Bonnet heat shield

[RubbishFettler]

Hi Folks

My 350i has the original TVR heat shield under the bonnet. There really isn't much clearance, the plenum is right up against, which can't be much good for air flow. If I was to look at changing it, can anybody say what sort of temperature develops under the bonnet; in other words, does the insulation need to be quite so deep?

Cheers

Steve

[ibroker]

Mine has none.

IN 4 years of ownership the lack of shield has made no difference to the paint on the bonnet. Just had the car resprayed and they did the underside of the bonnet in a glazed black, I asked if I should heat shield it and the said I should not bother. Unless its done well I always think it can look tatty.

[RubbishFettler]

Have you noticed any difference in cooling without the heat shield, or just no difference either way?

[mrzigazaga]

Hi Chaps...The 280i bonnet insulation was touching in a few areas and it definitely hindered the airflow...It was a good sound insulator and more of a heat soak than reflector being foam backed perforated vinyl.

Dyna-mat and AF178 adhesive works the best..I think the air moved a lot more freely when i fitted that...The 350i didn't have anything as far as i remember but i added some foil tape and since i have run a cold air feed from the nosecone to just under the air filter i have noticed the running temperature is significantly lower, Especially on the motorway...Almost a quarter lower than before which then stays that bit cooler when exiting and sitting in traffic...Which is nice...

Hope this helps...Ziga

[440Interceptor]

Watching this thread with interest.

My bonnet heat shield used to foul the throttle linkage and help it wide open a couple of times... My mechanic bolted on a little tin shroud to stop it. Now I am starting from scratch I will be looking for something thinner and reflective to glue in place.

[ibroker]

RubbishFettler said:

Have you noticed any difference in cooling without the heat shield, or just no difference either way?

Cant realy answer that as it never had shielding in the first place.

[ibroker]

RubbishFettler said:

Have you noticed any difference in cooling without the heat shield, or just no difference either way?

Cant realy answer that as it never had shielding in the first place.

[gmw9666]

there is a chap on the PH adverts that does the griff / chim thin silver heat shield.

I am sure he said he was going to start doing wedges.......cant remember what price he said, more than 50 but less than 100 IIRC

[Sireatalot]

Morning..

Thought I'd share my under bonnet heat shielding pics..

The original padded matting was quite old and tatty looking but I wanted to ideally keep it due to it having the TVR logo. However, opened the bonnet one day and found this.



Due to the state of the 'underside', decided to carefully remove alltogether and use the heat reflective silver foil tape.. it now looks like this.


This is two layers worth, 1st layer running from lights to windscreen, 2nd layer running horizontally.

Tape cost approx £12 for 2 rolls and it took me about few hours to apply.

have noticed the temp gauge needle alot lower whilst stop start driving in traffic, probably due to a better airflow over the engine.

[440Interceptor]

Looks great! I am fortunate in that my bonnet is off the car, just been painted. Have justed added another job to the list.

Supplementary question; what is that wire mesh under the padding? The same stuff is under lots of the carpet around the footwells in my car so it must be to dissipate heat? Maybe I could replace it with the shiny stuff in the cabin too...?

[Sireatalot]

Not sure why the mesh is used. It was extreamly brittle and flaked off whilst i removed the padding.

Dont think using the silver heat reflective tape under carpet within footwells would be worth it as it wouldn't be reflecting any heat. ( also, I like the extra warmth in the footwells when the heater decides its not playing )

[RubbishFettler]

Thanks guys, there does seem to be a consensus that the original isn't ideal and increased airflow would be a real benefit, so the foil tape looks a good way to go, unless that's going to be a big disadvantage with sound- let's be honest though, if noise is a problem, you don't buy a wedge.

Just out of interest Zig, do you have any pics of the air duct you fitted?

[bradderztvr]

RubbishFettler said:

Hi Folks

My 350i has the original TVR heat shield under the bonnet. There really isn't much clearance, the plenum is right up against, which can't be much good for air flow. If I was to look at changing it, can anybody say what sort of temperature develops under the bonnet; in other words, does the insulation need to be quite so deep?

Cheers

Steve

Don't worry about it touching the plenum, this is quite common, mine has a nice imprint of the top of the plenum and I have not experienced any probs over the last 30yrs.
However I like the look of Sireatalot's replacement foil!

[mrzigazaga]

RubbishFettler said:

Just out of interest Zig, do you have any pics of the air duct you fitted?

Hi mate...I do...The plan is to fit another the other side but i need to make a collared intake first and fit it to the piece of rear spoiler that cannot be seen from the front... I could of poked it in the side but there was nothing to tie it to.
I think the piece above it where i intend to fit the feeds is the air scoop for the rad but i should imagine it won't hinder it much.
At the minute it catches on speed humps...

Its positioned under the air filter..I was actually quite surprised that just one air feed made a noticeable difference...



Hope this helps....

Cheers...Ziga

I wonder if the mesh was some kind of RFI screen...The struts originally had an earth to this mesh and there is no other apparent reason....Could be twaddle but makes sense...

Edited by mrzigazaga on Wednesday 9th March 14:10

[RubbishFettler]

Cheers for that, yes I can see how speed bumps would be a problem, but gives extra food for thought

Steve

[440Interceptor]

You might be right Zig, there's always an earth strap near to the places the mesh was placed.

[RubbishFettler]

Just fitted the new shield today, all one piece for £25.95 and easily applied with temp resistant spray glue. If anybody is interested, got it from Fleabay

http://www.ebay.co.uk/itm/111648904845?ru=http%3A%...

One bonus I hadn't thought of, the new stuff reflects loads of light into the engine bay for working

Excuse the scruffy garage in the background, by the way.

Steve

[mrzigazaga]

Looks nice...Shiny....