Return Flow Intercooler Vs Regular Front Mount Intercooler Question

[yoshiii335]

What brands do you find to be restrictive Stao?

Have you got a darker photo from further away?

Have you got a darker photo from further away?

Here are some newer pics

[GTR_JOEY]

Some of the JJR ones, and also Blitz. For this reason I've installed a blitz return flow on my current R34 and curious to see what it does. I've noticed some of the blitz coolers has very narrow tube, mine doesn't, but it has very tightly packed fins inside those tubes.

I've done a test based on 600x300x68mm and 600x300x100mm coolers. There are no differences in response, while the IT was 10 degrees less with the 100mm, that lead to 10kws gain top end. For a cooler setup that what I recommend.

Great info, thanks mate

[yoshiii335]

Great info, thanks mate

Ok for those sizes I understand

But the intercooler I have now, any guess from anyone about how much power I can put thru it until I have to change it?

[GTSBoy]

More than 9000!

[Therealsandybang]

Yep have a blitz return flow and I'm getting funny restriction issues with my new setup. Haven't confirmed cooler. Need to pressure test it.

Although rb Brennan is running over 300kw with the same return flow..

[yoshiii335]

Yep have a blitz return flow and I'm getting funny restriction issues with my new setup. Haven't confirmed cooler. Need to pressure test it.

Although rb Brennan is running over 300kw with the same return flow..

Ok, cool. I have an idea now.

Maybe I should pressure test mine before I decide to use it before the upgrades.

[89CAL]

I dont want to Hijack the thread, but it seems on topic.

If anyone has any intercoolers that they know are fantastic or awful, maybe post in here. Ive been thinking about upgrading to a new cooler for a while but ive been recommended expensive cores that cost $1200 or so and im not even sure mine needs replacing so not keen to drop that sort of cash

[Therealsandybang]

Man the $400 Kkr worked for me

[M@&k]

I'm also interested in this topic. I specifically got the Blitz SE return flow cooler for my car, as many people have made good power with them. I haven't really gotten the results I was hoping for, and my tuner is convinced it's because of the cooler. The only difference I can think of is that I'm aiming to run fairly high boost 20psi+ which makes me think that perhaps the pressure drop across these return flow coolers get magnified at higher pressures.

Be very interested to see results from Stao's testing on his R34!

Also, anyone have any experience with the Plazmaman entry level cores?

[GTSBoy]

The only difference I can think of is that I'm aiming to run fairly high boost 20psi+ which makes me think that perhaps the pressure drop across these return flow coolers get magnified at higher pressures.

Pressure drop across a core will not get worse with increasing boost, except inasmuch as on any given engine increased boost equates to increased air flow.

Pressure drop is a function of flow rate, not absolute pressure. If you pump up a pair of identical coolers to 10 psi and 30 psi, then allow 100HP worth of air to flow through them, the pressure drop will be very small. (Unless tiny intercooler, but let's assume typical FMIC size for Skylines here). If you allow 200HP of air to flow, still small pressure drop on each, but now probably measurable. Make 400 HP flow through both and the one with higher boost pressure will probably actually give a lower dP, because the velocity of the air in the core tubes is smaller. The increased density of the air at higher pressure will increase dP, so you'd need to do a calculation to work out which effect was bigger.

If you take typical engine-IC setup and run it at 18 psi boost, you will get a certain amount of airflow. That will result in a certain pressure drop. Wind up the boost to 22 psi and now the engine is going to flow more air. That increase in air flow quantity (mass) is what causes a higher pressure drop across the core.

[RBrennan25]

Also very interested in this topic. I have a return flow cooler which I bought specifically to maintain stock piping route and to be stealthy as it was a street car and daily driven. It's now got a fair amount of work done and makes 320rwkw on 22psi with a Hypergear SS2 bolt on. It makes around 315kw by around 4500rpm (give or take a couple of hundred rpm) and basically plateaus until redline, so there's obviously a small restriction, because on low boost it continues to make power until redline.

I spoke to my tuner (Paul at Pulse Racing) and he said the two main restrictions will be the exhaust (full 3 inch but with a cat and a muffler, because it was a daily and I wanted a little bit of noise reduction) and the intercooler. Both he and one of the other mechanics think that the cooler is pretty much at the absolute maximum as it is now, and changing that to a proper cooler would make a big difference.

Very interested in Stao's results because he agreed that there's probably more in my set up with a better cooler and if his results support that, it's something I will consider as my car sees more and more track work

[GTSBoy]

Nobody should ever look at anyone else's results to decide if their cooler is causing a big dP or not. It only takes the installation of a couple of tapping points, a couple of lengths of hose and a couple of boost gauges (or even just one gauge) to see what the dP across a core is.

