Centre Exhaust Box removal

[jasohal]

Hi..

There have been a few posts regarding this where the centre box has been replaced with a straight though pipe on various cars.

I understand that there will be less back pressure as result of this and thus maybe a slight power increase , and the exhaust note should deepen.

However, has anyone done this and experienced any problems with idling, acceleration, misfires etc and any difference in MPG .i.e does the car take more fuel as result of this change in the exhaust setup / does the car need to be 'tuned' up in any way ?

The reason for these questions is that I once did this many years ago on a peugeot 205 1.9 GTi - what a car that was !! and had to have it retuned for it to run right.

Finally, this should not have any negative effect on the cat as the box I believe is after the cat ?

p.s. I am thinking about doing this with the E320 coupe...

 

[BTB 500]

So far so good on mine. AFAIK the engine management system should take care of any slight change of tune required due to the reduced back pressure (just as it does if you use different octane fuels).

I think the mod. might actually prolong the life of the cats ... less restrictive, less heat buildup.

PS you might want to check first whether a 'modified exhaust' will affect your insurance premium.

 

[Shude]

PS you might want to check first whether a 'modified exhaust' will affect your insurance premium.

You could tell them, but they ask you what difference it makes. If you tell them it made no difference except that it is a repair, then you're probably fine.

Proving any kind of performance, value or "desirability" increase is very difficult.

 

[MangoMan]

Hi Shude, yeah, thanks for asking this question, I also have asked in the past if anyone has done it on a CE/Coupe because I was thinking of getting it done on my 300ce.

I haven't got a Cat, but I do have a silencer there in place of it. Confirm it is the box by the rear axle that you are going to remove? What I also call the 'centre' box.

Please let me know how it goes aswell, thanks.

Bill.

 

[BTB 500]

You could tell them, but they ask you what difference it makes. If you tell them it made no difference except that it is a repair, then you're probably fine.

Removing the centre box surely can't be a 'repair'. Replacing with a different one (free flow etc.) possibly could.

I know to my cost that for some companies a car is either completely standard, or it's modified. The latter attracts a higher premium and a higher excess ... and they don't actually care what the mods are. The fact that you have changed it at all flags you as being a higher risk.

Elephant (who I'm with now) simply have a check box on-screen that says "modified exhaust". Selecting that didn't affect my premium.

 

[Shude]

Elephant (who I'm with now) simply have a check box on-screen that says "modified exhaust". Selecting that didn't affect my premium.

We're risking going off-topic, but when I reported the AMG backbox to my insurance company (directline at the time) they ceased being interested when I told them it was bought from the stealership. Same goes for the rims, bodywork and other oem mods.

 

[BTB 500]

Yet it was Direct Line who upped my premium and excess when I told them that my R129 had 17" (M-B original) wheels fitted in place of the factory standard 16" ones!

As mentioned, I think removing a silencer completely is more obviously a 'modification' than replacing it with a slightly different one. Depending on who you're insured with it may make no difference at all, but to be on the safe side you should ask.