Exhaust Vibration[I think]
Discussion
Hi guys, after some advice please.
Put the JCR centre section on the car 991.2 GT3, professionally fitted and all was good. Had a couple of really nice days out with window down slightly and could here a vibration, once you gave it the revs and flaps opened you couldn't hear it at all, seems to be when the exhaust is hot and valves closed. Coming back into town I put it in auto for easiness and the flaps close, that's when you can hear the vibration, but it is intermittent.
Double checked everything and all seems good, I undid the 3 bolts and stuck some pieces of 2 mill exhaust gasket in between the OEM tip plate and the mating plate on the Titanium piece and tightened up. It was a lot better but still does it when the exhaust is hot.
My plan now is to now take the OEM plate off and take it to my engineer who will put some Granville exhaust paste around it for me, leave 10 mins to get a skin on it and tighten up and see what happens, I can also tap the plate on the JCR to see if there is any vibrations which I very much doubt. Will be a shame if I cannot stop the vibration and revert back to stock as the sound is just menacing, have had 4 full systems of Akrapovic on my BMs before and you do get the odd rattle of the exhaust valves opening and closing when hot, but think its definitely the titanium heating up quicker than the mating plate on the OEM tips causing it. I thought i could hear it at times doing it with the OEM section on, and also thought could it be the valves. They are very tight and snappy when you pull the rod out so have sort of dismissed that.
I know there are a few of you guys who have had the JCR on your cars, did you have any problems as far as vibration goes? Any help or advice would be very much appreciated.
Cheers.
Put the JCR centre section on the car 991.2 GT3, professionally fitted and all was good. Had a couple of really nice days out with window down slightly and could here a vibration, once you gave it the revs and flaps opened you couldn't hear it at all, seems to be when the exhaust is hot and valves closed. Coming back into town I put it in auto for easiness and the flaps close, that's when you can hear the vibration, but it is intermittent.
Double checked everything and all seems good, I undid the 3 bolts and stuck some pieces of 2 mill exhaust gasket in between the OEM tip plate and the mating plate on the Titanium piece and tightened up. It was a lot better but still does it when the exhaust is hot.
My plan now is to now take the OEM plate off and take it to my engineer who will put some Granville exhaust paste around it for me, leave 10 mins to get a skin on it and tighten up and see what happens, I can also tap the plate on the JCR to see if there is any vibrations which I very much doubt. Will be a shame if I cannot stop the vibration and revert back to stock as the sound is just menacing, have had 4 full systems of Akrapovic on my BMs before and you do get the odd rattle of the exhaust valves opening and closing when hot, but think its definitely the titanium heating up quicker than the mating plate on the OEM tips causing it. I thought i could hear it at times doing it with the OEM section on, and also thought could it be the valves. They are very tight and snappy when you pull the rod out so have sort of dismissed that.
I know there are a few of you guys who have had the JCR on your cars, did you have any problems as far as vibration goes? Any help or advice would be very much appreciated.
Cheers.
Edited by Melvynr on Wednesday 5th February 20:29
Before pulling the system apart again, I'd suggest checking the ancillary items likely to have been moved or removed as part of the install, such as the heat shields. Just because you can only hear the noise when you;re at town speeds, doesn't mean it's not there all the time, you probably just can't hear it because of all the other road and engine noise.
Thanks , good advice and will do that.The heat shields are still there at the top of the Titanium piece but are very very close, they are still solid though.
I have been tapping the front of the tips in a forward motion and you can hear the vibration, will be off work tomorrow so will just take the tips off and re tap the plate on the centre pipe.If that stops it, then I think I have it cracked.Thanks for your reply.
I have been tapping the front of the tips in a forward motion and you can hear the vibration, will be off work tomorrow so will just take the tips off and re tap the plate on the centre pipe.If that stops it, then I think I have it cracked.Thanks for your reply.
Hi Melvyn, sorry to hear of your troubles. No vibration when installed on my 997. If the heatshields on a 991 are anything like those on the 997 and the clearances (or lack of) are the root cause, they're only like glorified kitchen foil and are fairly easy to "re-model" locally.
Your approach seems a good one. Fingers crossed it isolates the issue and you get it sorted.
Your approach seems a good one. Fingers crossed it isolates the issue and you get it sorted.
Hi, thanks for the reply.
The guy I bought it off took some pics of the piece, a thing of beauty to be honest and all blued up, however, he pointed out a slight ding at the back top piece of it.I am just wondering if he had the same prob and wedged something in at the top to see and thus causing the little dink.
