All this Exhaust Talk!

[Bristol4Boris]

Can someone explain the whole exhaust thing?

The differences between RSR's, 200 cat cells and a bypass etc. do I need both?
I think I might know a bit, but that's probably dangerous, for instance will a bypass go through the MOT?

Will there be any change in performance, fuel economy? the costs involved?

I am interested in getting a more throaty sound, without going down the Citroen Saxo route!

So many thanks for the advance replies, and apologies if this has been discussed before ( It might help newcomers to this site. )

 

[orangecurry]

basically :grin:

Cars like the 993 already have most of the performance available from the exhaust as it comes from the factory.

If hiowever you put in a less restrictive CAT, then you can release a bit more power.... but you need a remap AFTER you've made any exhaust/breathing changes, otherwise it may make no difference.

The car has a fixed 'map' to decide at what rpm/etc it puts out x amount of fuel mixed with y amount of air.

This is a standard map, which therefore can be improved by someone like Wayne to suit the individual car... either before or after any breathing modifications.

Any RSR/Hollamby :grin: type changes are just noise, and only noise. Just like the man himself..............

 

[Millomboy]

I must say, I like the sound of a bypass, but drive my car with roof open as much as possible, and am not sure if the extra dB would start to get on my nerves. Having had the car since October and not managed to get the radio to work (tbh the engine sound is my entertainment) I think I should probably live with the car a bit longer before going down the bypass route.

 

[Kimbo]

Good post OC.

Apart from the last bit.

 

[orangecurry]

Took your time. I expected more vitreol :grin:

 

[graemeho]

I must say, I like the sound of a bypass, but drive my car with roof open as much as possible, and am not sure if the extra dB would start to get on my nerves. Having had the car since October and not managed to get the radio to work (tbh the engine sound is my entertainment) I think I should probably live with the car a bit longer before going down the bypass route.

The good thing about the bypass is that you can't really hear it when cruising (even with the roof down) but if you boot it you get the ROARRRRR :grin:

Do it you won't regret it :thumb:

 

[Kimbo]

The good thing about the bypass is that you can't really hear it when cruising (even with the roof down) but if you boot it you get the ROARRRRR :grin:

That's the beauty of it.



OC, keep looking over your shoulder.

 

[Bristol4Boris]

Thanks, but can anyone answer my question, will a bypass go through an MOT??

 

[RobIpswichUK]

Simple answer re MOT is YES. Plenty of us have had replacement cats and bypasses and all passed MOT no problem.

 

[adamw]

Simple answer re MOT is YES. Plenty of us have had replacement cats and bypasses and all passed MOT no problem.

Absolutely!! Providing no dodgy aftermarket chip (accell racing) is fitted :lol:

 

[GT4]

+1

Annoyingly, I had to swap my AccellRacing Chip out for the MOT.

But I love the extra grunt, so it went back in after :bandit:

I think it is either/or with the chip and cats (as far as emissions go)

But with both noise and power improvements, the cats would be my choice if I had to choose just one.

 

[Lig]

Hi all,

Just to be clear are we talking about a muffler/rear box bypass here? So you use your standard original cats but with a pipe and tail pipes to bypass the mufflers?

So with this set up you get a much better sound that isnt too boomy right???

And does this not have any adverse effect on the engine due to lack of back pressure or am i barking up the wrong tree here.....

Thanks in advance,
Lig.

 

[adamw]

But I love the extra grunt, so it went back in

Be careful that the chip doesn't burn the powerspeed cats out gt4. This is what happened to richyd's

 

[Zingari]

Here's a before and after:

Yes just noise (no power advantage) but not intrusive and more burbling air-cooled sound :thumb:

On the 964 the G-Pipe was fitted along with a power map which goes along with the theory the settings needs to be changed to adjust emissions etc.

 

[GT4]

But I love the extra grunt, so it went back in

Be careful that the chip doesn't burn the powerspeed cats out gt4. This is what happened to richyd's

Thanks.

Not sure how I monitor that before it happens.

Perhaps I should just bite the bullet at get a proper ChipWizards/Wayne Schofield map :dont know: