Competition Exhaust Silencers

[wardy18 33 1 Cars]

Hi all,

 

One thing i need to do over the winter is to quieten the Hilcllimb 205 down a fare bit, she's known all round the pits as one of the loudest cars that runs an sits a smidge under the msa noise regs so im thinking as soon as i fit in my new block with much more cr its going to have even more of a bark.

 

I currently run a competition centre silencer and a small Cherry Bomb silencer on the rear, im 99% sure my system bore is 2 1/4" as i was always told this was ideal for the set up and 2 1/2" was too large!!

 

So i need a new and bigger rear silencer to replace the cherry bomb, this can be a proper Rear Silencer with Tail Pipe built in or just a centre silencer i can use on the rear and add a section of S/S pipe for the tailpipe.

 

WHAT DOES EVERYONE ELSE RUN in competition to give me some ideas as all i can find so far is Ashley boxes

 

Best Regards

 

Simon

[Cameron 16]

I've got a single 6" x 10" oval x 500mm box on mine, with 2.5" bore. Its 97dB @ 5K, should give you a bit of a ball park figure.

[DamirGTI 327]

You need -> an vacuum cleaner , bit of pipework , coke bottle , and pile of old OE silencers :

 

http://autospeed.com/cms/A_111371/article.html

 

.. sorry i dunno the answer i'm using std. Arvin exhaust with just the competition back box .. it's kinda loud for long motorway driving , so i've made an "bolt on" flange extension on the two rear silencers , this loud one and another spare (quiet) Arvin silencer which i just bolt on instead the loud one when i'm off for a longer journey

 

Damir

[wardy18 33 1 Cars]

I've got a single 6" x 10" oval x 500mm box on mine, with 2.5" bore. Its 97dB @ 5K, should give you a bit of a ball park figure.

 

What make is it?

[Cameron 16]

Its unofficially a BTB Exhausts one, I made it when I was on placement there.

 

It'd probably be a bit expensive as silencers go, but well worth it!

[Craigb 2]

Mines running a powerflow rear silencer that i modified to make it repackable, and that just comes in under the road rally sound level , which i would have thought was lower thann the hillclimb regs

[brumster 135 1 Cars]

My old single-box Powerflow didn't stay packed for long either and soon went the wrong side of 100dB I like Craig's idea of making it repackable because otherwise I can only say mine blew all it's wadding out after 4 competitive events

 

I now run a twin-box system 2.5" with Simpson boxes. 550mm x 8" oval on the back, repackable, and a 140mm oval centre silencer. Makes a nice 91dB on Mr.MSA's meter now

[Cameron 16]

If you're going to make it repackable, it pays to use E-glass or S-glass (S is better as its far far lighter) rather than the basalt s*ite that Powerflow put in theirs. It'll last way longer.

[wardy18 33 1 Cars]

Powerflow looks good so far by looking at the site but im a bit unsure as there arnt very good reports of them from you guys

[wardy18 33 1 Cars]

could always stick this in but doesnt look like it has a great deal of sound deadening capabilities

 

fleabay

[Tom Fenton 1,526]

I know a few people who have made systems with Jetex boxes with decent results.

[Craigb 2]

Powerflow looks good so far by looking at the site but im a bit unsure as there arnt very good reports of them from you guys

 

I have had the powerflow silencer on mine for 6 years now , the only issue was when the packing came out , hence why i made it repackable with teh better material as suggested by Cameron .

 

The main benefit for them for me is the fact that they are strong . Mine has had some serious off road abuse and is still going . As a road system they don't have the best reputation. But they are definitely fit for my purpose

[wardy18 33 1 Cars]

fleabay 2

[wardy18 33 1 Cars]

I have had the powerflow silencer on mine for 6 years now , the only issue was when the packing came out , hence why i made it repackable with teh better material as suggested by Cameron .

 

The main benefit for them for me is the fact that they are strong . Mine has had some serious off road abuse and is still going . As a road system they don't have the best reputation. But they are definitely fit for my purpose

 

How do you go about making them Repackable??

 

Really not sure if i would want to spend say £100 on a new silencer only to cut it up and re-work it, but then i suppose this would only need doing when and if the packing removes itself!!

[Craigb 2]

I'll get a photo up soon .

 

but basically i cut a circular section from the end , around the tail pipe , and made up a larger disc with six or eight holes in to pop rivet it on to the end . The disc had a new tailpipe welded to it .

 

As you say though ,only needs doing when its starts to get the MSA limit. this applies to any box you chose though .

[wardy18 33 1 Cars]

yes mate please, id like to see how it looks

 

i will measure my little cherry bomb and try and get somethin double the size in a powerflow silencer, maybe the 150mm dia x 500mm length with 2 1/4 ID

 

to start with though i will contact a couple of tuners and see if they think that the 2 1/4 bore will be suitable for the new engine, i dont want something daft like the exhaust bore to be holding ponies back from the engine

[Cameron 16]

You want to have your largest silencer right at the back of the system as sound is amplified down the sections of pipe. You'd be way better off without any cherry bombs and just have a single decent sized rear silencer. You'll probably find (as I did) that with a decent rear box you don't need a centre silencer.

 

2.25" should be fine for a 2.0 N/A engine.

Edited October 18, 2009 by Cameron

[wardy18 33 1 Cars]

I would love to loose the centre silencer i must say, i have plenty of pipe so i can fit a section of pipe in the centre to replace the silencer and fit the 150x500mm rear silencer on the rear and see how it sounds

 

at the moment it has a Raspy sound to it and i hate raspy sounding exhausts

[wardy18 33 1 Cars]

2.25" should be fine for a 2.0 N/A engine.

 

Oh.....no good for a 2.3ltr lump then?!?!

[Cameron 16]

Might be worth a try, 6" round silencer might be borderline by itself.. But you can never tell until its fitted.

 

Oh right, didn't realise it was a 2.3! What sort of power is it making?

[wardy18 33 1 Cars]

the 150 x 500mm is a 6" round silencer

 

the 2.3 is going in over the winter which is why my 2 1/4 was fine so far, i have no idea on power expectations tbh!! it'll be an enormously torque'y engine rather than bhp!! 220bhp would be nice and maybe 200ish lb ft torque but thats goin on my limited ideas of power outputs

[Cameron 16]

2.25" should do, you might get a tiny bit more power with a 2.5" but nothing really noticeable. You may as well stick with what you've got.

[wardy18 33 1 Cars]

ok cool thanx, maybe ill keep a new 2.5" system as my next development stage!!

 

so you think the 150 x 500mm 2.25" will be suitable on its own at the end of the system or a larger like a 180mm round (7.2")?????

[Cameron 16]

I don't know to be honest, a 7" box will be pretty heavy.. Depends if you'd rather go overkill or try it in stages.

[wardy18 33 1 Cars]

think ill stick to the 6 and see how it goes, if its still not enough then I can always stick my little cherry bomb in the centre

 

Thanks for the help mate