MickH Posted May 18, 2022 Report Share Posted May 18, 2022 Hi guys I have finally pushed it too far. Ive had a designtek switchable exhaust on for about a year, and decided to put the race manifolds on as well. Got those fitted along with an induction kit. And im about to say something that I never thought I would ever say. Its far too loud Has anyone else done the same and had the same issue? Quote Link to comment Share on other sites More sharing options...
map Posted May 18, 2022 Report Share Posted May 18, 2022 Haven't used the DT gear but my own Tweaked 986 is now loud. So loud that I am going to have the silencer replaced with a much higher capacity silencer pack. Hopefully I won't lose the over run burble... There's plenty of induction noise too (I have a bespoke cold air intake housing a 400bhp capacity cone filter) but that only really makes itself felt under hard acceleration so it isn't a constant companion. When that's upgraded along with the rest of the inlet system I am expecting that to get louder too. Do the race manifolds that have just been fitted to your car have cats as well? Is it actually louder or has the noise changed tone? Quote Link to comment Share on other sites More sharing options...
And.rs1800 Posted May 18, 2022 Report Share Posted May 18, 2022 How loud was the exhaust with the standard manifolds on Mick? is it bearable on a long journey with the valve open? Mine is standard but starting to blow a little,I’m thinking about a non valved designtek (I doubt I’d ever have the valve closed anyway). Quote Link to comment Share on other sites More sharing options...
cptspaulding Posted May 18, 2022 Report Share Posted May 18, 2022 Too loud even with the exhaust on tame mode? Quote Link to comment Share on other sites More sharing options...
MickH Posted May 18, 2022 Author Report Share Posted May 18, 2022 On tame mode its fine. But for comparison Tame mode is only slightly quieter than loud mode before I swapped the manifolds @map Ive fitted the mrn cold air system. Is that similar to yours? Quote Link to comment Share on other sites More sharing options...
map Posted May 18, 2022 Report Share Posted May 18, 2022 30 minutes ago, MickH said: @map Ive fitted the mrn cold air system. Is that similar to yours? Just had a look at that and it seems the filter sits in the bodywork void between the wing and the engine compartment. Mine is currently all in the OE locations. I now wonder if the source of your excess noise is the MRN intake. That’s positioned right by the passenger shoulder and is dragging a lot of air into the engine. That intake airflow will be pretty loud. Can you swap the intake back to stock and then compare? Quote Link to comment Share on other sites More sharing options...
BBB Posted May 18, 2022 Report Share Posted May 18, 2022 1 hour ago, And.rs1800 said: How loud was the exhaust with the standard manifolds on Mick? is it bearable on a long journey with the valve open? Mine is standard but starting to blow a little,I’m thinking about a non valved designtek (I doubt I’d ever have the valve closed anyway). I have this exhaust on standard manifolds. It’s definitely louder/deeper than OEM with valves closed, but in a perfectly acceptable way and I really like it; not a drone box. But, with the valves open it’s REALLY loud and I only use it that way in tunnels or open country roads. I wouldn’t go for the non-valved version if it’s equivalent to valves open. 1 Quote Link to comment Share on other sites More sharing options...
MickH Posted May 19, 2022 Author Report Share Posted May 19, 2022 10 hours ago, map said: Just had a look at that and it seems the filter sits in the bodywork void between the wing and the engine compartment. Mine is currently all in the OE locations. I now wonder if the source of your excess noise is the MRN intake. That’s positioned right by the passenger shoulder and is dragging a lot of air into the engine. That intake airflow will be pretty loud. Can you swap the intake back to stock and then compare? I've fitted the baffle back on and its slightly quieter now. The intake is definitely making the issue worse. However I'm still leaning to the manifolds being the issue, as my mate was behind me in his beemer and he couldn't hear his own engine over the noise of mine Quote Link to comment Share on other sites More sharing options...
map Posted May 19, 2022 Report Share Posted May 19, 2022 3 hours ago, MickH said: I've fitted the baffle back on and its slightly quieter now. The intake is definitely making the issue worse. However I'm still leaning to the manifolds being the issue, as my mate was behind me in his beemer and he couldn't hear his own engine over the noise of mine Did the 3.2 987 have the cats on the manifolds? 987s are a bit modern for me. If it did and the motorsport manifolds have deleted the cats then they're almost certainly the cause of the excess noise as you suggest. In terms of the air intake - based on this link: https://www.mrnracetechnologies.com/product-page/987-cold-air-induction-kit can you remove the cone filter and the 90o bend it's attached to then refit the cone filter to the metal pipe. This will put the cone filter back into the void previously occupied by the air box. This is probably less work than swapping the manifolds. And it will clarify just how much of the noise is from the intake. I know that 99x cars have to run additional silencing on their intakes to hit noise regs so a high flow intake creates a lot of (subjectively) intrusive noise. 1 Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted May 19, 2022 Report Share Posted May 19, 2022 (edited) When I've considered adding tube headers to my ebay dronebox I thought I'd put some aftermarket 200 cel cats downstream from the manifolds. I think there's space. The stock manifold cats do look very restrictive. Can't find headers with sports cats already in place without spending £££££££. The other thing I mean to do is get a balance pipe welded between to two sides as they're not connected. I think that will sound better. I don't really want it that much louder. Generally you only notice intake noise with your foot down. Edited May 19, 2022 by JonSta Quote Link to comment Share on other sites More sharing options...
Davey P Posted May 19, 2022 Report Share Posted May 19, 2022 I can't believe nobody on here has stated the obvious: "If it's too loud, you're too old..." (Just for the record, I am too old ) 1 Quote Link to comment Share on other sites More sharing options...
