Exhaust midbox floor clearence

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Kevin
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Exhaust midbox floor clearence

Post by Kevin » Sat Aug 01, 2020 9:58 am

Can anyone please advice me on how much clearence there should be between the floor & the top of the exhaust midbox's ? (GTC)
I can currently, just get my hand in between the midbox & floor, after driving the floor in that area is getting very hot. I am struggling to get the exhaust system any lower & have lowered the back box's to try & increase the gap. It is exactly the same on both sides.
Thank you for your help.
Kevin.



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scimmy_man
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Exhaust midbox floor clearence

Post by scimmy_man » Sat Aug 01, 2020 11:13 am

any lower and you run the risk of losing them on speed humps,
you can add a heatproof shield/fabric above the exhaust box


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justfur
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Exhaust midbox floor clearence

Post by justfur » Sat Aug 01, 2020 7:39 pm

I fitted a piece of 1.75mm stainless sheet between the boxes and floor, can't say how successful it is just yet....you could add a washer in there as well for an added air gap.


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philipmasonfrance
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Exhaust midbox floor clearence

Post by philipmasonfrance » Wed Aug 05, 2020 8:46 am

just had a scrabble under my GTC. I reckon about two fingers (!!!) clearance - say 4 cms. But I doubt any two exhaust systems are the same 40 years down the line. I think I would try the heat-reflecting stick on stuff - and let us know how you get on!



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guybetts
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Exhaust midbox floor clearence

Post by guybetts » Wed Aug 05, 2020 7:31 pm

I've got about an inch (25mm) at the narrowest point (back of the 'midbox'), but the floor slopes upwards towards the front and over the chassis rail that the front seat mounts are fixed through. There seems to be plenty of air around the midbox under mine. It's a Stainless system, and the box is quite a flat oval. The system is up as far as I dare go, to avoid damage from humps, potholes etc., without clattering against the chassis!

I wouldn't think the heat from the exhaust is hot enough to cause any damage, but fully appreciate that heated seat feeling on hot summer days is not everyone's cup of tea :D

Guy


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Kevin
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Exhaust midbox floor clearence

Post by Kevin » Sat Aug 08, 2020 6:28 pm

Thank you all for getting under your cars & checking your, exhaust midbox clearence!
I have now glued on some exhaust shielding material to the floor, above the midbox's. The clearence under my car seems to be roughly the same as on Guy's car, around 55mm at the front & 25mm at the back of the midbox.
After taking the car for a good test drive I measured the floor temperature, 77C (171F) is this an acceptable temperature on the fibreglass floor?
I also have replaced the doughnut rubbers with some stronger rubber supports, these stopping the exhaust from bouncing against the floor on bumpy roads!
The exhaust system is stainless, supplied by QRG & was fitted myself.
Thank you all for your help with this.
Kevin.



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Old and Slow
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Exhaust midbox floor clearence

Post by Old and Slow » Sat Aug 08, 2020 9:47 pm

I thought anything above 50C is too hot to touch; 77 seems like an awful lot!!


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guybetts
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Exhaust midbox floor clearence

Post by guybetts » Sat Aug 08, 2020 11:48 pm

Old and Slow wrote:
Sat Aug 08, 2020 9:47 pm
I thought anything above 50C is too hot to touch; 77 seems like an awful lot!!
I've not done a thorough investigation, but it does seem that fibreglass can withstand heat substantially more than this - above 150 DegC. Mind you I'm not sure I'd want to test that :shock: The splash guards are pretty close to the downpipes, and don't seem to have deteriorated. Conversely, there is heat shielding at the back of the engine compartment in the GTC.


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