I'm getting a SMB 4" to 3 1/2" DP and 3 1/2" resonated metal cat MP with PICS!
Thread Starter
Joined: Apr 2003
Posts: 4,057
Likes: 262
From: Around
I ordered the SMB Downpipe 4" tapered to 3 1/2" for stock twins (or BNR's sometime in the future) but without the RHD squished area; also the 3 1/2" Metal cat with muffler midpipe. I'll keep updating this thread with progress and pics!
First pics: downpipe expansion chamber!
First pics: downpipe expansion chamber!
Thread Starter
Joined: Apr 2003
Posts: 4,057
Likes: 262
From: Around
The 3.5" resonated midpipe is not on the webpage, I emailed Grant at SMB and custom ordered it. I won't comment on prices as this was a special order but go ahead and email Grant, he's a great person to work with.
Joined: Oct 2001
Posts: 4,772
Likes: 2
From: My 350Z Roadster kicks my RX7's butt
Yeah, that's a tight setup. I bet you gain another 1lb of boost. You know he also has a 3.5" cat back and you can get a resonator welded in the strait section to quiet dow the street port.
I have a SMB 12" resonator on my mid pipe and a 18" resonator on the strait section of my custom exhaust with a 18" long Racing Beat muffler and it's 94db on the C scale and 90db on the A scale from 10' away (less 10db at 15' away).
I have a SMB 12" resonator on my mid pipe and a 18" resonator on the strait section of my custom exhaust with a 18" long Racing Beat muffler and it's 94db on the C scale and 90db on the A scale from 10' away (less 10db at 15' away).
Trending Topics
I emailed Grant, and man was I supprised how great the deal was. Hopefully by October I can order a 3 and a half inch system with the resonated midpipe. I'll be going with the 4inch tip cat back that looks a lot like re amemiya's dolphin titan muffler tip with it angled down. I think this would look best with a diffuser. I can't wait to see pics of your stuff when you get it.
Joined: Oct 2001
Posts: 4,772
Likes: 2
From: My 350Z Roadster kicks my RX7's butt
Very nice! I actually would have saved money going with them instead of my custom metalit cat and resonator. I started with a mid pipe then welded in a cat, then Spiral Flow, then a resonator. That's over $200 in welding and i'm sure yours is quieter since it's oval and mine is round. That exhaust and JDM 99+ twins would be a very nice combo.
Yes, it is tight polished but it will literally discolor in about 5 min once the engine is on. It will turn a purplish blue just like headers. It's best to heat coat them before use since they can only coat and garantee the inside when it's new and clean.
Yes, it is tight polished but it will literally discolor in about 5 min once the engine is on. It will turn a purplish blue just like headers. It's best to heat coat them before use since they can only coat and garantee the inside when it's new and clean.
Be interesting to see if the w/g can handle that.
Thread Starter
Joined: Apr 2003
Posts: 4,057
Likes: 262
From: Around
Well it's installed!! The DP fit perfectly! I could even bolt it to the oem tranny mounts! Everything fit perfect and the WBO2 prior to the cat is in a perfect location, easy to reach and the wire can be routed away from the hot metal easily! I'm very happy with it.
The DP sounds hollow and tinny but my previous one was ceramic coated and thermo wrapped so it was quieter. I boosted 10psi to redline no prob but I'm using some getto 2.5" pcv 90deg bends at the IC because I installed an efini y-pipe and it was the fastest way to mate it while I have custom pipes made. I guess this and the 3" RB dual cat back isare keeping boost at bay.
The car will be shipped to PR this week so I wont be able to see or drive it for over a month!
I'll let you know when I get it back from the shippers...
The DP sounds hollow and tinny but my previous one was ceramic coated and thermo wrapped so it was quieter. I boosted 10psi to redline no prob but I'm using some getto 2.5" pcv 90deg bends at the IC because I installed an efini y-pipe and it was the fastest way to mate it while I have custom pipes made. I guess this and the 3" RB dual cat back isare keeping boost at bay.
The car will be shipped to PR this week so I wont be able to see or drive it for over a month!
I'll let you know when I get it back from the shippers...
Thread Starter
Joined: Apr 2003
Posts: 4,057
Likes: 262
From: Around
Well, I got the car, fixed the IC pipe install and put in the PFC! One thing I noticed its that the tranny tunnel gets much hotter with this system! I love the sound! I will install new injectors and tune the pfc and come back with a dyno in a few weeks...
I'll also post some pics from under the car
I'll also post some pics from under the car
Last edited by neit_jnf; Oct 17, 2007 at 07:50 AM.
Thread Starter
Joined: Apr 2003
Posts: 4,057
Likes: 262
From: Around
well I haven't taken the car to a dyno but it did feel great at any boost level! I ran it a few times at 17psi until the clutch went out, haven't run it that high anymore.
https://www.rx7club.com/power-fc-forum-47/few-charts-fun-almost-17psi-stock-seq-twins-803497/
I then installed a new clutch and other things,
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-car-back-861806/
Then I had the twin power go bad and I believe this is what caused the nice smb cat to melt down
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-twinpower-went-bad-smb-metal-cat-melted-now-car-acting-strange-871146/
so in all it lasted two years and about 10k miles.


https://www.rx7club.com/power-fc-forum-47/few-charts-fun-almost-17psi-stock-seq-twins-803497/
I then installed a new clutch and other things,
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-car-back-861806/
Then I had the twin power go bad and I believe this is what caused the nice smb cat to melt down
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/my-twinpower-went-bad-smb-metal-cat-melted-now-car-acting-strange-871146/
so in all it lasted two years and about 10k miles.


Wow. That sucks.
FWIW, I've had good luck with both of my metal cats. I melted 2 used stock cats on my previous FD in 3 years of ownership.
The first was a Random Tech universal 3" in/out metal cat that I had welded into an ebay mid pipe. I ran it for 3 years about 10k miles and the core looked perfect when I sold that setup.
The second is an SMB cat + muffler mid pipe combo. Its been on 3 years and about another 10k miles. I haven't personally looked at it since the install but my mechanic said it looked fine when he did my motor recently.
I had a decent amount of track time on both setups.
FWIW, I've had good luck with both of my metal cats. I melted 2 used stock cats on my previous FD in 3 years of ownership.
The first was a Random Tech universal 3" in/out metal cat that I had welded into an ebay mid pipe. I ran it for 3 years about 10k miles and the core looked perfect when I sold that setup.
The second is an SMB cat + muffler mid pipe combo. Its been on 3 years and about another 10k miles. I haven't personally looked at it since the install but my mechanic said it looked fine when he did my motor recently.
I had a decent amount of track time on both setups.








