Dale FZ1

It's back on with the front bar assembly all nice and neat. Must have been on/off 50 times for trial fitment and checking for clearances with those guides.

I ran the smallest 48 trim GT2871 cartridge with stock housings on an RB25. Excellent response, and best result was 225kW on 12.5psi. No boost control issues. No surge issues. I did feel that the bigger OP6 turbine housing would have been a worthwhile improvement on top end flow. A HKS turbine housing with RB spec flange would be the best match, if one could be sourced for the right price. Hypergear's housings would be a good next-best option, and brand new. Personally, I would just have Stao machine up a compressor housing too and make up the whole unit. Should be a great turbo to match up with a RB20.

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.

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.

No. Your instructions are written as a guide. FPR takeoff is from a convenient point in the plenum, and the guide just helps pick up a convenient point. Use a decent quality type hose and you can sheath it and/or cable tie it to stop it chafing or subject it to heat etc if you want. Bottom line is to use a hose-spec that's not going to be affected by heat, and protect it/route it away from exhaust pipes/manifolds. The suggested pickup is only for somewhere to get a reliable MAP signal.

It's holding on well up high. Would like to know what sort of ignition timing the thing takes...

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.

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.

Very stout result Mick. You've got to be pretty chuffed with that. My estimate was well shy of the mark, thought the manifold would have become a problem for flow around 320kW. +1 for graph with a readable scale (rpm on X axis if possible) +1 also for a look at the torque curve please.

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.

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.

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.

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.

You might get lucky, but I found my oil temps weren't well controlled with the cooler mounted between intercooler and radiator. It's been moved and hangs underneath the RHS headlight. Time will tell if it works better there.

So your 32 does run hot at track speeds? It's interesting how things come together at times. Just done a service leading up to first event for the year. Pulled the Pro S off OEM manifold in-car. What a bitch. Made me think about the whole Kando option, and external gate setups with proper fabricated manifold etc. This is now a realistic and financially viable option. Not dissimilar to the situation with in-tank fuel pump options. Things are much better than they were just a few years ago...

Direct fit all the way. It is no fun when you have to trial fit the thing half a dozen times to make sure the cradle is seated all the way home, the pump/bracket/clamps aren't fouling on the tank, and the sock is as low as possible in the tank... I was happy with the end result but it took some work. Unsure with the Nismo or Tomei pumps, but with the 044 there was a significant improvement from upgrading the power feed to the pump. Stock wiring just couldn't do the job.

Are you referring to the wastegate takeoff, or the whole manifold? Did he give an indicator of what diameter tube is used for the standard item? The square-ish angle of takeoff for wastegate does not look ideal, but Noel has reported good results...

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.

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.

Very true. I have first hand experience in a gravel rally car with a 3/4 length, sill-to-sill bash plate. Worked awesome but needed vents to get rid of exhaust heat. Started frying the floor, burning paint, the works. Very uncomfortable .

Rear wing looks great. Power? Is it cabin adjustable? Not sold on the flat bottomed steering wheel. The engine shopping list is extensive and looks pretty good. Don't discount the use of a stock RB25 throttle though; it will pass more than enough air mass for whatever a GT30 or 35 can throw at it. And also make for easier tuning off-idle.

I've been running the stock gauges, and would never have known that it was an overheating issue. It was only that I do my tuning, and knew the failsafes I had written into the tune. But it still took a bit of looking to confirm my suspicions. A decent calibrated gauge would have helped shortcut to the problem. I want to stay on-task with this thread, but dug up this effort at a full undertray on an RX7. Way beyond my plans and resources, but interesting to see. Fish-eye lens shows full-length view but sadly gives no real idea of what is done around the front bar leading up to a basically flat undertray. I'm pretty interested to get some input from a few of the SAU people with a motorsport profile who are prepared to comment and/or post up some pics of their setups. Hopefully a few PMs will encourage them to share their experiences.

I know the thread is about air guides etc, but on reflection it's about management of total airflow. These pics apparently show a stock undertray/diffuser, and a sheet aluminium version. I'd still like to see pics of any stock guides around the GTR intercooler and radiator sides/top

I like the idea of a bonnet vent to relieve air from the engine bay post-radiator. Might be worth looking at in due course. As my work progresses the oil and power steering coolers will have ducts feeding them from the outer openings on the front bar. Pics will be posted up once the cardboard templates morph into metal. On the undertray/splitter, I've thought that a small lip from plastic on the trailing edge may/should work to further reduce airflow to the rear of that point. (it's not lost on me that it will probably cause turbulence as well). Perhaps that might assist with creating a bigger pressure differential through the engine bay and exhausting/drawing air through the heat exchangers at the front of the car.

Bar and plate. A bit heavy, but it's served a reasonably good purpose to date. Unknown just how restrictive those things are to the airstream.