Intercooler performance, maybe not so good

[ISX]

Alright so we all saw the youtube by now with the 2 gauges. Well that was a spearco intercooler... I was looking at a thread on CF and noticed a guy from diesel power mag said after stock boost numbers, the stock intercooler would start to fall on its face. Meaning anything over ~20psi. When they did their test they registered a 73F difference over ambient. They then swapped in a BD fancy intercooler and it maintained 10F over ambient max. This apparently made a 250F EGT difference. Now this was on a 1998 12 valve and one guy told me the VP44 trucks have intercoolers that flow 8% better, though I'm not sure. Still, testing needs to be done. Mike sees a good bit higher IAT than ambient and says the coolant heats the air but I am wondering if the intercooler heats the air as boost raises and sorta takes the place of the hot coolant. If he has a lot of boost then there is a lot of air flow and I am not sure it would gather much heat from the manifold. I think there is a balance act going on between intercooler heat and manifold heat between low and high rpm but I would have to test this to be sure.

[Mopar1973Man]

Mike sees a good bit higher IAT than ambient and says the coolant heats the air but I am wondering if the intercooler heats the air as boost raises and sorta takes the place of the hot coolant. If he has a lot of boost then there is a lot of air flow and I am not sure it would gather much heat from the manifold.

My +40*F offset is measured at 0-5 PSI of boost. Right now its a +50*F offset because my winter fronts are still in. (30-35*F outside temp = 80-85*F IAT)

[JOHNFAK]

Don't know but I read on CF that a number if very high HP trucks run stock intercooler

[ISX]

Try this again. The High HP thing is interesting and I wonder if that means the intercooler is actually good. There is obviously conflicting stories so I shall set out to figure it out. Of course mind doesn't have any of that coolant in the intake manifold crap to skew the results.

http-~~-//youtu.be/gECw7g_iAos

Also, where is this coolant? My 12V intake manifold looks identical. Eidt: more I look um, is the IAT on yours actually screwed into the actual head as in straight into a valve channel?

[War Eagle]

Alright so we all saw the youtube by now with the 2 gauges. Well that was a spearco intercooler... I was looking at a thread on CF and noticed a guy from diesel power mag said after stock boost numbers, the stock intercooler would start to fall on its face. Meaning anything over ~20psi. When they did their test they registered a 73F difference over ambient. They then swapped in a BD fancy intercooler and it maintained 10F over ambient max. This apparently made a 250F EGT difference. Now this was on a 1998 12 valve and one guy told me the VP44 trucks have intercoolers that flow 8% better, though I'm not sure. Still, testing needs to be done. Mike sees a good bit higher IAT than ambient and says the coolant heats the air but I am wondering if the intercooler heats the air as boost raises and sorta takes the place of the hot coolant. If he has a lot of boost then there is a lot of air flow and I am not sure it would gather much heat from the manifold. I think there is a balance act going on between intercooler heat and manifold heat between low and high rpm but I would have to test this to be sure.

