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I'm going turbo 6.0 in my trans am over the winter and want good airflow and little to no performance loss due to exhaust restriction, but I DON'T want a bumper exit exhaust and dumps would probably be my last resort. I'm not sure which turbo I'm getting yet because my mechanic is building the car for me, but I want to be around 700rwhp through a 4l80e (maybe 800rwhp). I currently have the borla adjustable 3" catback on the car but worried it won't be enough for a turbo setup. I have stainless works on my 5th gen Camaro and my Mustang and love the way they sound.
Also, let's discuss one particular product I recently saw for sale used on a Facebook group. Any turbo guys use this 3.5" stainless works catback? Pic attached. Can anyone comment on sound and if the air flow is worth the upgrade to a 3.5" pipe at that power level on a turbo setup? Or should I stick with my borla adjustable 3" and not spend the money needlessly? What full-length exhausts can you recommend for a turbo setup on a 4th gen trans am? My mechanic said he's had good luck with 3" Magnaflow because the mufflers flow really well and that's more important than a 3" pipe vs a 3.5".
The hard part is getting anything over a 3" to fit nicely under the car and still have ground clearence. A lot of guys with run a boost referenced exhaust cut out that dumps and a 3" full exhaust all the way back. Gives you best of both if you are not wanting a bumper exit or dump.
I've been running a Borla catback on my Turbo Z28 since 2008. My ET's have been good but my MPH are not. I'm pretty sure I have too much back pressure. I would say fit the largest pipe you can thru there. I just glanced up at the price of that Stainless works setup. I have a BMR K-member I'm installing this winter to gain some extra space and will try to get something larger than the current 3" thru there. I might opt for a electric cutout that would open up when I'm racing. Good luck!
Boost referenced cutout doesn't sound like a terrible idea. I have an electric cutout on the car currently at the Borla adjustable spot, so I could even reuse that and use it manually if I wanted to. So that would mean the restriction between the over axle pipe and tailpipes is being eliminated. But is a 3" downpipe from the turbo to the axle still enough airflow?
My car is street driven, so ground clearance is definitely an issue. I'm lowered on Strano springs and already I scrape my torque arm crossmember on speed bumps if I don't take them at a 45 degree angle. I'm also looking into a 4" catback system from Spintech, but my issue is 1) ground clearance and 2) what I would do about the torque arm crossmember... I guess I'd have to get the flat one and run the pipe under it, but that sounds like it might rub and will hurt my clearance even more.
700whp is fine for a 3" downpipe. I had a 3" downpipe to a full 3.5" over axle exhaust made to a large magnaflow. Did a cutout off the 3" downpipe that was probably 4' long.
Only thing I don't like about a boost activated cutout is spraying exhaust all over the underside of my car. Especially if it's right off the turbo and in the engine bay... doesn't seem great.
Only thing I don't like about a boost activated cutout is spraying exhaust all over the underside of my car. Especially if it's right off the turbo and in the engine bay... doesn't seem great.
Spraying what? Exhaust gases itself? Obviously don't point it directly at a fuel or brake line, but there's no issue with it being towards the body.
Ok, I guess spraying was not the appropriate term. I just meant I don't want soot and **** all over my lines and suspension/body. But it will be pointed down and someone mentioned that I have a wastegate anyway so I'll already be venting exhaust under the car/engine bay anyway. So I guess my complaint isn't really valid.
Looking into the mufflex crossflow 4" spintech catback. Emailed MWC and they said I'll probably have to get the true dual crossmember and modify it to work for my setup if I go that route. =/ Bad news. My buddy has it and a Spohn torque arm and said it works fine for him...
Run an electric cutout but place it far enough down stream so the heat from the turbo doesn't drastically shorten its life.
I run a full 3" exhaust through a big *** Magnaflow muffler at the rear so its got a nice tone at cruise but is still quiet.
When I want to have fun I flip a switch and let it eat and yes it as awesome as it sounds.
My cutout is right under the driver floor board at my feet so its nice and loud and with it being that far from the turbo has lasted three years and going (knocks on wood).
I'd also like to add I don't think its about as much the flow as it is relieving the pressure, just my $.02.
Run an electric cutout but place it far enough down stream so the heat from the turbo doesn't drastically shorten its life.
I run a full 3" exhaust through a big *** Magnaflow muffler at the rear so its got a nice tone at cruise but is still quiet.
When I want to have fun I flip a switch and let it eat and yes it as awesome as it sounds.
My cutout is right under the driver floor board at my feet so its nice and loud and with it being that far from the turbo has lasted three years and going (knocks on wood).
