How does one determine the right size of intercooler? I would assume that one that is too big (volume) will cause a lag as the pressure builds. Also one that is to small will not be as effective at cooling temperatures.
Trial and error or what?
libbybapa is right (as always)
bigger is better. even if you have a 2-5 psi drop, just imagine how much the charged air temps will drop. a small intercooler will become hotter faster, and be less able to discharge that extra heat as fast, so you get 'heat soak' which is not good at all.
i'm going to be building a water intercooler setup sometime in the summer, but for now i'm trying to fit in at least a small intercooler. my water intercooler heat exchanger will be huge

but the actual intercooler will be nice and small, and fit even with a/c still installed
Apparently ones from Merc Sprinter vans are good (if you can find a cheap one). Cheers for that nugget of info gents, once I've got it running right, fitting a larger intercooler is on my list of things to do...
Cheers,
Tom
Where did you get that one from? That is what I need for my truck.
I got it from some fly by night out of his garage type place on Ebay.That particular Intercooler is compact as its only 2.5" thick with 2.5"in/out.Most I/C's I've seen are 2.5"in/out but are 3" thick which was no good for me.If you can put a 3"thick IC on you truck then thats your best bet as they are more common.
Sprinter IC has plastic ends, and they are 90° sharp bended...Can it hold 1.5 bar of pressure?
Just if someone would like to know, IC is the same that is in VW LT...
That looks like a Powerstroke intercooler....
The brick in our 1Z Passat TDI is 7 3/8" wide, 8 3/16" tall, 3 5/16" thick, with 1 5/8" ID in/outlet. Works well with the Passat, but would work far better if it actually had some nice airflow.
I think one of the main reasons for the pressure drop is the thermo-contraction of the air, resulting in less volume filling the same space=less pressure.
So if a 5PSI drop occured, you're likely seeing huge temp drops.
I'd go with the largest one you can fit where ever you can fit it. It'll lag when the turbo first starts to turn over and build a baseline system pressure. In other words, startup. Past that, the lag should be near unnoticeable just from a bigger intercooler.
I'm fairly sure the stock 7.3L intercooler is smaller than the stock 6.0L. Odd how a larger needs a smaller. Both of those are Powerstroke Diesels.