IF CATS removed.....Or

m5 rus · 19th May 2004, 10:14

I am going to remove

my cats as they restrict flow and put pre-cat back exhaust.....The sound should be NICE....

Will do ECU the car to Non-Cat prog...I been told that the car will eat more petrol, as the ammount of fuel supplied to the cylinders will be Fixed....So should get a better throtle response..

DOES ANYBODY KNOWS if I can CHIP the M5 after I REMOVE THE CATS......

Or may be I should not Remove the CATS, make CAT back sys and put a Chip.....

Black M5 · 19th May 2004, 12:32

Don't do it. I did my car started to run rich big time. If you want more power,i say go for the cat back exhaust along with intakes (filters or cold air) or you can even add headers and racing cats as well.

m5 rus · 20th May 2004, 07:47

Thanks for your advise....Now I will definatelyl Not remove the Cats....

I will put a Chip and a Cat back exhaust....The road are to dirty in winter in Russia to put CAI....I am affraid that it will suck up too much Dirt

....

Is there is a point to put the Racing Cats without Headers...

They wont give me much HPS, 5 at the most or less....

Do you have Hamann steering wheel in you BEAST...or not If yes, do you like it???

Ahmed · 20th May 2004, 10:03

you cannot replace your cats to high flow cats and keep your stick heads. you have to install headers!

m5 rus · 20th May 2004, 10:50

I have been offered to put G-power Racing Cats without headers...They cost $1.300 for set of 2...

H K · 20th May 2004, 17:03

Hi

I disagree with Black M5 and Ahmad. I have removed the Cats but had the car programmed for that. If you dont, then you will get the check engine light and most likely the car will go into some kind of mode. Take them off if some can program the ECU for you. I had the B&B before and with no cats, the sound was unbelievably sweet. At present I dont have that set up, but I do have headers, cams and free flow exhaust and all is great. By the way, if you are looking for performance mainly, then get cams first and you wont regret it.

Good luck

gra8fuldd ed · 20th May 2004, 20:01

M5 rus:

WHY do you want to remove your CATS? They are there for a reason. If you to eliminate what you think is "Restrictive AirFlow" ... Then but on a Full Cat-Back Exhaust system ... i.e. For one ... The Tubi Cat-Back Exhaust is quite excellent. By doing that ... you will elimainate your stock resonators which is the most restrictive portion of your exhaust.

IF you are going to put on those G-Power CATS ... Then also install the G-Power Headers with them as well as the G-Power Exhaust. They were made to function is inconjuction with eachother.

Here in the USA ... No too mant M5 owners go for the G-Power products. Seems as though that the availability and servicing is not as good as with other available parts.

What ever you end up doing ... You will need to some sort of Software to program (Syncronize) all your elements.

Talk to the various people (Tuners) that have M5 Software in your city or area and see what their experience and advice is.

Good luck and let us know what you decide.

SC'dKellenersM5 · 20th May 2004, 23:02

O/T

Ed if you want my brakes...let me know. Or talk to you know who...

m5 rus · 21st May 2004, 08:11

Quote:

Originally Posted by gra8fuldd ed

M5 rus:

WHY do you want to remove your CATS? They are there for a reason. If you to eliminate what you think is "Restrictive AirFlow" ... Then but on a Full Cat-Back Exhaust system ... i.e. For one ... The Tubi Cat-Back Exhaust is quite excellent. By doing that ... you will elimainate your stock resonators which is the most restrictive portion of your exhaust.

IF you are going to put on those G-Power CATS ... Then also install the G-Power Headers with them as well as the G-Power Exhaust. They were made to function is inconjuction with eachother.

Here in the USA ... No too mant M5 owners go for the G-Power products. Seems as though that the availability and servicing is not as good as with other available parts.

What ever you end up doing ... You will need to some sort of Software to program (Syncronize) all your elements.

Talk to the various people (Tuners) that have M5 Software in your city or area and see what their experience and advice is.

Good luck and let us know what you decide.

I have been told that Cats restrict AirFlow to exhaust....I want to remove Cats

and put Cat-Back Free flowing Exhaust.....This will give me optimal free flow curve...The BMW dealer can re-program ECU, there is a program for my M5....I have checked..with BMW....

Some people say do it

, so say DON't

gra8fuldd ed · 21st May 2004, 09:29

Quote:

Originally Posted by m5 rus

I have been told that Cats restrict AirFlow to exhaust....I want to remove Cats

and put Cat-Back Free flowing Exhaust.....This will give me optimal free flow curve...The BMW dealer can re-program ECU, there is a program for my M5....I have checked..with BMW....

Some people say do it

, so say DON't

Hmmm ... Not that I doubt you ... BUT ... I do seriously doubt that any legitimate and fully authorized BMW Dealership would re-program the E39 M5's DME after you've REMOVED the CATS ... Unless that Dealership is willing to seriously risk the loss of their dealership.

BUT ... I suppose stranger things in this life has happened.

IF ... You truly want to remove your stock CATS ... and IF you believe that your M5 will perform better without them ... then you should put on a set of quality ceramic coated headers (i.e. Supersprint or Hamann as an example) and use their High-Flow CATS. Then you can add the Exhaust of your choice.