anthony1956 Posted September 26, 2012 Share Posted September 26, 2012 might this help with noise reduction on my KR500 currently denied by the Swiss test ? I need to get 95dba down to 75dba in a EU moving noise test (wot at 30mph for 20 metres with mics at 7.5 metres either side of the mid line, in third gear) Anthony Link to comment Share on other sites More sharing options...
Unclefester Posted September 26, 2012 Author Share Posted September 26, 2012 AnthonyM.....what's your current setup? Do you know how much of the 95db is exhaust noise and what's induction only? Have you got an airbox? Do you have induction trumpets in it? Pity you can't leave the car here for a few weeks, I could use it to mock up the standard chassis version of the large Festaire box, which for a 75db limit could be made with some more sound insulating walls. I was going to do it on Roger Swift's car but have been too busy recently. He's several hours from here.... Edited by - Unclefester on 26 Sep 2012 14:35:28 Link to comment Share on other sites More sharing options...
Unclefester Posted September 26, 2012 Author Share Posted September 26, 2012 Dave Jackson, Just read your thread. Those trumpets were £100 each? Whew......mine are more like £100 for 4! Edited by - Unclefester on 26 Sep 2012 14:38:39 Link to comment Share on other sites More sharing options...
jackb_ms Posted September 26, 2012 Share Posted September 26, 2012 Unclefester Who made your trumpets? Jack Link to comment Share on other sites More sharing options...
Unclefester Posted September 26, 2012 Author Share Posted September 26, 2012 My French fabricator. I could make more, but they aren't the same as the ones which go on the Jenveys, which have a flange. This would need two other operations to make and they'd be more expensive. I have enough spare alu tube for another 14 sets! Edited by - Unclefester on 26 Sep 2012 17:57:13 Link to comment Share on other sites More sharing options...
Jason Plato Posted September 26, 2012 Share Posted September 26, 2012 look at it another way, the two trumpets at £200 gave 20lb uplift, that's good value :) Link to comment Share on other sites More sharing options...
Neil66 Posted September 26, 2012 Share Posted September 26, 2012 Different inlet lenghs are not a new thing - I think I've heard this even in F1 or some formula circles in days gone by... The natural progression to this is variable inlet lengths - and for one they were used on the 2007 Norton Rotary Racer Link to comment Share on other sites More sharing options...
Jason Plato Posted September 26, 2012 Share Posted September 26, 2012 yeah, they are nothing new. Think they first came into thinking in 1960's in F1 and can am etc. the downside is that longer trumpets are bloody noisy. Link to comment Share on other sites More sharing options...
anthony1956 Posted September 27, 2012 Share Posted September 27, 2012 she's not been out of the trailer for nearly a year.. erm.. maybe we could sort something as she is just sitting here doing nothing.. fair old hike tho. no, no existing air box. trumpets.. just the standard fit the moving noise test showed 95 db (+/- 1) on both sides upon pass by. Edited by - anthonym on 27 Sep 2012 08:24:02 Link to comment Share on other sites More sharing options...
Unclefester Posted September 27, 2012 Author Share Posted September 27, 2012 An airbox would certainly help. The trumpets might have some effect on noise, but I doubt it'd be much. Mine are pipes with a lip rather than being a conical section, so would have less 'trumpet' effect amplification of induction noise. I hadn't thought about it when I built the airbox, but it's true that it could be made much more sound insulating while still keeping a larger internal volume than the original Scouse design. This is all very well on an SV, but you couldn't fit one like mine on the standard Caterham chassis as there isn't the underbonnet space available. I think Bernard Scouse tailored the original airbox to the Caterham's limited clearances. Link to comment Share on other sites More sharing options...
jackb_ms Posted September 27, 2012 Share Posted September 27, 2012 Do you think 4 trumpets could be made for roller barrels Jack Link to comment Share on other sites More sharing options...
Unclefester Posted September 27, 2012 Author Share Posted September 27, 2012 I've not looked at a roller-barrel setup. Can you post some decent pix? Link to comment Share on other sites More sharing options...
jackb_ms Posted September 28, 2012 Share Posted September 28, 2012 I can take pictures from my engine bay hopefuly tomorow f it stop raining... Jack Link to comment Share on other sites More sharing options...
Unclefester Posted September 28, 2012 Author Share Posted September 28, 2012 Post them or mail me direct and I'll have a look. Away over weekend. Link to comment Share on other sites More sharing options...
Anton Posted October 2, 2012 Share Posted October 2, 2012 Uncle F - missed this post first time around - glad to see GJ is still running! Link to comment Share on other sites More sharing options...
Unclefester Posted October 2, 2012 Author Share Posted October 2, 2012 CJ has had a 6 year break, and is now re-engined and fretting for some action. She will also be having a full repaint and colour change very soon. Link to comment Share on other sites More sharing options...
Anton Posted October 5, 2012 Share Posted October 5, 2012 *arrowup* *thumbup* Link to comment Share on other sites More sharing options...
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