Engine Cooling

[Hybrids]

I have recently purchased another race car, Nissan Pulsar GTi-R.
The previous driver had issues with engine cooling.
Looking at the set up, I think I can understand why, but I wanted to throw it open to the more knowledgeable to check I have my theory right...
Anyone not familiar with the GTi-R, originally they had a horizontal intercooler mounted beneath the bonnet scoop, this has been replaced by a front mounted IC, there is nothing directly under the main scoop anymore (except the engine), aft of the main scoop there are 2 smaller exit ducts.
The PO has raised the trailing end of the bonnet approx 10mm "to aid air flow".

My understanding is that area is high pressure and will not aid cooling,
The main scoop collecting air into the engine bay is only increasing air pressure and not aiding anything.

My thoughts are:
Blank off the main scoop
Lower the trailing bonnet edge as it should be
Fit slightly larger exit ducts
(It does have a high capacity radiator, but currently is not sealed around the edges, this will be attended to)

Pic of the current set up



I appreciate your input

[Chris Y]

I think your ideas are going the right way Gareth. That scoop will probably be creating a region of high pressure or stalling the air under the bonnet.

I've never been convinced about raising the back edge of the bonnet. Under normal circumstances, it's a high-pressure area, which is why the heater usually draws air from that region. I guess it all depends on the angle of the windscreen, but I think the original intention by raising the back of the bonnet was to reduce the angle 'twixt bonnet and screen, speeding up the flow of air, and then being able to suck the air from the engine bay because of the pressure differential. Trouble is, I don't think most people are able to raise the back of the bonnet sufficiently to have any impact on air speed in that region.

[JohnD]

You might investigate the flows by the old 'aero tuft' method.

This would show you if the flow at the lifted rear of the bonnet was in, out or shaking about (turbulent), and if the redundant front-facing scoop was stalling or not.

John

[Notso Swift]

A mate of mine use to have one of these, also fitted with a frontmount, and I had the brainwave of using the scoop as a cold air feed. He then plated off the scoop, had a 3" exit and then to flex pipe to the turbo.

FWIW He never had overheating issues, gearbox issues on the other hand

[MacrosNZ]

I'd suggest changing to a standard non-turbo pulsar model bonnet and see if that has an effect.

Don't forget air won't go in if it can't get out...

[alfredstalone23]

Hi Gareth, just want to ask, if you already fixed your concern with your car, because I have a friend with same car situation.

Thanks

[Hybrids]

Thanks for replies, I will be running the car next month for the first time since August, hence the lack of updates regarding success... or not.
Though I have not yet blanked off the bonnet scoop, it is still on the list of things to do, I need to stay with the stock GTiR bonnet as one of the clubs I plan to race with stipulate stock silhouette.
I have panelled in around the rad and pieces either side of the IC to ensure all air entering the front grilles go through the radiator.

[Paceracing]

Simple things to check first....

1. Daft question perhaps, but I take it the pipework is connected the right way around for the rad?
2. The cooling fan is not working against the flow of air?