ITB Noise level - help needed on silencer

[Meek_racing]

My car was 103db on the static test last week so only just passed the noise limit for Oulton.

Does anyone have any tips/advice on where to place a silencer and what to use if I make my own version? Reason for asking is that I'm thinking of turning the decat into a proper silencer so that I can use it on other trackdays with lower noise limits. I'm running a 182 manifold on my 172 cup with bolt flange for the yozzasport system, I'm thinking this will be a good place to start so that the exhaust doesn't need to be chopped up etc...

Does it make any difference if I use an cylindrical baffle plate and use packing material or just the baffle plate on it's own? I can either use thin wall tube or rolled sheet and pop rivet like the yozzasport back box. If it works out to be effective I might get a few knocked up for selling

 

[Ph1 Tom]

Just a sensible exhaust would sort it. And a sports cat.

It's going to be loud with itbs, no cat and a single silencer.

 

[leeds_182]

Mines proper quiet with the btb on even with the decat.

 

[Dan519]

Fit a cat. biggest noise reduction measure you can take

 

[Meek_racing]

I don't really want to use a sports cat as it will end up knackering the internals surely? Likewise I would like to try and keep the yozza before going down the route of another system. If this were the case, what is a quiet one to get?

 

[Meek_racing]

Fit a cat. biggest noise reduction measure you can take

will it not beat the crap out of the internals though over time?

 

[mike1pow]

I measured 90Db with jenvey's and unsilenced ktec. Had the cat in place though

 

[Cup_Phil]

Mines proper quiet with the btb on even with the decat.

I need to hear yours - if it really is then my oreca group n system is off in the bin and I'm forking out for a btb next year!!

I don't really want to use a sports cat as it will end up knackering the internals surely? Likewise I would like to try and keep the yozza before going down the route of another system. If this were the case, what is a quiet one to get?

What do you mean by knackering the internals?
As I've said in my PM I run a 200 cell sports cat inbetween the 182 manifold and the oreca. It made absolutely no difference to the rolling road output, MOT's fine and nearly halfed the noise. It was absolutely unbearable with a decat on, inside or outside.
I've then had to fit another silencer to the oreca because it's a stupid exhaust.

 

[Meek_racing]

Does it not deteriorate the catalyst material? I'll slap the old sports cat back on this weekend and do another db reading.

 

[Cup_Phil]

Nah not unless you've got it mapped to pop and bang and dump loads of fuel in the exhaust on over-run lol

 

[Dan519]

if your lambda sensor is working and setup properly, the cat will be fine

 

[Meek_racing]

Quite the opposite, it's very lean! I have never heard it do any pops till the first track day with them and even then it was only now and again and they were small

As per PM, I'm going to put the sports cat back on and do a db reading. I will also get a silencer made up in work and see if that makes any difference noise wise. Will report back here with the results

103db was at 5k btw, I always thought they tested them at 4k?

 

[Cup_Phil]

They test them at 3/4 revs - so if you're engine does 8k they should test at around 6k
Usually they just look at the rev counter - decide it does 7k so test at around 5k

If you're just using the space where the cat used to be I think a sports cat will quieten it down more than a short silencer will

 

[fake ben taylor]

isnt the stock cat essentially a sports cat anyway?

 

[Meek_racing]

isnt the stock cat essentially a sports cat anyway?

More or less, mine came with an aftermarket sports cat to fit a 182 manifold.

 

[Tony Hunter]

I've melted 2 cats.

 

[Ph1 Tom]

I've melted 2 cats.

To make biofuel?

 

[Ph1 Tom]

More or less, mine came with an aftermarket sports cat to fit a 182 manifold.

Just pop that back on then, problem solved.

 

[Tony Hunter]

To make biofuel?

It purrs along now

 

[SharkyUK]

It purrs along now

I bet the car's feline a lot better to drive as well...

 

[Dan519]

I've melted 2 cats.

your fueling was around 9:1 though

 

[Tony Hunter]

Good odds that.

 

[Cup_Phil]

your fueling was around 9:1 though

Hahhaha pops and bangs map innit

 

[Dan519]

Hahhaha pops and bangs map innit

I'd laugh if the prick who mapped it hadn't bore washed it and buggered the engine

 

[Cup_Phil]

Most of the clio mappers recommended on here haven't got a fecking clue what they're doing - hence why I always recommend shopping around for a proper mapper rather than someone who's just self-taught on a laptop for the last 3 years

 

[p@blo]

Lol! Excellent usage of winking smiley there Phil

 

[Silent_Scone]

I'd laugh if the prick who mapped it hadn't bore washed it and buggered the engine

9:1???? Was that who I think it was

That was worse than mine was.

 

[Tony Hunter]

9:1???? Was that who I think it was

That was worse than mine was.

I think you maybe right in your thinking, no wonder I'm down on compression! Now poor Danny has to fix it.

 

[Silent_Scone]

My rings were f**ked also.

 

[Tony Hunter]

Bedford borewash.

 

[Rhys Beal]

I run a Orbisoud cup racer exhaust with 182 manifold and replaced the cat with a 300mm straight through silencer. Ran 100db static

 

[Tony Hunter]

Janspeed are making me an exhaust for the race car, so be interesting to see what that comes out at.

 

[Dan519]

Most of the clio mappers recommended on here haven't got a fecking clue what they're doing - hence why I always recommend shopping around for a proper mapper rather than someone who's just self-taught on a laptop for the last 3 years

can't be bothered with that arguement. The fact he didn't even know how to strap a FWD car on the dyno properly (side to side, not over the wishbones like RWD) was scary enough

 

[Silent_Scone]

I actually spoke to someone from TrackGroup at an event we covered not that long ago, they had a few interesting things to say...a lot of these places are as bad as each other.

 

[Tony Hunter]

I actually spoke to someone from TrackGroup at an event we covered not that long ago, they had a few interesting things to say...a lot of these places are as bad as each other.

Which is why I try to keep out of all the politics. I just need the engine fixing. Hi Dan.

 

[p@blo]

Which is why I try to keep out of all the politics. I just need the engine fixing. Hi Dan.

What's up with the engine Tony - oil leak?

 

[Tony Hunter]

Na, power leak.

 

[Cup_Phil]

can't be bothered with that arguement. The fact he didn't even know how to strap a FWD car on the dyno properly (side to side, not over the wishbones like RWD) was scary enough

LMFAO that's how they do it in *insert name of bullshit european race series here* mate

 

[p@blo]

Na, power leak.

Lol

Must've had you sumped as to why it was gradually losing power

 

[p@blo]

*stumped