VX SS Commodore - My diary.

[Ginger Beer]

I recall the episode of John Cadogan v Andrew StPier-White. Re: ASPW claiming Toyotas intercooler and bonnet venting was not done the right way. Science won.

The only reason Subaru went top mount was for WRC where rally cars tended to kill front mount intercoolers, Toyota followed suit, as well as other manufacturers, for rally it kinda made sense, the designers just followed suit because people thought it looked cool

There is typically gaskets that seal the bonnet and intercooler, and ducting after the intercooler to let the air out behind the engine, but it still isn't optimal

This is why most circuit cars that originally came wirh a top mount switch to front mount and either use a "non vented" bonnet of a NA car, blank the scoop off, or go carbon fibre, some with vents in the right position to actually use the low pressure zone at the front of the bonnet just behind where the radiator sits

I had one of these on my R33 circuit/drag car that was actually designed and tested when it was developed, it evacuated the underbonnet air just behind the radiator, increasing the efficiency of the cooling stack of a engine oil cooler, a large intercooler, the condenser and the radiator, even on long sessions at the circuit my temps were always on point

If your not monitoring cooling temps, under bonnet pressure testing looking for high pressure vs low pressure zones, doing wind tunnel testing and/or wool tuft testing your doing it wrong

In saying this, if your running a carburettor, a reverse cowl or bonnet scoops like the Monaro or XB-XC GT's, with some underbonnet ducting, is the best way to go

A old mate made up some fibreglass underboonet ducting for his XB GT that went from the vent to the filter body on the carburettor sealing off from the engine bay, the intake temps were greatly improved, he seen it on one of the race cars at Bathurst years ago and made his own

I've seen similar on old carbie Holden race cars (VK's) with reverse cowls

Like this, but this is for the XB interior windscreen vents, think of it like is attached to bonnet, the bonnet vents/scoops, and then a hole in the wide bit that seals to the carbie when the bonnet is closed>

BUT, for EFI, you need to really look a bit deeper if your looking at lowering underbonnet temps, and cutting in random holes with scoops or vents is definitely NOT the way to go

 

[Chuckmeister]

Awesome feedback guys....I really appreciate everything I can read. I've got a new oil cooler going on. I'll see how that goes first.
If I cant get rid of, or regulate heat, and oil temps are still crazy then I have to do something drastic. I can feather those vents into the bonnet so you could barely see them if needed but if it needs airflow then thats what I'll have to do. Bonnet scoops are not an option with this car. Or I'll need to vent the air somewhere that is less obvious. This heat has caused a bearing issue that I cant afford to happen again. Like I mentioned I'll check the new oil cooler...go from there...
Having said that my engine came back today today from the machine shop looking lovely and shmick, started to be put together. Hopefully by next week its sitting in the bay with the trans bolted and the measurements can be made on the tailshaft. Happy to see things moving forward.
Also got my new cam specs...if I'm reading things right...on a Friday night after all...its a pretty nasty cam. Looking forward to the final result.. If I'm reading the chart right...which I might not be until I check with the builder (ton of stuff on the chart for a non mechanic)...the cam is 239.8 / 249.8 /113 custom grind. I believe my builder got a phone call from Crow asking how the cam went, as they have had a couple of good results only to be told its not done yet lol. You get that !!

 

[Ginger Beer]

A nice big oil cooler up front will 100% fix oil temp issues

Are you still running your undertray?