After all this talk about intercooling I decided to run some simulations using Performace Trends EA pro 3.3 simulator-http://www.performancetrends.com/Eng...r_Pro_v3.3.htm
This is a powerful simulator with a retail price of 469$.
The results are pretty interesting. And it appears what is going on with intercooling is not so simple. In any case intercooling makes more power, but the biggest power increase is from reducing temps before the air is ever compressed.

The engine is modeled after my combo using a G-trim blower.
I ran 4 comparisons with and without an intercooler. The intercooler is modeled to out flow the blower to take any restriction out of the mix.
I used 22' peak timing, 100 octane- rich gas and did not change that for any of the tests.
Sim 1= no intercooler with 85' ambient and 50% humidity at sea level
Sim 2= a 50% efficient intercooler with same weather conditions
Sim 3= a 100% efficient intercooler with same weather conditions
Sim 4= no intercooler with 45' ambient,50% humidity at sea level.

Well the results are interesting. No intercooler and 85' ambient shows the lowest power, highest tendency to knock and intake port temps and boost are just about exactly what I saw in real life of 190-200' and 13psi.
Adding a 50% efficient intercooler drops boost about 2psi and reduces charge temps from 190 to about 135'. Again almost exactly what I see in real life! However power is increased slightly. And it seems the biggest data change is VE% is increased by the addition of the intercooler.
Adding a 100% efficient intercooler drops boost about 3psi with intake port temps reduced to a whopping 73'. Again power is increased by a better VE%, better thermal efficiency, and some work loss changes.
And the last sim was to demonstrate that density changes before the blower have the most effect. And the results show this very clearly.
Dropping ambient temp to 45' with no intercooler shows the most power even though intake port temps are 100' higher than the 85' ambient with 100% efficient intercooler combo.
I could have run a sim with an intercooler and the 45' ambient and shown even more power of course. Also when looking at the data screen shots below, Knock index numbers greater than 1 indicate detonation could be a possibility.
The lowest tendency to knock was of course with the intercoolers. Timing could have been advanced in those sims to make even greater power.
Here is the graph and output data for each sim.

 

Cool.....so when it gets to 45 again, my Incon is gonna kick ***!!! That sounds like a very cool program. Thanks for sharing the info.

 

The software is very powerful and you can do a TON with it. Makes something like dyno2000 seem pretty weak. Looks like I was wrong with some of my thinking about intercooling.
VE% is improved with intercooling!
Just for kicks I just ran the 45' ambient combo with a 50% efficient intercooler and it picked up 22hp and with much less chance of Knock.
This shows intercooling becomes even more powerful with better air going into the blower or turbo, as a 50% efficient intercooler only showed a 14hp increase with the 85' ambient temps.
Peak VE rose from 158% to 164% with the intercooler.
So even though intercooling after the charge is compressed can't increase oxygen %, it still adds power from VE% increases and maybe some pumping work.
If the intercooler is not a restriction then it's all good.

 

Cool, thx!

 

FWIW, a normal intercooler should be able to fetch you 70 to 80% efficiency without any problems.

 

Intercooler efficiency varys quite a bit with changing conditions.
I used 50% and 100% just to show the trends clearly in the sims.
Also these sims are modeled with a perfect intercooler causing no flow restriction. A poor flowing intercooler is not going to have real world results that equal these sims.
In the other thread the person asked about running c16 with no intercooler.
Running a sim with c16 and no intercooler with the good 45' air, shows about the same knock index as a 100% efficient intercooler and only 93 octane with my combo.
But a lot more power is made with the intercooler and 93 octane, again from what looks like VE increase.
Using 100% alcohol fuel and no intercooler shows about the same intake port temp as a very good intercooler with gas but with even greater power from the alcohol fuel properties.
So if I were building a drag only car without an intercooler, alcohol fuel is certainly the way to go.
Don't know why I did not run these sims a while ago. Just to lazy I guess.
Steve

 

NoGo, I had thought most of the intercoolers were that efficient, but finally got a chance to look at some data. Even some of Garrett intercoolers are only about 50% and only a couple get close to 80%.

