Legal sidepipes......

[*Cobber*]

The rules haven't changed in WA as far as I know but you can apply for a general exemption to run a left hand side pipe.

[Tatsushige]

I know a few guys as soon as they had their cars licensed, the fake pipes were off and really ones on .... I never did that Honest officer!

[hogster]

As this is my first cobra experience I want it boots and all............side pipes included, even if I have to carry fire blankets and lay them over the pipes everytime I pull up somewhere.

Having said that, I can see that with my second car would be a much better beast. I have learned so much from this one so far and I can appreciate that with the knowledge and design skills Warren has, a superior undercar system would be a walk in the park, even easier if the car was built from scratch with an undercar system in mind.

I would have to be in to mine with some serious cutting, and I'm not that good. The car was designed for pipes and I like them........I like them a lot

Now back to the business, what is the recipe for legal noise from the burn sticks. Anyone??

[*Cobber*]

Pot scourers got mine down to 83 db @ 3500 rpm.

With the scourers removed if you get on the right pedal they are noisy but not offensive.

2 1/4" stainless spiral louvered tube 25" long with a layer of S Steel wire wool and a few layers of "E glass" matting behind packed tight gives a great mellow sound.

The outer shell of the muffler section has an air gap and the muffler slides into the 3 1/2" section of the pipe, the muffler section is warm but touchable after a drive.

http://www.youtube.com/watch?v=t_0-5lvAo-I

[Tatsushige]

OH *Cobber*,

That video made me miss OZ and mainly Kalumanda

[hogster]

Thanks Cobber, I was after a usable formula to ensure that I can get the dang things quiet enough.

Boxhead - no worries, not sure when I'll next get to Alice, but I will - and we should have a refreshing beverage or three.

Thanks Aussie Mike also for the pics and advice.

[LoBelly]

Originally Posted by Aussie Mike

... Gav has found some great fiberglass matting used for lagging pipes that works a treat...

This is great timing coz I just happen to be re-doing my side pipes...

Does the matting work a treat in terms of noise or temp or both?

and

where can I get it / what should I ask for?

thankyou

LoBelly

[*Cobber*]

Give these guys a try, minimum buy is enough to do at least 20 pairs of pipes, but is fairly reasonable. They supply most of the leading muffler manufacturers & V8 teams.

http://www.lancastergfa.com.au/index.shtml

http://www.lancastergfa.com.au/acoustic.shtml

The fine stainless wool first wrap stops the E glass from blowing out or melting. the E glass is also a good heat insulator.

[boxhead]

Lo Belly,
I am not sure what the stuff I got from Gav is called, but he did mention it is used as a heat shielding on the gas burners he works on.

It is about 15mm thick but can be seperated like sheets, I split it to about 5mm thick. I then wrapped pot scourers around the perforated tube, and wrapped the wadding around the pot scourers inside the Aussie Mike pipes.
It has lowered the noise dramatically and has helped alot in the heat of the pipes.
I think that if I wanted to lower the noise further and permenantly I could weld a baffle plate inside the perforated tube, so the exhaust must pass through the wadding, but this would also be very restrictive.
So mine will stay as they are and have more pot scourers jammed inside the perforated pipe to get it quet enough to pass noise testing.
The pot scourers I used are the stainless steel swaff type that are about the size of a tennis ball, but are spun in a circle when made, so you can open them out like a big donut.

I thought I had pics when I put them together but can not find any.

[boxhead]

Wazza,
You forgot some of the Cons of the under car system
1= to fit the system under the car I am guessing they will be under the chassis, so to have a decent size set of pipes your car will need to be pretty high to gain gound clearance to be both legal or practical (since the car will be used every day you will not wanting to be going out of your way to avoid speed humps).

2= with a Cobra that high of the ground it will not be as pleasing to the eye as it could be.

3= you say it is to be used as a daily driver, but then mention on a high horsepower engine where your chasing every last drop of power it could make a 40hp difference, do you really want an engine that is "on the edge" so to speak in a daily driver?

But then I suppose being in a State where legal side pipes are not an option then you really have very little choice if you want to stay out of Mr Plod's vision.