[Therealsandybang]

I'm currently doing tests on blitz return flow cooler to see if it's causing a restriction with the hypergear atrs43ss2 because I hit a restriction around only 230rwkw.

So far cat, airbox, muffler, bov have been elimInated by tuner.

I will let you know of results.

Edited February 27, 2015 by Therealsandybang

[RBrennan25]

Nobody should ever look at anyone else's results to decide if their cooler is causing a big dP or not. It only takes the installation of a couple of tapping points, a couple of lengths of hose and a couple of boost gauges (or even just one gauge) to see what the dP across a core is.

Would do exactly that after seeing some results. I don't see a problem in using a set up which is almost identical to mine as just a gauge before going ahead and changing a set up that I'm already quite happy with. That said if there is a big difference in IAT after changing core sizes (and please note I meant a REALLY noticeable change in IAT not just a couple of degrees) then maybe for a bit of extra safety or the same power for less boost maybe it's worth it?

[GTSBoy]

Would do exactly that after seeing some results. I don't see a problem in using a set up which is almost identical to mine as just a gauge before going ahead and changing a set up that I'm already quite happy with. That said if there is a big difference in IAT after changing core sizes (and please note I meant a REALLY noticeable change in IAT not just a couple of degrees) then maybe for a bit of extra safety or the same power for less boost maybe it's worth it?

My main concern is that what looks like the same cooler might have a core with very different internals and hence very different dP.

The other thing with IAT is that what results you get depend VERY strongly on the usage model of the car. Remember that an air-to-air cooler is not really a steady state heat exchanger. Per what the coach wrote on AS about 15 years ago, they really function in most usage models as a heat sink that you load up with heat when on the gas and that then dumps heat back into the intake air and the external air after you back off. For 10s squirts on the road (which is all most people get most of the time) that represents what really happens. What matters then is how big the cooler is as a whole - ie, how much heat it can absorb from the charge air before it becomes fully loaded and starts to operate as a steady state cooler.

On the track, if you can keep on the power much more of the time, then you might go closer to saturating the core more of the time. On the dragstrip, you may well saturate a typical core by half track, but that will vary a hell of a lot depending on power level and so on.

I guess what I'm really saying is that however you test the IAT, whether on more or less steady state at medium - high power levels on the dyno, or just looking for peak on a single blatts on the road, you need to keep in mind that the results are affected by both size and count of tubes and the mass, and what you learn from one type of test might have quite different results in the other type.

Having spent all that time saying the above, I guess what you're really asking is, "Is it worth putting up with a bit of extra dP and hence less boost at the engine and lower power in exchange for not sending hot air to the engine?" The answer is probably a qualified yes. If you were using E85 you'd probably put up with more air temp. If you were running up against the knock limit on 98, then you have to wonder whether the reduced IAT is worth more than the equivalent reduced exhaust manifold pressure if you were to run a less restrictive (and lower cooling performance core) but just not turn the boost up as far. I wish I had a few months and a free dyno to answer some of those questions!!

[KiwiRS4T]

I had a Just Jap return flow (probably not quite as good as the Blitz) and it pretty much topped out at 240 kw, Got an Hybrid HDi cross flow (and an RB30 etc etc) and it has taken me to 314AWKW @ 1.5bar

[RBrennan25]

I wish I had a few months and a free dyno to answer some of those questions!!

Hahaha absolutely. But like I said, I'm just using other people's results as a gauge, if like 10 people come back saying they have significant pressure drop and increases IAT then maybe it's time to jump on the dyno and take readings of both before and after the cooler. But realistically I'm on E85 and making good power so it's more just perfecting a safe and quick set up than trying to milk every kw out of it. And this will be happening over a long period cos it's all too damn expensive haha

[zebra]

Im planning on testing the standard side mount on e85 shortly.

see what happens...

[hypergear]

I've been building turbos for RB owners for a number of years and there is a pretty clear pattern emerging, The most people whom experience boost dropping issues are fitted with some sort of a return flow cooler. I was curious and undecided wither if it is an intercooler issue, there for purchased a R34 GTT car with a genuine Blitz return flow cooler fitted.

Today's run, I'm using a high flowed OP6 turbocharger with a high pressure actuator. Maps sensors were tapped from both sides of the intercooler and results was some how expected. Running high pressure actautor with no boost ebc connected, sensors is reading a 3.7psi drop across the core, and which I'm sure if EBC is adapted, the percentage of drop will be much greater.

Didn't make expected power:

So Return flow coolers should not be used when expecting beyond 250rwkws. And in my personal opinion it should not be used at all.

[KiwiRS4T]

Fair enough. Mine choked at about 240awkw. Would have been interesting to put the hybrid on that engine but I changed the engine and intercooler at the same time

So Stao are you planning to put a better, crossflow intercooler on and retest?