Gary

 

How much oxygen in 408 cubic inches of air at 13psi@ 160 degrees? How about 408 cubic inches of air at 11 psi@95 degrees?

 

A 50% effeciency from the intercooler indicates that the intercooler or connected tubing has been sized improperly.

A properly sized intercooler will reduce the air charge velocity sufficiently enough and allow a large enough exchange area to cool the inlet charge.

An intercooler operating at 50% provides barely enough reason to beat the boost drop across the intercooler.

-Kevin

 

Most air to air intercoolers are only 50% efficient... A really good spearco core with good tanks is better than that but dont expect like 75% or something.. Especially after packaging constraints in the chassis..

Lets say we have 300* inlet and an the air temp of what is blowing thru it's OUTSIDE is 100* the differential is 200*.. A 50% efficent IC will create a 100* drop. Half the difference between ambient air temp and the compressor outlet.

You have to take into account 50% of what...

Air to water without chilling the water but just running it thru a radiator will get around 75%.... Ice that water and you are at 100% plus...

 

Nope.

Your doing the intercooler efficiency calculation wrong, and the website that you got it off of is doing it wrong as well (http://www.turbocalculator.com/intercooler.html) That is merely a ratio calculation of air temperatures.....also done incorrectly, because your suppose to do that in absolute temperature!

Intercooler efficiency is based off of the inlet temperature to the intercooler, the outlet temperature to the intercooler and the ambient temperature.

Efficiency is how effective an intercooler is at removing the temperature of the air it ingests. Being that the above formula doesn't even mention the intercooler inlet temperature, how can it possibly determine efficiency.

I will use some design calcs on S_J_H's system to determine his intercooler efficiency. Follow below.

Convert all temperature to absolute assign variable:
SJH's Reported Inlet Temp Without Intercooler = 195 F = 364 K = Tib
SJH's Reported Inlet Temp With Intercooler = 135 F = 330 K = Tia
Ambient Temperature = 85 F = 302 K = Ta

Determine Pressure Ratio's

SJH's PrePressure Ratio = (13 psi + 14.7 psi) / 14.7 psi
SJH's PrePressure Ratio = 1.884

Determine Intercooler Inlet Temp (Check supercharger efficiency, Es)
Tib = {[(PR^.28) - 1] * Ta} / Es
Tib = [(1.884 ^.28) - 1] * 302} / Es
364 K = 58.6 / Es
Es = 1 - (58.6 K / 364 K)
Es = 83.9% - His supercharger efficiency shows a little high (usually around 80% at best, most likely some small temperature measurement error), but either way it shows that his supercharger is operating in the 'sweat spot', which is good.

Determine Intercooler Efficiency (Ei): - Error, refer below

Tia = [Tib * (1 - Ei)] + Ta
Tia = [364 K * (1 - Ei)] + 302 K
330 K = [364 * (1- Ei)] + 302 K
28 K = 364 * (1- Ei)
Ei = 92%

SJH's Intercooler Efficiency is at 92%.

This is a little high as well, with SJH's intercooler, I would have expected something in the high 80's. However, as I mentioned earlier, there was a little error in the temperatures.

SJH, if you care, post up your actual temperatures that you were seeing and we can figure out your total system efficiency, intercooler efficiency, supercharger efficiency, and expected power gain.

 

I made mistake in the efficiency calc. I divide by Tib when I should have divide by the Supercharger induced temperature increase.

Intercooler Efficiency:

330 = ((1.84^.28 - 1 * 302) / .84) * (1 - Ei) + 302
Ei = 58.1 %

Lower than what I would expect. Still, if you normalise his blower effiiency to what Vortech advertises for that PR you get.

