Hi everyone,

I have just installed Fabspeed mufflers on my MY'99 C4.

The installation went well (aside from some VERY rusty nuts on both the muffler brackets and the sleeves that attach the muflers to the catalysts - the UK's rather inclement weather not helping here!!). The mufflers clear the heatshields on both sides of the car (at their closest point by the rear lower corner of the muffler) by about a quarter inch or so and the tips clear the rear apron correctly. There is no contact between the mufflers and the car's bodywork. All the joints are gas-tight - if I block off the tailpipes with a hand with the car cold and idling there are no leaks as the pressure builds.

The -ve battery terminal was removed after the install to reset the OBD-II and I have run the car approx 100 miles since including some hard acceleration runs (up to 155 mph - bad boy) to allow the electronics to re-map correctly. At full throttle and over 5000rpm the souind is absolutely amazing (if frighteningly loud)!

The problems I have are these:

1) Each side sounds different and varies differently with different rpms and throttle openings - WEIRD!
2) There is a massively loud boom throughout the car at 2000 - 3000rpm even at very small throttle openings. Very very loud and unpleasant.

I've had the OBD-II checked on my mate's PST-2 (He used to work for an official Porsche Center and is now an independent Porsche Specialist) and no fault codes were logged so I have to assume the variocams and other systems that might immediately account for the odd symptoms are working correctly.

Does anyone have any idea what might be causing the problems?

Hope you can help

Thanks, Ian W

 

Ian: does the booming change as the engine heats up? I ask because I have a set of B&B TriFlows on my M5, and they are very loud and boomy when the car is cold started, but the boom goes away quickly with a little heat.

BTW I have GHLs on my 996; very close fit, but no problems.

Steve
99 996
00 M5

PS: what area of England is your home? I lived in Suffolk for a few years; a very easy drive to both Snetterton and the Lotus factory.

 

Ian,
Where are you?
Is this a one off boom then its gone or do you mean it is a loud drone (resonance) that stays around until you get past a certain revs?
If you're nearby we could compare setups as I have the Maxflow system too.
Cheers,

 

Hi Scouser

I'm only in Manchester (live just near the airport) so can get together if you like - would be interesting to compare installations as you suggest.

The sound is an overpowering droning that is always there between 2-3000rpm irrespective of the engine temperature and goes at higher rpm.

Kindest

Ian W

 

I am in South Wirral just down the M56 J6. approx 30 miles to the airport from here. Fancy a trip over? I would be able to hear you coming
PM me and we can arrange something.

Cheers,