Intercooler?

[Michael211_2000]

What does the intercooler do and how does it do it? I'm inclined to think it's somehow using lake/sea water to chill the intake air before it goes into the cylinders... but I'm not sure.

My jetboat uses a tall tunnel-ram that gets ice-cold as air is drawn thru it, such that it cools the incoming air once it gets cold enough itself (only takes a minute or two of run time before it gets real cold and starts working). The SeaDoo intercooler though seems to work on a different principle.... can warm lake water being pumped thru the intercooler actually cool the incoming air flow?

Thanks!

- Michael

 

[JoeZ]

Water to air or air to air it doesn't really matter as much as it's ability to pull heat out of the compressed air. The pressurized air get VERY hot, so getting rid of as much of that heat as possible is important. Good thing about water to air intercoolers is that they can't be heat-soaked as easily, and typically don't have to be as large. Now you can get extra performance out of larger air to air intercoolers, and PWCMuscle sells a couple that work to do that.

http://pwcmuscle.com/index.php?main_page=product_info&products_id=18

 

[Michael211_2000]

So the intercooler is actually there to compensate for the air that is compressed (by the supercharger) and therefore hot... ergo, even if the water flowing thru the intercooler is in the mid-80's, it'll still be cooling the compressed air down. Am I understanding this correct now?

The tunnel ram on my jetboat's engine is a totally different beastie then, since there is no supercharger and the air is not compressed... it's chilling the air down in order to compress the air (colder air being denser) in order to get more air/fuel mix into each cylinder. Hmmm... interesting!

Thanks for the info Joe!

- Michael

 

[JoeZ]

Yep that's exactly correct. I have owned a couple of turbocharged and supercharged cars, and the intercoolers were always important upgrades if seeking additional power. If the intercooler (air to air specifically) was too small, they could reach a point where they are not able to dissapate the heat and would be considered "heat soaked", thus unable to cool the incoming charged air. A larger intercooler was a quick way to cool down the compressed air for some additional "free" horsepower. That's why you see large intercoolers on the front of all of the ricers with turbos.

 

[Michael211_2000]

Very interesting... come to think of it, I used to own some Peterbilt trucks with Cat 3406B engines which were turbo-charged, and they too had air-to-air coolers in front of the radiator. I never really understood what the things were for back then, just that they were necessary.

Am I correct in that a turbo charger is pretty much the same as a super charger, except the turbo is exhaust flow driven while the super charger is mechanically driven? Otherwise they both do the same thing, compress air into the engine... right?

Seems like 1 big advantage of a turbo charger would be that when it finally fails it doesn't usually lose parts inside the engine core since it sits fully outside of the engine, whereas the super charger DOES lose parts into the engine when it dies! Eeek!

Regards!

- Michael

 

[JoeZ]

Yes, you are correct about the differences between turbos and superchargers (exhaust pressure vs crank power). However, there are many, many designs for superchargers. For instance, the centrifugal supercharger (as used in the supercharged seadoos) is essential a turbo compressor housing connected to a gear drive.

If a turbo fails or the impeller explodes, it is still possible for parts to end up in the engine. However, it's usually more rare because typically speaking the piping for a turbo is a lot more complex and something like an intercooler should catch debris.

In my experience, superchargers definitely are more complex and fail more often than a turbo. The power band comparison is more favorable for a supercharger though IMO