I haven't seen the You Tube video so I am not sure if there is something about it that is confusing or if the engineering/science of it is in question so I am going to jump in here and say something in an attempt to answer what I think your question is about. My challenge is to not make a long winded response here. First off I don't have any real engineering data or test data at my finger tips but when you compress air it heats up big time. Such as the compression that takes place in your cylinders. In your cylinder when you compress the charge it heats up high enough to ignite the fuel. I am guessing that temp is somewhere above 200+ of degrees. Well when your turbo compressor sends compressed air to your engine, that is heated air from the compression process of your turbo charger. I don't have specific knowledge how much heat gain takes place there but it will be less than what occurs in your cylinders, but never the less the air moving into the combustion chamber would be expected to be much higher than ambient air. Hot air contains fewer O2 molecules per given volume than does cold air so if you can cool the pressurized air to lower temps you can shove more O2 molecules into the cylinders than if you didn't cool the air. AS you know the more O2 molecules you have available the more fuel you can burn and thus the more power you can generate. So the intercoolers function is to cool the charged air so your engine can generate more power. Now I am not going to discuss the science and engineering that goes into heat transfer but let's suffice to say that without your intercooler your engine intake air would be much hotter and therefore not capable of generating the power of any intercooled engine (assuming the intercooler is sized appropriately). So there are formulas that can calculate the O2 molecules available per volume and per given pressure and per given temperature. They basically say that as the volume remains the same and the pressure goes up and the temp comes down then the O2 increases. I can't say how much of a temp increase occurs due to the air flowing through the hot intake manifold but that would occur even without your intercooler. The intercooler (by design) is placed in front of the radiator so as to avoid picking up heat from the radiator and thus limiting the possible transfer of heat out of the intercooler from the the charged air before it goes into the cyclinder. When the ambient air is hot outside and flows across the intercooler you will not get as much cooling of the compressed air going into the cylinders as you would on a cooler day but it is still better than having a turbo charged non-intercooled engine. The colder you could make your fresh air intake, would then help limit the air temp climb that occurs during the compression process and thus help limit the air temp that goes into your cylinders. In the race arena, it is not uncommon to find efforts being made to cool down the intercooler with ice or LNG so that the intake air is as cold as they can get it in an attempt to have more O2 so as to burn more fuel and make more power. Hopes this helps.

[Mopar1973Man]

I've seen oon 12V's where the same 1/2" pipe plug there are 2 of them under the manifold which are also coolan passages. Where on the 24V head they are not present except the one in the rear. But yes I've check the 1/2" plug on mine and yes its coolant passage with in about 2" of the IAT sensor.

[JOHNFAK]

The colder you could make your fresh air intake, would then help limit the air temp climb that occurs during the compression process and thus help limit the air temp that goes into your cylinders.

but thinking out loud ..... this goes against mikes theory of warmer air = better effeciency/mpg. eg his IAT design seems on diesels its has more to do with CFM than temps ....... but thats just from seeing high HP and efficient engines with stock intercoolers. Alos backing this up is the increased efficiency you can get from head porting (supposdely) over things like intercoolers/cold air intakes. Kinda makes you wonder why BHAF/BIG RAM intake /intercoolers and such dont really seem to net anyone anything under 500+ HP .....

[diesel4life]

but thinking out loud ..... this goes against mikes theory of warmer air = better effeciency/mpg. eg his IAT design .....

Fuel effieciency and horsepower : almost never go hand in hand. Colder air most definitely will make better horsepower, my cousin races a stock car and loves running at night because the cars all pick up a few extra ponies running that high test fuel compared to running during the day when its well above 90 degrees. With the IAT mod its more about manipulating the timing to maintain fuel mileage because with the colder the air temps the more the vp retards the timing to remain emission compliant. Without any IAT mod I think it is beneficial to run a filter thats drawing air from the engine compartment rather than down by the front bumper, but I could be wrong... But going back to the cold air intake Ive seen a few people put them on turbo charged vehicles because they fell victim to the hype...personally I dont see where they really made much difference. Just my opinion

[War Eagle]

but thinking out loud ..... this goes against mikes theory of warmer air = better effeciency/mpg. eg his IAT design seems on diesels its has more to do with CFM than temps ....... but thats just from seeing high HP and efficient engines with stock intercoolers. Alos backing this up is the increased efficiency you can get from head porting (supposdely) over things like intercoolers/cold air intakes. Kinda makes you wonder why BHAF/BIG RAM intake /intercoolers and such dont really seem to net anyone anything under 500+ HP .....

I can't dispute simple chemistry and physics. The cooler the temperature of the air charge the greater the O2 molecules you can get into a given volume. Pressurize that charge and keep it cold you can pack in even more. Add fuel and you make more power. Creating tons of power may not net you better mpg. I interpreted the discussion was about making power relative to intake charge temp. Now if you start messing with timing and duration for the purposes of emission then you can change how much power you make and how well your engine will run and what temp it likes it's aircharge etc. All of this will impact the power you can make as well as the mpg's you might get for a given power.

