robhtid

Well-Known Member

• Apr 18, 2020

• #1

Hi guys just a quick one. Is anyone running a de cat, keeping the centre box and using a side exit so it only retains the centre box. What is this like noise wise? Loud? Really loud? Droning? Great for an off roader but not a daily driver? Any input would be great thanks

 

swatts70

Active Member

• Apr 18, 2020

• #2

I'm running my Td5 with de cat and no centre box and the noise increase in minimal. Just a turbo whistle as revs increase and a low down growl as revs pick up. Nothing that is too noticeable from inside the car.
Will be putting a side exit on later this year hopefully and then it will be a straight through and I doubt if there will be much more noise then.
Hope this helps.

 

robhtid

Well-Known Member

• Apr 18, 2020

• #3

Thanks but I'm hoping to retain the centre box to keep it at a minimum

 

swatts70

Active Member

• Apr 18, 2020

• #4

To be honest I heard more increase in noise when I lost the cat than when I removed the centre box.
The centre box really doesn't do much apart from restrict a bit of power.
It does not sound like a boy racers car at all.
There's cars coming out of the factory with standard fit exhaust systems that are noisier than my disco.

 

robhtid

Well-Known Member

• Apr 18, 2020

• #5

From what your saying there isnt much point in me keeping the centre box, I will try it first tho as it's only welding a few 45s on the end to get rid of the back box. Thanks

 

swatts70

Active Member

• Apr 18, 2020

• #6

I just bought a centre bypass pipe. Was easy to do, just bolt in place of centre box.
Think I got it from fleabay.

 

bankz5152

Well-Known Member

• Apr 18, 2020

• #7

My 110. Decat, Allisport "Bullet" mid box, 3"straight rear pipe.



Its loud but not upsettingly so. I drive 350m a week and its fine for me, sometimes a bit loud

 

Stanleysteamer

Well-Known Member

Full Member

• Apr 18, 2020

• #8

swatts70 said:

I just bought a centre bypass pipe. Was easy to do, just bolt in place of centre box.
Think I got it from fleabay.

Click to expand...

I did the same, except for the fleabay bit. Is an early one so no cat anyway, chnaged it to improve perofrmance and mpg. No noisier and made no difference to either of the things I wanted it to, so reverted back for insurance reasons. Only real way to get an improvement is to do what I did to my D1 which was to replace the whole system with a stainless perfomance single box exhaust. this gave a noticeble improvement in lowdown torque, a much smoother drive, and only a gentle growl, AND the mpg was slightly improved.
Don't know if there is one for the TD5 available off the shelf but woulda thort so. A quick search should decide that either way.

 

robhtid

Well-Known Member

• Apr 19, 2020

• #9

I'm not really after improving the performance as it goes well as it is, I've got a decat egr removal and remap. I wanted to side exit because my tail pipe is looking abit scabby and I like the look of the side exit. Also the last time I took my caravan somewhere there was a long steep pull and at the top I had a rather black front corner to clean when I got there!

I just wanted to know if anyone has a decat and then did a side exit while keeping the centre box and how it affected the noise. Thanks