My new "race" exhaust with no mufflers gets quite a bit hotter then my old system, and subsequently has melted some paint on my GT bumper. I'm wondering if anyone makes, or has made heat shields that fit into the tailpipe openings in the GT rear bumper? Similar to what is available to many other cars.
Haven't seen anyone post a custom shield as you described.
Regarding your heat issue, hard to make any recommendations without seeing pictures of your custom exhaust, exhaust tips, and location to bumper. Typically a very hot tailpipe is the result of running to lean, timing advance too far, or in some cases running too rich. Also sometimes a small leak in the exhaust, depending on location, can suck in fresh air which can also result in high exhaust system temps (as it helps ignite any UN-burnt fuel).
Well according to my wideband, the car isn't running lean, if anything its running a hair rich. The new exhaust has no muffler at all, and uses the c5 tips that were on my old system, and in exactly the same location in regards to proximity to the bumper. The old exhaust system never got as hot, and I can only assume its because it was a bit smaller diameter (2-1/4 vs. 2-1/2) and had a muffler. This is a picture of the same system I have on my car now.
[This message has been edited by Bridgetown (edited 09-14-2014).]
With the engine you have in your car, I would also suspect the 2 1/4 inch exhaust is causing the heat increase. If you are set on the high end of ignition timing, that will also jack up the temperature.
Based on your comment that system ran cooler when muffler was present, it could be that the muffler acted like a scavenger improving your exhaust flow, that in effect would not only improve performance, but can also reduce exhaust pipe temp a bit.
Just my thoughts on your issue.
Not that I have a heat issue, but I think it would be great if someone produced some great looking carbon fiber shields for this area (at a reasonable price). It would add a very nice cosmetic touch to the rear of the car, if they wrapped slightly to the flush surface of lower bumper, and also covered entire pocket.
With the engine you have in your car, I would also suspect the 2 1/4 inch exhaust is causing the heat increase. If you are set on the high end of ignition timing, that will also jack up the temperature.
The problem is you only have a test pipe, no cat, and no muffler. There are fewer bends than the stock exhaust, and no large chambers to drop the pressure and slow the gases down. Combined with a coated exhaust system, the heat is staying in the system until the tips.
I'm not sure adding a bit of carbon fiber to the body, above the tips, will really help much. A decent muffler would do wonders for you though. Even a resonator in the front to rear transfer that goes under the cradle, would help a little.
Even with the 2 1/2" the culprit could be it's 2 1/2" thru the entire system. As said by poster above the system is not allowing any expansion, or gas slow down. One way to look at a muffler is that they do act like a heat sink, and reduce tailpipe temp. The trick is to find a muffler that doesn't restrict flow much and gives you the sound you like.
I know we aren't running same engine, but my systems uses Sanderson cc90 headers, to 2 1/2", to 3" collector, to FlowMaster 3" inlet thru pipe, and out stock tips.
I'm not sure adding a bit of carbon fiber to the body, above the tips, will really help much. A decent muffler would do wonders for you though. Even a resonator in the front to rear transfer that goes under the cradle, would help a little.
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Originally posted by 2.5:
Drop the pipe farther from the plastic maybe.
The issue with these solutions is ground clearence. My car is pretty low, so putting a muffler in the above mentioned location wouldn't work, and lowering the system won't work either, as it is already the lowest point on the car, and does occationally "kiss" the pavement under hard driving. I think that the solution might be adding a muffler in place of the existing resonator, and adding some paint protection in the form of a heat shield.
The issue with these solutions is ground clearence. My car is pretty low, so putting a muffler in the above mentioned location wouldn't work, and lowering the system won't work either, as it is already the lowest point on the car, and does occationally "kiss" the pavement under hard driving. I think that the solution might be adding a muffler in place of the existing resonator, and adding some paint protection in the form of a heat shield.
I would put a cat where the test pipe is in that exhaust. If that doesn't help, I would then rework the rear section back to factory style with a muflfer in the stock location.
There are plenty of reasons why the eBay posting for that exhaust says "off road use only" in it, and your heat issue is one of those reasons.
