RSR exhaust box

[Barry]

As seen on my old blue 911 (fitted, I think in 2004??). In fact that was a system that evolved from conventional and then twin pipe only (raised so the outlets went half-diameter up into the valance in an Audi TT stylee, although some said more Beetle than TT ).

Anyway, that was too noisy, so the third outlet went back on, but rotated 90d, and pointing downwards in a smokey old diesel stylee . I also added a couple of restrictors to the twin outlets (hidden inside), unitl I got the sound about right.

The only thing I never got around to was to let in a blank in the bumper 1/4.

Next car perhaps .....

[TheEasyLife]

Hi Barry, that exhaust was removed last year and replaced with a near identical stainless steel one custom made by TurboThomas. It is pictured and described in detail on this thread. http://www.ddk-online.com/phpBB2/viewtopic.php?t=25393 and theres a few pics on the www.turbothomas.com website along with Bootsy's. The new exhaust transformed the car into one I can drive for more than 30 minutes without needing earplugs. Your modified exhaust was starting to rust and had a number of small holes in it which only added to the noise... I should have measured the sound level before it was replaced but you live and learn. I still have it somewhere in the garage if I could be bothered to get it refitted then measured for sound levels.

Cheers

James

[Mike]

I think Mike is looking for 100% factory look

of course the 100% original factory look is no back box at all, just open megaphones!

We have an original set of mega's with an original hanger that holds them on which we will use when we start it up for the first time on the engine dyno
later this summer for the max power runs. Should then be able to swop them over to the new back box and map the power loss both with flaps open and
flaps closed and see how it effects the torque as well.

The new back box on mine will be finished in ceramic black to help it blend in, as you can see from the picture below of the original prototype car a grey
box would not look right at all, you can also see the single pipe outlet from when it ran it's standard engine as the recce car, Barry kindly made the cut
out for me in my quarter bumper and fitted up a blanking plate so I have the option if I'm really stuck with noise regs to put on my single outlet box.

Will post pictures on the 'My New Project' thread when we get to that bit

[964RS]

I have a friend who had a box made by another friend.

It had 3 outlets. One in corner as normal and then 2 central straight exit pipes.

The 2 central ones had custom screw on caps made. The noise with them off was fantastic but with them on far more subdued.

It was still a straight through pipe though.

Must be better idea than filling a box with crap and wiring up pulley systems?

If you're interested I'll get pics and cost (don't think it will be expensive really as not much to it) and see if he know difference in decibels on and off.

Simple system and doubt it affects performance much either.

[Mike]

It had 3 outlets.

That's what we are trying to avoid.

[Lightweight_911]

My 'long term' project will wear this decal with pride ...

[Bruce M]

Okay, another stab.....

In order to get a clean flow of gas into and out of the centre section, you really need to graft on an elbow to the straight through pipe. Say one near the inlet, that curves forward to end up facing inwards against the lower rear side of the silencer skin. The outlet could come in from the top section (front side of the skin) and curve down/back to merge with the outlet.

Very tight but possible. However, if you only fitted a butterfly in the middle of the straight through pipe (forcing the gas to take a round trip) there would be a lot of turbulence when you had it in "race" mode from the attached diversionary piping.

Another idea would be to also have another slightly smaller pipe that slides up from each tail pipe to cover the extra inlet/outlet when you have it in straight-through setting. These could easily be fitted by hand or by cables if you are really creative.

[Nick Moss]

I have just put a standard silencer on my ST rep in preparation for Spa next week end, oh it sounds so boring now
I shall be back to my dual outlet immediately afterwards!

[mrg3.6]

However, if you only fitted a butterfly in the middle of the straight through pipe (forcing the gas to take a round trip) there would be a lot of turbulence when you had it in "race" mode from the attached diversionary piping.

Looking forward to seeing where Mike takes this one

Selection of electric butterfly valves over on Summit Racing: http://www.summitracing.com/parts/SUM-670150/

Martin

[Mike]

well now this looks interesting, seems like one end of an RSR box with a lever in it bolted one way, then the other.......... ummm

[IanMcLeod]

well now this looks interesting, seems like one end of an RSR box with a lever in it bolted one way, then the other.......... ummm

Very clever design Mike. So you are not making it switchable from the cockpit?

Ian.

[964RS]

Dont switch it after some 'spirited' driving.....if you want to keep your fingers!

[Mike]

So you are not making it switchable from the cockpit?Ian.

Ian, this is Mk1 made to test the principle of the internals of the box and get some decibel figures which we should have today.
Cables, rods and levers into the cockpit could be offered if really wanted, but I wouldn't bother as it would look unsightly under
the car and even more expensive in what has already been a costly process

[TDK]

Nice, now all you need is an asbestos glove!...





Simon.

[Mike]

actually all you need is a 6mm allen key!