I have some options to try, will get to the bottom of it.Cheers.
The guy I bought it off took some pics of the piece, a thing of beauty to be honest and all blued up, however, he pointed out a slight ding at the back top piece of it.I am just wondering if he had the same prob and wedged something in at the top to see and thus causing the little dink.
I have some options to try, will get to the bottom of it.Cheers.
An update guys
Took car back today, tweaked the exhaust away from the top heat shield and still no different. Guys put a pipe on cats while engine running and the driver's side one is vibrating like hell.
Booked in with Porsche on Tuesday, will see how I get on with warranty. Have a very good relationship with the guys as they also have the BM franchise which I've used for the last 20 years, so touch wood, the warranty might cover it. Cheers.
Took car back today, tweaked the exhaust away from the top heat shield and still no different. Guys put a pipe on cats while engine running and the driver's side one is vibrating like hell.
Booked in with Porsche on Tuesday, will see how I get on with warranty. Have a very good relationship with the guys as they also have the BM franchise which I've used for the last 20 years, so touch wood, the warranty might cover it. Cheers.
Hi Melvyn, glad you got this sorted. Did Porsche replace a side muffler, or a cat (they're different items). The catalytic converter is part of the manifold. I think I asked on a different thread whether there was any tapping or other persuasion during the removal of the centre muffler or fitting of the bypass which could have loosened the cat "brick"..
Oh, and Just to clarify from a few posts back....I am the guy you bought the bypass from! The pipe was dinged due to a slight slip during it's initial fitment (not by me I hasten to add). The clearances were fine after some very minor heatshield manipulation. There are posts on the JCR Facebook page with photo's of the installation on my car. It was only removed as I wanted to return my car to entirely standard spec', and after the initial novelty had worn off, the additional noise wasn't for me. Which absolutely confirms I'm getting older than I'd like to believe!
Really pleased it's all sorted for you now.
Oh, and Just to clarify from a few posts back....I am the guy you bought the bypass from! The pipe was dinged due to a slight slip during it's initial fitment (not by me I hasten to add). The clearances were fine after some very minor heatshield manipulation. There are posts on the JCR Facebook page with photo's of the installation on my car. It was only removed as I wanted to return my car to entirely standard spec', and after the initial novelty had worn off, the additional noise wasn't for me. Which absolutely confirms I'm getting older than I'd like to believe!
Really pleased it's all sorted for you now.
D.no said:
Hi Melvyn, glad you got this sorted. Did Porsche replace a side muffler, or a cat (they're different items). The catalytic converter is part of the manifold. I think I asked on a different thread whether there was any tapping or other persuasion during the removal of the centre muffler or fitting of the bypass which could have loosened the cat "brick"..
Oh, and Just to clarify from a few posts back....I am the guy you bought the bypass from! The pipe was dinged due to a slight slip during it's initial fitment (not by me I hasten to add). The clearances were fine after some very minor heatshield manipulation. There are posts on the JCR Facebook page with photo's of the installation on my car. It was only removed as I wanted to return my car to entirely standard spec', and after the initial novelty had worn off, the additional noise wasn't for me. Which absolutely confirms I'm getting older than I'd like to believe!
Really pleased it's all sorted for you now.
Hahaha, it's a small world.Oh, and Just to clarify from a few posts back....I am the guy you bought the bypass from! The pipe was dinged due to a slight slip during it's initial fitment (not by me I hasten to add). The clearances were fine after some very minor heatshield manipulation. There are posts on the JCR Facebook page with photo's of the installation on my car. It was only removed as I wanted to return my car to entirely standard spec', and after the initial novelty had worn off, the additional noise wasn't for me. Which absolutely confirms I'm getting older than I'd like to believe!
Really pleased it's all sorted for you now.
It was the driver's side muffler that had gone, Porsche said they hadn't had one on a GT car that had failed before but after listening to a sound clip the tech sent, they pretty much agreed it was the muffler. They sent a new one over straight away, there was nothing loose in the one taken off. Tech wanted to cut it open as it is double skinned we think and maybe a weld had broke, anyway Porsche wanted it sent back for a look at it. It was all done under warranty, the part was 2.6k which at them prices the system would be getting on for 10k which is crazy when you can get the full Akra for 8-9k with discount.
Made up with the centre bypass, beautiful tone to it when hot. It was very good of you to point out the slight dink in it as well, you cannot see it so more than happy to buy it. Tried to give you feedback as well, but never got a mail from Ebay asking.
Am getting older as well, but it's still great fun hitting a red line. Cheers pal.
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