Bonnet popped open......

[Quietlybonkers]

.....at 135mph.

Any thoughts on how to affix a second bonnet catch, or should I just give in and get the ally posts that were discussed on PH a week or two ago? Don't really want to, as it will spoil the looks on my 99 Chim.

[Quietlybonkers]

Thanks Phillpot - I like the sound of both the splitter and the electromagnet. I will make enquiries. A second mechanical catch looks likely to be difficult.
The lift forces on the bonnet at speed are huge, as the whole bonnet is shaped like an aerofoil. Even with the bonnet/wing joins fully gaffer taped the up-force managed to break the tape.

[Quietlybonkers]

whipmawhopma said:

Quietlybonkers said:

.....at 135mph.

Any thoughts on how to affix a second bonnet catch, or should I just give in and get the ally posts that were discussed on PH a week or two ago? Don't really want to, as it will spoil the looks on my 99 Chim.

Is this a question or did this really happen? If so how high does it lift up?

It really happened, on a track day, one mile down an RAF runway, today. The bonnet lifted six inches or so, what I didn't know was would it go higher? I managed to pull up at the side of the track without further incident, and gaffer tape it down. It's an aerofoil shape, and the air travels faster over it, creating lift. If it's not held down tightly, it lifts.. Once it had lifted six inches, the wind pressing down on it stopped it lifting any further.

[Quietlybonkers]

SILICONEKID340HP said:

Have a look at this thread ..Im going to buy just one .
http://www.pistonheads.com/xforums/topic.asp?h=0&a...

Thanks, they are the ones. Its just that mine is a later Chim, without the boot hinges and door catches that match so well with the bonnet catches.
I would prefer the electromagnet for looks, but can see that the mechanical catches are a more positive kind of safety. I certainly don't want the lifting bonnet again, and the track day at Marham was a blast - nothing to hit and an interesting 3 mile track at a bargain price - so I will be doing it again. It's a two day event, so I will gaffer tape the bonnet shut tomorrow.

[Quietlybonkers]

Back there tomorrow all day - at £50 a day it was a no-brainer! Had a good lesson on lines and styles from a Land Rover/Jaguar test driver in his Holden Monaro to start the day, and thoroughly enjoyed myself for the rest of the day, despite spinning a couple of times. The same guy is going to drive my car tomorrow to show me how to get it around the corners better.

Oops, sorry, didn't mean to make it worse

[Quietlybonkers]

haircutmike said:

Slow in, fast out with your tyres, careful with lift off when near the limit, you'll defo spin!

Yes sir! Schoolboy driver knows you are right, and it's the same as the Holden driver told me I will try to remember.....
One spin was muppetry - I tried to change down too late and mid-corner, instead of just steering and slowing. Typical beginner's mistake, watching the car in front instead of concentrating.
The other one was just as you said - too much speed going into a sharp corner and couldn't hold the slide on the stripey paint (end of a runway markers)
In the afternoon, with warmer tyres and driver, and the circuit reversed, every corner was approached at 115 mph and then hard on the brakes, but correct entry speed made the corners really flow and even my quiet stealth-TVR sounded great and behaved itself (most of the time).
Time to wash the car and get back to the circuit, gaffer tape in hand.

[Quietlybonkers]

Thanks everyone for all the suggestions, I will give all of them some thought and select probably a combination of fixes.

[Quietlybonkers]

Gaffer taped the darn thing shut for today's session and had no problems other than not being able to check the oil and water.
I will have a muse and decide what to do next. Obviously it is only a track day issue, as I wouldn't be speeding on the pubic highway.
Pins or splitters, that is the question. I too like the look of the splitters on the black Chimaera, and not all bonnet pins look too horrendous.
Or I can just carry a roll of black gaffer tape with me to track days.
Thanks everyone for your contributions

[Quietlybonkers]

WTF is doe snot?

[Quietlybonkers]

Thanks Bobfather, that is a great analysis of all the factors.

All bonnet movements occurred on a dead smooth operational RAF base runway. Tornado GR4s will be flying out of there tomorrow morning.
In my case, I had the passenger side flapping fairly wildly from about 90-100 mph, so taped that down
Then at 135 mph I had so much force on the bonnet that it not only detached the gaffer tape, it also pulled the bonnet catch peg out of the closed bonnet catch, meaning that the bonnet must have bulged enough for the peg to pull right out without the catch opening. Have a look at your own bonnet catch if you don't know what I mean.
I need as much under bonnet cooling as possible on hot, high revving, hard working track days. Most of today was spent between 4000 and 6000 rpm, but the car was always between 70 and 92 degrees C.

So the solution for me is I guess not splitters, it is better fixing of the bonnet to the car. Pins (or gaffer tape) is probably the answer to my issue.
Unless the cool air passing over the engine will still be adequate with a splitter fitted.
Now I know what the vents in the bonnet are for.

Thanks everyone - do you all agree?

[Quietlybonkers]

haircutmike said:

Er, no!

Gutter spiitter pointing forward pulls bonnet down so bonnet won't pop up.

Nearside corner flaps because of poor design, fit pins.

Pack bonnet catch forward a couple of washers and ensure that you have the plasticsleeve on your bonnet pin.

All imho, of course.

Still jealous!

Thanks Peter - I will look out for next year's track weekends and see if we can get a bit of a TVR weekend going. They normally do two of them, but occasionally they have to cancel at short notice due to needing the track back to fly their Tornados off the main straight. The chance to spin the car at high speed and know you aren't going to hit anything was actually a real boon for muppets like me. In the mean time I will have a think about how to sort out the bonnet, and thanks everyone for your great contributions.

Stuart the test driver pronounced my car very nice to drive, his only suggestions being less sticky tyres to loosen the back end a bit (errr, I don't think so!!) and a longer gear lever or greasing the linkage, to make the gear change a bit slicker. As the box was only out last Monday to have reverse sorted, and I cannot imagine that Mat didn't grease the linkage before he re-inserted the box, the gear-change must now be as good as it gets. To be fair, it was getting a bit sticky towards the end of the day. He did like the standard TVR aircon - I did the entire weekend with the roof right down, to avoid overheating......me, not the car.

[Quietlybonkers]

haircutmike said:

Er, no!

Gutter spiitter pointing forward pulls bonnet down so bonnet won't pop up.

Nearside corner flaps because of poor design, fit pins.

Pack bonnet catch forward a couple of washers and ensure that you have the plasticsleeve on your bonnet pin.

All imho, of course.

Still jealous!

Thanks Peter - I will look out for next year's track weekends and see if we can get a bit of a TVR weekend going. They normally do two of them, but occasionally they have to cancel at short notice due to needing the track back to fly their Tornados off the main straight. The chance to spin the car at high speed and know you aren't going to hit anything was actually a real boon for muppets like me. In the mean time I will have a think about how to sort out the bonnet, and thanks everyone for your great contributions.

Stuart the test driver pronounced my car very nice to drive, his only suggestions being less sticky tyres to loosen the back end a bit (errr, I don't think so!!) and a longer gear lever or greasing the linkage, to make the gear change a bit slicker. As the box was only out last Monday to have reverse sorted, and I cannot imagine that Mat didn't grease the linkage before he re-inserted the box, the gear-change must now be as good as it gets. To be fair, it was getting a bit sticky towards the end of the day. He did like the standard TVR aircon - I did the entire weekend with the roof right down, to avoid overheating......me, not the car.

[Quietlybonkers]

GTRene said:

wonder what something like this will do to the car...it has little wings and a big splitter.



or this



some are not really fit in the nice curvy TVR's

Mutt's nuts Rene......very much food for thought. Where can I get either of those, please?