Radiator Air Guide

[Dale FZ1]

My intercooler is now fully ducted to the radiator on all sides. All air gaps are sealed. Top guide plate is in two parts which will allow a bit of trialing to see if full separation of the upper/lower flow paths works or is even necessary.

The side plates upper section should work to trap air passing through the radiator without letting too much spill around and escape around the headlights.

Forward facing guides/scoops on the intercooler to be made and ensure air does not spill around the intercooler without passing through it.

[Dajae]

Looking good mate is that an oil cooler on the side? What was your material of choice? Easy to work with?

[Dale FZ1]

Power steering on LHS. Engine oil cooler is on the RHS. They will get their own shrouds in due course, but the primary issue is in cooling the engine.

Using sheet aluminium in 1mm. It is very workable but requires a folder to give the shapes required.

Edited February 12, 2012 by Dale FZ1

[Dajae]

How much was your power steering pump?

Awesome, do you have a plan to track the differences the ducting makes? I know jaycar have some good temp gauges you could use if you dont already have one..

How long did it take you to produce the ducting you have?

Thumbs up again mate

[Roy]

Nice work on the shrouds. Far nicer result then my 20mm thick clark foam/rubber which is cut to size and squeezed into the gaps between the radiator and cooler. About the only thing I will add is people try to duct a large surface area into smaller core etc thinking they are capturing more air and aiding cooling. Really what is more likely to happen is increase drag and cause too high a turbulence at the face of the cooler core and actually limit the flow through it.

[Dale FZ1]

Thanks Troy, I like that piece of thinking. I had a conversation with a cluey bloke who suggested the frontal openings only need to be as big as the total frontal area of the heat exchanger, minus the frontal area of the tubes in the core. ie. as big as the air passages through the core.

It makes more sense the more I think about it.

[wolverine]

I remember being called a dick for suggesting this a few years ago.

Liking your shrouds Dale.

[Dale FZ1]

I'd back your thinking ability Andrew

I consider Troy is right about drag - sticking what is effectively a big forward facing funnel on the nose of a car won't aid cooling. But I will have a couple of guides fitted to the front of the intercooler to stop air from spoiling around the core once it has passed through the front bar openings. No point losing what is already taken in.

I will apply the cross sectional area concept to ducts for my engine oil and P/S coolers, but they probably won't happen until after the first event for this year. They are a distant second priority at this stage but something to think about.

The current shrouds have enough pull through the cores that a sheet of newspaper will get sucked in hard and hang on the vertical when the thermos switch on. Attention to decent gap sealing must have worked reasonably well.

[GTSBoy]

I dissent. Let's say the open area of the inlet to the cooler is bigger than the flow area through the core. What WILL happen, is that the air will slow down and stagnate in front of the core. But it won't stagnate to a standstill, it will stagnate to a velocity fast enough to make the air squirt through the core. The velocity pressure is converted to static pressure, which increases the pressure differential across the core and increases the flow rate too. Of course, if you go too far, then the air will stagnate hard enough that it will have to go back out around the edges of the inlet to flow over/under/around the front of the car.

The stagnation will NOT negatively affect the contact of the air with the fins/tubes and will NOT interfere with cooling. With more air flowing across the fins/tubes at higher velocity, the convective heat transfer coefficient WILL be increased, resulting in more heat transfer.

My point is, trying to make the inlet area exactly equal to the flow area across the core is as arbitrary a decision as making it exactly equal to the frontal area of the core or equal to frontal area +20% or any other thing you can think of. In reality, What is most important, as this thread is already partly about, is making sure that whatever quantity of air that does enter the core can get away afterwards. Also, given that a lot of this discussion involves stacked cores (the intercooler followed by at least the radiator, if not an oil cooler as well), you really need to consider getting the upstream pressure as high as you can to overcome the resistance of the stacked cores. This is especially the case if you have ducted them together so the air has no choice but to go through all of them in series.

The real problem is that for absolutely every different type of car, type of radiator and intercooler (or oil cooler, etc), different bumper bar possibly, difference in fan shrouding, undercar tray presence/absence, etc etc etc, you will come up with a different answer about how big the inlet to the core ducting should be. There can be no hard and fast rule.

[Dajae]

IMHO, regardless of frontal area being exposed to airflow, unless there is a substantial pressure difference, you wont get effectively cooling. If for example (this is exaggerated to show a point), you had the entire front bumber assembly ducting air to the intercooler (lets just say this is the only heat exchanger), you would now have a HUGE high pressure zone infront of the core. So, in theory, this would only aid in cooling as the low pressure is more likely to "suck" the air through the cooler.

But, as we all remember from physics, nothing gets "sucked" into a space, it gets *pushed*.

