3" Exhaust Question, Especially for Turbo Guys

[99riocobra]

Alright, so I ordered an axleback exhaust the other day just as something to get me through the last few times I'll drive the car before winter settles in. Next year I'll be doing the Hellion TT setup, and obviously I'll free up the rest of the exhaust before then.

I figured all along I'll just run an o/r x-pipe and the LP Gen 2 over axle pipes since I'm lowered on Sportlines. Now I'm second guessing myself though that I should have gone with a full 3" Magnaflow catback (as opposed to the 2.75 over axle pipes later). I've read lots of fitment issues (hitting axles, body, etc) with lowered cars and 3" catbacks so that is what initially steered me from that.

So in the end my question is this, are the fitment issues with 3" catbacks on lowered cars enough that I should forget about that and stick with the axleback and eventually upgrading to 2.75" over axle pipes? Or are there enough benefits in a full 3" vs 2.75", specifically in a turbo application, that it's worth going that route?

Thanks for any input.

 

[Jedisalami]

had magnaflow competition mufflers and over the axle 3" and it fit like a glove, didnt hit at all and I was on h and r supersports, so it was low

 

[WIPLASH1]

Just by being under the car looking at the 2.75" piping, it's obvious there SHOULDN'T be an issue making 3" OTA pipes clear everything. There's plenty of room above the axle and around the braces/suspension components.

 

[99riocobra]

had magnaflow competition mufflers and over the axle 3" and it fit like a glove, didnt hit at all and I was on h and r supersports, so it was low

Yeah H&R SS are a little lower even. So was this the full Magnaflow Comp catback then? I'm looking at doing the Street, but the ota pipes would be the same.

Just by being under the car looking at the 2.75" piping, it's obvious there SHOULDN'T be an issue making 3" OTA pipes clear everything. There's plenty of room above the axle and around the braces/suspension components.

I agree there's definitely room for it, I think it's just companies designing around stock ride height rather than ensuring it's further away for lowered applications.

 

[Jtaugner]

I have the MBRP 3", mine scrapes if I have more than one person in the car over speed bumps etc.

On BMR Springs

 

[Squamishcoyote]

Magnaflow comp 3" catback... Doesn't hit anything but the tips NEVER stay centered.

 

[OveRBoreD]

Im installing my MBRP race v2 in a couple hours today. Will report back but I have high hopes for this catback.

 

[Jtaugner]

Im installing my MBRP race v2 in a couple hours today. Will report back but I have high hopes for this catback.

Do you have an Off Road X/H?

Report on the sound, I have the Street Series with Lethal OR H and it sounds.. bad.

 

[99riocobra]

I have the MBRP 3", mine scrapes if I have more than one person in the car over speed bumps etc.

On BMR Springs

Gotcha. And I assume you've done all you can as far as adjustment goes?

Magnaflow comp 3" catback... Doesn't hit anything but the tips NEVER stay centered.

Glad to hear that on a magnaflow catback, except the tips not staying centered would annoy me to no end! Are you lowered as well?

 

[Jtaugner]

Gotcha. And I assume you've done all you can as far as adjustment goes?

I've pushed it up, I'm sure I could force them up a little more, but without a hangar in that area it I feel like it's gonna droop a little anyhow.

Another downfall is that you can't use any axleback with this. It's a slip on joint instead of the ball type that comes stock. So either I gotta throw my stock OTA pipes or buy Lethal's so I can swap axlebacks.

 

[04sleeper]

I have the Lethal Stainless 3" OR-X and Magnaflow 3" Competition Cat-Back.

No issues here with clearance on Eibach Pro-Kit.

 

[WIPLASH1]

Magnaflow comp 3" catback... Doesn't hit anything but the tips NEVER stay centered.

And you're tight where the x-pipe ties into the OTA piping? I couldn't get mine centered without deforming the rubber hangers to "pre-load" or pull in one direction or the other. To keep them in place I cut rubber spacers to fasten to the rods to keep everything offset. 3,000 miles and they haven't moved.

