Sports Exhaust or De-Cat !

["Yellow Peril"]

I'm looking in to getting a sports exhaust for my 500 griff or de-cat it, I had a 4.0 griff it sounded great but wanted somthing quicker, now i've lost the sound !

[Guillotine]

pre-cats out, with the centre box "piped" ie, solid pipes of a different length inserted, will regain 95% of the pre-cat sound whilst still passing the MOT.

If fully de-catting, leave centre box alone. cat chamber will act as a sound box! MOTs Fail!

not sure about the 500 being quicker than a pre-cat. I thought the extra capacity was there to over come the catalyst loading. I guess they may be a touch quicker. I know that removing my cats didn't increase my power tho just allowed freer revving.

[rev-erend]

If you objective is a better noise then a sports exhaust (modified centre box) must be the way to go .. you get a great noise and don't have to spend hundreds / many man hours before every MOT.

Removing the cats is really a lot of work for little gain. That huge space will just act like an expansion chamber loosing ex gass velocity (& noise) .. why bother ?

[starmist]

Many people who have fitted a sports silencer have been disappointed with the modest increase in noise.

Starting with a standard system, completely removing the contents of the middle silencer created a great noise - sort of 60s muscle car rumble.

Guillotine and I were both at Mech Repairs with mine like that and his completely unsilenced, and there wasn't as much differnece as you would think.

[cerbagriff]

Try talking to Brian at Fernhurst, he did a sports exhaust on my Griff and it is loud, even pops and crackles a bit, not the most efficient I dare say, but damn good fun.

[Ballistic Banana]

For some reason my Griff sounds a bit meaner than some.(as been told by others) dont know why but have the wadding taken out and straight through pipes put in the back box.
Havent bothered with the pre-cats(although have thought about it at times) as it sounds mean/loud enough to me.
Also a garage told me it would make to much difference to the sound it has at the moment.

BB

[gerjo]

I replaced the original silencer with one half the size and took out the pre-cats. Together with the P404 cam it sounds a lot more aggressive and louder (plus 7 db).

How about ACT's new manifolds with removable cats?

>> Edited by Gerjo on Saturday 12th February 14:25

[Hilts]

Went from a 400SE to a Griff500 so was obviously taken aback by the (lack of) sound. Had the precats taken out and some custom made straight through pipes fitted. Much better, but what was even more impressive was how much more freer revving it was. Highly recommend it.

[starmist]

I have the ACT manifolds and cat bypass pipes. They are a lot louder than the standard manifolds, so much so, I had to put a silencer back in! Expensive, though.

[gerjo]

starmist said:

I have the ACT manifolds and cat bypass pipes. They are a lot louder than the standard manifolds, so much so, I had to put a silencer back in! Expensive, though.

I'm thinking about these: how much more power did they give you? Did the engine sound improve?

["Yellow Peril"]

Cheers for all your help. i think is is going to be a new sports exhaust and manifold, a chap from David gerald is going to steer me in the right direction!

[Painey]

gerjo said:

starmist said: I have the ACT manifolds and cat bypass pipes. They are a lot louder than the standard manifolds, so much so, I had to put a silencer back in! Expensive, though. I'm thinking about these: how much more power did they give you? Did the engine sound improve?

Can I second that request as I might be interested in some of these in the future?

Cheers - Chris

[starmist]

With standard silencer, not much louder, with empty silencer, much loder (just noise) with sports silencer, about right, although David Redden, who has the same set up reckons his is too loud.

[WildfireS3]

starmist said:

With standard silencer, not much louder, with empty silencer, much loder (just noise) with sports silencer, about right, although David Redden, who has the same set up reckons his is too loud.

You can never be too loud.

[gerjo]

and how about the power gains of the ACT manifolds?

>> Edited by gerjo on Wednesday 16th February 15:57

[jellison]

just the straight through - decat more buggering about and doubtfull you will get more power either way unless a rechip. Less work with straight throughs.
Austec - 150 quid alot less than Fernhust - more pops and bangs if the std chip is slightly over fueling apparently. Last one loads of bangs, this one (pre the New Vette engine) just as loud but less popping and banging on the over run - only way was to go out when really cold day!