As long as the low pressure area behind the cooler can be maintained (read: air flow escaping the engine bay area) then this ideal cycle can continue. And, as you said GTS, the real world case of stacked cores has to be addressed. So in this instance, ideally you wouldnt want 100% of the air going through the front of the car through the intercooler followed by radiator, as the accumulated hot air could harm this whole process.

I wavered from my initial point a bit, but you get the idea.

Pressure difference and maintaining escaping air flow is king.

[urtwhistle]

sooooooooo its not the size of the hole its the way you use it lol

the more I think about this the more it makes sense why my car ran hotter with it completely ducted with the radiator fully sealed.

Edited February 16, 2012 by urtwhistle

[Dale FZ1]

I dissent...With more air flowing across the fins/tubes at higher velocity, the convective heat transfer coefficient WILL be increased, resulting in more heat transfer.

What is most important, as this thread is already partly about, is making sure that whatever quantity of air that does enter the core can get away afterwards. The real problem is that for absolutely every different type of car, type of radiator and intercooler (or oil cooler, etc), different bumper bar possibly, difference in fan shrouding, undercar tray presence/absence, etc etc etc, you will come up with a different answer about how big the inlet to the core ducting should be. There can be no hard and fast rule.

I'm in general agreement with you.

Every heat exchanger will have a point where they can work to a certain level of efficiency, and then gains become harder to achieve. That would apply to both charge-air flow capacity and internal pressure drop, and also to cooling-air flow capacity.

Interpreting Troy's comments, my understanding is that by trying to drag in too much (how much is too much?) of the cooling airstream can rapidly increase vehicle drag without seeing significant corresponding improvement in heat transfer across the intercooler/radiator/other heat exchanger. In other words, he's saying to look at balancing the conflicting objectives.

I'm certainly not in a position (time or financial) to go modifying bar-openings just to test out a theory on the size of ducts/scoops, but the view is worth giving an outing. It would appear that decent frontal aerodynamics can/should result in a certain increase in air pressure at the nose of a vehicle in motion, thereby giving an extra dose of encouragement for the cooling airstream to pass through the cooler(s). That seems to be a function of an effective splitter.

And yes, unless the engine bay is being effectively scavenged then there is poor airflow through the heat exchanger, and bad outcomes for temperature control. It was that realisation that pushed me to try a few things out and try to understand what issues were influencing my particular setup.

What works for me might be overkill for someone else if for example my intercooler is too tightly finned and can't pass big airflow through it. In this hypothetical, my "workaround" might solve the issue, at the expense of aerodynamic drag/instability, or just lots of detail work and fabrication effort,when a change in the spec of cooler could resolve things more easily. Which is why from the outset I indicated I do not expect a hard and fast answer but just want some informed/experience based commentary. FWIW, Fineline has indicated a fairly trouble free run due to what he believes is the right spec of engine radiator. That's what works for him (sorry Noel, had to drop your input in).

I think this thread is pushing into a few different areas but cooling is becoming more obviously a complicated field. Forced induction engines just have to dissipate much more heat and it helps to run this thread to improve my limited understanding.

Bring on a few more ideas, and pictures please. I'm not after works of mechanical art, just pictures oof functional setups and experiences.

[Dale FZ1]

the real world case of stacked cores has to be addressed. So in this instance, ideally you wouldnt want 100% of the air going through the front of the car through the intercooler followed by radiator, as the accumulated hot air could harm this whole process.

Agreed. That's why I moved my oil cooler and PS cooler to underneath the headlights, and let them have their own air feeds. Pre-heating the airflow prior to passing it through the radiator is not going to cool the engine to best advantage...

Also I liked the idea of putting the intercooler top-guide to a point partway up the radiator. So that top section of the radiator gets all of the airstream coming through the grille, and whatever is drawn/pushed through the intercooler ducting goes through the lower section.

[GTSBoy]

Agreed. That's why I moved my oil cooler and PS cooler to underneath the headlights, and let them have their own air feeds. Pre-heating the airflow prior to passing it through the radiator is not going to cool the engine to best advantage...

Also I liked the idea of putting the intercooler top-guide to a point partway up the radiator. So that top section of the radiator gets all of the airstream coming through the grille, and whatever is drawn/pushed through the intercooler ducting goes through the lower section.

It's funny that you should say that. Because it was only a few weeks ago that I mounted my PS cooler under my headlight (other side from yours - my cold air induction breathes from under the LHS light).

And the divider you put in is the smartest part of the whole thing (and the rest of it is pretty smart to start with).

[Dale FZ1]

the more I think about this the more it makes sense why my car ran hotter with it completely ducted with the radiator fully sealed.

Chris you indicated that your setup used high density foam. Not exactly sure what product but presuming like stretching/exercise mat? Depending on your intercooler design (to some extent) I could see that unless the vehicle was in constant motion and at a reasonable speed (arbitrarily say 80+km/h) then the system would have been working hard to draw/push air through the two heat exchangers. Otherwise the pressure differential may not have been enough to ensure decent cooling flow through the stacked cores? (and there is your barge-board effect).