[Mopar1973Man]

Fuel effieciency and horsepower : almost never go hand in hand. Colder air most definitely will make better horsepower, my cousin races a stock car and loves running at night because the cars all pick up a few extra ponies running that high test fuel compared to running during the day when its well above 90 degrees. With the IAT mod its more about manipulating the timing to maintain fuel mileage because with the colder the air temps the more the vp retards the timing to remain emission compliant. Without any IAT mod I think it is beneficial to run a filter thats drawing air from the engine compartment rather than down by the front bumper, but I could be wrong... But going back to the cold air intake Ive seen a few people put them on turbo charged vehicles because they fell victim to the hype...personally I dont see where they really made much difference. Just my opinion

Few things you can't mix MPG and racing to together that's a apple to orange comparison.

As for cold air intake your turbo discharge is still going to be high.

http-~~-//www.youtube.com/watch?v=nf7ladNL7V8

Once again comparing gasoline naturally aspirated vs. diesel turbo charged that's another apple to orange comparison.

VP44 advances the colder the air.

VP44 advances with low to zero boost.

VP44 retards with hotter air.

VP44 retards with high boost.

Which also follows the Autoignition Temperature...

The autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external source of ignition, such as a flame or spark. This temperature is required to supply the activation energy needed for combustion. The temperature at which a chemical will ignite decreases as the pressure (Boost) or oxygen concentration increases. It is usually applied to a combustible fuel mixture.

(My theory)

Basically if the intake air is a bit warmer than typical then the diesel fuel is injected and can convert to vapor faster and ignite faster than colder air giving the illusion of advanced timing. Being that cold air below 100*F IAT temp will reduce MPG for every 10*F below 100*F I typically lose about 1 MPG. So at 80*F IAT I typically lose -2 MPG's. With the dead of winter with 20*F IAT temps I was down to 14 MPG's. Cold air is NOT MPG friendly with diesels. Also keep another though going.

Why did Cummins add a grid heater to heat the air if the temperature was below +60*F IAT?

Maybe it was inefficient at low IAT temps? I know the coolant jacket is also... Just food for though...

Why does the MPG fooler work as explained from Quadzilla tech's.

No doubt, stabilizing the IAT will help, I agree 110%. There is a too low and a too high number. If the IAT drops too low the ECU retards the timing just like too hot due to fears of detonation and stabilitiy of combustion in diesel fuels. No doubt winter blend fuel hurts this as well.

So you can definitely stabilize things but, I think the anomoly in the summer time is that when running a box with timing advance you actually get a steeper timing advance curve from the box by fooling the IAT.

The way the timing and fueling works on the can bus on these trucks is that we all just basically go to the MAX allowable advance and fuel number as soon as the VP computer will let us without locking it up. We can physically demand more fuel and timng but, the VP computer will shut down thinking there is an issue. As a matter of fact our peak numbers for fuel and timing can already be reached on a stock truck, its just that we can re-shape that curve and reach those max #'s when and where we want.

So basically fooling the IAT retards the timing and the box sees the opportunity to make an even bigger change going to max and it does it sooner.

Sort of complicated but, I can see where it works.

What we need to do on these older trucks is some tracking of the IAT across the actual timing advance range at the pump and not via the OBD port since its slow and suspect on that sort of parameter, I know when we start changing the fueling the timing numbers the obd reports some weird stuff that is not exactly right.

[diesel4life]

Hmm, I certainly wasnt comparing mpg and racing as you put it (read first sentence in previous post).Nor was I comparing turbocharged to naturally aspirated engines I was making examples of now each react differently to a CAI.

[JOHNFAK]

Guess what I mean is why don't air intake pushers , intake filters , intercoolers and everything else pre ignition make any measurable difference to our trucks