I have the Lethal Stainless 3" OR-X and Magnaflow 3" Competition Cat-Back.

No issues here with clearance on Eibach Pro-Kit.

This axle-back is straight pipe right? How does this setup sound with the twins? I've got an identical setup coming off the jackstands tonight. I've got the same axle-back but it's the quad tips. I'm really worried about drone as this setup was BRUTAL NA. I bought stock GT500 mufflers until I could get the turbo's on in the interim.

 

[CSG]

And you're tight where the x-pipe ties into the OTA piping? I couldn't get mine centered without deforming the rubber hangers to "pre-load" or pull in one direction or the other. To keep them in place I cut rubber spacers to fasten to the rods to keep everything offset. 3,000 miles and they haven't moved.



This axle-back is straight pipe right? How does this setup sound with the twins? I've got an identical setup coming off the jackstands tonight. I've got the same axle-back but it's the quad tips. I'm really worried about drone as this setup was BRUTAL NA. I bought stock GT500 mufflers until I could get the turbo's on in the interim.

I have the same with twins and it has a lot of drone.

 

[99riocobra]

I've pushed it up, I'm sure I could force them up a little more, but without a hangar in that area it I feel like it's gonna droop a little anyhow.

Another downfall is that you can't use any axleback with this. It's a slip on joint instead of the ball type that comes stock. So either I gotta throw my stock OTA pipes or buy Lethal's so I can swap axlebacks.

Yeah I know what you mean there, you’re married to the mufflers if you go catback. I would just go with the 2.75 ota pipes, I just don’t want to end up with a “what if” situation ya know..

I have the Lethal Stainless 3" OR-X and Magnaflow 3" Competition Cat-Back.

No issues here with clearance on Eibach Pro-Kit.

Good to know! Since you’re running the same X-pipe I’ll be running with a Mag catback, does the piping bottleneck down at the connection to the x-pipe?

 

[04sleeper]

This axle-back is straight pipe right? How does this setup sound with the twins? I've got an identical setup coming off the jackstands tonight. I've got the same axle-back but it's the quad tips. I'm really worried about drone as this setup was BRUTAL NA. I bought stock GT500 mufflers until I could get the turbo's on in the interim.

It is a straight through set up. It does drone and I will most likely put some Bullet mufflers in place of the resonators to reduce or hopefully eliminate it.

Good to know! Since you’re running the same X-pipe I’ll be running with a Mag catback, does the piping bottleneck down at the connection to the x-pipe?

It does. It uses the factory clamps. I don't think it is hurting much though.

 

[99riocobra]

It does. It uses the factory clamps. I don't think it is hurting much though.

Got it. Hopefully not. I might see what I can do about that in the end.


So general consensus is that if I can make the 3" fit right then go with that? Or does anyone see any woes with going with the 2.75" and it not cutting too much power?

 

[Torchy]

Putting 3inch on my car as we speak. Will know something at end of day. I'm prepared with torch and ball peen hammer.

 

[OveRBoreD]

image by OveRBoreD302, on Flickr

The size difference is pretty insane between 2.75 and 3in. I'm glad I went 3. Fitment was good with my MBRP v2 race. Unfortunately my JBA x pipe sucks for fitment(too narrow and long) so I won't have any videos until I get that altered. Until then it's the stock h pipe. It does drone with the stock H but it's not bad and I think it will be much better with the X.

 

[Jtaugner]

Got it. Hopefully not. I might see what I can do about that in the end.


So general consensus is that if I can make the 3" fit right then go with that? Or does anyone see any woes with going with the 2.75" and it not cutting too much power?

I would get the Lethal OTA if I had to do it again. The extra flow and the ability to change mufflers when I want greatly out weighs anything that a 3" would give.

 

[Force Induced]

I have a stainless works 3" OR X with the manganflow 15176 3" kit which is the quadtip for the GT500.