Exhaust popping / shaky idle golf gti

[kahunajb]

Hi there I m new to the forum and this is my first post so here goes.....

I had a superflow custom cat back ss exhaust fitted to my mk4 golf gti 2.0 a couple of weeks ago (yes i wish it was a 1.8T but anyway) at alba tyres in Leeds cost £330 fitted. Initially it was too loud so I went back and they fitted a resonator which sorted out this problem and it is now a lot quieter but charged me another £100. My main issue with it now is that it pops/backfires a hell of a lot when you take your foot off the throttle and when stationary when reved (it was also doing this before the resonator was fitted). I appreciate that some people like this sound but it can be a bit inappropriate on occasions and I would prefer if it didnt do it at all. Is there any way that this noise can be eliminated?

Also i have noticed that my car now very occasionally ever so slightly stutters at slow speeds its not very regular and it doesnt seem all that serious but obviously shouldnt be doing it. Also I have now noticed the the rev counter at idle wobbles slightly which i dont think it was doing before. Not sure if both these things are related to the new exhaust but pretty sure they have developed since its fitment which has left me a bit puzzled.

Your thoughts would be appreciated.

Cheers

[Singlespeed]

Popping from the exhaust is normaly due to a poor joint in the exhaust system or manifold. When you close the throttle, the gasses traveling down the exhaust, draw air into exhaust through any poorly sealed areas and allow unburnt fuel to explode in the hot exhaust pipe.

This wont do your cat any good!! If you have one left

[kahunajb]

Thanks for your quick reply. I have read quite a few things off the internet regard popping exhausts some say that it is normal with some exhausts and nothing to worry about others say like yourself that it can cause damage to the cat which I am worried about just dont know what to believe.

[kahunajb]

Had my car in the garage today as the popping had got worse and turns out there was an air leak which has now been fixed however my exhaust still pops although not as bad as before. The garage who fitted the exhaust originally say this is normal and nothing to worry about. Is this true and ideas?

[mobitune]

As long as there are no air leaks, I wouldn't worry.

[Singlespeed]

Glad that the bangs have reduced a bit...

Have a read of this post here http://www.pistonheads.com/gassing/topic.asp?t=425533. The reply by V8cerbera, 3/4 of the way down the page explains things fairly well.

A bit of ocasional popping is normal for highly tunned cars, or cars with free flowing exhausts. If the exhaust is now sealed correctly, and you are still getting big bangs, it may be worth having the engine re-tunned.

[kahunajb]

Thanks for that very useful.

So presumably this means that it is normal but will shorten the life of my cat. Is it harmful to the engine at all?

I appologise for my stupidity but what would having my engine re-tuned involve and how much would it cost?