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Discussion Starter · #1 ·
Hi

Thinking about decatting or at least gutting the cat when it will inevitably need to come off for the MOT, to repair duffed exhaust mounting bracket :doh:

I gather from various posts that de-catting will reduce turbo lag, which will be very welcome given the sdi's reluctance to move sometimes.

I don't have any wish to go any faster generally so I shan't be turning up the boost or doing any other performance mods. (already blanked off egr tho).

Question - will my fuel consumption be affected by decatting? any increase in noise? I have no particular wish to sound like a boy racer.

Cheers, M.
 

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other_rover
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Hi

Thinking about decatting or at least gutting the cat when it will inevitably need to come off for the MOT, to repair duffed exhaust mounting bracket :doh:

I gather from various posts that de-catting will reduce turbo lag, which will be very welcome given the sdi's reluctance to move sometimes.

I don't have any wish to go any faster generally so I shan't be turning up the boost or doing any other performance mods. (already blanked off egr tho).

Question - will my fuel consumption be affected by decatting? any increase in noise? I have no particular wish to sound like a boy racer.

Cheers, M.
I have fitted a decat instead, much less messy. Slight increase in whistle from turbo - sounds good and possibly a bit perkier down below. I have also turned up boost and still get 47mpg on average
 

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Decatting won't make fuel economy any worse so no need to worry there.

You'll get a little more turbo whisle from the exhaust particularly if you have the single silencer exhaust as fitted to the later 600's but it isn't intrusive or noisey, and unless you wind the window down I verymuch doubt you'll even notice.

If you are to do any mod though I'd recommend a box from our resident electronics whizz Ron. They make the car so much more drivable, and gets rid of that horrid flat spot when you go to pull out at roundabouts etc, if you know what I mean.
 

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Discussion Starter · #4 ·
Decatting won't make fuel economy any worse so no need to worry there.
Excellent.

You'll get a little more turbo whistle from the exhaust particularly if you have the single silencer exhaust as fitted to the later 600's but it isn't intrusive or noisey, and unless you wind the window down I verymuch doubt you'll even notice.
Acceptable.

If you are to do any mod though I'd recommend a box from our resident electronics whizz Ron. They make the car so much more drivable, and gets rid of that horrid flat spot when you go to pull out at roundabouts etc, if you know what I mean.
Arse, I was rather hoping the decrease in exhaust resistence would cure that "am i going, am i not" pause just after clutch release. I'll have to look into this box option.
Thanks E_T_V.
 

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Yes that is the pause I'm on about! Seriously though a box makes a BIG difference to the drivability. I don't know whereabouts you are in the country but perhaps someone local has one fitted that you could try out.
 

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the decat pipe cured the "am i going, am i not" pause just after clutch release
you are on about on my 600.
also you really do need to get the tuning box off rover ron, it feels like a different car to drive with it fitted
 

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Discussion Starter · #8 ·
Right, update -

As I have no spare cash at the moment whatsoever, I decided to gut the cat rather than fork out for a decat pipe to be fabricated. All went well, even came off without a fight which was unexpected.

Now having taken it for a test drive after, it is running ok and to my relief, no louder than before. However, the turbo doesn't seem to be having any real impact until 3Krpm, which is at least 1K higher than I would expect it to. Any thoughts on why this might be?
 

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I presume you gutted the cat off of the car so the bits didn't go into the exhaust and so possibly blocking it up.

If so check the boost hoses for leaks as they are common.
 

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Discussion Starter · #10 ·
I presume you gutted the cat off of the car so the bits didn't go into the exhaust and so possibly blocking it up.
Yes sir.

If so check the boost hoses for leaks as they are common.
Will try that tomorrow. I presume the turbo will boost whilst the car is being revved whilst stationary? As that's the only way I can think of to highlight a leak?
 

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Get somebody to rev the engine, whilst you listen in the engine bay for any hissing noises. That will tell you that a hose has split, quite probably the intercooler hose.

Cheers
Skelo
 

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Look for fine oil spray around the pipe leak if you find it hard to spot the leaking pipe. The oil leak leaves tell tale marks around where the pipe is leaking if it is a small hole.
 

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Discussion Starter · #14 ·
Look for fine oil spray around the pipe leak if you find it hard to spot the leaking pipe. The oil leak leaves tell tale marks around where the pipe is leaking if it is a small hole.
Yes, there is quite a lot of oil and associated grime pressumably from the last time the intercooler hose split, about 10months ago, with the previous owner. Will have to have a clean up whilst inspecting.

I'l report back later on. Cheers.
 

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Discussion Starter · #15 ·
Right well today I took both undertrays off and cleaned 125,000 miles worth of oil, grit and grime off them. Whilst they were off I had a feel of the lower intercooler pipe and it seems to be in good condition. Also checked the top, altho that was replaced last year anyway.

Got an assistant to rev the engine whilst squeezing the top intercooler hose and it very effectively un-squeezed my hand so clearly it IS generating a fair amount of boost. Maybe it feels like the turbo isn't kicking in as low now because the power delivery is more smooth. I don't know. Anyway, seems to be working ok and car is much less grumpy from cold now so thanks to all at MG-Rover forums, especially Mr E_T_V.

Cheers.
 
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