Factory Exhaust db?

[USCANAM]

Been reading some pretty high db quotes on some of these Ultima forums.
I have the factory S.S. exhaust for my CanAm,and about 600hp.
Does anybody know what the db would be for this setup at around 7000 rpm.
My home track (or maybe it will be ex-track) has a limit of 98db. They are tough there because our road course uses the start finish line of a NASCAR track, concrete walls on both sides, and that's where they measure.
Thanks All
Jack

[G Man]

Off the top of my head and standing correction - the factory exhaust is rated at 100db at 2/3 revs for SVA in UK.

In Europe tracks measure dba at 2/3 max revs which is between 98 and 105 db

I had a repackable exhaust made by primary designs in Thame to fix this, it replaces the factory one like for like,

You can use ceramics coatings, Aston martins did this to reduce the boom to pass SVA

This guys are the ones in Uk, we uses their agents
Tech Line Coatings - www.techlinecoatings.com/

G Man

[canam-phil]

The measurement at the SVA test and the track you have mentioned will be hard to compare. Echo from hard structures will play an important part and no tests will ever be the same in real track situations!!! My practical experiments in my acoustics module for my degree were an eye opener.

Our tracks tend to measure quite close to the car (<1m)

Phil

Phil

[ultimaandy]

Hmmmmm noise...

I took mine to a 98db circuit and had it tested.... 108db on tarmac with no walls anywere nearby, it was gradually increased to the required 5200rpm as my rpm limit is 7000 and it is measured at 3/4.

Was quiter than the new Lambo though who was having fits when they wouldn't let him out on track.

My car passed SVA only two months earlier and is not any noisier than any other Ultima I have met appart from one that had special 98db silencers made.

The light at the end of the tunnel is that I spoke to the factory who said they are now providing quieter silencers, more restrictive (ie less power) but should get you down 5db.

I have my doubts that my car will ever get down to 98db (to high an rpm limit) and don't know of any Ultima that has over 500bhp that has... would love to be proved wrong and hear how they did it though as I would so love to go to Goodwood.

[k wright]

I haven't got tyhe motor or headers yet but it appears that the options for silencers are wide open after you get past the headers. Assuming you can fabricate your own mounts.

Is this true?

Ken

[Steve_D]

Has anybody looked at the possibility of fitting an extra silencer across the back of the car outside of the body?
It would simply slide into or over the existing tailpipes and be held on with springs (as are some race car exhausts). It would not need to be sealed and would only be used for the track.

[Steve_D]

Just thought of the downside to my idea.
The silencer would leave the car looking rather like the arse end of a VW Beetle.
Still it may be worth it if it means entry to a track you were otherwise rejected from.

[k wright]

Not a bad idea if the fear grill is removable. It is likely that you could fit an axtra crossflow silencer inside the body work if your willing to remove the turndown pipes on the end of the factory silencers.

[G Man]

You could buy a track day baffle which fits on the enf of the exhaust for help quieten an engine, the problem is you need to be within a couple of db of legality.

G MAn

[bigmack]

I'd check into the different mufflers that are available. There is a lot to choose from, in all sizes, shapes, and type of construction. The major players here in the states are Dynomax,Borla,Flowmaster,Edelbrock,Magnaflow,Straight LIne Performance,etc... Most manufacture a racing muffler to meet either 95db track rules or 100-105db track rules or no track rules. The factory mufflers aren't bad, but they might be a little on the loud side to comply with strict track rule enforcement. I could have sworn remembering a good friend blow a 118db around a circuit in the UK. The factory exhaust may also need need repacking after a while. Flames out the back tend to accelerate this need.
A few owners have the factory mufflers redone with additional baffling and internal cones, etc... Mufflers are relavitevely cheap here in the states. I'd probably just replace them if they become an issue. I don't have the outer case dimensions, but its a centered 3" inlet and offset 3" outlet. My track is not too strict about the DB ratings, and it hasn't been a real issue when registering the car here in the states. Also, the guys in the UK may not be required to run cats. In the U.S. you may have to run them depending on your states requirements. The cats will also quiet things down a bit, and is something else to keep in mind. Unfortunately, I do not think the factory will sell you just the headers.
Cheers!
-Mack

[USCANAM]

Thanks for the replies chaps. Just got back from my home track where I was fastest on the dry, but when the weather turned British, I could of used some rain tires.
So far the reports on the sound level don't sound too promising, but we'll worry about that next Spring. Meanwhile, we'll keep all your tips handy and see what comes up.
I've had good results in the past with stainless steel scouring pads (North American term)inserted carefully in the exhaust system. Cuts power down a bit, but it allowed me to run.
regards
Jack