Rb25 Intercooler Sizes.. Can A Fmic Be Too Big?

[Jswljones]

I've been searching around and I found alot of threads on here but I'm getting different answers so I figured that I'd just ask...

I have a A31 Cefiro that has a RB25 swap right now...

as far as power upgrades it's still pretty much stock except boost controller and Apexi PFC

but I'm building a RB30DETT on the side and I have the front bumper off and before the car goes in for paint I'm mocking up the new FMIC for it and cleaning it up

Since doing this and seeing it on the car I'm kinda falling in love with it and I'm just wondering would it be a good or bad thing to run my FMIC now??

The size is 30 X 11 X 5 in

I have a 45V4 turbo on my RB25 S1 with fresh studs and everything so far is in top shape.

Not looking to abuse the engine just trying to make it reliable and will get it tuned again in a few weeks so I figured might as well do this now if I'm going to do it at all...

You can check out my build in my sig.

here are some pictures of the intercooler be mocked up

I've heard of intercoolers being too small on a car but never really ran into a problem of them being too big...

So my question is, what can I expect performance wise if I run this on my car now?

Is it a bad thing to run this big of an intercooler on a stock engine? or not?

Any advice or anything else you guys can offer or threads I should read on this subject?

Thanks in advance for your help!

Edited April 18, 2013 by Jswljones

[GTSBoy]

First up, the intercooler pictured is not 30x11x5. It is at least 500mm wide, 200mm tall and 76mm thick.

As such, it is neither very large, nor is it too large.

It is probably almost impossible to fit an intercooler that is actually "too large" to a car anyway. Especially if you need to fit it in legally (ie not cut anything). I'm not saying that from a position of ignorance. As a heat exchanger/heatsink, bigger will always be better, and the extra lag/lack of response that some people complain about from having more capacity in the inlet tract is mostly in their heads anyway.

BUT......it is probably true that you can put a core in that is bigger than you actually need both for the amount of power the car will make and the usage model. For a street car you'd be hard pressed to be on full noise for more than 10 seconds at a time. As such you'd have a hard time heatsoaking a biggish intercooler unless you have a lot of power available. And these days the serious kids are going E85 for big power and intercoolers become less critical.

[Jswljones]

I'm from the US, my measurements reflect what we use here, not sure what the metric measurments are...

with that being said I don't have to worry about it being legal or anything this is stricly a is it a good idea question, and if so what should I expect of of it.

thanks for your insight though, I have read about the lag issue but not with the RB engines so i'm wondering if this would be an issue with this size and set up?

[Dan_J]

the only bad things about any intercooler is pressure drop due to core design/ size and extra lag from large piping.

edit: although a well made large intercooler can be better then a shitty made smaller one so just test it out. you can measure pressure drop by hooking up the boost gauge from the piping near/ or on the turbo

Edited April 18, 2013 by Dan_J

[Jswljones]

So basically go ahead and try it?

It can't be worst than the stock one... LOL!

[benelli]

So basically go ahead and try it?

It can't be worst than the stock one... LOL!

Do it! Got nothing to lose and just cool air to gain.

I fit a blitz intercooler on my R33 that was rated for +500bhp and i was just aiming for 350BHP and like GTS Boy said there was no "lag" and i figure most of this lag is also just people talking. I figure design and making sure there are no leaks and clean welds is more important than size.

[Dose Pipe Sutututu]

There won't be any real noticeable lag, but of course it won't feel like a factory sidemount.

[marto184]

I run a 600 by 300 by 75 greddy intercooler and the change in repsonsiveness isn't even noticeable. Best idea too. Car runs better. Idles better. Just better in general

[GTScotT]

If your planning to have a bigger setup later down the track there is no risk. You will need a large intercooler for anything over 300whp regardless, and by throwing the term RB30DETT around I am assuming you are going to end up with about 500whp. In which case you should have a good sized cooler.

You will notice a minor drop in punch from the stock turbo when going to the large cooler but nothing you wont be happy to live with under the circumstances. Do it.

[Ben C34]

I run a 600 by 300 by 75 greddy intercooler and the change in repsonsiveness isn't even noticeable. Best idea too. Car runs better. Idles better. Just better in general

How does the intercooler affect the idle? ?

[Dose Pipe Sutututu]

How does the intercooler affect the idle? ?

it doesn't

[Ben C34]

I know that, but according to the post I quoted, somehow it does.

[Jswljones]

Thanks for your input guys, I'm just gonna go ahead and put this in, gathering the rest of the parts as we speak.

I've been honlding off on doing any type of engine mods and it's kinda nice to be doing something with it even if it's not that much.

[Dose Pipe Sutututu]

I know that, but according to the post I quoted, somehow it does.

probably previously there were leaks in the SMIC, there's no way a FMIC can affect idle unless there are leaks

[marto184]

yeah that was the issue... Gets better fuel economy too..not heaps but about 50km per tank.

[speeddemon778]

Hey guys, ive been reading this thread and I recently got an r33 gtst and want to install a front mount intercooler and cold air intake (with stock turbo for now) and im just wondering if you have any tips or know if any issues I may come across? I want the car to be reliable so I don't want to do anything that may cause problems

[Dose Pipe Sutututu]

Hey guys, ive been reading this thread and I recently got an r33 gtst and want to install a front mount intercooler and cold air intake (with stock turbo for now) and im just wondering if you have any tips or know if any issues I may come across? I want the car to be reliable so I don't want to do anything that may cause problems

stock airbox

stock bov

Blitz Return Flow kit

[Joshbigt62r]

What John said ^^^ get a K&N panel filter to.

[speeddemon778]

I have a k&n cold air intake at the moment would it be worth installing or just keep the stock? I also want to get a fmic? will hopefully be looking into getting a bigger turbo in the not so distang future.

[speeddemon778]

what I mean is an tips for installing the fmic^