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Twice pipe exhaust insulation?

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#1 S30Stig



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Posted 29 September 2016 - 02:14 PM

Hello everyone! I'm doing a slow restoration on my 1972 240Z and I'm at the point of sorting out the exhaust. I believe we're going to go with the twice pipe setup for 3-2 headers from thezstore.com. This kit from what I understand recommends that you widen the opening in the rear fender to accommodate both pipes which is something I definitely don't want to do. My solution would be to modify the piping in the kit so that I have a center-exit exhaust which would go with the retro-racer look I'm after with my car.


The only concern I have would be that there would be more heat in a much closer proximity to the stock fuel tank. So what would be the best insulation for the exhaust? I would assume header wrap would be plenty being that far down the exhaust system. Any input is greatly appreciated as I'm used to lifted trucks with miles of space between everything.

Thanks in advance!

#2 Pillar



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Posted 30 September 2016 - 05:03 AM

Many other people have run a center exit exhaust like you are talking about doing without any issues as far as heating the gas tank.  Unless you are sitting still for a long time, there should be enough airflow back there to dissipate the heat.  Since you live in the North-East, I would advise against any header wrap on the exhaust unless you are sure that the car will never see the wet/salt.  The twice pipes exhaust can already rust pretty easily and wrapping it in something that will hold moisture will only make that worse.  Results may vary of course, but I would be very hesitant about wrapping it if you want it to last (again, if you plan to never get the car wet, it may be fine).   

#3 S30Stig



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Posted 01 October 2016 - 10:04 AM

I'm fortunate enough to have a garage for winter storage right now so salt and rain really never touch the car. It's the unexpected 10-15 minutes of standstill traffic that's all to common in NJ that has me concerned. I think I'll try to fab up a plate to go between the tank and pipes once I go ahead with the kit. Two different layers of air should be plenty of insulation even if I end up sitting in a little traffic.

#4 Tony D

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Posted 22 October 2016 - 02:42 AM

So I take it they are not stainless steel supertrapps slung under the tank then...

There were some photos I posted of the rally cars and the shield they had under the stock tank. It attached  to the pipes somewhat like the later model 280Z mufflers had an integral muffler heat shield along with the physical shield between the tank and muffler that secured to the package shelf floor.

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