calvinchan

Anyone on here with Cargraphic Sport exhaust interested in trading for the race one? I'm not sure if there's much a price diff between them two. I could check if sports is more expensive I can put $$ on top.

Race is a bit too loud for me. Sounds amazing tho.

mrd_spy

Sports is a lot more due to buying 2 x HSK cats.

Voyager6

Last week I put new O2 sensors, Cargraphic race headers and race cup exhaust on my car, replacing Sport Headers and the Cargraphic Sport Exhaust due to the mufflers getting plugged and generating back pressure. I dissected one of the sport mufflers on Sunday. Other than some deterioration in the steel wool packing have broken into steel dust and welding to the two interior pipes, it was OK. The exhaust was heavily insulated and the stainless steel had a lot of blue coloring to it.

The car melted one set of Sport headers in October last year and the replacement was starting to deteriorate. I had a local dyno shop test the car and it was running 11.2:1 air to fuel ratio and was off 22 HP at redline and 45 HP at 3800 RPM. I had the dyno shop crack the exhaust and got the 40 HP midrange back. I ordered the headers and exhaust from BGB and got them installed a week ago and re-dynoed last Friday and picked up the missing HP as compared to the June 2015 BGB delivery dyno run, but got no more.

The sport exhaust is well build and has three layers of packing. I can see why it is drone resistant. The Race headers and cup exhaust is loud and drones horribly in my BGB 3.8L X51 conversion 981 S. I was told there was no packing in the Race Cup mufflers, which I wanted to prevent the new exhaust from plugging up with Carbon.

V6

electron mike

I might be interested in swapping my Fabspeed sport headers for your race headers.. I like more noise.

Edit... nevermind, you said exhaust not headers. My bad.

Peter_GT4

The car melted one set of Sport headers in October last year and the replacement was starting to deteriorate

Can you tell what exactly happened to your CG sport headers and why?

Is there a general reliability problem with those headers when used with the stock exhaust? Or is it more or less related to your special setup and tune or maybe track use only?

Peter

Voyager6

Long post. It is a bit of a story.


The failed headers weren't CG headers, but another manufacturer who I won't name because the failure was not their fault.


Shortly after getting the car in July 2015, the Cargraphics sport exhaust began to leak at the over axle pipe to the rear muffler slip joint. I did not think of anything at the time. However, the air to fuel ratio had to be rich, plugging the rear mufflers and increasing the leak as time went on.


After about 5 nights at the drag strip and two DE weekends, on the drive home after the last DE, I got a CEL for catalytic converter efficiency not up to par. I cleared the codes multiple times and it came back faster and faster.


The car actually got faster at the drag strip, the more the exhaust leaked. When I checked it last October, there was a carbon streak about two to three inches all the way around the slip fitting. I checked the clamp and it was tight.


My guess is the fuel system was off and too much fuel was being injected and this coated the converter with carbon. The first set of headers, the ceramic matrix looked covered in glossy black glass.


I trailered the car back to BGB in February and they replaced the headers, did some other non-related work and glued (at my request) the slip fittings.


Car was down on HP as the drag times were worse. I watched the highway mileage in eco mode. Normally the car got 30 MPG. The first set of headers died at 24 MPG highway. In June, after one evening at the drag strip, two rainy DE weekends and one good one, the mileage had dropped to 26.5 MPG on the second set of headers.


I had the car dynoed locally and they showed 22 HP lower at redline and 45 HP less in mid-range than what the car dynoed (both on DynoJets) in 2015. Air to fuel ratio was measured at 11.2:1. I had the dyno shop loosen the rear flange to the over axle pipe to create a very small leak and redynoed the car. It picked up the mid-range HP, but did not gain anything at redline. To me this was near proof of rich fuel and a plugged muffler.


I jumped in on the BGB Cargraphic group buy and ordered a set of Race headers. I consulted with BGB on a set of mufflers that had no packing to get plugged up. I figured there were multiple causes for the rich fuel mixture and needed a free-flowing exhaust to debug the car. John Tecce told me the only exhaust he knew of that did not have a muffler with packing was the Cargraphics Race Cup exhaust. I wanted a system that could not easily plug up from header to tail pipe and affect the analysis. I called other manufacturers and they all indicated to me at that time that they had some form of packing. So I ordered the CG Race Cup mufflers from BGB, which came in two weeks ago.


I thermally coated the entire exhaust and headers, wrapped them and had them installed along with new O2 sensors. I had the lambda sensor adaption deleted and drove the car. The first day I got 19 MPG. The next day, I went to the drag strip and run the car hard. The following morning, I got 27 MPG driving to work. Later that day, I went to the dyno shop and got 31 MPG, so things were adapting quickly.


At the dyno, I picked up the missing HP and the air to fuel ratio was good, about 14.3:1 at idle and in Sport Plus mode at full throttle, got between 13:1 and 13.38:1. Car is running as expected. Yea!


The second set of sport headers look good on the inside. Everything is a light gray color. I think they will clean up and work with a free flowing exhaust. I think I caught the problem just in time.


BGB has been very helpful, staying in contact with me during this time and I want to thank John and the BGB crew for their support, given their very busy schedule.


V6

Peter_GT4

Thanks a lot for the detailed explanation!

Sounds like a combination of very special circumstances in your case,
will keep an eye on it anyway.

Peter

Jimmy-D

If you were leaking a little exhaust fluid( similar to what comes out of tailpipe in AM) out of the slip joint that is nothing uncommon and should not be part of any issue

Voyager6

It was certainly unique. Hope I never have to deal with that again!

Last Sunday, I dissected one of the CG Sport mufflers to see what the cause of the plugging was. Really didn't find anything. The mufflers are well designed and there were three layers of packing around two perforated tubes. The outer layer of packing was a (probably ceramic) heavy mat. Followed by a loose woven white fiber (likely ceramic), then a heavy layer of steel wool. No carbon was seen, but the case was blue/purple in color, indicating moderately high heat was experienced. Nothing was collapsed inside the muffler.

The steel wool had some strands welded to the interior exhaust tubes due to heat and there was a lot of metal dust in the steel wool. I suspect temperatures, pressure, and vibration broke up some of the steel wool, causing the dust, but I can't see anything to cause the magnitude of the plugging that I experienced. I was expecting a big block of carbon in the packing and it wasn't there. It probably didn't help that the exhaust and mufflers were insulated and probably sent more heat to the mufflers than expected.

To clarify a point I made in the prior post... As far as the slip joint leaking, both sides leaked the same, so it was not confined to just one side. Prior to changing the exhaust last week, I inspected the slip joint connection and there was just the barest hint of carbon starting to leak past the glued joint.

V6

Voyager6

Not fluid. Dry carbon, streaking about three inches down the pipe toward the muffler. You could hear the leak get worse over time.

V6

Jimmy-D

^Interesting. - What ever sports car I have had I always get that little black water from the tail pipes on the garage floor beneath them. Now- I have a valveless exhaust on my GT4 that was put on about a month ago. When facing the rear of the car I get the same black water under the right rear slip joint before the pipe enters the exhaust coming from the headers(exactly where you had indicated) The Master Mechanic at my Dealership said no big deal and that is not uncommon no matter how tight the bracket may be. He works on a bunch of Porsche race cars so I trust what he has to say.

I am just trying to find the correlation