Growling noise

[Captain Jack]

Hello all,

I've had this problem for a little while now, which is when I am in a higher gear and lower revs (say 4th gear/30mph) and put my foot down, there's a distinct growling noise coming from the engine/exhaust (not sure where). I always blamed it on the flexi pipe, which had a hole in it but when I replaced it last year, the growling sound didn't get any better (in fact, I think it's louder now).

So, I thought that the MOT test a few months ago would pick up a hole somewhere in the exhaust system, but nothing was mentioned. I had a look under the car and noticed that the exhaust joints look a bit tatty and rusty. I had this exhaust since I bought the car but I don't know when it was replaced, if ever. So I am thinking of replacing the whole of the exhaust with the stainless steel type. How much would these cost from the likes of Powerflow? And would they decat the thing as well or is it only usually done from cat converter onwards?

[Doggy]

Can't comment of Flower Po etc. (I'm sure someone will be along shortly who can).......

I de-catted mine when replacing the flexi-section and TBH regret it. Mine was completely clear and unsurprisingly, with the benefit of hindsight, made no discernable difference to perormance / response.

While I don't like catalysed diesel exhaust fumes either, it now smells like a 1960's Routemaster bus.

[Captain Jack]

Ah hmm, OK. I think I need to replace cat anyway with a proper "Type approved" one, as the one I have is a cheapo one which has been "raspy" since I fitted it.

Any ideas on the growling noise when accelerating from low revs in higher gear? Or is the exhaust it?

[Doggy]

Does it only do it with the super-dooper remap, or do you still get it with std power?

I've still got what I'd described as a vibration at low revs / full throttle. Had hoped it was uneven running due to dodgy injector(s), but it's still there. I've rechecked all the mountings / torque reaction bushes etc to no avail. My latest theory is the torque compresses the dmf rubber till there's no give left......

(mine doesn't do it with std power map installed).

[Captain Jack]

Unfortunately, mine does it with both maps.... There's no real vibration that I feel, just the noise.

[Doggy]

Description fits an exhaust component with a loose baffle or something similar, so changing it may be the way to go. I don't think I'd queue up to spend loads on a 'type approved' cat as this just seems a total rip-off from the price differences I've seen.

See what the stainless suppliers can offer?