intercoolers...

[greasemunkey]

well i was looking into intercoolers because im retarded about most all things turbo and i wanted some more knowledge on how they work, but anyways, i just found this in wikepedia "The thicker and larger the intercooler, the more turbo lag it produces. A larger intercooler typically contains a larger volume of air which increases the times needed to put the intake tract under pressure." is this true? i always thought of intercoolers as big intakes...the bigger the more air can be sucked in when i want to accelerate

[Bballjamal]

I never really understood why I saw boosted civics (etc) with huge ass intercoolers that took up the entire stock bumper space, yet saw insane cars at the track running smaller, more efficient units....

I thought there was something I might not have known but I haven't gotten a good explination yet on why

All I can really see is;

-bigger cooling 'catch' area
-more air/cooling capacity needed for higher bar


Yet, I see 700+hp cars with a regular sized unit that fits perfectly

[japan4racing]

I never really understood why I saw boosted civics (etc) with huge ass intercoolers that took up the entire stock bumper space, yet saw insane cars at the track running smaller, more efficient units....

I thought there was something I might not have known but I haven't gotten a good explination yet on why

All I can really see is;

-bigger cooling 'catch' area
-more air/cooling capacity needed for higher bar


Yet, I see 700+hp cars with a regular sized unit that fits perfectly

alot of that has to do with efficiency. a turbo is basically a compressor. when you compress air it heats up. so if your turbo is not working efficiently its gonna produce more hot air that if it were running efficiently. alot of ppl rather than getting the proper turbo and running in its efficiency range take the cheaper route and get a bigger intercooler. i actually have one of these huge intercoolers on my car but simply becuase the price was right and the intercooler i had heatsoaked way to easy. there is a bunch that goes into choosing your properly sized intercooler but for your typical street car its not usually made into a big deal. i did not notice any power loss or rediculous lag when i hadd a larger intercooler to my set-up....but the cold side of the intercooler is alot cooler now so i know my intake temps are better. thats al that matter to me right now in my street car...cooler intake temps = more power and less chance for detonation

[japan4racing]

ppl commonly mistake and intercooler as a kind of intake..no air enters the system at all through the intercooler..same with i/c sprayers...no nitrous is introduced to the system. they work like radiators/heat exchangers. and yes you can effect the lag by introducing more/bigger piping or larger intercoolers....obviously in order to hit your boost mark you have to pressurize the system and with more area to pressurize it will take longer..sometimes its noticeable and sometimes its not.

[greasemunkey]

+1 ty

[Dietcoke]

Your intercooler is going to flow a certain amount (CFM) of air. There are two important factors CFM notwithstanding that you have to consider. 1: efficiency and 2: pressure drop.

The former, efficiency is pretty basic.
Temp In-Temp Out
------------------------ X 100 = Thermal Efficiency
Temp In-Temp Ambient

Example:
Ambient temp = 86F
charge temp = 230F
outlet temp = 108F

230F - 86F = 144F inlet rise temp
230F - 108F = 122F drop
122F/144F = 84.7% EFF

Make sense? Obviously more efficient is better


The latter, pressure drop. When you increas the volume in the intake tract, your going to lose pressure. There's more vacant space for the turbo to pressurize and overcome, so you MAY or may not induce extra lag. An enourmously oversized intercooler WILL indeed lose you power over a proper intercooler by this effect, but a properly sized intercooler will usually net you similiar response to a stock piece, if not better.


Another consideration is the design style of the intercooler. Most factory pieces are tube/fin designs which is a cost compromise. See picture below.


The superior design, would be a bar and plate design (look at the intercooler and you understand where it gets that name) because it is more efficient, and has a lower pressure drop then a tube/fin I/C of the same size.


Best thing is to just do your homework. Bigger isn't better, there are just too many factors to consider. Remember, this is a supporting mod. It may make 10hp over your stock intercooler on a dyno, but on a HOT day when you're really beating on your car, a quality intercooler will keep you from heat soaking, and the benefit will increase two, threefold over a stock piece.

In other news, I had one of these show up today for the sky, 680cfm of love... 45% larger then stock and bar/plate

[greasemunkey]

ok, so basically if i get a smaller one i risk heat soaking if i run it hard but less lag, and if i get a huge one it will be safer but more lag got it thanks

[winmutt]

ok, so basically if i get a smaller one i risk heat soaking if i run it hard but less lag, and if i get a huge one it will be safer but more lag got it thanks

A VNT can help with the lag.

[Dietcoke]

ok, so basically if i get a smaller one i risk heat soaking if i run it hard but less lag, and if i get a huge one it will be safer but more lag got it thanks

You need to find one that suits your engine's needs. There IS a balance. On most street cars, you don't need to compromise. You can get one thats just right for your motor, just do the research beforehand. A quality piece can be expensive though, my bell unit was $900.

[Bballjamal]

Good stuff! +1 to who I can!