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.

[phillpot]

Some time ago there was talk of a kit that used an electro magnet on the nearside.

Ignition on (engine running) energised, bonnet held down.

Ignition off de-energised, bonnet opens as normal

Was planning on making something up myself but sold the car before I got around to it.

Did however get around to making a small splitter which definately helped with "bonnet flapping" at speed. Doesn't look a lot but made a difference............

[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.

[whipmawhopma]

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?

[Jonny cobra]

Is that splitter on the wrong way round ????

JC..

[TVR500Morgan]

phillpot said:

Did however get around to making a small splitter which definately helped with "bonnet flapping" at speed. Doesn't look a lot but made a difference............

Sorry for the slight change in subject. I like the idea of this but do you find it creates any lift at speed ?

[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.

[SILICONEKID340HP]

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

[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.

[haircutmike]

QB, the splitter makes a lot of difference although mechanical fixing works for me!

[haircutmike]

BTW, jealous of your T/D!

I can't remember what a fast car's like having driven an 85 bhp tranny motorhome all week!

[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

[haircutmike]

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

[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.

[bobfather]

phillpot said:

Some time ago there was talk of a kit that used an electro magnet on the nearside.

Ignition on (engine running) energised, bonnet held down.

Ignition off de-energised, bonnet opens as normal

Was planning on making something up myself but sold the car before I got around to it.

Did however get around to making a small splitter which definately helped with "bonnet flapping" at speed. Doesn't look a lot but made a difference............

That splitter is on backwards. It's supposed to cut the air flow like a snow scoop causing a pressure zone in front that forces the air to the sides of the car. With the splitter the way round you have it all it'll do is cause lift at speed and make your steering light

[Goaty Bill]

bobfather said:

That splitter is on backwards. It's supposed to cut the air flow like a snow scoop causing a pressure zone in front that forces the air to the sides of the car. With the splitter the way round you have it all it'll do is cause lift at speed and make your steering light

That sounds about right to me too.
I think somewhere here, someone came up with a splitter constructed from plastic.
Was it bassfiend?

Anyway, the idea was that they get smashed up, so make one out of something cheap and disposable.
Make several, and keep the spares handy.
Whoever it was claimed it made a difference...

TVR always charged a fortune for new ones. Mine ended up in the scrap yard quite early on, on the advice of the service manager at my TVR dealer.
It seems even they felt guilty about charging that much for something you were likely to destroy on a monthly basis.

[trev4]

May be the splitter we had no problems at 140 on the straight well only my nerves when my 18 year old son was driving.

Quietlybonkers said:

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

[phillpot]

bobfather said:

That splitter is on backwards.
With the splitter the way round you have it all it'll do is cause lift at speed and make your steering light

I got the idea from a thread some time ago, it's made from a piece of plastic rain guttering. Back then there were two schools of thought as to which way round it should go.
All I can say is it definately reduced bonnet lift and car felt stable and steering positive at high speed.

To test the "which way round theory" this is my S Series....



With such crude aerodynamics my opinion is that as long as you have something deflecting air from under the bonnet it's gotta be better than nothing

[daveparry]

These work at speeds ranging from silly to Bloody hell!


Obviously I mean the splitters!