330 = ((1.84^.28 -1) / .72) * (1 - Ei) + 302
Ei = 64%....... still low, but getting to around what you should expect for an air to air.


Either way, my point being that if you are getting 50% for your intercooler then there is something wrong with the system.

 

NoGo, For a 100% efficient intercooler, EAPRO3.3 uses this definition-
If the intercooler is 100% effective, the intake charge would be brought down to its original (ambient) temperature as specified by Air Temp in the Weather Conditions in the Calculation Conditions menu with no change in boost pressure.
for typical predefined intercooler efficiency, EAPRO3.3 uses the following-


Descriptions-
0% No Intercooler -No cooling of the intake charge takes place, that no intercooler is installed.
25% Steady Runng Air-to-Air- The intake charge is brought back 25 % to its original temperature. This level
simulates a typical air-to-air intercooler which has been running continually at full
boost for over 30 seconds or more. An intercooler's effectiveness tends to drop
under sustained full boost operation as the intercooler tends to heat up.

50% Quick Accel Air-to-Air -The intake charge is brought back 50 % to its original temperature. This level
simulates a typical air-to-air intercooler for a short “burst” to full boost from a light
load condition. The intercooler will not be as hot and can cool the incoming air
better until the intercooler heats up.

75% Air-to-Water -The intake charge is brought back 75 % to its original temperature. This level
simulates a special intercooler which has a volume of water around the fins. This
intercooler is more effective because the water probably starts cooler than an air to-air intercooler and the water takes longer to heat up (has more “thermal inertia”)
than just an air cooled intercooler by itself.
100% Air-to-Cold Water -The intake charge is brought back completely (100%) to its original temperature.
This level simulates a special intercooler which has a volume of cool water around
the fins. This intercooler is more effective because the water starts much cooler
than an air-to-air intercooler and the water takes longer to heat up than just an air
cooled intercooler by itself.
125% Air-to-Ice Water -The intake charge is cooled to even colder than its original temperature. This level
simulates a special intercooler which has a volume of cold water and ice around
the fins. This intercooler is more effective because the water probably starts much
colder than the surrounding air and takes very long to heat up.
Other -Other types of intercoolers are possible which use freon, or water or alcohol sprays,
or cooling fans to keep the intercooler very cold. You will have to estimate how
well these work and select from one of the 5 choices available.

I also am able to model the cfm flow of the intercooler to determine any pressure drop from restrictions and can of course specify any efficiency number of my own choice.

Take a good look around and ask guys what their IAT temps are and not many have intercoolers near 70% efficient as supplied with kits.
Thanks for the offer but this simulator can spit out those numbers out and a whole lot more .
Those are actual temp and boost numbers. As you see the simulator was able to predict them exactly.
Charge heat buildup does not just happen instantly. It takes a while for the heat to be built up under boost. So efficiency is changing throughout a run. It starts out high and then gets worse.
The difference between a hot and cold blower alone can show a 20-30 degree change in IAT.
Steve

 

Yes I know it is done in absolutes... convert the example to absolute temp, figure out the efficiency then convert back to std temp.... Same answer right..... The point was'nt the perfect exact formula but an example of what 50% efficiency means to the lay person..

Is'nt that what I said?

Lets say we have 300* INLET and the air temp of what is blowing thru it's OUTSIDE (ambient) is 100* the differential is 200*.. A 50% efficent IC will create a 100* drop. Half the difference between ambient air temp and the compressor outlet.

Yes I got the #'s off that site and added my own words... I was looking for a good generic example..




I sure saw inlet on my first post...

About what I expect... make some back to back pulls w/o cool downs and watch it plummet.....

SJH the 50% quick accel model is also a good representation of a ducted cool air steady running system.... That is kind of like ram air thru a core... Sufficient ductwork is inplace to move alot of air thru the IC core...

Big IC with big enough opening...

