Can an intercooler be too big?

So, the factory intercooler on my baja turbo is busted and leaking. 

I had picked up a hyperflow (made by turboxs apparently) aftermarket subaru top mount intercooler that i honestly hadn't planned on using anymore. I just hadn't sold it yet. 

Well, i have it. 

But is berkeleying HUGE. 

before i go to all the effort to fit it, should i? This is a stock turbo car, that will have at most a bigger catless exhaust, header and uppipe and downpipe, and mild tune. At most. It IS a challenge car, but it is primarily a beater with a heater. 

So, to install, or not and why? Im not turbo literate, and this is my first boost experience. So be gentle and spoon feed me please. 

The answer is no.  Space, however, will more than likely dictate the reality you inhabit.

Pretty much all of your problems are practical ones involving making it fit, yes.  That said, a smaller intercooler with better airflow is probably better than a bigger one that's got lousy ducting.

Dusterbd13-michael said:

This is a stock turbo car, for now.

FTFY

rustomatic said:

The answer is no.  Space, however, will more than likely dictate the reality you inhabit.

This. Plus that one's only big for a TMIC, it would be a totally normal size for a FMIC.

I expect  the larger intercooler will increase lag due to the increased volume of the system past the turbo (it has a larger chamber to bring up to pressure). How much and is it a meaningful amount? I have no idea. 

fusion66 said:

I expect  the larger intercooler will increase lag due to the increased volume of the system past the turbo (it has a larger chamber to bring up to pressure). How much and is it a meaningful amount? I have no idea. 

I have been told by an OEM-adjacent engineer that is absolutely a thing with big intercoolers.  He also said that many of them were poorly designed as well (though I don't recall the details).

The only intercooler that is too big, is the one that won't fit.

mfennell said:

fusion66 said:

I expect  the larger intercooler will increase lag due to the increased volume of the system past the turbo (it has a larger chamber to bring up to pressure). How much and is it a meaningful amount? I have no idea. 

I have been told by an OEM-adjacent engineer that is absolutely a thing with big intercoolers.  He also said that many of them were poorly designed as well (though I don't recall the details).

 

Volume/lag was my first thought. That's more space the turbo has to pressurize before you get the goods. 

There may be a bit of lag, but the turbo on the Baja is made to spool quickly. Since the Baja wasn't happy with sudden boost in the first place and you've never driven it while it was working properly, I'm betting you won't notice it and things will feel better overall.

 

z31maniac said:

mfennell said:

fusion66 said:

I expect  the larger intercooler will increase lag due to the increased volume of the system past the turbo (it has a larger chamber to bring up to pressure). How much and is it a meaningful amount? I have no idea. 

I have been told by an OEM-adjacent engineer that is absolutely a thing with big intercoolers.  He also said that many of them were poorly designed as well (though I don't recall the details).

 

Volume/lag was my first thought. That's more space the turbo has to pressurize before you get the goods. 

The 13T flows 390CFM at 14.7psi, which is 184 liters per second. How much intake volume is an 'oversized' intercooler actually adding?...

I think the answer is that, yes, an intercooler can be too big.  But that one is probably not.

It takes a nonzero time to fill the extra volume, but remember that also means you have a reservoir during shifts (like an accumulator for intake air) to help minimize pressure drops.

If you can make it fit, run it.

Just how much bigger are we talking?  I'm a bit rusty on my Corky Bell, but I think he said no more than about 15% bigger than optimal.  At 20% bigger, you'll start to notice a bigger difference.  But, as Brett_Murphy pointed out, if it's undersized from the factory, you have to factor that in.  If this is 25% larger, but the factory intercooler was 10% too small, you're probably fine.

Can someone else with a Corky Bell book confirm that for me?

That's not too big, as long as it fits. The extra volume could create a bit of extra throttle lag, but the Subaru pipe routing is so short, it's likely still better than most cars. The increased size helps twofold. Not only is it physically larger with more cooling capacity, but the larger volume means that the internal velocity (and drag) is much lower. Your turbo won't have to work as hard and heat the air as much for the same manifold pressure. So the air going into the intercooler will even be bit cooler to start with. 

Thanks y'all. Ill see if it'll physically fit the engine bay and engine of the baja. If so, game on!

Any considerations or things to pay specific attention to on install?

Dusterbd13-michael said:

Any considerations or things to pay specific attention to on install?

will the hood close?

In reply to AngryCorvair (Forum Supporter) :

Umm....

Thats actually something i hadn't thought about. This thing is WAY thicker.

Dusterbd13-michael said:

In reply to AngryCorvair (Forum Supporter) :

Umm....

Thats actually something i hadn't thought about. This thing is WAY thicker.

TNWSS

In this particular situation effing send it ;)

I'm here for early 00's era hood tilt spacers on a Baja

Trim hood to fit and add STI scoop?

STM317 said:

Cut the hood and add an STI scoop?

I already bought one. You are reading my mind I also kept the flat hood off the parts car.

STM317 said:

Trim hood to fit and add Hemi Dart scoop?

fixed