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| twr7cx |
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Anyone seen any reasonable variable exhaust systems?
Basically, my current exhaust is far too loud still (Pacemaker Competition Headers with modified 3" flange, 3" cat converter approximately 350mm long, 3" Lukey Race hot dog approximately 600mm long, 3" Lukey Race straight through muffler approximately 450mm long, to 3" hot dog approximately 400mm long) and changing to more restrictive mufflers will effect out right performance. I'm after something that will change automatically (e.g. above certain revs, or when it sensors boost or no vacum). From a bit of googling I found an Australian dude who sells an electronic setup, but it started at $900.00ish. I've also read that the new XR8's have some such setup, but couldn't find any further details. Any ideas? |
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| cjh |
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So your thinking of a Yamaha EXUP system????....could be done....lots of $$$$.
This is my Cat. Thats a 600mm steel rule next to it. My exhaust isn't loud, only has 1 muffler. This is a link for the EXUP system. http://en.wikipedia.org/wiki/4-stroke_p ... lve_system
_________________ http://youtu.be/jJTh9F3Vgg0 |
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| twr7cx |
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Yes, similair, but what I was thinking was perhaps a setup with like a butterfly in the exhaust system, near the end rather (as I think the Yamaha setup is up in the headers), which causes more backpressure and the exhaust gases to travel slower in the mufflers so muffling the sound more, and for it to be pressure sensative so it opens right up when it senses boost or no vacum. If the spring on the butterfly is not too firm the exhaust gases should be able to push it open a bit more too as required.
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| twr7cx |
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Something like the VariFlow:
http://autospeed.com.au/cms/title_Out-t ... ticle.html http://autospeed.com.au/cms/title_Pure- ... ticle.html http://autospeed.com.au/cms/title_Pure- ... ticle.html Now from what I recall when I found the websit selling the VariFlow, prices started in the $700.00 range. The product has been bought out and is sold from some other company. However, from Googling it, I've come accross some ricer forums, in which people are talking about a $200.00 version from Drift available through Autobarn, that shows potential! |
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| twr7cx |
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A similair thing at http://www.dmhperformance.com/ - basically with this one you have a quiet restrictive exhaust then it opens up and dumps it.
Found the drift one - http://www.shopdrift.com/Products/D1-EC ... -80mm.aspx - it's mechanical though, I want something automatic. |
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| twr7cx |
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It's almost like an exhaust brake for a truck I would imagine. From what I understand the exhaust brake on a truck is a valve that is shut when you engage it (althought I'm not sure if they work on the engines exhaust valuves or a seperate valve in the exhaust pipe system), it's shut using the compressed air. I just need the opposite, instead of shutting when the air is compressed (i.e. boost), I want it to open.
It looks like the concept isn't new, just no one has perfected it yet or taken that step further. |
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| cuppas |
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why not just set it to the runner changeover switch in the BBM? thats like 3500 or so isnt it? then youd just need to fabricate a butterfly somewhere in the line and splice the wiring?
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| 93_eb_fairmont |
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I think I read in the last street machine or top gear mag that Di Fillipo were doing them, still were more than $1000 though. Alternatively, a butterfly valve with a spring with enough tension to close half way at lower revs but with enough airflow keeps it open. Probably be hard to fabricate.
_________________ How many bears could Bear Grylls grill if Bear Grylls could grill bears? |
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| Nigel |
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You guys talking about the Varex Mufflers - I think theyre used in the current HSV's as wel
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| cuppas |
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varex mufflers are illegal as theyre manually controlled as opposed to ECU controlled
i figured my idea would neatly sidestep that issue? |
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| asnmcguinness |
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http://www.xforce.com.au/cars/view_car/29
I know its already been mentioned, but you can set them up to change at a certain speed according to the ad, been trying to get a price for a mate but the supplier around here is slack and wont call me back. But still illegal, even though not actually advertised as such
_________________ EF Falcon Gli |
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| twr7cx |
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cuppas wrote: why not just set it to the runner changeover switch in the BBM? thats like 3500 or so isnt it? then youd just need to fabricate a butterfly somewhere in the line and splice the wiring? I have a JayCar frequency switch for the AU VCT module, which comes in at lower revs than the BBM changes, so I'd look to using that. What I need to find however is an electronic flap to put in the exhaust. |
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| twr7cx |
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asnmcguinness wrote: http://www.xforce.com.au/cars/view_car/29 I know its already been mentioned, but you can set them up to change at a certain speed according to the ad, been trying to get a price for a mate but the supplier around here is slack and wont call me back. But still illegal, even though not actually advertised as such Doesn't phase me the legalities. From what I hear the Varex systems usually s**t themselves in about 12 months. They don't seem to have a very good reputation. The other issue that there mufflers are all made to be at the end of the system, I don't really have room there. |
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| TerroristGHIA |
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I too have looked into this, but here in NSW, with the valve open is where they measure the noise of the exhaust. So even if i had one, it would still need to be quiet when fully opened, so it defeats the purpose of them if you ask me.
Brett
_________________ The Terrorist ED Retired due to RUST. |
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| twr7cx |
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TerroristGHIA wrote: I too have looked into this, but here in NSW, with the valve open is where they measure the noise of the exhaust. So even if i had one, it would still need to be quiet when fully opened, so it defeats the purpose of them if you ask me. defeats the purpose in your case yes. But in my case the exhaust noise isn't going to be measured. I'm wanting it for my own use to quieten down the car. |
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