The closest examples I have seen of this involved a big mouth front (big enough to expose the whole core).. The front edge of the core was right next to the body work or had a short cowl or duct around it... Then ductwork between the radiator and IC between them 360* around... The hood usually has a cowl induction look or many vents... as well as inner fender vents or other strategies...

That is one of the problems I see with real world FMIC efficiency on f bodys... Since the air dam below the rad is bringing air inbetween the IC and radiator it creates turbulance and a higher pressure behind the IC than if it was closed off on the bottom between them so due to a lower pressure differential less ambient air flows across the IC core... Flowing thru one into the other via a duct eliminates turbulance and increases the velocity and CFM...

The point is to create as low pressure area behind the core and a high pressure area at the inlet as possible in a real world car.... IMHO a cowl induction hood works best as a heat vent. It helps bring air thru the IC (if ducted) and radiator (all cars) while cooling the entire engine compartment... You can see the heat waves just roll out of them when stopped...

 

I am not disagreeing with you. Just stating the facts. Intercooler styles and layouts are not created equal. Just pointing out like anything with turbo systems you cant just get components and expect them to work well.

Gary

 

I would be interested to see what the model of your 3 examples would say when you fix the same Mass Air Flow through the various configurations.

If the Mass Air and RPM were the same through all these variation I would predict that the power should be identical and the pressure/temperature is irrelevant. You should actually lose power with the addition of the intercooler. After all the intercooler is a detonation prevention device, not a power adder.

I am suggesting that accounting for the Mass Air Flow is the controlling influence of potential power and only by maximizing the Mass of Air in the combustion chamber will the full potential be reached.

I came to this conclusion after I lost power by adding headers and needed an explanation that would consistently predict the outcome of other modifications. Improvements to the intake side of a blower seamed to hold the most promise without changing the blower configuration.

But then again I could be wrong

 

adding an efficient intercooler will usually allow increased timing and a leaner fuel mix which offsets any loss in power due to boost drop. So by itself adding an intercooler might drop power, but when you tune the car to take advantage, you should come out ahead. You losing power by installing headers is a mystery - I can only think that the tune was off.

 

Thermal efficiency is one aspect there are also pressure drops that can occur across an IC just due to airflow thru the core...

Just up the boost control a touch. A good core has a minimal drop...

 

Draco “You losing power by installing headers is a mystery.”

Just account for the Mass Air Flow, for example for a positive displacement blower
CFM is directly proportional to RPM
So by reducing exhaust pressure with the headers we see manifold pressure drop, significant flow or Mass Air must escape through the overlap, with less pressure filling the intake cycle there is less mass for combustion, further the chamber is richer than before because the MAF is still seeing the same Mass flow. The Blower is now experiencing less; manifold pressure, temperature, and power draw, but is flowing the same Mass of Air. We now have to lean out the mixture and can add timing, but I could not get the same power as before and be safe.

V8_DSM…. “Just up the boost control a touch”

Yes, this is what I did.

 

And that is how I had felt about intercooling.
However many people told me no, you are wrong and there is more taking place than meets the eye. A lot of people seemed to think the reason was because cooler denser air, somehow is flowed more efficiently through the engine.
So that is exactly why I took the time to run the sims
The simulations seem to agree that intercooling can add power without adding more boost or timing. The blower speed was held constant in all sims which represents about as much control over the mass of air as you can have.Yet TOTAL cfm increased through the motor with the cooler air and VE is increased.
The intercooler HP increases from the sims may be on the generous side as I modeled the intercooler to out flow the blower. So it shows no losses from restrictions or frictional losses. It's more theory than reality as most intercoolers will be introducing more friction and restriction to the air path.
One thing is very clear though, density/ air cooling changes before the blower have a MUCH greater impact than density/ air cooling changes after compression.
Examine the data screen shots I posted. There is more data on each sim but that's as much as would fit on a single screen shot and seemed like the most relevant parameters.
I don't think anybody will be able to come to any hard conclusions from any of this. But what the heck, it makes for some good tech talk.
Steve