Exhaust is a constant question that pops up, and sound clips and photos are probably the only way to convince someone of what system is best for them. I started a community-maintained exhaust page, with the goal being a single page with objective reviews, photos, and sound clips. Sound clips should be one at idle behind the car and one at WOT inside the car. I put my A'PEXi GT up with an idle sound clip, and my RB duals are up too (no audio yet). Anyway, check it out:

http://howto.globalvicinity.com/gv_w...i=66&co=1&vi=1

You can either update it yourself with your setup (one entry per system please), or send me a review, photos, and audio (or video), and I'll update it for you. Go ahead and post custom systems too; I'll come up with a good way to organize them later. The page will be there forever, so just update it when you get the chance.

 

I just updated the RB duals with an audio clip at WOT. I don't have a way to record stereo, so it doesn't do the duals justice.

 

Gimme ten minues, I can get you a pecestter header through a 2.5" pipe, with the 2.5"-3 1/8" Corksport catback.

 

Do you have a standard for where microphones should be positioned? Inches? Feet? Above, below, etc...

Also, how do you compensate for different recording equipment/media? Maybe you should post the recording conditions too?

 

I did ~3ft with my digicam, think I mighta' overpowered my microphone... is that good enough?

 

I think the best recording conditions are to position the mic where an observer's ear would be. When I recorded the A'PEXi GT's idle, I had the camera on a tripod about 5' directly behind and 5' to the right of the exhaust, at head height. When I recorded the RB duals, I had the camera around my neck, with driver's window and sunroof open. Those are probably good conditions, but you can hear the camera banging around a bit in the RB recording, so some way to secure it (possibly to the passenger's headrest) might be best.

I don’t think we’ll be able to compare volumes in the recordings, because most recorders compensate for volume by themselves. We can compare exhaust notes and get a feeling for volume from reviews.

 

wotnartd, if you play the file back and it doesn't sound blown out, then it's fine. It would probably be best to record it about where your head would be if you were a bystander though!

 

I did inside and outside, with and without silence insert. All at the same distance. I'll work with what I've got, and then get some new ones later, along with some SPL readings.

I got a sweet fireball, too.

 

Ha!

 

Ok, I updated the page with a set of recording standards.

 

Wow, the Duals are quiter than I thought they would be. With my setup, you can't even hear the buzzer at WOT.
If I can get my car running by swapping in another engine (I'm crossing my fingers) then I will post up a clip with the RB header/presilencer and Apen N1. I have a clip of this setup on my old engine with ported intake/exhuast and turbo housings, but I don't know where it is. I had to give the camcorder back to my parents before I got it downloaded, so I don't know what happened to it.

 

It'd be sweet if someone w/ a TII posted up a clip w/ the RB full exhaust

i really wanna hear what a 59hp increase sounds like

 

sounds like a quiet rotary. my buddy has the full rb 3" TII dual exhaust on his half bridge setup. he used to have the apexi n1 junk and it was just waaaay too loud.

 

Here is an idea for you...

Why not hit the horn at the start of the recording session.

This way, everbody should be able to use the sound of the horn as a control. Most RX horns should have a similar sound, and the playback levels can then the syncronized to all of the horn sound levels.

 

^ what if somebody has "la cucaracha" for there horn...haha

O ya steve this is a very sweet idea for the exhaust clips, I hate finding a link after searching for exhaust clips just to find it has been removed. I will def. send you an audio clip if i get my exhaust setup soon enough.

 

I like that idea, but the problem I see is most recorders continuously adjust their volume. You can hear it in action at the very end of my RB clip - after I hit the redline buzzer, I pressed in the clutch, so all you hear after that is the wind. The wind was there the whole time, but the exhaust note overwhelmed the wind. Once the exhaust was gone, my camera raised its gain until the wind was just as loud in the recording as the exhaust used to be. It's like the audio version of moving a video camera from pointing at the sun to pointing in the shadows; in a few seconds, it adjusts to the light. In a similar way, most audio recorders readjusted to sound levels. If we had a constant sound throughout the recording that others could reproduce, like talking at a regular speech level, we might be able to calibrate the recordings. But the problem there is we can't hear the exhaust (and risk sounding like idiots)! If there's a way to turn off that automatic volume control, then the horn would work, but since everyone’s recorder will be different, I think we may be stuck with comparing exhaust notes from audio, and volumes from reviews!

