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Intake Air Tempuratures

Paveltolz

Paveltolz

Доверяй, но проверяй
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Location
Saratoga Springs, UT
Question - I've a temperature gauge to monitor IATs that reads 100-280F. However, I've managed to misplaced the tempurature sender before I got around to intalling it.:eek:

Checking the manufacturers web site, the difference between the 100-240F and 100-280F senders is $30 ($27 vs $57).:???:

I don't know what would be considered Normal since I haven't monitored IATs till this week nor do I recall seeing much dialoge on the subject. Searching the site revealed only this little tidbit from the Tech Library, "Significantly higher in turbocharged and supercharged engines due to the compressed air being warmer."

Do I need the extra 40 degrees of monotoring? I've been using my OBD-II reader to check things out and I'm not seeing anything over 120 and today's high here was just under 80F. Then again, what War Wagon sees in Phoenix during July and August might be of interest.

Seems to me if IATs got to 240F that would indicate a bigger issue than knowing if they were at 260 or 280.

Somebody help me avoid another learning experience by purchasing another wrong non-refundable part:hihi:

Thanks
 
I've done a little monitoring of mine with my lap top GMTD scan program. Mine would run on a 90 degree day avg 135~150 & at wot it would spike over 200.

Now this is based on my memory & I'm getting old & senile so take it for what it's worth...:scratchchin:
 
"For what its worth."

It is worth a lot and I thank you both and any others that help me or anyone else. Thanks.
 
Mine runs at about 3lbs boost at 70ish mph with my custom program & my patented screen door spring helper (LOL). When I stab it WOT the boost will spike to 15~18lbs & then level off at 13ish until it shifts into OD then it drops with rpms to about 10ish.

My EGT's run around 500 at cruise & at wot will spike to about 1000ish.

All info with no trailer running empty & all info from my feeble memory...

HTH's
 
Since i have put my K47 air intake i run around 135-161. 135-141 at around 4.5 pounds of boost, 145-155 at 5.5 pounds, and 6-7 pounds of boost is around 155-161. This is going 70mph. Hope that helps
 
Yes, it all helps and thanks. I was doing some research in the manuals on another topic and "the General" says the IAT's range is -40C to 151C, -40F - 304F so there are some extremes built in to the system. "The IAT sensor sends a signal to the PCM relative to the incomng air...[which] is used by the PCM to adjsut fuel delivery."
That helps explaine the weirdness when I was using that wooden "throttle body" spacer with the IAT affixed...no ground, no signal and a PCM "lost". Probably a default setting utilzed in the mean time.

I'll see if the manufacturer will be able to provide a sound and economical answer. Wanna bet they recommend the $57 vs the $27 part?
 
And I,ve had some recollection that iat,s reported to actually drop if boost is increased, using a tm ,from stock, up to 12 lbs or so before increasing? Something to do with getting more cool air into cylinder ?
 
Diesel -T said:
And I,ve had some recollection that iat,s reported to actually drop if boost is increased, using a tm ,from stock, up to 12 lbs or so before increasing? Something to do with getting more cool air into cylinder ?
Click to expand...

Depends.

More air into the cylinder (higher boost or more air mass) at the same fueling rate means the engine goes "leaner" compared to lower boost.

Diesels are the opposite of gas engines in the regards to lean/rich and hot/cold.

A "lean" diesel is actually a cooler running diesel and a rich one is hotter. (IOW - more fuel -richer mix - hotter egts)

Crank the boost up without adding fuel and it "leans out" the enigne, which makes it run cooler.

Well, until the turbo moves out into the ineffecient part of the turbo map and increases IAT unacceptably or creates a big enough restriction in the exhaust that a thermocouple sees higher egt's.

Diesels can be seen to run anywhere from 3:1 to 40:1 airfuel ratios. 40:1-ish being idle (little fuel, little heat, little power) and 3:1 being "coal rolling" smokescreens (lots of fuel, lots of heat, lots of smoke and lots of power-maybe).

I've seen a few figures for "optimum" burning bounced around in discussions, but the most common one seems to be 14.54:1 A/F ratio for diesel.

However, real world experience (after talking to a couple "dyno guys") seems to indicate that 14.54 is too "smokey" and somewhere around 18:1 gives the best balance between power and "smoking" in most diesels they've tuned.

My results after playing around with tunercat and tuning my 6.5 so far seem to bear this out. Although I have no way of measuring the A/F ratio right now. I'd pop a wideband sensor into my diesel's exhaust, but I think the soot would kill it in short order....
 
Last edited:
Diesel -T said:
And I,ve had some recollection that iat,s reported to actually drop if boost is increased, using a tm ,from stock, up to 12 lbs or so before increasing? Something to do with getting more cool air into cylinder ?
Click to expand...

Tom, I would bet you meant EGT's
 
Spoke with a friend tonight that saw his IATs hit 278F before defueling. Then again, he was running 110+mph at sea level in the summer.... Doubt if I'll get there but if I did I guess the 280F sensor would be the right choice.
 
I have seen temps approaching 300F as well, running way too much boost of course and going too fast. I also still pull air from under the hood, something to change soon.
 
My truck cruises 135*-161* factory tuning, 3-4.5 psi at 60mph, spikes 9 psi boost and 161* is only as high as I have seen with cruise set at 60 mph.
 
If you're pulling any kind of load up a long hill you should see IAT in the 250-300 range even with the ATT. I can set mine on a sustained 10 pounds of boost and my ScanGauge2 will "peg" at 299 degrees F. Then the EGTs start looking for 1200+. Now I'm talking about a hill that takes several minutes of sustained power with a load of 7500 pounds or more (15k combined). My stock PCM would start to defuel at 220*F. Now I just keep an eye on the EGT and keep it under 1200 with my right foot.

I've got an auto transmission temp gauge tapped into the upper intake manifold. 0-280, and I've had that pegged, too. The ScanGauge reading from the DTC port is a lot faster response.
 
Thanks Oregon HT. I understand the stock PCM will start defueling around 275.
I spoke with the service techs and they said they don't recommend the gauge since it is for water and the sensor won't read air that well. They do have an Intake gauge but they haven't perfected the sensor yet so I'll have to wait. Good of them to keep me straight and not sell me something I don't need. If I start towing anything besides single sod pallets etc around, I'll hook up my scan gauge to get the IATs (good suggestion).
So, with a Transmission pan that won't accept the tapping for the tranny sender and a water temp gauge I haven't decided what to do with, I have a hole in my Three gauge pillar that needs a job. Fuel Pressure...guess so.
 
I have the same thing, my top gauge is filled with the tranny temp, but not hooked up & I am thinking I would rather have the fuel supply pressure there as I don't often tow anything.

So what fuel pressure gauge & manufacture do ya recommend?
 
I'm annal retentive so I'll go with one from ISSPRO as it will match the EGT and Boost gauge. Only issue is I need to find a seperate vendor for the hose to the isolator as the low pressure gauges are mechanical and, as printed on the ISSPRO and other gauge sites, must be mounted outside otherwise. So, add a few more $$ to the plan and move forward. ISSPRO doesn't offer it.

Next month...I'm over budget for toys this month.
 
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