EVO Chris Posted May 19, 2022 Report Share Posted May 19, 2022 (edited) 987.1 cats, 1 in the manifold and 1 in the the exhaust at the coned entrance per side..987.2 both cats are in the manifolds. I would put the std manifolds back on, just as I did. I have a Carnewall modded pipe and for a while 200 cell cats and not switchable....too loud, sold the manifolds a few weeks later to a forum member with a switchable and he loves em. Edited May 19, 2022 by EVO Chris Quote Link to comment Share on other sites More sharing options...
EVO Chris Posted May 19, 2022 Report Share Posted May 19, 2022 4 minutes ago, Davey P said: I can't believe nobody on here has stated the obvious: "If it's too loud, you're too old..." (Just for the record, I am too old ) We are too old, a little noise is nice though Quote Link to comment Share on other sites More sharing options...
DisplayName Posted May 19, 2022 Report Share Posted May 19, 2022 Further to the concesensus - I have a TopGear Manifold,valved backbox and sport cats and when it's open it's loud, too loud in most scenarios. Fine for that odd time 🤪 Quote Link to comment Share on other sites More sharing options...
edc Posted May 19, 2022 Report Share Posted May 19, 2022 @Berty987 did some Dyno tests many years ago and found the 987.1 manifolds to be quite well optimised already. Quote Link to comment Share on other sites More sharing options...
MickH Posted May 19, 2022 Author Report Share Posted May 19, 2022 Thank you for all of the replies @map It had 4 cats, 2 were removed when the backbox was fitted, it was loud but I do love a loud exhaust. However the other 2 have now gone with the race manifolds and its overly loud and very raspy. I'm hoping that evens up when they carbon up. @JonSta I have looked at this too and know exactly where you are talking about. Its one option. The other option is to see if I can adjust the actuator on the switchable exhaust. I really want to make this work as it cost me a small fortune to get the manifolds fitted (9 of 12 studs snapped and had to be drilled out). Quote Link to comment Share on other sites More sharing options...
map Posted May 19, 2022 Report Share Posted May 19, 2022 57 minutes ago, MickH said: @map It had 4 cats, 2 were removed when the backbox was fitted, it was loud but I do love a loud exhaust. However the other 2 have now gone with the race manifolds and its overly loud and very raspy. I'm hoping that evens up when they carbon up. If I’ve understood this correctly the exhaust system hasn’t got any cats in it at all. Once a year that could be tricky 🤔 This might also explain why it’s so much louder - there’s almost no sound attenuation in the system now. Expect that with some mileage the carbon buildup will help moderate the noise - mine certainly calmed down after a few thousand miles. Quote Link to comment Share on other sites More sharing options...
MickH Posted May 19, 2022 Author Report Share Posted May 19, 2022 12 minutes ago, map said: If I’ve understood this correctly the exhaust system hasn’t got any cats in it at all. Once a year that could be tricky 🤔 This might also explain why it’s so much louder - there’s almost no sound attenuation in the system now. Expect that with some mileage the carbon buildup will help moderate the noise - mine certainly calmed down after a few thousand miles. I have a solution for that yearly issue. Im going to go see my exhaust guy though and see about some sportscats Quote Link to comment Share on other sites More sharing options...
½cwt Posted May 19, 2022 Report Share Posted May 19, 2022 3 hours ago, Davey P said: I can't believe nobody on here has stated the obvious: "If it's too loud, you're too old..." (Just for the record, I am too old ) And have a steel roof with lining and even more sound deadening than a cloth roof has!! It is all beginning to make sense now. Quote Link to comment Share on other sites More sharing options...
Davey P Posted May 19, 2022 Report Share Posted May 19, 2022 Just now, ½cwt said: And have a steel roof with lining and even more sound deadening than a cloth roof has!! It is all beginning to make sense now. Mmmm, peaceful........... 1 1 Quote Link to comment Share on other sites More sharing options...
Ninesomething Posted May 19, 2022 Report Share Posted May 19, 2022 I'd have thought the older you get the deafer you get so it evens out.... 2 Quote Link to comment Share on other sites More sharing options...
½cwt Posted May 19, 2022 Report Share Posted May 19, 2022 54 minutes ago, Davey P said: Mmmm, peaceful........... Cayman - chilled motoring. 1 Quote Link to comment Share on other sites More sharing options...
MickH Posted May 19, 2022 Author Report Share Posted May 19, 2022 1 hour ago, JonSta said: I'd have thought the older you get the deafer you get so it evens out.... WHAT!!!!!?? 1 Quote Link to comment Share on other sites More sharing options...
red rocket Posted May 19, 2022 Report Share Posted May 19, 2022 21 hours ago, And.rs1800 said: thinking about a non valved designtek I would advise caution. I have a non-valved Top Gear exhaust which I believe is the same as the Designtek (I suspect manufactured by TG). The sound when first fitted was fantastic at high speed/revs but the drone at around 50mph was appalling, so much so that I had to get it modified by TG themselves. My car is a 2.7 so you might fare better on the S but do your research. 1 Quote Link to comment Share on other sites More sharing options...
Jonners Posted May 20, 2022 Report Share Posted May 20, 2022 On 5/18/2022 at 7:20 PM, MickH said: Hi guys I have finally pushed it too far. Ive had a designtek switchable exhaust on for about a year, and decided to put the race manifolds on as well. Got those fitted along with an induction kit. And im about to say something that I never thought I would ever say. Its far too loud Has anyone else done the same and had the same issue? I can't believe what I'm reading 😂 1 Quote Link to comment Share on other sites More sharing options...
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