 

Thanks! My own frustrations with the broken-link syndrome partially fueled the creation of that entire site. The main reason though was my experience searching for VDI swap tech reference. I'm sure many of you have experience sifting through gazillions of search results to make sure you're not missing anything. The reference site I came up with lets anyone in the community update any reference page when they have an improvement. That way, each reference page is as up-to-date as possible, and has all the info in one place. Hence my post above, where I said, "if you have an exhaust system to review, update the page yourself" - the site lets you do that! In this case though, I'll do it for you if you need your audio clip hosted. Anyways, I might have gone a little overboard with my frustrations, but I hope the site proves useful to some in the community.

As a side note, I have a pretty comprehensive VDI swap reference up so no one needs to go through what I did again.

 

Although getting something like that is a good idea, I'm more concerned with how it sounds. Then again, I run stock manifold, no cats, stock mufflers... so it's semi-loud.

Wow, the truel duals are ALOT quieter than what I would of thought.

 

Yeah, RB did a good job, it's powerful but understated. At a stoplight in traffic, you can't really hear it as much as smell it; when I had the A'PEXi GT, I was always worried when a cop was anywhere near me. Now it's not so bad, and as long as I keep the load low on acceleration, it barely draws attention.

 

I think it's stupid to just record the idle...

The idle recording should be idle, and then revved to 5K-ish out of gear a few times...

Just make sure to do it after the car is warm.

You can really get more info from that than from a recording of WOT from inside the car.

You also can't call it objective to put only the idle clip of the GT, and only the WOT clip for the RBs on the site.

 

Ok, here's a compromise

* Idle: Centered 5' behind the RX-7, at head height.
* Redline: Centered 5' behind the RX-7, at head height.
* WOT: 2nd gear to redline buzzer, with the mic positioned where the driver or passenger's head would be. This is under load (i.e. merging onto the freeway) with the driver's window and sunroof open.
2.

 

I agree with the no-load idle to redline, that's a third standard we can have. I'll update the page. Exhausts sound completely different at 5k no load and with load.

Patience! This is a community project, with the goal being an objective exhaust review. I started posting my clips, now others have to chip in too. Unfortunately I don't have a clip from my GT at anything but idle, and maybe someone else can provide that. Also, my RB idle clip had too much wind, so I was unable to post it yesterday - I have to redo it today. Anyway, if you record your exhaust, I'll be happy to post it for you, or you can post it yourself. Just remember photos, review, and audio.

 

Ok, I updated the RB sound clips. They're not ideal, but people can get a pretty good idea from those, and that's way better than where we were before.

edit: we might as well combine the two idles into one, the way I did with the RB - I've updated the standard again!

 

heres a video of my car going up to 3500 rpm under load

http://vids.myspace.com/index.cfm?fu...eoid=895403142

racing beat header/collector , straight pipe (no cat) 2.5" , borla dual catback , 2.5" before y pipe to dual 2" to 2 1/4 or 2 1/2 " tips (not sure on size), streetported motor, removed 5/6 ports , kn intake

 

That no-load redline clip is hardly ideal.

80% of that clip is idling, and you only revved it once.

IMO, you should idle it for about 5 seconds (there's really no reason to have a seperate idle clip), rev it to 4K, 5K, 6K (three times or so).

Or start, idle 5 seconds, rev three times (successively higher, with more and more throttle each time).

Make sure the engine is already warm before doing this, because for one thing, the idle will sound different if it's cold, and two, you need the oil to be warm before you start revving it.

I think the redline should be saved for the under load clip since there isn't much reason to redline a car at idle (this isn't GT4...)