The Great R33 Intercooler Dilemma

[RBrennan25]

I've read heaps of these threads and I agree that there isn't really an exact point where the return flow coolers are no good anymore, possibly due to manufacturing flaws or different set ups or whatever. But, has anyone ever tried a normal cross flow intercooler and then just using a return flow piping kit? Would that solve the problem of the inefficient core? I've seen off the shelf kits and always wondered about them, but don't have a car to try it on now

[GTSBoy]

It's not that the return flow cores are particularly inefficient. In fact they could be the best cores or the worst cores in any given cooler. And you can't contemplate using a return flow piping kit with a normal core, because part of what makes a return flow cooler setup is that they steal some of the core height to fit the return pipe into. If you put a full height core in then there is no room for the pipe without it dragging on the ground or completely replacing the bumper reo.

The problem with return flow coolers, once you get up to that critical power level, is that the end tank on the far end just has to suck a fair bit, due to the crazy u-turn exit the air has to do.

[V28VX37]

I've read heaps of these threads and I agree that there isn't really an exact point where the return flow coolers are no good anymore, possibly due to manufacturing flaws or different set ups or whatever. But, has anyone ever tried a normal cross flow intercooler and then just using a return flow piping kit? Would that solve the problem of the inefficient core? I've seen off the shelf kits and always wondered about them, but don't have a car to try it on now

I've seen pics of setups with standard core and custom return flow piping. You are likely to have ground clearance issues if you run the return pipe under the cooler.

The craziest setups are the ones where you punch a hole into the battery tray and run a cross flow cooler with return piping that snakes back over the engine to the standard plenum. That doesn't make any sense to me whatsoever.

To be honest I don't think the cooler type is necessarily the issue though, it's more the core volume and quality.

To know for sure you'd need to do back to back runs comparing different coolers and keeping all other factors unchanged, exactly what Stao has done.

[Ke55pig]

Would love to have q couple cooler cores to just swap over on the dyno

[jet_r31]

Surely turbo choice has a lot to do with it.

If you use a turbo that likes high pressure ratios surely its not going to be effected nearly as much by the pressure drop.

the return flow deal is a 2 prong sword though. You lose power from heatsoak, so you have to pull timing etc, but you also lose power from pressure drop(which is also obviously causing heat in its self.)

We run 30psi with a 3076 .63 and a cooling pro return flow..it tapers to 25psi by mid 6000's rpm ...id like to see the boost pressure before the cooler..lol. ..have to check it one day

but we have no heatsoak issues because we run water injection ontop of e85

Just e85 and its still shit and suffers from heatsoak on kill..with water its the most consistent car ever, even after hrs and hrs on a dyno..

cheers

darren

Edited November 29, 2015 by jet_r31

[R31Nismoid]

My Blitz made 289kw yesterday - Told it was a restriction because the pipes run on the hotside of the engine. I would probably end up going Plazmaman in the next couple of months to be honest.

Because the pipes run on a hot side that makes them a restriction?

That makes absolutely no sense.

I think you guys need to measure an intercooler's ability to cool down the charged air as well as pressure drop.

Measuring the out put power based on an intercooler is not a good way of determining it's efficiency.

Absolutely agree.

Also with the Hypergear results earlier, they are all 25psi, so obviously E85. Most people will be running PULP and sub 20psi, there is potentially quite a bit less restriction.

All coolers will have a pressure drop, you ideally don't want any more than 2psi max.

Surely turbo choice has a lot to do with it.

If you use a turbo that likes high pressure ratios surely its not going to be effected nearly as much by the pressure drop.

the return flow deal is a 2 prong sword though. You lose power from heatsoak, so you have to pull timing etc, but you also lose power from pressure drop(which is also obviously causing heat in its self.)

That is where I am headed as well - It very much depends on what you are doing as to "how much" of an issue it actually is.

The old heatsoak issue isn't as much of an issue, depending again on scenario. I've seen outlet temps vs throttle body temps on the old return flow and there is not a whole lotta difference at WOT at a race track (circuit, drag would be different). However there is certainly an issue in peak hour traffic, but then who's hitting WOT to 40km/h?

Also to throw something in the mix I know I shouldn't... Bar/plate vs tube/fin is another fat can of worms to get the new kids to investigate in their own time

(such an evil laugh I have going right now)

[zebra]

Easiest fix is Methanol and no intercooler.

Hell, I'd be game to try it on E85 on a drag car.

[Ke55pig]

Could possibly just use a alloy straight pipe and run car up on dyno to see what boost it makes and power with out the cooler lol then u would know how restrictive it is haha

[Daz]

Bigger better - bigger better

[kingtube69]

Because the pipes run on a hot side that makes them a restriction?

That makes absolutely no sense.

Absolutely agree.

Also with the Hypergear results earlier, they are all 25psi, so obviously E85. Most people will be running PULP and sub 20psi, there is potentially quite a bit less restriction.

All coolers will have a pressure drop, you ideally don't want any more than 2psi max.

That is where I am headed as well - It very much depends on what you are doing as to "how much" of an issue it actually is.

The old heatsoak issue isn't as much of an issue, depending again on scenario. I've seen outlet temps vs throttle body temps on the old return flow and there is not a whole lotta difference at WOT at a race track (circuit, drag would be different). However there is certainly an issue in peak hour traffic, but then who's hitting WOT to 40km/h?

Moreso heatsoak being on that side. He said the intake temps were a bit high with no heatshielding etc.

[Trex]

Easiest fix is Methanol and no intercooler.

Hell, I'd be game to try it on E85 on a drag car.

