STR Prep - Exhuast (tip to tail)
Registered User
Joined: May 2008
Posts: 200
Likes: 15
From: Boulder, CO
So I have the Berk HFC (non STR legal version) and I have been putting off the conversion to legal mod for some time. Is this something that a local muffler shop should be able to do? It's reall just removing the bung, cutting it down and re-welding it in, right?
I'm not familiar with the capabilities of local shops besides one about an hour away. Where did you all do this mod?
I'm not familiar with the capabilities of local shops besides one about an hour away. Where did you all do this mod?
Thread Starter
Joined: May 2004
Posts: 1,531
Likes: 3
From: Tucson
I was originally thinking I would go with the lite spec, but given the combination of my budget shrinking and them being backordered and I'm not sure I'll get it in time, I think I'm going to do the custom route. I'm thinking I'll use the OEM exhaust up to the split, then put a v-band flange there, then have a vband flanged turndown at the axle for national events. For street driving most of the time, local events, and/or when I have problems with meeting sound I'll have a second axle back section that has a small muffler/resonator and a turndown at the bumper. So my questions:
1) For those of you that have done the v-band on oem exhaust approach, where should I weld the flange? at the split, or upstream from it?Early on there was some talk that the turndown at the axle had to be welded on at a certain point so that the axle assembly doesn't take out your v-band clamp.
2) I'm trying to shop for a small muffler/resonator thing for the second axle back section, and it's really tough to shop for mufflers. Anyone know a vendor that lists weights? I tried jegs and summit racing, neither list weights. Amazon lists weights, but they're very approximate at best. There's burns stainless obviously, but they are $$$$$. Not to mention there's pretty much no way to know which do a good job of reducing sound.
3) Anyone have any ideas for what to use as that small muffler/resonator? Ideally I want something that just barely gets me to 93 dB worst case with that second axle back section. If anything I want quieter sound at the expense of a couple more pounds. I haven't measured the space I have to work with yet, has anyone already done that? I'm guessing one of the 6" round 12" long jobs should be adequate.
Thanks for any input on any of those questions...
1) For those of you that have done the v-band on oem exhaust approach, where should I weld the flange? at the split, or upstream from it?Early on there was some talk that the turndown at the axle had to be welded on at a certain point so that the axle assembly doesn't take out your v-band clamp.
2) I'm trying to shop for a small muffler/resonator thing for the second axle back section, and it's really tough to shop for mufflers. Anyone know a vendor that lists weights? I tried jegs and summit racing, neither list weights. Amazon lists weights, but they're very approximate at best. There's burns stainless obviously, but they are $$$$$. Not to mention there's pretty much no way to know which do a good job of reducing sound.
3) Anyone have any ideas for what to use as that small muffler/resonator? Ideally I want something that just barely gets me to 93 dB worst case with that second axle back section. If anything I want quieter sound at the expense of a couple more pounds. I haven't measured the space I have to work with yet, has anyone already done that? I'm guessing one of the 6" round 12" long jobs should be adequate.
Thanks for any input on any of those questions...
A2) My exhaust got much louder with the HFC. I am shopping for a muffler now to make sure I can run at the SD Tour. The second resonator is not cutting it at this point. I just ordered one of these cheap $37 mufflers off Amazon (Amazon Link) to start and then will consider dropping some $$$ for a two stage Burns light weight stainless. Two stage is the only way to make sure the sound reduction is adequate. I know others that have used them for mod classes.
Lawson Industries 77925 INSYNERATOR Bullit High Performance Muffler (7 lbs?)
Burns Two Stage 3.8 lbs
A3) Not sure. The stock resonator as a muffler hit 91 dB at prior SD Tours, but that was before HFC.
Joined: Jun 2010
Posts: 1,881
Likes: 6
From: Near Philadelphia
Thanks Rob, lots of good info. I finally decided I don't have time to mess with this right now and ordered a Greddy RS. It's the replacement for the Ti-c so should be similar in that it'll be nice and quiet. I can also try running without the axle back portion, I've heard that can meet sound sometimes. Even with the whole thing it'll only be a little over 22 lbs or something. I figure then I can sell it after a season or so and either get the lite spec or design my own super awesome exhaust.
Registered User
Joined: Sep 2005
Posts: 1,866
Likes: 2
I expect the sound to be similar from my readings at Nationals ... 88-91 db. With the cut located at the bend and aiming it towards the ground, I hope it helps keep it down. If it is too loud, I can cut off the resonator and add a larger/quieter section.
This exhaust came from Josh Owens. It's off an '00 S2000 and fits my CR without issue.
-Marc
This exhaust came from Josh Owens. It's off an '00 S2000 and fits my CR without issue.
-Marc
Joined: Jun 2010
Posts: 1,881
Likes: 6
From: Near Philadelphia
Thread Starter
Joined: May 2004
Posts: 1,531
Likes: 3
From: Tucson
It makes a difference but not likely enough to rush and do it before an event. When I put on the header and HFC it felt like the difference between the AC being on and off.