[driftking123]

I'm looking for opinions, so lay it on me.

I installed a 3 inch speed engineering cat back system earlier this year and it deleted the second cat. It sounded great. Well, last month I had stainless power headers installed, but the shop that did it could not fit the cats that came with the system to the 3 inch SE pipes. They were able to clamp it to the SE pipes, but there wasn't enough room for the cats to fit. So I brought my car to another shop, but they said the same thing. They recommended getting weld in high flow cats. I found 7 inch long 3 inch diameter ones for 130 a piece. But then I have to have the shop weld them in, so all in I'm probably around 500 dollars. This is on top of the 1150 headers, with cats that I can't use.

But I am considering another option. I still have my stock cat back exhaust. I was thinking about taking off the 3 inch SE pipes to install the cats that came with the headers and put my stock pipes back on. I could do it myself and save money on install. So no more money spent.

The opinion I'm looking for is am I losing hp by going from the 3inch to the 2.75 stock pipes?

My current setup is the headers, LT2 intake, flex fuel, mishimoto cai, and ported stock TB, but getting a 95mm this Christmas. I plan on getting either a mild cam or ECS system. That choice is for another debate. Lol.

I'm leaning towards cam.

Anyway, I'm not tracking my car, never have, but one day would love to. So for now, it's just for fun and I'm 99% sure I'm not doing anything else after the cam or supercharger.

So, do I spent more money to keep my 3 inch pipes or switch back to my stock pipes?

Oh and by the way, my current fitment is rubbing on my heat shield and resting on my lines (the rubber) going to my rear diff. So putting the stock stuff back will make everything fit like it's supposed to do.

help..

Thanks

[m6-lt1]

Originally Posted by driftking123

I'm looking for opinions, so lay it on me.

I installed a 3 inch speed engineering cat back system earlier this year and it deleted the second cat. It sounded great. Well, last month I had stainless power headers installed, but the shop that did it could not fit the cats that came with the system to the 3 inch SE pipes. They were able to clamp it to the SE pipes, but there wasn't enough room for the cats to fit. So I brought my car to another shop, but they said the same thing. They recommended getting weld in high flow cats. I found 7 inch long 3 inch diameter ones for 130 a piece. But then I have to have the shop weld them in, so all in I'm probably around 500 dollars. This is on top of the 1150 headers, with cats that I can't use.

But I am considering another option. I still have my stock cat back exhaust. I was thinking about taking off the 3 inch SE pipes to install the cats that came with the headers and put my stock pipes back on. I could do it myself and save money on install. So no more money spent.

The opinion I'm looking for is am I losing hp by going from the 3inch to the 2.75 stock pipes?

My current setup is the headers, LT2 intake, flex fuel, mishimoto cai, and ported stock TB, but getting a 95mm this Christmas. I plan on getting either a mild cam or ECS system. That choice is for another debate. Lol.

I'm leaning towards cam.

Anyway, I'm not tracking my car, never have, but one day would love to. So for now, it's just for fun and I'm 99% sure I'm not doing anything else after the cam or supercharger.

So, do I spent more money to keep my 3 inch pipes or switch back to my stock pipes?

Oh and by the way, my current fitment is rubbing on my heat shield and resting on my lines (the rubber) going to my rear diff. So putting the stock stuff back will make everything fit like it's supposed to do.

help..

Thanks

I would put the stock stuff back. You’re definitely not losing anything in the bolt on phase going back to 2.75 inch pipping and I’m fairly certain you won’t be losing anything when you go cam. You need to be making supercharged built motor power levels before going 3 inch does anything. Remember zl1’s come with 2.75 inch piping and manufacturers these days are trying their best to squeeze out as much power as possible.

[greenz28]

I can't quite follow what you have bought, so maybe can clarify and someone will have a better idea what to do.

So first, you bought a "3 inch speed engineering cat back system". Is that the manifold x-pipe plus some other axle back mufflers? Like this for the x-pipe, then which axle back system did you get?

https://speed-engineering.com/collec...16-6-2l-engine

Then you bought the stainless power headers, and it sounds like you selected the cats they offer. So these? The ones with "factory connection" that are the shorter versions intended to connect to the OEM x-pipe instead of the longer versions that connect all the way back to the axleback?

https://stainlessworks.net/headers-2016-camaro/

If all my assumptions are correct, I wonder if you could buy the additional piping from stainless power to go all the way back to whatever axleback you have on the car now. Basically, exchange the factory connection option to upgrade to the "Stock Axleback or SW Axleback" option they offer. Those may fit your selected axleback or at least be able to be massaged to fit them. Then you could keep you stock exhaust system uncut and stored away for a future date when you or if you sell it, someone wanted to put it back to stock.

[driftking123]

Originally Posted by m6-lt1

I would put the stock stuff back. You’re definitely not losing anything in the bolt on phase going back to 2.75 inch pipping and I’m fairly certain you won’t be losing anything when you go cam. You need to be making supercharged built motor power levels before going 3 inch does anything. Remember zl1’s come with 2.75 inch piping and manufacturers these days are trying their best to squeeze out as much power as possible.

WOW, I forgot that the ZL1 has the same exhaust.. Another question for ya, I had the second shop tune my car to get rid of the check engine light and to make it run smoother. They got it running great. They dyno'd it for me and got me to 452hp and 471 tq. Would going back to stock pipes mess with tune at all?

Originally Posted by greenz28

I can't quite follow what you have bought, so maybe can clarify and someone will have a better idea what to do.

So first, you bought a "3 inch speed engineering cat back system". Is that the manifold x-pipe plus some other axle back mufflers? Like this for the x-pipe, then which axle back system did you get? ----Yes this was the system I installed in my garage. SE also sent me the "header" pipes by mistake, so the shop used those pipes to connect to the header.

https://speed-engineering.com/collec...16-6-2l-engine

Then you bought the stainless power headers, and it sounds like you selected the cats they offer. So these? The ones with "factory connection" that are the shorter versions intended to connect to the OEM x-pipe instead of the longer versions that connect all the way back to the axleback? --- I actaully bought this system, but from the shop who installed it--- https://fastmodz.com/products/2016-2...902ed58760b100

https://stainlessworks.net/headers-2016-camaro/

If all my assumptions are correct, I wonder if you could buy the additional piping from stainless power to go all the way back to whatever axleback you have on the car now. Basically, exchange the factory connection option to upgrade to the "Stock Axleback or SW Axleback" option they offer. Those may fit your selected axleback or at least be able to be massaged to fit them. Then you could keep you stock exhaust system uncut and stored away for a future date when you or if you sell it, someone wanted to put it back to stock.

I have the stock NPP muffler and am keeping that for now. The fitment issue was fitting the cats from the header to where the bend starts, before the 2 pipes meet in the middle and run back to the muffler. The shop who installed the headers, does not have a welder so clamping was the only option. And they won't fit without welding. The second shop said they could weld in cats, but because of the type of bends the SE system has, they can not fit the cats that came with the headers. They said I need shorter cats. These cats measure 14 and 16 inches in total. That's why I was looking at the 7 inch cats from SE.

I'm leaning towards putting the stock pipes back on.