longtubes with "quick disconnect" cats

[vincentjm]

Hey guys

So I've been thinking about getting SW longtubes for a while now, but, I still need cats. Can't go for the high flow, ones because I'm not allowed to put in an aftermarket cat due to regulations etc.

Will a muffler shop be able to essentially cut a part of the headers out so I can switch between a straight pipe and stock cats using just clamps?

Cheers!

 

[EFI]

All headers use some sort of bolt-on connection, whether it's clamp or ball & socket. So a shop can build you a pipe using the OEM cats to match that fitting depending on which headers you get.

 

[vincentjm]

All headers use some sort of bolt-on connection, whether it's clamp or ball & socket. So a shop can build you a pipe using the OEM cats to match that fitting depending on which headers you get.

Yeah I was just wondering because the stock cats are on a bit of an angle iirc. And they will sit much lower, right before the midpipe probably

 

[EFI]

Well that will be an issue then, maybe turn them sideways so the angle is towards the middle of the car instead of up? That will require a bit more bending, but essentially you will have pipe come off the header angled towards the middle of the car, then back towards the outside of the car to match the cat inlet angle.

 

[vincentjm]

Well that will be an issue then, maybe turn them sideways so the angle is towards the middle of the car instead of up? That will require a bit more bending, but essentially you will have pipe come off the header angled towards the middle of the car, then back towards the outside of the car to match the cat inlet angle.

Just had a quick lots at some pictures. I'm not sure if there's enough clearance for the huge stock cats to fit...

 

[EFI]

Yeah that's going to be an issue if you absolutely need stock cats.

 

[Bluelightning]

Yeah, definitely an issue if you need the stock cats. I'd probably just forget the longtubes, get some MAK cat delete pipes, and then weld a flange to the stock cat so you can bolt it back up to the driver's side after you cut it off to weld the flange for the MAK pipe. That way there's no issues with them inspecting, and when you get back home you can just reinstall the delete pipes.

 

[Meraki Autoworks]

We can get you a price on the SW headers.

As for the cats fitting.. I feel like it might rub. Is it required to have two sets of cats?

-Josh

 

[Bluelightning]

We can get you a price on the SW headers.

As for the cats fitting.. I feel like it might rub. Is it required to have two sets of cats?

-Josh

I believe he's in Switzerland and they are require to have the factory cats.

 

[Andy13186]

Maybe they could be re positioned to where the resonator is? would need some long o2 extensions and stuff though. Not sure if its worthwhile.

 

[crcpdx]

I have Mak cat deletes and they do bolt on and off pretty easily. However I don't recommend on a NA car. I didn't Dyno, but only gained a tenth in the quarter, and because of Low end TQ Loss, the car actually feels slower on the street.

 

[VooDooDaddy]

I have Mak cat deletes and they do bolt on and off pretty easily. However I don't recommend on a NA car.

Why not?

I didn't Dyno, but only gained a tenth in the quarter, and because of Low end TQ Loss, the car actually feels slower on the street.

Huh....?? WTF

Please tell us all how a car that gains speed, any amount of speed, "feels" slower?

And lastly, how does eliminating a restriction in the exhaust system, no matter how small, somehow equates to a loss of torque??

 

[Jay-rod427]

Maybe they could be re positioned to where the resonator is? would need some long o2 extensions and stuff though. Not sure if its worthwhile.

The cats need to be close to the cylinders. They need the heat to function. That far away might cause codes, or clog them.

 

[crcpdx]

Why not?



Huh....?? WTF

Please tell us all how a car that gains speed, any amount of speed, "feels" slower?

And lastly, how does eliminating a restriction in the exhaust system, no matter how small, somehow equates to a loss of torque??

The car feels slower on the street because of where the power is being made. On the street I rarely run the car wide open from 5000 rpm to 7800. More wot hits are from 2500 to whatever. You've heard of big turbo cars that are dogs on the street? Same concept just on a much smaller scale. Too long to explain how you lose TQ on a motor pushing too much air. Let's just say that's why mustangs like long tubes vs shorty headers.

 

[VooDooDaddy]

The car feels slower on the street because of where the power is being made.

Removing the cats, which is a restriction (with no other changes being made) will not affect "where the power is being made", which means the HP/TQ curve. The only thing that will happen is the curve will be the same, only the numbers will increase, even if the increase is only slightly higher.

You've heard of big turbo cars that are dogs on the street? Same concept just on a much smaller scale.

No, no, and just well..., NO

"Big turbo cars" suffer from turbo lag, which has absolutely nothing in common with removing the cats on an NA car. "big turbos" have more inertia which takes longer for them to spool up, but the upside is bigger turbos will make more HP (because they move more air), only higher up in the rpm range versus a smaller turbo. Sorry, but your comparison involving "big turbo cars" and removing the cats on a NA car is invalid and completely laughable at best.

Too long to explain how you lose TQ on a motor pushing too much air. Let's just say that's why mustangs like long tubes vs shorty headers.

"Too long to explain" because any explanation on your part would be from a place of ignorance.

In short, the idea of "an engine needs back-pressure to make torque" has been debunked for at least twenty years, and this persistent myth needs to die a quick death.

Any time a restriction in an exhaust system is removed, the engine will make more power and more torque. PERIOD.