Gussie Cup

Ia anyone aware of a web-site/previous post that compares db ratings for various exhaust systems?

I'm tempted to fit a Mongoose GrpN spec full system before Donno on Saturday but I'd hate to get there only to be told it was too loud.

Alternatively, does anyone know a db reading for the Mongoose GrpN (de-cat) system?

Thanks

Squizz

Surely being Group N, the DB rating is one suitable for any FIA sanctioned event and therefore should be OK for all circuits?

Or am I being naive?

Mind you, I'm sure I'm partially deaf so what do I know?!

Gussie Cup

Squizz - I've no idea!!

I just know that if its louder than 98 db on Saturday, I'm going home a disappointed man!

Can anyone shed any light on the 'GrpN' status and what it should mean?

Is anyone else at Donno on Saturday using this system?

MarkF

Group N means that the part is registered with the FIA at the manufacturers original specification. Don't know exactly about the noise aspect of a Mongoose system but for rallying the noise limit is 100db@4500rpm. Of course this is a constant engine speed and doesn't cover things like pops and bangs when you're on and off the throttle

Gussie Cup

I've now been told about a device (Super Trap) that fits into the tailpipe and can apparently reduce the noise by up to 10 db.

I'm at the NEC tomorrow for the Autosport show so I'll be checking a few stands out just in case.

Thanks for the help
Ben

Squizz

In my experience circuit noise testing comes in two forms:

1 - Goodwood. Where a probe is placed in the tail-pipe and you have to maintain constant revs as directed by the marshall.

2 - Castle Coombe. Where I seem to remember a noise gun being directed at cars on their way past, which could obviously by affected by pops & bangs, etc...

"I'm not helping much, am I !!"

Dave T-S

...judging by public opinion mine would fail a noise test everywhere!!!...

Blackscooby

SS de-cat Mongoose on my UK94. Noise tested for Harewood Hillclimb by Stewards.

93 ~ 94db @ 4500RPM

firefox

I think all this Grp N and Grp A stuff is poop...

Half the products have never been used on Grp N and Grp A cars... its just marketing crap.

J.

Blackscooby

I don't recall my SS mongoose system being sold as a Grp N system....just a stainless system.

I thought that group N is normally OEM spec built to a higher specification, better materials etc.

Ie a Group N Mongoose system would have to be the same bore as the Std exhaust... Surely restrictive.


Mark

Gussie Cup

Mark (BlackScooby) - I only hope the 93 ~ 94 db reading is right! (Cheers)

My 94WRX (Also a BlackScooby)is now fitted with the Mongoose. I'll pick it up tomorrow morning, have a blat, er, I mean, 'test', and post my opinions.

I suppose the real test comes at Donno on Saturday( )

BTW, the 'Group N' bit is cos its apparently not the normal Mongoose system. They make the standard stainless system, and then they make a few of this other type as well.

Andy Hall knows more details as its his exhaust so maybe he could explain?

(I'm taking it to him after I pick it up to take a reading so I'll post the results.)

Gussie Cup

Well, its now on and boy oh boy.....

We measued it this morning at 96 ~ 98 db @ 4500rpm. (Cheers Andy)

It sounds great - as for what it actually is, I'm even more confused because its a 3 inch pipe from Turbo to exit with no cats. All the parts fit together telesocpically i.e I couldn't swap the backbox for another as the system comes as a whole.

Either way, I don't care cos it sounds absolutely MENTAL and I haven't stopped grinning since.

Even better, I reckon it'll get through the noise test tomorrow and thats the main thing.

Thanks to all who posted - see you at Donno tomorrow

Pete Croney

If it is a group N system, it will be 2 1/4 inch ID throughout the whole system with a cat in the downpipe.

When I say whole system, that includes the tailpipe.

The regs on Group N say that no part of the exhaust may be larger than the diameter of the factory system, where it leaves the cat.

Blackscooby

Pete,

That just confirms my understanding of Gr N spec.

Mark

Blackscooby

Flippin' eck.
Thats quite loud. How was it measured ?

Mine is a Mongoose SS system 3" from turbo to tail pipe. Decat. I'm sure it wasn't that loud !

Does sound well
The flames are a lovely touch too

Mark