V12Godspeed

I am thinking of removing all four cats with the installation of my Kleeman headers. Need some advice, what will this do to my car, will there be any gains/losses. I made a search and could not come up with anything. The advice is appreciated. Thanks.

By the way they will custom make an exhaust that will run from the headers through where the secondary cats are.

chiromikey

it's possible you'll give up too much back pressure and lose hp.

jangy

How much back pressure is needed is all about how much air are you pushing through. What mods do you have. If you are talking K4, then I'd say the OEM exhaust without cats would be CHERRY!! Personally, i get scared with messing with cats, especially with K / EVO (just because of the ECU crap). But if you are going there, why not go all out?

516mbtek

check engine light will come on too...plus you will lose torque

jangy

Check engine will be dealt with through the ECU modification.

516mbtek

i see...the ecu mod eliminates catalyst monitoring I guess?

516mbtek

...try it and let us know! (mine will b next then)

jangy

Yes. Actually that part is what scares me, since MB is trying to make it hard for the tuners to do by hiding the codes and continually changing them. The risk is that K / EVO can turn off the ecu's link to the o2 sensors, and then MB will release a new flash update that will undo it. Then K / EVO have to go figure it out again. It is a nasty revolving door. In the past, it was never enough of an issue that MB would get so involved. Now, I guess it is costing them enough to make them pay attention.

AMG_55

if you loose anything it will br tq, not hp, you will more than likely gain hp up top.

if i get a 997s im gonna straight pipe it (after the cats though, no mufflers) and aftermarket headers, ill put it on the dyno before and after to see what happens

newton22

No inspection in NY?

chiromikey

you're absolutey right, tq in the lower rmps will be the most obvious but a loss of too much back pressure won't necessarily deliver hp on the top either.

V12Godspeed

well I am not yet pushing the K4 but that is my goal, Right now I have ASP pulleys and then the Headers, then ECU...After that comes the throtle body. The craziest Idea in the shop tonight was to run 116 Octane since I will not have the cats, I would have to get a separate ECU to mod it all the way up there and getting the tunner that will increase it up to 116 octane, then installing a methanol kit to cool off the supercharger and baddam, according to my mechanic this will be done, but let me not get ahead of myself one thing at a time...of course then I swap back to my regular ECU after i decide to just cruise.

How much torque am i looking to loose, and of course I will gain a few ponies in the run that is always a plus...the torque is always in exageration...what good is it If i can't put it to the pavement.

BENZGal

Jody,

I removed my resonator, deleted the secondary cats, and modified the Rt. and Lft. muffler without any HP/TQ loss. Someday I need to post a sound clip of the way my beast roars. It is one of my favorite mods!

As for worrying about the ECU? I found a service advisor that works on my car with the mods and leaves the ECU alone. Matter of fact, I ran into an issue realated to some of the recall software being removed that caused my front battery to not recharge. The dealership did a custom reload to the ECU without changing the Powerchip software. It's all about building relationships. MB can do a million software updates and I will be OK.

V12Godspeed

Thanks for the advice, definitely need to post a soundclip!, I would love to hear how it sounds. They are definitely going that route of removing all four cats, we will see of the outcome. Thanks.

jamusa

I keep getting the same battery signal for the front battery.......the dealer changed it out about a month ago,but it reappear today.I cleared it and drove for about 100 miles,then it reappear again.
I guess i will be seeing my dealer sometime this week.

PTE

You would be supprised what $20.00 willn't get you !!

V12Godspeed

Not sure I understand the comment, could you please explain...thanks.

PTE

A small token of thanks to the Svc Manager/ Writer & the tech , will always help them to remember your special requests. As Quoted by BENZ gal
As for worrying about the ECU? I found a service advisor that works on my car with the mods and leaves the ECU alone. Matter of fact, I ran into an issue realated to some of the recall software being removed that caused my front battery to not recharge. The dealership did a custom reload to the ECU without changing the Powerchip software. It's all about building relationships. MB can do a million software updates and I will be OK.

Cylinder Head

iTrader: (1)

Jody, usually I'm a *****-out kind of guy with my cars, but removing cats is a tricky process and while you may see some great performance gains on a heavily breathed-on car, your E55 in its current state of tune is unsuitable for such a mod. Its just going to be extremely loud and the lack of backpressure will probably lose you a little power (not a lot, maybe nothing, but I doubt it would give you any gains). As far as noise goes, take some baby steps. The headers will make it a bit louder and removing one set of cats will make it even more throaty, see how you like it in that state and if you're not satisfied then go for the gusto. A de-catted engine is a loud engine, a very loud engine indeed.

V12Godspeed

Thanks for the advice guys....I will have to sit down with the person that is designing me the exhaust...One of the main reasons I just don't delete the 2 primary cats is not to butcher the stock system in case i want to just put it up and take it down for warranty reasons. I will see if perhaps we could modify or add some aftermarket cats, biturbo suggested some hi flow kleeman cats. will look into that.

Cylinder Head

iTrader: (1)

If you're going to buy high flow cats, don't shoot yourself in the wallet buying Kleeman units, there are a million manufacturers of high flow cats out there that work just as well, use generic units and give me the money you save so I can buy new headers.

chiromikey

save some money and buy vrus' high flow cats...they're quite impressive and priced MUCH better!!!

here's a picture of victor's cats on my custom system:

zdkdeeier493

Mikey HOW is your undercarriage so clean???

chiromikey

i climb under there and hand polish everything every weekend...don't you???




j/k...i live in arizona where it never rains.

516mbtek

did you do anything to ur 210 55 as far as exaust? If so, what and were there any performance or sound gains?