over a good catback? I'm currently running the Grott 1 7/8's with the crappy Grott y-pipe. My intermediate is a good SLP 3" with a Magnaflow muffler. Cutout open at the track only.

Question is: has anyone done a 3" dual with an X crossover and dumps before the axle and picked up anything, either at the dyno or at the track. I'm planning on putting a Dynomax race bullet (the longer ones) on each side. Doing the dual will cost me the same as having a y-pipe made.....

Thanks.

<small>[ July 15, 2002, 06:35 PM: Message edited by: ONYXSS ]</small>

 

DevilBird on here has never dynoed his car, and hasn't gotten any good runs in since he went to duals over his ORP into a cutout... but I'll atest to the HELL OF AN IMPROVEMENT in sound quality. True duals simply sound badass. nuff said.

 

I had TTS longtubes going into an duals (no x pipe) into Dynomax bullets dumping at the axle and it was 80% as loud as open headers. Too loud for me and my local law enforcement.

 

I plan on dynoing/track testing a true dual setup vs. an open y-pipe real soon. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

PSJ, did you use the 16" bullets or the 24's ? Not sure the longer ones will make THAT much of a difference, but I'm curious. My car isn't daily driven anymore, so I can take a little noise, but I probably wouldn't enjoy it if it were obnoxiously loud.

 

I guess I had the 16's.

Put it to you this way, the high school guys loved it. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

I have 3" to X pipe, and to 3" Flowmasters and its was a BIG differencr in the feel of the car. I had Lts, no cats and the loudmouth before and it sucked and sounded like @ss and had no low end <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

You cant smack the smile off my face when I drive around now <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

I would say I picked up about 6-10 rwhp with the true duals over 3" Y and !catback. It's hard to say since I also added a pulley and went from 3.23's to 3.42 which might have cost some rwhp. Biggest difference on the dyno is a super flat rwhp curve from 5300 - 6300.

On the track I went from a 11.99 in -700 ft DA to 12.flat in +1100 DA.

But, like MONGOOSE said - the sound improvement is unbelievable. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ONYXSS:
<strong>Question is: has anyone done a 3" dual with an X crossover and dumps before the axle and picked up anything, either at the dyno or at the track. I'm planning on putting a Dynomax race bullet (the longer ones) on each side. Doing the dual will cost me the same as having a y-pipe made.....

Thanks.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have the exact same setup you are referring to, and the same grott headers...

I chucked the o/r pipe for a true dual exhaust (merging to an xpipe) that dumps before the axle.

To be honest, I felt that I lost a little bit of low end torque for daily driving, but I definately picked up some top end. I picked up a tenth or two at the track as well, and the sound is just :worship:

The other big differences the exhaust made were the weight savings, and my flat *** top end dyno graph.

I have a very flat power band in the upper rpm's, and that was thanks to the true dual exhaust, which breathes substantially better up top.

Here is an old dyno to illustrate.

Mods at the time were a lid, ls6 intake, grott headers, dual 3" exhaust w/ xpipe, ASP pullies, aluminum flywheel, carbon fiber driveshaft, and fuel pressure regulator......HOWEVER, this dyno was done through a 12 bolt 33 spline axle Moser and 3.73 gears <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> so keep that in mind.

<img src="http://www.nissaninfiniticlub.net/vbulletin225/attachment.php?s=&postid=194" alt=" - " />

The only negatives I have are a resonance at 2000rpm and crappy clearance. I'd do it again in a heartbeat. I can't wait to hear it w/ my new heads/cam setup going on <img border="0" alt="[devil]" title="" src="graemlins/gr_devil.gif" />

 

My exhaust setup...

MAC headers, no cats, Dr Gas 2.5" x-pipe system, Dynomax bullets (16"), and turndowns before the axle.

Nice, smooth, and mellow when cruising. No rasp or drone either. When you put the pedal to the metal though...look out.... <img border="0" alt="[hail]" title="" src="graemlins/gr_hail.gif" />

I have dual cutouts too. I haven't installed the cutouts yet....can't wait to see what that sounds like. I'm going to put them about 12-15inches after the header collectors <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I don't know to any gains cause I was getting false KR when I tested the new exhaust at the track. Its fixed now, so I'm just waiting for some decent weather. To fuggin hot and humid lately. Too me it feels like a gain on the top end, but not much if any on the bottom end.

Oh...and ground clearance is definitely better than the y-pipe. It tucks up close to the floorpan. It doesn't have that annoying hang down like the y-pipe does.

One thing is for sure...anywhere you go, you'll definitely get compliments on the sound. Its so unique on a 4th gen f-body.

btw...when I do heads and cam...I'll be switching to Grot headers with the same exhaust setup, only it'll be 3"

<small>[ July 16, 2002, 07:22 PM: Message edited by: DevilBird ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by DevilBird:
<strong>My exhaust setup...

MAC headers, no cats, Dr Gas 2.5" x-pipe system, Dynomax bullets (16"), and turndowns before the axle.

Nice, smooth, and mellow when cruising. No rasp or drone either. When you put the pedal to the metal though...look out.... <img border="0" alt="[hail]" title="" src="graemlins/gr_hail.gif" />

I have dual cutouts too. I haven't installed the cutouts yet....can't wait to see what that sounds like. I'm going to put them about 12-15inches after the header collectors <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I don't know to any gains cause I was getting false KR when I tested the new exhaust at the track. Its fixed now, so I'm just waiting for some decent weather. To fuggin hot and humid lately. Too me it feels like a gain on the top end, but not much if any on the bottom end.

Oh...and ground clearance is definitely better than the y-pipe. It tucks up close to the floorpan. It doesn't have that annoying hang down like the y-pipe does.

One thing is for sure...anywhere you go, you'll definitely get compliments on the sound. Its so unique on a 4th gen f-body.

btw...when I do heads and cam...I'll be switching to Grot headers with the same exhaust setup, only it'll be 3"</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Grott 1 7/8?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2000LS1:
<strong>Grott 1 7/8?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yeah...most likely.

I've changed my exhaust out 4-5 times just testing stuff out. Also reading about other types of systems for a couple of years. I think Grotts are for me when the time comes.