This is all just my opinion and the reason for side pipes on my car is that part of being a Cobra is having the live side pipes.

[*Cobber*]

The E glass needle mat in the link above separates as Boxhead mentions and would be the same stuff, the finer s steel wool will reduce the noise a little bit more than the fairly open pot scourers.

[sambo]

Originally Posted by boxhead

Wazza,
You forgot some of the Cons of the under car system
1= to fit the system under the car I am guessing they will be under the chassis

Depends which kit you buy. The Harrison has a recess built into the gearbox tunnel rails to allow the exhaust to be tucked up out of the way, with a large open area to accomodate cats closely to the engine. The lowest point on my car looks to be leading edge of the T56 bellhousing. Still not live pipes, I know, but this isn't the wild west down here.

[Aussie Mike]

Thanks for the heads up on the stainless wool Cobber. I'll have to look into that.

I like the pot scrubbers because they stretch out into a ring shape and you can easily stack them along the outside of the baffle tube. That's a trick Scotty (OZVenom) showed me.



Here's one loaded up ready for the fiberglass mat. This is one of the baffles with a Cat converter.



This is the flange design I'm using now. Much easier undo and swap around. These are Dave's pipes. They use a 2.5" stainless perforated baffle tube.



The outer skin slips over the flange area and is retained with a clamp hidden in the back. The other end of the baffle is located with a bolt through the side of the pipe so it doesn't rattle. All hidden from sight behind the pipe along with the O2 sensor bungs.



The pipes in the top of the pic are my track pipes and odly enough I don't have a problem with leg burns. probably because they finish in front of the door

Cheers

[LoBelly]

Originally Posted by Aussie Mike

...This is the flange design I'm using now. Much easier undo and swap around. These are Dave's pipes. They use a 2.5" stainless perforated baffle tube.

I purchased 2 sets of perforated pipes 2.5" and 3" but it didnt seem to leave much room inside the 4"OD sidepipe so I went with just the 2.5" inner. If/when I redo them I think that design will be the go. Be prepared for questions.

LoBelly

[Dale McBain]

Mufflers!!!!

We don't use no stinking mufflers in the USA!

Guys you have to stand up for what is right and proper!

Dale McBain
SPF #469
Snohomish, WA USA

[*Cobber*]

We live in a "fine" country down under.....

Cars get taken off the road for just about any minor modification.

We can't even carry a loaded hand gun in the glove box.

[Rebel1]

Originally Posted by *cobber*

we live in a "fine" country down under.....

Cars get taken off the road for just about any minor modification.

We can't even carry a loaded hand gun in the glove box.

Hehehehehe good reply

[Tatsushige]

Originally Posted by *Cobber*

We live in a "fine" country down under.....

Cars get taken off the road for just about any minor modification.

We can't even carry a loaded hand gun in the glove box.

Hey move to Japan or the UK and you can not even have a gun!

God I miss my HK USP 9mm

Now I just have Airsoft to pratice with, but have to say playing Airsoft with the Japanese Babes is great fun

[Aussie Mike]

OK, here's a pic of the 2 different baffles.

The one installed is the 3" track day baffle. With this baffle I've also extended the collector section to about 15". From what I've read this longer collector area should work pretty well with the LS1.

The thing I like about this design is I can change the collector length or put in a venturi style collector insert and not affect the look of the side pipe.

The baffle on the ground is the 2.5" street baffle. This one has a cat converter incorporated into the front of it. The OD on the cat body is 4" (add a bit for the welds) and the OD of the outer skin of the side pipe is 4.5" so it slips over the whole thing with a bit of an air gap. I'm also going to try wrapping the cat in some fiberglass exhaust wrap tape to limit the heat transmitted to the outer skin of the pipe



Here's a couple of pics of the billet rear mounts I made for the pipes. These have turned out pretty nice and look like they will work OK too. They are attached to the chassis with rubber mounts. They should let the motor rock around but still support the end of the pipe.



The mount is sandwiched between two steel plates welded to the body of the side pipe.



I've got to get these pipes off to the ceramic coater. I really want to get them back and hear them run.



Cheers

[Jerry Clayton]

Mike---hows the dragster project???

Jerry