Catback for LS2 240SX?
Thread Starter
Launching!
Joined: Jun 2016
Posts: 284
Likes: 53
Catback for LS2 240SX? My 240SX currently has the 2.5 inch Bosal catback that my brother was using back when he was driving the car with the stock KA24DE. This just seems wholly inadequate for an LS2. So I'm looking to upgrade. There are, of course, TONS of catbacks available for the S13, most of them with 3" tubing. Is this adequate for an LS2? There is also the HKS Hi Power, which is available with 85mm (about 3.3") tubing. Might this be a better choice? Or is there something out there that might be better yet that I don't know about?
3 inch exhaust is good for 600+hp. The more power you make the more exhaust restriction will rob. You can make 1000hp on a 3inch exhaust, but you probably leave 100hp on the table.
For a normal LS2 setup, 3 inch is plenty.
For a normal LS2 setup, 3 inch is plenty.
My 240SX currently has the 2.5 inch Bosal catback that my brother was using back when he was driving the car with the stock KA24DE. This just seems wholly inadequate for an LS2. So I'm looking to upgrade. There are, of course, TONS of catbacks available for the S13, most of them with 3" tubing. Is this adequate for an LS2? There is also the HKS Hi Power, which is available with 85mm (about 3.3") tubing. Might this be a better choice? Or is there something out there that might be better yet that I don't know about?
Andrew
I don't have direct experience with the cat-backs that you listed, but I can share some experience with single exhausts.
When I was playing with RX7s I had a LS6 in a FC. It had headers and I had a custom single exhaust built. The 3" header outlets were merged with a Y-pipe and went to a single 3.5" pipe. From there it was a straight shot with the 3.5" pipe and went to a big round Magnaflow muffler. The car sounded great and made right around 400rwhp.
I never ran it without the exhaust, so I have no idea what losses the single exhaust caused, but I think a single 3" exhaust might be on the small side.
You can see pictures here:
http://www.norotors.com/index.php?to...67836#msg67836
Andrew
When I was playing with RX7s I had a LS6 in a FC. It had headers and I had a custom single exhaust built. The 3" header outlets were merged with a Y-pipe and went to a single 3.5" pipe. From there it was a straight shot with the 3.5" pipe and went to a big round Magnaflow muffler. The car sounded great and made right around 400rwhp.
I never ran it without the exhaust, so I have no idea what losses the single exhaust caused, but I think a single 3" exhaust might be on the small side.
You can see pictures here:
http://www.norotors.com/index.php?to...67836#msg67836
Andrew
I have the HKS Hi-power 85mm setup with a 3" Y-pipe and long tube headers on my L33. I really like how it sounds and it's actually surprisingly quiet while cruising. The car is getting a blower in a couple weeks and should be around 500whp, we'll see how it sounds with boost 
3" to 3.5" will cover most of our needs. My LS1 S14 had a single 3" exhaust and did well with it. If you are going FI in the future might want to bump it up to a 3.5" just in anticipation. As noted above too small of a size reduces your final output. Most KA NA based exhausts are 2.5" which would likely restrict your power a bit.
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If you find a turbo that supports around 650-750 horses, the exhaust outlet is often around 3". I have one such turbo on my 5.3 in a 240sx, and yes its 3" exhaust back. Going larger after the turbine outlet sets the size to begin might slow things down.
non turbo applications are different; you want the exhaust to match the acoustic properties of the manifolds, and in turn they need to match the cam profile and desired operating range. It has much less to do with size and more to do with length, form, design.
non turbo applications are different; you want the exhaust to match the acoustic properties of the manifolds, and in turn they need to match the cam profile and desired operating range. It has much less to do with size and more to do with length, form, design.
Thread Starter
Launching!
Joined: Jun 2016
Posts: 284
Likes: 53
I have the HKS Hi-power 85mm setup with a 3" Y-pipe and long tube headers on my L33. I really like how it sounds and it's actually surprisingly quiet while cruising. The car is getting a blower in a couple weeks and should be around 500whp, we'll see how it sounds with boost