There's one bloke on here who has no cooler with water meth. But as you said, it's stupid if it's not a dedicated drag car. Or you'd need it spraying the whole time

[89CAL]

My Blitz made 289kw yesterday - Told it was a restriction because the pipes run on the hotside of the engine. I would probably end up going Plazmaman in the next couple of months to be honest.

Ive been told the plazmaman intercooler is the way to go but they are just so damn expensive. I need a new one. Pretty sure mine isnt anything special. One of the early GKtech kit coolers

Need to get heat out of my engine bay as well. Awful lot of heatsoak but i dont have the problem of the piping running over the engine etc

[zebra]

There's one bloke on here who has no cooler with water meth. But as you said, it's stupid if it's not a dedicated drag car. Or you'd need it spraying the whole time

You could drive it around on the street, just don't flog the guts out of it everywhere

[hypergear]

Also with the Hypergear results earlier, they are all 25psi, so obviously E85. Most people will be running PULP and sub 20psi, there is potentially quite a bit less restriction.

All coolers will have a pressure drop, you ideally don't want any more than 2psi max.

The intercooler pressure drop tests were all running P98 fuel.

Some of yous will argue. Few of people might notice early developments with my GTR single, I've used various of turbos including, TD06, GTx3071 and 76 plus 82 equivalent. Always 24psi mid range and 17.5 up top, all netted up making 330awkws on E85 fuel regardless of wheel sizes. Its only when the OEM cooler was replaced to a 600x300x100mm item before I could get it holding 24psi and over 400awkws.

They are my findings with different types and make of intercoolers, might or might not apply to other setups.

[CEF33Y]

I made my own return flow piping with a normal style core.

Pipe runs behind cooler, I run an aftermarket front bar so have alot of room though.

In saying that I've recently changed to a Apexi front mount kit, with the traditional pipe run.

Planning to get back to the dyno to see if it changed anything. Seat of the pants feels the same.

Holding boost up top just the same.

Boost controller obviously gets its feed post intercooler, so it should hold boost the same, but possibly pre intercooler boost level would be lower, if the cooler/pipework is more efficient.

Car is running cooler, but pretty sure thats because of increased airflow around/through the cooler.

My car made the power I was expecting for my combo with original china cooler and return pipework (even with that tight 180 deg bend), 240rwkw @ 20psi, dropping 2psi at redline

So I never bothered measuring pressure drops across the core, or IAT's

Keen to see what the dyno says though, Apexi cooler internals look a bit more "open" and more consistant than the china core.

[hypergear]

Measure boost pressure out of the turbocharger and boost pressure before the throttle body. That will give you an pressure accurate reading of pressure drop across the cooler kit

If there is a tangible drop, then measure boost pressure drop out of the turbocharger and just after the cooler.

The differences will be the pressure drop across the actual return flow piping.

The greater amount of boost you run, the greater differences in pressure drop you should see.

[R31Nismoid]

The intercooler pressure drop tests were all running P98 fuel.

Some of yous will argue. Few of people might notice early developments with my GTR single, I've used various of turbos including, TD06, GTx3071 and 76 plus 82 equivalent. Always 24psi mid range and 17.5 up top, all netted up making 330awkws on E85 fuel regardless of wheel sizes. Its only when the OEM cooler was replaced to a 600x300x100mm item before I could get it holding 24psi and over 400awkws.

They are my findings with different types and make of intercoolers, might or might not apply to other setups.

Running 25psi on PULP?

That just be asking for trouble IMO. Most people keep to a more sensible 18-20psi and turbos that hit the sweet efficiency there. Not a lot of room for error with anything at 25psi, and everyone has had that issue with a batch of fuel at some point.

Anyway the main point was running 18psi vs 25psi, you're going to notice restriction much more, generally.

[Dose Pipe Sutututu]

Running 25psi on PULP?

That just be asking for trouble IMO. Most people keep to a more sensible 18-20psi and turbos that hit the sweet efficiency there. Not a lot of room for error with anything at 25psi, and everyone has had that issue with a batch of fuel at some point.

Anyway the main point was running 18psi vs 25psi, you're going to notice restriction much more, generally.

not true... cylinder pressure causes motors to go kapow NOT pressure generated by boost.

[R31Nismoid]

Higher boost will:

1. Increasing boost will increase the cylinder pressure (how can it not?)

2. Increase the intake temp

3. Lead to higher chance of knock/detonation, far more prominent with 98 Octane PULP vs 105 Octane United E85

4. And potentially, show more in efficiencies in the intercooler system

In relation to point 4, think about wind resistance, or rather the power to over come it, is velocity^3 (If my memory is correct) - so it's not linear, and as such I would not expect an intercooler pressure drop to be the same from say 15psi to 25psi if the core itself is reaching it's limitations.

[Ryno]

But if Blitz or JJR return flow cooler kit is purchased or a must have for road legal purposes, I did engineer a turbocharger for my self during time been, or whom ever in my shoe.

http://www.sau.com.au/forums/topic/55845-rb25-turbo-upgrade-all-dyno-results/page-52#entry7503629

Your argument about 25 psi of boost is relevant but is probably confusing the point a little.

It may be easier to think of it as the airflow limit of the intercooler... By using a larger turbo you could run into these same issues at a lower boost purely because the cooler can't flow the required amount of air.

You can see from the above graphs, the 68mm cooler starts being a restriction (compared to the other two) at only 160 rwkw of airflow... That really is quite significant and I imagine most people that have that brand of intercooler, would make some decent gains by swapping it out.