simontaylor wrote:Martin, could you expand on your calculations above for me.
Okie doke
Assumption: 100% volumetric efficiency. This is near enough impossible in this engine but the theory is sound...
A 4 stroke engine draws half its capacity per rev - ie a 2.5 litre engine draws 1.25 litres every revolution. A naturally aspirated engine is operating under atmospheric pressure - ie 1bar positive pressure pushing air into the cylinders
A turbocharged engine running a bar of boost is doubling its capacity. This is why you need a 2 bar map sensor to run a bar of boost, a 3 bar to run up to 2 bar etc.
So at a bar of boost, a 2.5 litre engine at 100% volumetric efficiency is "breathing" 2.5 litres of air every rev. Times 5500rpm = 13750 litres per minute.(and for anyone who says that putting the air filter in the engine bay is a bad idea "because it gets warm air" needs to be shown some of these figures.... at this speed, the engine is drawing in nearly 230 litres of air every second. I don't think it hangs around in the engine bay long enough to get hot because of the engine! But I digress.)
13750 litres = 485.576 665 368 cubic feet
Thanks to
http://www.onlineconversion.com/
Now the engine is anything but 100% volumetrically efficient (is that correct grammar?!) but I think it's fair to say you're getting close, if not surpassing the limit of the ability of the chargecooler to efficiently flow the charge.
We had trouble with the TT DeLorean and restrictive intercoolers. The result was lots of noise and crap power on what is essentially a Z7U engine with no mods, just two turbos and an adaptronic. The charge temps were getting MUCH higher than you guys have talked about....