Rob Walker Posted February 13, 2006 Share Posted February 13, 2006 We ran a 280 bhp Duratec all day at Castle Combe on Saturday and had no problems with either the static noise test or on track monitoring. The day had a 100db limit. This is great news for anyone contemplating a duratec transplant. The car runs wide open induction through the bonnet and a large 7" Side exit silencer. Several of the grads cars failed the noise tests. I was surprised I had expected the car to fail on drive bye induction noise. Minister were also present testing a C400 duratec which I think was also ok on noise. Link to comment Share on other sites More sharing options...
Jason Plato Posted February 13, 2006 Share Posted February 13, 2006 Thast cos you were driving it like a a crafty butcher 😬 *wink* Link to comment Share on other sites More sharing options...
MikeW Posted February 13, 2006 Share Posted February 13, 2006 Hi Rob, Good to catch up with you ( briefly) at Coombe. Good track day Was surprised about the noise testing ( for the Duractec) although I don't think the drive by sensing is really a problem at Coombe. It was only one of the Grads that had a problem- 103 db static from a 1600 X Flow Fortuntaely an additional silencer sorted it Shame about the Radical MikeW Mega Grad Race No 9 Link to comment Share on other sites More sharing options...
Rob Walker Posted February 14, 2006 Author Share Posted February 14, 2006 I must confess I am puzzled why these Duratec engines produce a lot less noise than other engines? It makes no sense the valves are bigger as are the ports ,inlet track is longer the Throttle bodies are 45mm. bigger than the K at 42 mm and with the same 90mm trumpets on the end and a foam filter it should make more noise. The only factor different is that there is no need to rev the engine as high to develop the same power . Link to comment Share on other sites More sharing options...
henry21p Posted February 14, 2006 Share Posted February 14, 2006 Looking at what happened at donny, i think the drive by tests are seriously affected by positioning of the meters and by the orientation of the induction and exhaust... the 21 i KNOW to be 101 static was ok on a 98 drive by whereas the duratecs were thrown off and the old fashioned K caterhams were fine. Only difference i can tell is that where the meter is at donny, the duratecs were blasting their exhaust note towards it rather than away from it. I would expect therefore that the meters at Cobe are on the other side and hence favour the duratec engine orientation? Or am i talking out of my cakehole? Link to comment Share on other sites More sharing options...
old captain slow Posted February 14, 2006 Share Posted February 14, 2006 Just a thought, but a half circle shield attached to the end of the exhaust so the noise tends to go down and out rather than up would probably get you past the drive by if the car is marginal. C7 CDW Link to comment Share on other sites More sharing options...
Rob Walker Posted February 14, 2006 Author Share Posted February 14, 2006 Dave 21P, Sorry to say you are talking out of your cake hole as you put . The on track monitoring at Donnington is on the pit wall at the start of the pit lane and the Duratec has its exhaust on the drivers side or off side therefore pointing away from the sensor. However the induction is pointing right at it. Combe also has its monitoring on the pit wall after Camp corner. Be interesting to see if we have a problem at Donnington, its likely that revs would be fairly low entering the pit straight and at the point of monitoring so we may get away with it. Rob Link to comment Share on other sites More sharing options...
Grubbster Posted February 14, 2006 Share Posted February 14, 2006 Rob - I found that at Donny I was just hitting the rev limiter at the noise meter so had problems (not a duratec though), after being black flagged I learned the art of shifting a few meters early and all was fine . . . . Roadsport build photo's here Le Mans 2004 photo's here Link to comment Share on other sites More sharing options...
dannylt Posted February 14, 2006 Share Posted February 14, 2006 The static noise testing at Combe seems to be the more important one I think, and it's lucky the duratec induction is on the "right" side. Rob - there are several mikes at Donny, not just on the pit gantry - but short shifting there will help. I'll be amazed if you get through at Donington with the induction noise so am all ears so to say! I think an airbox will be required for Donny & Bedford. Link to comment Share on other sites More sharing options...
Jason Plato Posted February 14, 2006 Share Posted February 14, 2006 I see the old chestnut that there are mutiple meters at donny is up again . There is only one meter at Donny - on the pit straight . My guess is that we are doing the revlimier in 4th at the noise meter @ 100mph ? I can only guess that the inlet noise of the duratec is a lower frequency given its greater cubic capacity of the cylinders ? - realy a guess but its all I can come up with for a reason ...... Link to comment Share on other sites More sharing options...
Grubbster Posted February 14, 2006 Share Posted February 14, 2006 Dave 😬 Certainly wasn't at the limiter in 4th by the meter in my humble Roadsport - you might be! And yes, I agree only one permanent mic for noise testing at Donny - there may be some mobile kit on certain days but I have never managed to get confirmation of this from my man on the inside. Roadsport build photo's here Le Mans 2004 photo's here Link to comment Share on other sites More sharing options...
old captain slow Posted February 14, 2006 Share Posted February 14, 2006 At Combe, the drive by is done on an ad hoc basis from the pit wall as the cars accelerate out of Camp. They will pull you if its over 100dBA. They use the same noise meter as for the static test IIRC. C7 CDW Edited by - David W on 14 Feb 2006 12:58:46 Link to comment Share on other sites More sharing options...
Rob Walker Posted February 14, 2006 Author Share Posted February 14, 2006 David W. I must put you right. The on track monitoring is not done ad hoc and with the same noise meter as the static. There is a fixed transducer on the pit wall and results are recorded and sent to the local council. After recently loosing their license to run F3 they have to take the noise emissions seriously. rob Link to comment Share on other sites More sharing options...
old captain slow Posted February 14, 2006 Share Posted February 14, 2006 Ah! A recent change then. They used to just hang the meter over the wall. C7 CDW Link to comment Share on other sites More sharing options...
Griff Posted February 15, 2006 Share Posted February 15, 2006 At Castle Combe the drive by test is just by the bridge at the pit exit just when you're flat to the floor. K & Duratec are usually OK as induction is towards the infield so it only picks up noisy silencers. Other circuits with offside noise meters (Bedford!!) will get you. Only time I failed at Castle Combe was when the silencer needed a re-pack. Noise police there are a helpful bunch who far prefer you to be on the circuit than off. I'm modifying the induction presently and they offered to do some before/after comparative static tests. Biggest problem at Castle Combe (village) is the retired locals and their lawnmowers - was told the council couldn't take circuit readings in the village during the summer because of the cacophony of mowers which were off the meter's scale 😳 I think the same people buy homes at the end of airport runways and complain about the din. It's not pink, it's medium red violet...! Link to comment Share on other sites More sharing options...
Rob Walker Posted February 15, 2006 Author Share Posted February 15, 2006 Griff the duratec induction is on the other side of the car to the K. Link to comment Share on other sites More sharing options...
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