Supercharging and aftercooling...
Supercharging and aftercooling...
(OP)
I searched for previous posts and didn't find what I was looking for, so I bring my question.
After reading up on supercharging and noticing that some cars and systems use an aftercooler to reduce inlet temperatures, I am wondering if an intercooler will reduce horsepower??
AS I UNDERSTAND IT --> The example system used 6.5 lbs of boost with just a supercharger and with intercooling it drops to 4 or so. This will provide the same amount of air (maybe slightly more), but at a lower temperature and therefore lower cylinder pressure. I don't have the inlet temperatures, but the system without intercooling produces nearly 50% more HP and compression ratio was kept to 10.5:1.
After reading up on supercharging and noticing that some cars and systems use an aftercooler to reduce inlet temperatures, I am wondering if an intercooler will reduce horsepower??
AS I UNDERSTAND IT --> The example system used 6.5 lbs of boost with just a supercharger and with intercooling it drops to 4 or so. This will provide the same amount of air (maybe slightly more), but at a lower temperature and therefore lower cylinder pressure. I don't have the inlet temperatures, but the system without intercooling produces nearly 50% more HP and compression ratio was kept to 10.5:1.





RE: Supercharging and aftercooling...
Blacksmith
RE: Supercharging and aftercooling...
More trivia: reducing the temperature of the air with an intercooler before it hits the cylinder helps eliminate predetonation, which is apparently a fair-sized problem in the performance compact sector.
So, if I ran a "precooler", cooling the air before it ever hit my supercharger, and then either ran the charger at a slightly higher ratio of engine speed than normal, or slapped a bigger charger on, would I increase the air density going into the engine? And even if I did, would it help me, or just mess up my air-to-fuel ratio and drive my ECU insane as it tried vainly to compensate?
AND... What about carrying a bottle of pure oxygen onboard for use like a NOS system, to give me extra zoom when I need it? Or is that just risking a huge explosion?
EMc
RE: Supercharging and aftercooling...
O2 has been tried many times (we die it on a drag bike back in the 50's) but it ,too, is impractical with the high pressure delivery system involved. Nitrus is still the most practical method of introducing more O2 into the combustion process.
Try a web search as all these nitrus and turbo kits are well tested and readily available from several sources, particularly the import drag segment of the market.
Rod
RE: Supercharging and aftercooling...
here's another take-
the supercharger is sucking atmosphere - at outside temperature. It would take refrigeration to get it colder.
after going through the supercharger, it is hotter. You can then run it through a simple heat exchanger, and cool it somewhat (transferring heat to atmosphere - it won't get as cool as outside air, but it will be cooler than what comes out of the compressor/supercharger)
the simple heat exchanger is called an "intercooler" or "aftercooler". No refrigeration required, fairly cheap, etc. That's why it is semi-commonly used on highly supercharged engines. Also because you really need to keep the charge temp down to avoid detonation under high boost...
- right, Rod?
(you're really having fun with the graphics, eh, Rod?)
cheers
Jay
RE: Supercharging and aftercooling...
I don't want to see 1400 degree exhaust temps, I want my daily driver to be just that.. I just want more kick, and bragging rights...
(btw.. the 6psi is an actual figure, the 4psi is my estimate with losses due to the restriction of the aftercooler)
RE: Supercharging and aftercooling...
In almost every case, the intercooled engine will make more power than a non-intercooled engine running at the same boost pressure, because of the higher density of the air. The non-intercooled engine will also be more prone to detonation because of the higher inlet temperatures.
RE: Supercharging and aftercooling...
Rod
RE: Supercharging and aftercooling...
I'll rephrase the question as "given a constant mass flow rate of air, (same number of molecules per minute) and the fuel to match- will increasing the temperature of the mix increase or reduce the power output?"
seems to me the following:
A lower inlet charge temp will cost less power to compress, and permit more optimum timing perhaps
oh, yes- depending on the type of blower, reducing the back-pressure in the inlet tract should either:
1- permit higher flow (in the case of turbocharger) or
2- reduce the horsepower cost of driving it (any mechanically driven device)
if the charge temp were too low (Alaska in winter?) you could get poor combustion?
common use for performance is to go for max charge density at minimum temperature.
comments?
jay
RE: Supercharging and aftercooling...
-=Whittey=-
RE: Supercharging and aftercooling...
Rod
RE: Supercharging and aftercooling...
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bummer
I wonder how Smokey's widow/estate would feel about it?
regards
Jay