Intercooler problems

[xman]

I have a MA70 supra with a 1jz-gte and recently replaced the jza70 cooler with a PWR
600x300x70 item.
Problem is the boost did not go up at all, if anything it droped a little. I used to get 12.5 to 13 psi, now maby 11 to 12 psi. It seems to cool quite well, always cold to touch on the out feed side and I'm told it's rated to 500kw..

Any idears...

[feral4mr2]

why do you think boost would of increased??

if the unit is larger than the i/c you ran before you would see a pressure drop across the i/c, not a increase.
also you will find your most probably getting better cooling of the charge air (which sounds like it in your post), which in turn would make up for the boost drop HP wise IMO when tuning the engine.

[thechuckster]

what you should have been measuring is air-temps coming out of the coolers - not boost.

a cold FMIC outlet is good ok?!

By cooling the air down, you've made it denser and thus (if turbo is working at the same load) reduce manifold pressure under boost. You should now be able to shove more air/boost into the engine

[Draven]

if you just wanted a bigger boost number, a $70 boost controller would do that

[nick.parker]

Where are you measuring boost? If after IC there will be no different if you have a boost controller that is regulating manifold pressure, however the lower IC restriction would mean the whole system is not working so hard for the same boost. If before the IC (turbo outlet) then I would expect to see the pressure drop a bit from what it used to be.....

[Jorrs]

if you just wanted a bigger boost number, a $70 boost controller would do that

word ^

i think you have misunderstood what the cooler is really doing for you..

[Squid]

The problem is you have come up against the ideal gas law. unless you drastically change the laws of physics, one intercooler cannot cool the air more than another, and not drop the pressure.

ideal gas law - PV=nRT
where
P = pressure
V = volume
n = number of moles
R = a constant
T = temperature.

The whole purpose of the turbo and intercooler is to increase the 'n' which is the number of moles (molecules) of oxygen entering the combustion chamber. The more moles of oxygen in the cylinder the more fuel can that can be burnt, which equals a bigger bang, bigger bang equals more power.

Re-arraging the formula, to PV/TR = n

Volume is fixed in the system (well it isn't quite, but for the purposes of this example it is.)

That leaves you with two options in order to increase the number of moles. The first is to increase pressure, the second is to reduce the temperature.

Now a turbocharger is very good at increasing the pressure, but it also generates heat (both from the compression of the intake air, and the transfer of exhuast gasses) this increase of temperature doesn't help our overall goal of more molecules of oxygen in the cylinder, so we cool the pressurised air using an intercooler, this system gives us the best combination of an increase in P and a decrease (or limiting the increase in) T hence helps achieve our goal of a bigger n!

[Sagluren]

everyone needs a bigger n

in lamens terms, the ic means you can run more boost but it wont make more boost.

sam.

[xman]

Thanks for the info.
I am familiar with the gas law and thermodynamics laws (and thought this may be the cause) but thought that the reduced back pressure from the larger IC would let manifold pressure come up a bit.
This confirms the old IC flow was good but cooling was not so effecient...

[ReQuieM]

You will get the best results from new piping, I went from about 11psi to hitting boost cut with 3" aluminium piping. The piping is the bigger restriction.

[rob1]

You will get the best results from new piping, I went from about 11psi to hitting boost cut with 3" aluminium piping. The piping is the bigger restriction.

from what size piping did you change?

[xman]

My cooler has 2.5" inlet/outlet, same as standard one and are located at the bottom of the tanks. If I went 3" I'd have to make change to all the angles cut holes in places I'd rather not. With this cooler the pipe work has had very few changes.

[EldarO]

you want the cooler that has the most fins, crammed into the smallest space, thereby increasing its surface area, which means more contact to the air, and more cooling (bro).

you'll get a pressure drop, and it'll handle more power, but you wont feel the pressure drop, as it'll raise the power level, slightly.

Elmo.

[30psi 4agte]

Just to get alittle technical ....

You dont always want the cooler with the most fins! If they are too close it can cause a wall like effect where it is easier for the air to flow around the cooler rather than through it.

But you are on the right track.

[Norbie]

My cooler has 2.5" inlet/outlet, same as standard one and are located at the bottom of the tanks. If I went 3" I'd have to make change to all the angles cut holes in places I'd rather not. With this cooler the pipe work has had very few changes.

It is extremely unlikely 2.5" pipe would be restricting flow in any way unless you're attempting to run monstrous HP figures.