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I install the catback !!
The sound while accelerating is more metallic until the 5000rpm after the 5000 it gets a little more screw but not too loud.
While traveling it sounds like the stock one!!!
if it were me, I'd just cut that perforated inlet section off, but there's no way of knowing how loud it will be until you try it
the two 50mm outlets are more than adequate, no advantage of going to 60mm and it will be a big hassle, you can maybe put big tips on it if you want that look
Interesting.... I think that port is a service port to empty pieces of broken cat during regular servicing. Lol.
I would also like to see internals of this OEM muffler. If anyone has any of the old pics that are no longer available here can you please post them up.
Im thinking along the same lines of just doing tips and black high temp black spray job. Cheap but effective and keep the spare coins for later plugs/ coils or whatever!
I do wonder what would happen if one would open up the capped port on the back of the stock muffler?
Would opening that port by-pass all the internal chambers and make stock muffler act as straight through?
It would be like it was straight piped. That capped part is the continuation of the main inlet pipe. On the inside it is perforated to allow the exhaust gases to expand into the rest of the muffler and out the exhaust pipes.
Well, that’s very interesting. I wonder why they terminated that pipe outside of the canister?
Ideally I think what I would like to do is to modify that end like a valve so I can open it when I’m on the racetrack and close it when I’m driving on the street.
I have to give it some thought, not sure what’s the best way to do that and if there’s something already on the market that I could use?
maybe something like this with blocker plate to close it when not on track
Last edited by Nadrealista; Feb 12, 2021 at 08:58 PM.
Probably a little heavier than your solution but you could open the exhaust from the driver’s seat. Though it says the valve is aluminum, so durability may be questionable.
the problem is when you’re not moving; you’ll melt your bumper/fuel tank/pretty much anything else dumping it under the car, even then you can still melt stuff when moving too
mistakenly did it way back in the day and would seriously recommend getting it out past the bodywork
not to mention it probably isn’t going to do anything close to what you think it will do other than being loud and annoying, if not harmful to yourself and others around you.
there’s a recent thread on here where someone did it out the rotor symbol in the middle of the bumper with some heat shrouding around it
and another thread where somebody wised up by converting the exhaust to full 3” by removing the OE restrictions that pretty much all off the shelf exhausts have
or you can play games by ignoring the details that count
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The main pipe that comes into the can is perforated with 1/4 holes. The the exhaust gases exit the holes and bounce around inside the can and exit through 2 s shaped resonated pipes that exit through the tips.
I gutted my exhaust by removing both of the s shaped pipes. it was a lilttle deeper and no louder.
Originally Posted by TomD_Cincy
It would be like it was straight piped. That capped part is the continuation of the main inlet pipe. On the inside it is perforated to allow the exhaust gases to expand into the rest of the muffler and out the exhaust pipes.
These both describe it well. I did an extensive search for pics and couldn’t find anything. This is why I often implore people to upload rather than link images. This pic sort of shows how the OE muffler inlet tube is perforated, or in this case acting as a strainer for an OEM ceramic cat core that came apart. So people fix the cat, but maybe not the core problem.
I seem to recall it just being open inside with maybe some hollowed out outer shell insulation material to try and keep heat from escaping into the trunk and surrounding components. Once you see inside one the external discoloration makes sense. It doesn’t really have much if any “sound packing”. Maybe the two tip outlet tubes also had perforated inlet extensions inside the muffler. That was probably 15 years ago, hard to remember exactly now.
So what I’m trying to say in the previous reply is that imo the muffler isn’t really the restriction until you improve everything ahead of it; including the OE size front manifold - midpipe connection and then the same for the rear OE donut midpipe - catback. Which repeating myself again, all the aftermarkets bolt-on parts retain those connections. So a 3” midpipe with an orifice restriction on both the inlet and outlet, plus whatever the rear muffler system is.
I’d suggest whacking the OE manifold just past the last exhaust port and making it along with the rest of the exhaust downstream from there a true 3” size. Then you can consider if the muffler is the restriction. The main reason I dumped the OE manifold is for weight first, and larger primary tubes second. The tubes are so short it likely has little impact and the 5 - 7 lb weight savings might not be worth considering for some people.
That will pretty much get you most of the advantage as long as the muffler is adequate. Or maybe just consider modifying the rear muffler to remove & install it easier (v-band inlet & convert hangers to bolt onto muffler body) with just an open pipe replacement going out past the body work on track day.
The only thing to be aware of there is to watch out how far it sticks out because any unprotected flesh that manages to touch it like bare legs etc will be instantly and permanently branded. I must have half dozen brandings at least in my arms over the years working under there with hot exhaust pipes.
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Anyone have any experience with Helmholtz resonators (i think commonly named j pipes)?
Have been looking into options for my fresh rebuild that is OEM specs but handbuilt by reputable builder. Car is pretty much stock everything with new style BHR coils.
Specifically looking for length, diameter and optimal location if you have experience at all.
I read somewhere these do their best work before mufflers at the highest point in system. Can anyone cofirm or debunk this?
Given how high that closed port is I might have to modify/remove that center trim peace on the S2 bumper to make this work and then it would be more of a straight pipe out. Will see what OP Frenke did to his. I do admit deleting stock muffler and putting smaller aftermarket auger style silencer or something similar to cut the noise down and flow well do look appealing for the same center exit.
Looks like there is perfecly placed opening under center plastic trim :-)
Last edited by Nadrealista; Feb 14, 2021 at 10:06 AM.
Am considering doing a custom version of this (with or without the extra male bit) plus a dummy tip on RHS. Probably in mild steel painted in high temp black. Thoughts and ideas?
My OEM muffler has got to be dead internally at 15 yrs.
Am considering doing a custom version of this (with or without the extra male bit) plus a dummy tip on RHS. Probably in mild steel painted in high temp black. Thoughts and ideas?
My OEM muffler has got to be dead internally at 15 yrs.
Thanks Moto. Yep seen that thread and that is an awesome exhaust and also mega $$. The pic I posted has dual passes through two 4 inch mufflers rather than single pass through .Also quite loud especially if catless i believe. Was looking for high flow, not ridicolously loud, and not top dollar either.
Thanks Moto. Yep seen that thread and that is an awesome exhaust and also mega $$. The pic I posted has dual passes through two 4 inch mufflers rather than single pass through .Also quite loud especially if catless i believe. Was looking for high flow, not ridicolously loud, and not top dollar either.
then you shoul do what I am planing on doing, modifying stock muffler to make it straight through with center exit. Open up that closed port on back of it and connect short pipe with v band clamp, that way you have option to revert back to stock quietness when wanted by closing the port with block of plate. 🏎
Interested to see how you go. Im not that fussed about centre exit though. I do have a couple of back boxes lying around so keep the build pics coming as i could change my mind later on.
Im sure others are watching with interest also. I feel for your bumper though. 😁