Interpreting the above, removing the top seal section should have given much more free-flow to the radiator and probably better low-speed cooling as you observed.

Edited February 16, 2012 by Dale FZ1

[Dale FZ1]

It's funny that you should say that. Because it was only a few weeks ago that I mounted my PS cooler under my headlight (other side from yours - my cold air induction breathes from under the LHS light).

Ok, photos please. Would like to see how it's mounted and plumbed, and ducted. Don't be shy.

My CAI has been deleted. Underbonnet changes saw my sealed airbox deleted, so the feed was spilling large quantity of air into the engine bay and obviously (now, after giving it some thought ) reducing the pressure differential across the radiator.

[GTSBoy]

Ok, photos please. Would like to see how it's mounted and plumbed, and ducted. Don't be shy.

My CAI has been deleted. Underbonnet changes saw my sealed airbox deleted, so the feed was spilling large quantity of air into the engine bay and obviously (now, after giving it some thought ) reducing the pressure differential across the radiator.

It would be nice if I could. Sadly, my car is on a hoist (waiting for the diff to come back properly set up) and I am on the other side of the world from it. Was sent away for 3 weeks....looking like it will turn into 6. I think I'm going to well and truly bust my usual 100 days away per year this year.

As to the ducting.....I have none for the PS cooler. It's actually the trans cooler for the Neo engine I bought, retasked. So it's about the same size as yours. That makes it at least twice as big as it needs to be, so I think ducting it will be gilding the lily somewhat. It's slung on two short steel brackets from the seam under the headlight, and an alloy brace bracket over to the inner gaurd/rail. It just hangs behind the top part of the brake duct (R32 GTR front bar on GTSt).

My intercooler was built in about 2000 or 2001. Back when you had to spend ~$2k to get a Jap one. So this is a cut down truck core. It was built as a turnflow, so my return pipe runs behind the bumper reo and uses the original cooler pipe holes in the LHS guard in front of the airbox. I used the dark grey open cell (but pretty much solid - ie air doesn't flow through it) to pack/seal the left and right sides of the intercooler core from the left and right sides of the GTR bar opening, and to seal the gap to left and right between the cooler and the radiator. That's back when it was installed, 10+ years ago. The bottom has always been open and I've always intended to do something about it, but that's not driven by need, because I have no temperature issues. It's just from principles of what it should be to make it work at its "optimum". Trouble is, no point "optimising" something that doesn't need it, so it's always somewhere down the bottom of the priority list. But I have been thinking more solidly about it lately. I got a top air plate into the car a couple months ago, and have been trying to decide between making the bottom plate out of alloy sheet (I have a folder at work so it's doable) or some PE or PP or ABS sheet. Plus more foam to make sure any gaps between the bottom plate and core, etc are closed off. Ghetto is good enough for me.

cheers

[Dale FZ1]

Intercooler shrouding is now complete.

Better view of the assembled duct between radiator and intercooler.

This forward facing guide is almost out of sight because it sits behind the front bar. Its intended function will be as a "fence" to make sure air passing though the bar opening doesn't spill around the heat exchanger rather than passing through it.

Compressible neoprene is used for effective sealing, with a bit of race tape across joins to stop movement. I'm pretty happy with it overall.

The first proper test will be next Friday. Hopefully it won't be a wet practice and I will find out just how effective these add-ons are at speed and under load.

[Dajae]

Nice work mate? Keen to hear of your results and for those of us playing at home, how many total hours work would you say this took you?

[Dale FZ1]

There are no secrets (with this setup at least) so the results will be reported on. If it helps others facing the same problems/issues then that's a bonus.

It would be good form on the part of more seasoned/experienced/knowledgeable campaigners to throw up some pics or words to explain what they've got, and whether it works (or not) for them. There's a lot of guff written/said from time to time about turbo-this/intercooler-that/water pump or radiator-the-other. It is notable that when it comes to actual constructive commentary/advice about making effective cooling systems for a forced induction Skyline used on a track based on actual experience - we have precious little added to my relatively uninformed attempt. I know there are people who have problems keeping their cars cooled adequately, and those who do not. I'm simply looking to identify a workable solution.

It's a bit diffiult to nominate how many hours were spent designing and fabricating/installing those air guides, because they were part of a total solution to the problem. Relocated oil and power steering coolers (+ mount and hose changes), delete CAI feed, mount and fit front bar, and what seemed like 100 trial fitments to ensure the ducts were mounted properly and did not foul/rub/vibrate on anything yet also appeared to have the capacity to achieve what I think I want them to do. Playing with cardboard templates helped to get the basic dimensions and shapes set correctly, but the time was in fitting and trimming, and trying to make it look reasonably neat when I have no fabrication or sheetmetal working skills.