sydr Posted 23December, 2014 Report Share Posted 23December, 2014 My '84 Carrera is in an advanced state of tune. Built by Autohaus Hamilton, the motor is very advanced, - until recently it probably was the only one of its type in Oz. I had a custom stainless steel free flow header system built for the new power plant with a twin outlet muffler. This was set up to maximise power output. It was lovely on the track - people would come to me to comment that "your car is the best sounding Porsche out there". The free flow system liberated stacks of power - BUT with my particular engine set up the system had a resonance at low revs - just between about 2200 and 2500 rpm that I found troubled me while driving on the road. On track at full noise, it was lovely. The resonance was cured with a valve that shut down most of one zorst outlet. The valve is switchable, so that for track use you can open it and for road use, close it. However, this did not suit my engine tune, in that it varied what should have been a constant and affected the state of tune. While the exhaust was still ahead of the old system it had replaced in terms of power output, the single outlet robbed it of a few Kw. I later removed the valve although the fitting is still present. Perhaps because my engine has 6 direct to head throttle bodies, was dyno tuned, running motec and set up for gas flow with both outlets fully open, closing one slightly affected its state of tune. I do not know it whether opening/closing one outlet would make any discernible difference for a less exotic state of tune. I've just had a new system built - headers, mufflers - the whole box n dice. Single outlet this time. Guess what? Still has resonance, I'm starting to think it may have something to do with my engine and its induction/duty cycle. Anyhoo, I now have two complete stainless steel zorst systems worth around $7000 a time to replicate and will sell the one that is no longer on the car. It is almost new - perhaps has 5000km of use, has no cat converter but that is easily fitted should you require it and also no heat exchanger for the heater - also an easy add on. This system breathes better than the SSI's that were on the car previously and makes more power. I can assure you of a deep, unmistable zorst rumble and a satisfying scream at full bottle. I'll take punishment to move it on and am open to sensible offers. System is currently at Autohaus Hamilton in Sydney; if you want to view it, contact me. Photographs are here, Flickr used to let me show the photographs directly but is resisting my charm . . . . Link to comment Share on other sites More sharing options...
clutch-monkey Posted 23December, 2014 Report Share Posted 23December, 2014 interesting crossover pipe! GLWS Link to comment Share on other sites More sharing options...
Cheshire Cat Posted 25December, 2014 Report Share Posted 25December, 2014 How much do you want for the headers/whole system? Link to comment Share on other sites More sharing options...
sydr Posted 26December, 2014 Author Report Share Posted 26December, 2014 Custom hi-throughput systems like these usually cost around $7,000 off the shelf systems somewhat less although I haven't priced one as it is not really relevant I'd know that you were serious were you to offer me around $2500 which would get you the headers plus the exhaust system complete Link to comment Share on other sites More sharing options...
Cheshire Cat Posted 26December, 2014 Report Share Posted 26December, 2014 I was thinking of headers for now... Not really ready for the whole system straight away. Link to comment Share on other sites More sharing options...
sydr Posted 28December, 2014 Author Report Share Posted 28December, 2014 Link to comment Share on other sites More sharing options...
sydr Posted 6January, 2015 Author Report Share Posted 6January, 2015 I was thinking of headers for now... Not really ready for the whole system straight away. Well someone make me a not so sensible offer then, I would like to get them out of AutoHaus Hamilton's way. So give me a fair price for the headers, have the zorst on me. Link to comment Share on other sites More sharing options...
Mick Posted 7January, 2015 Report Share Posted 7January, 2015 Is the system still available? Link to comment Share on other sites More sharing options...
sydr Posted 7January, 2015 Author Report Share Posted 7January, 2015 Sorry Mick, sold today. Link to comment Share on other sites More sharing options...
Mick Posted 7January, 2015 Report Share Posted 7January, 2015 My luck Link to comment Share on other sites More sharing options...
andrew911 Posted 20January, 2015 Report Share Posted 20January, 2015 Got the cats and tips welded up and the whole system installed yesterday. Sounds like a race car Next week I will look at few options to correct the drone, but for now it sounds great with one side blocked off. I am going to use an acoustic spectrum analyser to pinpoint the frequencies inside and outside the cabin and after some calculations will be making up few resonator pipes to start testing. Link to comment Share on other sites More sharing options...
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