S130 bonnet/hood vents

[burninator]

That looks amazing! I love the look of the hood with those louvers there.

[260DET]

This is getting way off topic but I can do that with my thread piss off nono

 

Anyway W, sounds like you are going to the FOSC, there are a couple of teams from the Q club going to that. I can't for various reasons.

[Whittie]

Yeah the FOSC bathurst event is fantastic! Make sure you get to it before they are not allowed to run it anymore (likely, with cams)

 

 

Anyways, did the track day today. I did about 50 laps over 4 sessions and the only time the car had cooling issues was when the fuse for the thermo fan came unplugged. And then it only overheated when I got to the pits and there was no airflow through the radiator.

 

I would like to say the vents fixed the cooling, but they didn't. It certainly helped, but it still gets hotter than I would like (about 200F, 93C). However, where before the temp would get to 90C, sit for a while and then keep climbing and boil in 5 laps, now it sits at 90 and doesn't move.

 

The vents are also not ideally situated. The panel beater, despite great pains to try and get it right on my behalf, put the vents too far forward ( the front of the vents is right above the radiator) and too far away from the center of the bonnet.

 

So, the vents aren't properly located, the cooling is not totally solved, but subdued, and I'm out of pocket WAY more than I expected.

 

BUT, it looks F'ing AWESOME!!!! (see attachment)

 

Oh, and just quietly, I was only about 0.5s a lap slower than that R35 on the short track with him on street rubber :D I was SOOO happy when he couldn't keep up with me on parts of the track!!! The straights were a different story though

[260DET]

Yeh I was going to say the bonnet vents were a bit too far forward but if your temp is not going above 90 on a hot day thats OK, mine runs around that. Oil temp is just as important.

 

Yeh I've heard that CAMS are carrying on a bit, typical, I only do AASA events at present.

[Whittie]

Yeh I was going to say the bonnet vents were a bit too far forward but if your temp is not going above 90 on a hot day thats OK, mine runs around that. Oil temp is just as important.

 

Yeh I've heard that CAMS are carrying on a bit, typical, I only do AASA events at present.

 

Well here I am, another Bathurst event over (wow, that sounds prissy considering the people who have never done it) and as is typical it started raining. Hence, I present to you, Bonnet Vent Aero Mod MkII:

 

 

 

The pics were taken at the motel after the last day at the track. Luckily it didn't rain at the event, but after Dad got stuck in the middle of the city when he picked the car up in the rain, I didn't want to take any chances.

[260DET]

Any incar video this year W?

 

Re the bonnet vents, I can't make any more suggestions except to comment that this S30 front aero thing should be approached as a whole package. Bonnet vents, partially blocked off grille opening, ducted radiator and a small undertray like the stock 260Z one, its all discussed here. Your bonnet vent air test tufts were fairly revealing.

[Whittie]

Any incar video this year W?

 

Re the bonnet vents, I can't make any more suggestions except to comment that this S30 front aero thing should be approached as a whole package. Bonnet vents, partially blocked off grille opening, ducted radiator and a small undertray like the stock 260Z one, its all discussed here. Your bonnet vent air test tufts were fairly revealing.

 

Hi Richard,

 

I take it you saw the vid on viczcar?

 

The car is getting a pretty major rebuild later this year and the rest of those mods will be done. Should be good to see how it all adds up at Bathurst again next year.

[260DET]

Yeh saw the vid, I'm Fairladys130 on YouTube. Will be very interesting to see how your S30 goes next year, the only comment I have to make is that it seems to have a lot of dive when braking. But you are the one who drives it, not me.

 

I'm hoping to bring the 280ZXT next year but with 450 WHP I'm a bit concerned about the very high speeds that will be involved. Can always knock the rev limit back from 7500 or reduce boost a bit I suppose, all in the interests of engine reliability of course

[Whittie]

Yeh saw the vid, I'm Fairladys130 on YouTube. Will be very interesting to see how your S30 goes next year, the only comment I have to make is that it seems to have a lot of dive when braking. But you are the one who drives it, not me.

 

I'm hoping to bring the 280ZXT next year but with 450 WHP I'm a bit concerned about the very high speeds that will be involved. Can always knock the rev limit back from 7500 or reduce boost a bit I suppose, all in the interests of engine reliability of course

 

Yeah, the springs are WAY too soft for bathurst. My whole car is a compromise though cause I still want to drive it on the road. For home and hillclimbs/sprints on cloased public roads it's good, but not so much on a dedicated track. I just can't justify 5-8k for suspension tho! Anyways, that's another thread.

 

For now, Airbox and splitter are the next jobs. Plus ally radiator!

[260DET]

To finish this topic off the pic below shows the final setup which works so well that I can belt around a race track and the temp just sits on 85 degrees C which is what the thermostat is rated at. Keep in mind that this car has a VG30DET, that front central vent is located right in front of the motor. The final improvement done was to instal those black kickup plates in front of the stock but opened out vents, they were instrumental is dropping the engine temp something like 5 degrees C. The engine bay stays cool too which has to be good for the electrics, fuel, etc.

 

As a possible side effect it may be that there is now so much disrupted airflow over the bonnet that its curved shape no longer aids lift at speed.

 

Overall? Job done

[daviddwillson]

Can't drive my car right now but wool tufts around the vents seem to be a practical way of seeing whats happening there at speed.

 

But the 280ZX bonnet slopes to the front more than the S30, and most other cars, which is why it could well be different.

 

What prompted me to check this out was what happended at the sprints the other day at speed. My bonnet is latched at both rear corners. One of the latches was not done up properly, the unlatched corner actually lifted up an inch or so due to the force of engine bay air exiting. To do that it had to twist the fibreglass bonnet a bit as well as lift the weight.

From what i have read around these forums about the Z bonnets is that the low pressure on the middle of the bonnet and the high pressure air under the bonnet is what causes it. Sort of like an aero plane wing with the pressure on both sides interacting to lift the wing without transport of medium between the bottom and top of the wing.

 

Also from what I've read is that the high pressure at the windscreen acts to STOP air flowing out of the rear of the bonnet. The heater inlet ducts are placed at the base of the windscreen so air is pushed into them, reducing the power required by the pump to suck air in.

 

I'm going to go for a drive today so I'll also put some tape just rearward of the bonnet and try leaving it popped (on the secondary stop) and see if there is any wind flow out of or into the engine bay by doing that.

[260DET]

Will have to come back with an update on the 280ZX sometime because in a moment of madne$$ I bought a lightweight bonnet and have redone the venting system. It will need pics to illustrate what has been done which is pretty cool

[aarang]

Just curious, did you trim the sheet metal on the hood below the vents as well? If so, would you have any pics? Thanks.