Intercooler Guru's - Question for you.

[Andres]

How much turbo lag is the result of a larger intercooler?



I did a conversion (an '03 HO Cummins into a Hummer H1) and bought the biggest intercooler that would fit under the hood. It's probably got about 30% more volume than stock. The stock wouldn't fit properly.



I notice that when I stomp the gas, it takes about a second or so to hit 25psi boost. I am wondering if the larger the intercooler, the longer the turbo lag as the turbo needs to "fill" the intercooler as or before it goes into the intake.



Silly analogy, but if the intercooler was the size of a house, it would obviously take about 6 hours to spool up to get reasonable boost. At the same time, a tiny intercooler would probably boost faster, but not get the air cool and dense.



I read the Banks pages (good stuff BTW), but didn't see this addressed directly.



The lag is pretty similiar to my '06 RAM.



By the way, I installed a Smarty in this thing. Easiest part of this project.



Thanks in Advance.

 

[Triton]

I don't think you can attribute much of the lag to the intercooler. Your turbo is what going to build the boost. The aftermarket coolers are a quite larger than stock but, the benefit is lower EGT's. A stock turbo can still handle the increased capacity of the cooler.

I just installed a Spearco intercooler in my truck. It's as big if not bigger than the other brands available. While still running the stock turbo, there was no difference in the spool up. The difference showed on the EGT gauge. They didn't climb as fast as they did before the cooler change. It wasn't a big difference but, with other added components and a larger turbo working together the EGT's are are lower than they could be without it.

The stock intercooler is said to be good for 500hp and up to 50psi. As long as you don't have one with the plastic ends on it... it should be good to go.