Stock intercooler efficiency
07-27-2006, 02:27 AM
#31
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I gained a decent amount of horsepower at higher than stock boost levels. I did a comparison a while back. (Using larger pipes and large intercooler) Here is the link. https://rennlist.com/forums/showthre...6&page=1&pp=15 The dyno comparison is most of the way down on the first page, along with an explination. I think anything over 300hp will benefit greatly. (Relative I guess)
07-27-2006, 03:03 AM
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Originally Posted by toddk911
Ok.
I thought, last this topic was discussed, there was not confirmation that the boost guage that is T's from KLR was getting reading from the manifold?
Even if that is the case, how could the WG modulate the before and after pressure drop?
I thought, last this topic was discussed, there was not confirmation that the boost guage that is T's from KLR was getting reading from the manifold?
Even if that is the case, how could the WG modulate the before and after pressure drop?
07-27-2006, 02:17 PM
#33
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Originally Posted by azmi951
Just a clarification, efficiency and effectivness are different calculations and use different parameters.
Efficiency is dependant on cross flow temperatures and mass flow rates and can be modeled as a simple system. It is something that is so heavily dependant on dynamic test conditions that it is kind of worthless unless compairing A to B or if you are always operating at steady state.
Effectiveness is a UNITLESS number that evaluates the overall performance of a heat exchanger based on its mechanical design and negates all cross flow conditions and flow rates. Some of the mechanical properties that nare needed are fin area, fin design, fin spacing, all the reynolds, nuselt and prantel numbers and convection coefficents, but it does not need any temperatures of cross flow fluids.
Effectiveness takes the variables out of evaluating a heat exchanger so it is based on only what does not change.
Let me play devils advocate and ask how do you KNOW for sure that peak inlet and peak outlet temps happened at the same time?
Could there not have been some kind of heat soak that would give false readings? I dont know but I could not put my confidance in it being the same. That is the engineer in me. Also I recently had a class called "heat transfer" where we investigated this type of stuff on a more basic level. I tried to calculate the effectivness of the intercooler but could not due to the complexity of the calcuations. I used the NTU Method for seperated perpendicular flow heat exchangers.
Efficiency is dependant on cross flow temperatures and mass flow rates and can be modeled as a simple system. It is something that is so heavily dependant on dynamic test conditions that it is kind of worthless unless compairing A to B or if you are always operating at steady state.
Effectiveness is a UNITLESS number that evaluates the overall performance of a heat exchanger based on its mechanical design and negates all cross flow conditions and flow rates. Some of the mechanical properties that nare needed are fin area, fin design, fin spacing, all the reynolds, nuselt and prantel numbers and convection coefficents, but it does not need any temperatures of cross flow fluids.
Effectiveness takes the variables out of evaluating a heat exchanger so it is based on only what does not change.
Let me play devils advocate and ask how do you KNOW for sure that peak inlet and peak outlet temps happened at the same time?
Could there not have been some kind of heat soak that would give false readings? I dont know but I could not put my confidance in it being the same. That is the engineer in me. Also I recently had a class called "heat transfer" where we investigated this type of stuff on a more basic level. I tried to calculate the effectivness of the intercooler but could not due to the complexity of the calcuations. I used the NTU Method for seperated perpendicular flow heat exchangers.All this “heavy artillery” is useless if not used correctly or only marginally useful if only used to question empirical numbers that at least make some sense.
Btw, most of these “ugly” equations are already embedded in commercially available computational fluid dynamics (CDF) software such as Fluent (http://www.fluent.com/) and many others.
On a board like this we will never get a truly in-depth analysis, but we can get quite close to answering the question: “Is this modification worthwhile compared to other available choices?” by simple and common sense analysis based on empirical data as “tedesco” has started presenting.
To answer your “Devil’s advocate question”, I think the two peak numbers were fairly close time-wise and if not, the error is likely miniscule.
I don’t have specific experience in the terms used for heat exchangers, but do have some general knowledge of both fluid dynamics and thermodynamics. Efficiency normally has to do energy conversion efficiency and therefore is unitless. Effectiveness has many meanings, but the particular formula I presented was lifted out of MacInnes book “Turbochargers” and it also passes the common sense tests of 0% effectiveness at no temperature drop and 100% for a temperature drop to ambient.
It shouldn’t be too difficult to calculate the power increase going from a standard IC to the apparently 90% efficient intercooler that “Corleone” is referring to (30ºC out at 20ºC ambient), based on simple assumptions such as no boost increase using PV=nRT.
It is always possible to muddy the waters with details to get the “exact number”, but using that formula will certainly get it close enough for my comfort level.
Originally Posted by azmi951
But dont get me wrong, I love to see this type of info and discussion, keep it up.
Laust
07-27-2006, 02:19 PM
#34
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Originally Posted by 95ONE
I gained a decent amount of horsepower at higher than stock boost levels. I did a comparison a while back. (Using larger pipes and large intercooler) Here is the link. https://rennlist.com/forums/showthre...6&page=1&pp=15 The dyno comparison is most of the way down on the first page, along with an explination. I think anything over 300hp will benefit greatly. (Relative I guess)
Laust
07-27-2006, 05:01 PM
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To the engineers on the thread:
Are they any heat exchangers around that could be adapted to an automotice IC ? i.e. something cost effective that was jsut not looked as being used for an intercooler?
Are they any heat exchangers around that could be adapted to an automotice IC ? i.e. something cost effective that was jsut not looked as being used for an intercooler?
07-27-2006, 05:19 PM
#37
For every 5 degrees C lower temp you will gain 1% power/torque or moore correct (273+T2)/(273+T1). Of course the pressure drop will also have its meaning. The higher boost/power (air volume) you will have as moore important the pressure drop will be. Thats why it will be better with a "bigger" IC (larger square surface at the tank inlet) as moore boost you have as the pressure drop will be lower.
07-28-2006, 12:13 AM
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Originally Posted by Laust Pedersen
Nice to know, but since intercoolers really like lots of (ambient) air flow, dyno results will show a bigger gain for a more efficient IC, that real driving will.
Laust
Laust
I can't beleive you have a Jalpa! My friend (His dad) used to own one in the 80's. We thought we were pretty cool driving around. I really liked it.
End result for the larger / more efficient intercooler. ... More power. So, for guys like Special tool who don't have much more to go to.....I think I remember him saying he's still on the stock core.