I'd also like to add I don't think its about as much the flow as it is relieving the pressure, just my $.02.
Gotcha, so like next to the transmission crossmmeber? Can I see a pic if you can get one?
Gotcha, so like next to the transmission crossmmeber? Can I see a pic if you can get one?
If your sitting in the drivers seat there's a recess right under your calves where it fits nicely, there's also a grommet in the floor right next to it which makes routing the wires way easier.
Placed there I get to listen to all the popping and whining turbine noises I want, absolutely sublime. = )
I'll see if I can get a picture, ground clearance is still an issue though as I'm on Strano/Bilsteins but to be honest its always been an issue.
I'm on the same, strano/bilstein. I'm worried if I drop the torque arm crossmember any more, I'll be banging every speed bump I see. but if I try to route a 4" pipe under it, it may not line up well and will probably have the same issue. MWC has a "kooks double drop" that claims to work for 4" exhaust pipe, so I have that as an option. But honestly the cutout that opens under boost sounds like the best option so far. Shouldn't affect ground clearance and don't have to tear up and/or sell my existing exhaust. This is a project that will take all winter but I'm just trying to see what my options are.
I'm on the same, strano/bilstein. I'm worried if I drop the torque arm crossmember any more, I'll be banging every speed bump I see. but if I try to route a 4" pipe under it, it may not line up well and will probably have the same issue. MWC has a "kooks double drop" that claims to work for 4" exhaust pipe, so I have that as an option. But honestly the cutout that opens under boost sounds like the best option so far. Shouldn't affect ground clearance and don't have to tear up and/or sell my existing exhaust. This is a project that will take all winter but I'm just trying to see what my options are.
Yeah I hear you about the speed bumps, I simply avoid them or know where I'm going as my crossmember will hit too.
From what I've read going back to the stock lifted 4x4 springs is the only way and that **** ain't happen so I deal with it lol.
Yeah I hear you about the speed bumps, I simply avoid them or know where I'm going as my crossmember will hit too.
From what I've read going back to the stock lifted 4x4 springs is the only way and that **** ain't happen so I deal with it lol.
Talking to you guys has made me realize there is nothing I will sacrifice ground clearance for lol... I take girls on dates to the mall in this car and drive all over Maryland. No way am I changing my crossmember. I guess it's going to be a cutout, either electric or boost activated. I'd really appreciate if you could get me some pics of your setup. I don't want to do before the axle as it's probably too far to push all of that exhaust; I'd like do close to the front of the car but have to be careful not to push it towards any lines or the transmission.
I've run a small quiet full length exhaust and a large controlled dump for a long time, works great
Street cars have exhaust
The electric and boost cutouts are both kind of a compromose
The electric is just kind of a pain in the dick and slow and the boost activated is convenient but you loose the spooling benefit of the open dump. which is considerable on a large turbo
I now control mine with the ecu and high pressure air, it's amazing
I've run a small quiet full length exhaust and a large controlled dump for a long time, works great
Street cars have exhaust
The electric and boost cutouts are both kind of a compromose
The electric is just kind of a pain in the dick and slow and the boost activated is convenient but you loose the spooling benefit of the open dump. which is considerable on a large turbo
I now control mine with the ecu and high pressure air, it's amazing
What do you mean controlled dump? Do you have an aftermarket ECU? I'm curious to hear how that works. The benefit of a 3" full exhaust is that I don't lose ground clearance to a lower-hanging crossmember, and that's probably my biggest concern for this car related to exhaust. Also it's not that slow... I have an electric cutout now and it takes like 5 seconds of holding the switch to open. The idea is you open it before you start the car if you want to be in beast mode and close it before you start the car if you're just driving it to work or don't feel like hearing it be loud. It's not something I use while I'm racing or driving around. I pretty much decide what kind of a drive I'm going for before I start moving.
I've run a small quiet full length exhaust and a large controlled dump for a long time, works great
Street cars have exhaust
The electric and boost cutouts are both kind of a compromose
The electric is just kind of a pain in the dick and slow and the boost activated is convenient but you loose the spooling benefit of the open dump. which is considerable on a large turbo
I now control mine with the ecu and high pressure air, it's amazing
Ehh I'd disagree on the electric cutout, yeah it doesn't open fast but only takes maybe 6-7 seconds to open.
I went with the cheaper QTP cutout and it hasn't given me hardly any issues, every now and then I open up the connector under the car and add some dielectric grease to keep water water out but that's all.
12-10-2018, 09:40 AM
Full-length Exhaust for Turbo 4th Gen 
