anyone have experience with removing the converter on their 2001 cl-s? i am wondering how it effects power, drivability, etc. i am looking to remove it and replace with a straight piece of exhaust pipe.


Case fixed by NOVAwhiteTypeS

 

are you taliking about the catalytic converter? I can't see that being good thing...you will loose a lot of back pressure....you'll wind up making your car slower. It is a high-flow cat so i wouldn't bother with that.

 

the fine is also quite large if you get caught without a cat.

 

i just can't see it making the car slower because it should have much better flow that way. i am expecting a small decrease in torque in low rpm range, but more power up high. i also have comptech headers and exhaust already installed so i figured to just continue with the opening up the exhaust theme.


case fixed by NOVAwhiteTypeS

 

it's a high flow cat...i don't think it will make much of a difference.

I think somebody tried it once....try doing a search...i can' t remember exactly.

 

omg...

 

Having been part of some flow bench tests of our catalytic converter at the manufacturer, there is little to be gained. At 400 CFM there was only about 5 - 6 inches pressure drop. A general rule of thumb is that for every inch reduction in pressure drop you might gain 1 HP.

Removing it might yield about 5 HP tops but that would be at maximum flow only. The side affects would be the requirement to run a HO2S2 spoof as there is an O2 sensor in the stock cat. If you are in an emissions controlled area, if caught the fines are serious. Also, no shop can legally make the change for a road going vehicle.

IMO, there are better ways to gain 5 HP...

 

I've done it, no emissions check in Florida.

I don't have any specific data, just seat of the pants, but I felt like it was waayyyy more responsive than with the cat. As for loss of Torque??? Our cars don't have any torque to begin with... much easier to pass people with the more responsive pick up...

I just recently put my cat back on, as I was taking mine in for the tranny service... 32K with NO problems (knock on wood), well, all I can say is the difference is noticeable, it really seems to choke it down.

The bad news, your engine light will always be on, and the increased smell, which you don't notice until you step around to the back of the car while running, and the noise, you definitely have an increase in noise... nothing major, but noticeable, and if you like it, it's kinda cool...

I'll be putting mine back on shortly... it's not a lot of work, couple of nuts... and voila, its off!

 

I suspect that the feel is attributed to optimism or possibly due to a low RPM loss. Often when something is lost down low with a small gain up high there is a transition which can be detected. But in the entire scope of thing, there is little gained.

Case in point, a well know GN racer was tuning his car with a few new parts he came up with. He made a pass and was sure that he ran slower. When he got his time slip it was faster than any previous run by two tenths. He later verified what occurred when strapped to the dyno. He found that the torque curve was flatter than before; this consistent acceleration over a somewhat peaky curve felt slower but was faster.

As for the engine light, how would you then know is something else wasn't wrong that could lead to engine damage?? With the light always on you can't tell if there are additional codes stored.

As previously stated, there are better ways to gain a few poise, IMO…

 

i installed a random tech. converter had ahp gain but lost lots of tor. car ran slower at the track. dont do it

 

Thanks for the heads up. It looks like this is not worth my time. I didn't realize there was a sensor that far back in the exhaust until I removed the heat shield. I don't think riding around with the "check engine" light on all the time is worth a couple of horsepower. I already have the comptech exhaust which sounds just right as is, so the added noise is also not what I am looking for. I guess its back to waiting on the icebox....

 

All very good points,

I don't run mine at the track or street race or anything, so I never really felt like the expense of comptech headers, etc was worth it to me. (as much as I would like to have them) Although, honestly, I never really thought about the engine light... I've never had a problem with any Ack or Hon that I've had, so didn't really think about some other code coming up... GOOD POINT!!!

Ah well, I'm tellin ya, it did feel a lot more peppy on the street with the pipe than it did now... bummer. I'm back to that punch the gas and hesitate crap...

Good info, thanks fellas.

Peace out