Exhaust Question

snkbte · #1 (**permalink**) 01-08-2005, 10:23 PM

OK - I'm thinking out loud !!!

I have spent the morning with my Cobra dreaming of the parts I need. My mind turned to the exhaust system and how to accomplish registration and yet have the side pipes I want. A light bulb went on and I had a thought!

I can not find any other reference this my idea so it maybe original. I'm posting to see how practical this theory is?

So, at the end of the extractors I'll run an exhaust system done through the chassis and out the back. ( this is simple enough and complies with the ADR ) However where the pipe bends after joining the extractors I want to put in a "Y" join and also run out of the car into side pipes. So At this stage after the extractor join and at the "Y" joint have a butterfly inserted so I can switch between the two systems.

Have the side pipes and internal exhaust set up with the same back pressure etc so the engine management runs and have either manual or an electric switching system.

In theory then if I want a quiet drive I would run the internal exhaust ( say in town ) and when out on the open road on just having fun turn the butterfly and run through the side pipes.

Well, what do you all think, shoot me down in flames or is it so simple that it took my simple mind to come up with it.

69TORINO-T · #2 (**permalink**) 01-08-2005, 11:18 PM

Hi SNKBTE, I have heard of that being done. The idea was to allow for running open headers but still be street legal after drag racing. I think it was done with a cable but see no problem with the method you stated.

Dave (69 Torino Talladega)

Bathrone · #3 (**permalink**) 01-08-2005, 11:47 PM

Its an ADR breach if that means anything to you

ledge · #4 (**permalink**) 01-09-2005, 12:56 AM

i would think that you would have a lot of trouble getting that through rego . I have heard that they wont pass fake side pipes if they can determine that there is a way you could hook them up after rego . The only way i have found to get around the problem is to make you system as if you were running side pipes but instead of having a tip at the end of the side mufflers have a flange there and run a basic 1 1/2 inch mild steel in and under the car joining in the middle and exiting out the back and if required to get the car under 90db put in a normal muffler under the car . Make it look like its meant to be there then after rego un bolt that section and bolt on a couple of tips to the back of the side pipes .

I am currently doing that now and should be done in about a month so i will post some pics when its done . My enginner was the one who told me this so it should be ok.

Paul

Ron61 · #5 (**permalink**) 01-09-2005, 05:32 AM

Don't know anything about your regs there but what about just setting everything up and then taking the side pipes off for inspection. The once that is done, put them on. I can takemine off in about 5 minutes, but I don't have to use the under car exhaust, so that would add time. Just a thught, but it may not work at all there.

As for doing it with a cable attachment, that is illegal in California and will get you a ticket. All cut outs here that go to short exhausts must have a cap bolted to them so you have to get out of the car and remove it. And the police do look for this on any car with pipes coming out short to the sides.

Good Luck,

Ron

Mike Simard · #6 (**permalink**) 01-09-2005, 08:38 AM

Good idea! Ferrari has a similar setup on some recent cars (except without sidepipes)

pneall · #7 (**permalink**) 01-09-2005, 02:04 PM

morning snkbte,

Your idea is good but it wont pass engineering in NSW at least.

You simply have to run under car system for engineering/blue slip.

You also have to do a pretty good job to pass the noise test.You will also end up with ground clearance problems( lowest part 100mm off ground) . Leeroy did a top job with his and there are photos in his gallery.

I used Ians rego set and only just got through the noise test after making on the day mods.

There are two tests , a drive by , passed easily . and a stationary one , much harder to pass.

The tests involves holding the engine revs at 2700 rpm with the noise test being taken 500mm from the exhaust tip.The level must not exceed 90dB. I got 89.

Good to see your motor arrived. Just get the right mounts and you almost home

Phil

Tenrocca · #8 (**permalink**) 01-09-2005, 02:49 PM

Gday Phil,

Happy new year. You up and running again yet? Did that sterring rack mod make any difference?

Cheers,
Andrew.

pneall · #9 (**permalink**) 01-09-2005, 03:00 PM

Tenrocca,

I was back on the road for a few days but not happy with electric water pump set up so have scrapped the idea and going back to std mech pump. Need to machine up a few brackets for idler pulleys etc.

Front steering mod seemed OK but will need wheel alignment before I am sure.

Hope to have it all together for Eastern Creek skid pan day on 30th Jan.

Phil