Had them installed yesterday. My advice, have a shop do it and save yourself the anguish. they didn't remove the splash guard or the black suspension brace. Took about an hour and a 1/2.

The butt dyno says there's a difference. Nothing spectacular, but there's a difference. It does feel more punchy. The sound is slightly more aggressive, but ever so slightly. I really like the sound of this car and look forward to other mods to compliment what I've started.

Engine mods thus far are the z tube and these cats.

<img src="https://g35driver.com/rides/spec/pix/winw_1093819995.jpg">

 

If / when you get a plenum (assuming you get the Crawford, or one as good as it) your car is going to come alive! So far you're modding exactly as I did. Z-Tube, Cats, then I did the plenum. With the cats I noticed a better throttle response, meaning the revs seemed to climb a little quicker in the midrange. When I added the plenum the revs climbed quicker from ~1000rpm through redline (damn rev limiter)... and I went from chirping the tires from the 1-2 shift and the 2-3 shift to burning major rubber between those same shifts. [img]/w3timages/icons/smile.gif[/img]

 

You have ther same mods I have--Z tube and cats. I noticed the exact same thing that you did.

'04 6MT coupe

 

I want a plenum. I've resisted modding too long, now i feel like a drunk in a liquor store.

I was wanting to hold off until the APS came out. I like the direct bolt on, but won't do the Kinetix. I was shying away from Crawford because of the core change. However, I was wanting your opinion on the Crawford plenum quality. Are there seal issues and so forth? For some reason I thought I had heard there being risks of getting bolts into your intake.

Changing the core may be preventative, as I can't be without the car for a day or two.

<img src="https://g35driver.com/rides/spec/pix/winw_1093819995.jpg">

 

winw,
I can see that you're starting to cramp up over the plenum. I want one too, but I'm going to wait until I can see and hear about the APS. Then I'll probably do it in the spring. Heck there will be snow on the ground in Minneapolis in Nov or Dec and I might as well just wait. I tend to drive less aggressively in the winter except for those easy power slides when nobody is on the roads/parking lots.

You're probably fine going with either the Crawford or Kinetix. I like the Crawford, but the latest Kinetix has been trouble-free, from what I've heard.

'04 6MT coupe

 

Did you notice any raspy sounds with the crawford cats?

 

Get the Crawford plenum. No issues for me at all. As neffster said, it really opens up the car. The plenum (old V2) was one of the first mods I did, and IMO, it's the best bang for the buck out there. You'll really notice it in the mid to high RPM range, where the car continues to pull, unlike the stock plenum. After you get the plenum, you might want to think about the TS reflashed ECU. Crawford and TS have worked together, and have jointly developed the Crawford flash.

Lou



350708-Plenum 04.jpg

 

No raspy sounds with the crawfords in my car. I guess some of the noise issues could have been from heat shield vibration? I don't know about other cats clearances, but the crawfords are well clear of the heat shields in my car.

I guess now that I type this, there is a 350z around here with Borla and R/T cats, his tone does sound what one could describe as raspy. Who knows. The car may sound a lot different inside the cabin with the windows down than it does to someone else on the street.

For all I know my car sounds raspy to someone on the street, like that 350z, but I can't hear it.

Overall the sound difference is almost inaudible. Within a parking garage, there is more of difference, but that kind of goes without saying. Before, with only the Z tube in, the car was loud as hell within a parking garage.

I've very happy with the performance difference and the slight sound difference. I'm pretty picky when it comes to sounds. I have a wife, coworkers and clients to keep happy, so I couldn't have some loud exhaust going on. The beauty of this car seems to be you can drive normal and no one knows you've done anything to the car. Open her up and she'll start singing.

<img src="https://g35driver.com/rides/spec/pix/winw_1093819995.jpg">

 

I too love the cats and plenum combo. The plenum did a little, but when I put the cats on they seemed to complement one another and I have the 1/4 mile times and G Tech to back it up. HP at the crank is about 300 with the plenum, cats and the Nismo CAI makes it sound cool but no measureable differences in times or HP.

I had an initial sealing issue with the plenum, but Doug happily exchanged them.. ...the second time around I torqued to factory specs and have had zero sealing issues. The black looks great under the hood and the combo made what others describe as an "exotic" sound...no raspiness whatsoever.

2004.5 Coupe/5AT/Ivory/Everything but front spoiler/Nismo CAI/Crawford V5/Crawford Cats

 

I just installed a pair of Kinetix cats on Friday morning. There were some minor fitment issues when installing them (i think they were an earliy pair before Kinetix changed their tooling) but we fixed it for the most part.....

However, now I randomly get some vibration on the heat shield. We were scratching our heads for a while trying to figure out how to get more clearance. My friend was thinking of drilling out the holes on the header side of the cat to enlarge them and trying to rotate the cat away from the heat shield a bit. Any thoughts? (Sorry didn't mean to hijack)

As to the sound, i like it alot. I detect a slightly more "metallic" feel to the exhaust when you go WOT, but the car definitely sounds more agressive and i can feel a difference. I'm looking forward to doing a plenum as the two mods seem to work awesome together.

 

Take a crow bar and bend the heat shield a little bit. I wouldn't wedge anything between the cat and the heat shield because the cats (I've been told) get in excess of 650 degrees.

 

Drilling the larger holes to help rotate the cats away from the heat shield might help, but then you might also lose some of the clean alignment that the interior of the pipes should have. Maybe it's not a big deal--it often only takes 1/4 inch of additional clearance to get rid of the touching against the heat shield.
But...you might be better off trading those cats for some new ones that will fit. It's kind of a hassle, but I believe that Kinetix will do the right thing if it comes down to exchanging them.

'04 6MT coupe