so I modded last winter, see pic.

I have added a ho-made cover to the top of airbox since I posted this & it appears to have dropped my IAT numbers slightly, not much.

Gonna start checking local junkyards for the K47 97 up airbox...to change mine out. Wonder how much difference if any it will make on the IAT's? I will verify but there are so many variables to consider that effect IAT temps that even with the data it will always be something to debate IMO.
 

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1999gmc said:
I had a thread I started a while ago on the other forum, and before my intercooler on a 100 degree day towing our 9000lb trailer at 55mph I would be just over 200 degrees IAT, when we would get to any incline it would climb to 304 on long grades. After the intercooler I saw 105 or so on a 100 degree day pulling same trailer, same section of freeway, and 140 IAT towing same grades that put me at 304 before.
Click to expand...

That is similar to my experiences pulling 18K g/n trailer, ICs work no bout, adoubt it :D they can be expensive and somewhat difficult to install especially in a 1500 truck.

That was with GM-8, since going ATT I've pulled 7K trailer sans IC and seen maybe 250F IAT thus far, before I head back to Ms from NY this fall I'll have my WMI installed,

There is from my experience, is a minor performance loss with a IC, but the cooling medium is free for the asking and unlimited, vs refill of a WMI tank and potential of mechanical component failure (pump/switch/nozzle).

One has to assess per their own situation which will be best for them, since I'm not a daily heavy hauler, and I've since swapped to ATT, I no longer have a need for the IC on my truck, I think I'll install it on my burb since it's paid for or sell it and run WMI on the burb as well as burb now is also ATT equipped.
 
Crankme69 said:
Wonder how much difference if any it will make on the IAT's? I will verify but there are so many variables to consider that effect IAT temps that even with the data it will always be something to debate IMO.
Click to expand...

IMO not much of a debate really, just look at your own numbers later this summer, does your IAT read higher in the summer or in the winter months, my IAT is always cooler in winter, anything < 70F ambient knocks back 30+F post turbo temps depending how hard into the manufacturing of boost I am.

How much power is lost with higher IAT can be measured with some math or on a dyno, is it huge; probably not enuff for you to feel it by seat of pants in normal driving, could be the difference between making 100 mph vs 115 max mph.

There is enuff power margin in a engine on flat grade empty 70-75 mph won't matter either, at grade with a load ? it could be the difference between overheat and non overheated engine, as you say variables and health of ones own engine play a significant contribution to the question.

But for me since the 6.5 is so heat challenged to begin with I prefer to not introduce any additional heat regardless of amount, into the mix. Lot of cold air induction air kits out there, way overpriced IMO for what you get, low on the bang for buck scale of things.

But a common denominator I see in all of them is isolation of under-hood air into the air stream, so it must be something that the folks with sharp pencils consider to be important.
 
Turbine Doc said:
IMO not much of a debate really, just look at your own numbers later this summer, does your IAT read higher in the summer or in the winter months, my IAT is always cooler in winter, anything < 70F ambient knocks back 30+F post turbo temps depending how hard into the manufacturing of boost I am.

How much power is lost with higher IAT can be measured with some math or on a dyno, is it huge; probably not enuff for you to feel it by seat of pants in normal driving, could be the difference between making 100 mph vs 115 max mph.
.
Click to expand...

When I'm driving in 90-100 degree days I sure as hell can feel the lack of power compared to normal days, or the opposite effect when its below freezing.

In the winter I boost up to 9-10 much much easier then I do when its hot out. And its not hard for my truck to boost to 10, I have to limit it with my foot so I don't code. My truck feels bogged down when its extremely hot out. Crisp clean and quick when its really cold out.

Must be the IAT's.
 
No doubt it's the IAT's Matt.

Where I work we operate a million pound an hour self powered recovery air compressor with a turbine to start it & maintain the speed at the Cat Crackers unit in a refinery. The compressor efficiency losses due to inlet air temps are recorded in history and are very obvious. We have over 12 years of historical data on tap.

I will be gather some data of my own to prove to myself the effects of the different air intake sources, I can't help myself I'm an old data junkie lol!
 
Crankme69 said:
I will be gather some data of my own to prove to myself the effects of the different air intake sources, I can't help myself I'm an old data junkie lol!
Click to expand...

Data is good, I grew up as an operator/data taker myself from back in my USN gas turbine days, it's hard to part with the desire to know, and the reason why my "temporary" turbo drive pressure gauge is still hanging from my center dash cup holder 3 years almost after I started experimenting with my ATT.

I need to rig a device to read my MAF that would be fun info to have along with rest of the stuff I've been accumulating on this beast over the years, have also been contemplating installing a flow meter to know just where my exact fuel mpg "sweet-spot" is.
 
Turbine Doc said:
Data is good, I grew up as an operator/data taker myself from back in my USN gas turbine days, it's hard to part with the desire to know, and the reason why my "temporary" turbo drive pressure gauge is still hanging from my center dash cup holder 3 years almost after I started experimenting with my ATT.

I need to rig a device to read my MAF that would be fun info to have along with rest of the stuff I've been accumulating on this beast over the years, have also been contemplating installing a flow meter to know just where my exact fuel mpg "sweet-spot" is.
Click to expand...



Got my attention there!
 
Crankme69 said:
I would really like a small display screen (like they have for the newer rigs...hint hint) that we could monitor / access the info from GMTD Scan with.
Click to expand...

Folks that could provide such a device consider us a market opportunity to not bother going after since regular production for the 6.5 ceased rite about the time the Diesel performance community started getting popular, and since we do have some finite limitations of our engine design that lets us top out where the newer Diesels start building for power we don't have too many options unless it is something "home-grown" within our community.

A mistake IMO as many thousands of 6.5s still roaming the hi-way.
 
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