jc Posted March 19, 2002 Share Posted March 19, 2002 Why do V6 and v8 engines sound the way they do? As they always have a different sound from 4 cylinders and the like... Link to comment Share on other sites More sharing options...
mav Posted March 19, 2002 Share Posted March 19, 2002 'Cos there is more? The 3 cyl. engine in the Vauxhal agilla sounds reminisent of a far away v6!!! Link to comment Share on other sites More sharing options...
Blatman Posted March 19, 2002 Share Posted March 19, 2002 And the flat plane TVR V8 sounds just like a 4 banger........ I think the noise is all to do with firing order/number of combustion strokes per 4 revs or something............ Where's Peter C when you need himquestion.gif Link to comment Share on other sites More sharing options...
John Hughes Posted March 19, 2002 Share Posted March 19, 2002 But nothing sounds better than a V16 BRM running on all 16 @ 10k rpm !!! John Link to comment Share on other sites More sharing options...
Morls Posted March 19, 2002 Share Posted March 19, 2002 Think of it like a drumming beat, but superimposed over 720 degrees of crank rotation rather than a bar of music. Usually the spacings between the big ends (as an angle) determine the gap between each "Bang". A (45 degree V twin) Harley has one of the most distinctive noises, the "Potato...Potato" sound being due to a big gap with no noise (675Degrees I think) followed by two Bangs within 45 degrees. The big gap between power pulses helps the back tyre regain traction between bangs which has made such an unlikely racer still competetive in a sport where traction is everything (US Flat track). Bang.Bang.........................Bang.Bang................... The four cylinder engines most of us use have equally spaced firing which gives a smooth (four beats to the bar) sound. Bang...Bang...Bang...Bang...Bang...Bang...Bang...Bang... A 45 degree V8 has a combination of the above with two drummers doing four beats to the bar but 45 degrees apart (or 45/720 of a bar out of time). And is ,of course, music to our ears.smile.gif On bikes, where traction is so critical given the tiny rear contact patch, "Big Bang engines" have dominated two stroke 500GP racing since 1990ish. The engineers found that by timing the sparks so all four power strokes happen within 90 degrees the big time without force to the rear tyre helped conserve tyres and made it simpler to control traction. They got the power of a four with the tyre friendly pulses of a twin. These sound very oddconfused.gif Mark Link to comment Share on other sites More sharing options...
EFA Posted March 19, 2002 Share Posted March 19, 2002 Blatman, The flat plane TVR V8 does not sound just like a 4 banger as the heads are set a different angles. Fat Arn This is a Testid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
Violet Elizabeth Posted March 20, 2002 Share Posted March 20, 2002 Not forgetting to sound of the 5 cylinder Audi Quattro, all sort of off-beat but quite nice with it. Link to comment Share on other sites More sharing options...
EFA Posted March 20, 2002 Share Posted March 20, 2002 Or a Fiat Coupe?? Fat Arn This is a Testid=red> See the Lotus Seven Club 4 Counties Area Website hereid=green> Link to comment Share on other sites More sharing options...
sjwb Posted March 20, 2002 Share Posted March 20, 2002 Absolutely rightthumbsup.gif The flat TVR sounds bloody awfulbiggrin.gif Even worse when you drive one. Now, listen to a 427 hemi and you are talking (watched Bullitt the other night)cool.gif Steve B Link to comment Share on other sites More sharing options...
yankeedoodoo Posted March 20, 2002 Share Posted March 20, 2002 And the F1 Matra 12 cylinder motors of 30 years ago could sing! Link to comment Share on other sites More sharing options...
Simon Dart Posted March 20, 2002 Share Posted March 20, 2002 Its all maths! A car is a musical instrument. Most piched sounds are made of fundamentals(the root frequency)and harmonics which are related to the fundamental in a regular mathmatical series stretching upward in frequency. I belive an engine will produce a fundamental determined by its RPM and the number of firings per rev. The firing order and number of cylinders produce repeatable intermodulation of the fundamental, producing a characteristic pattern of harmonics, hence Fours, V6's have similar characters. The combustion pressure pulses, coming from the cylinders also interact with the cylinder volume, the exhaust and any other volumes they may be connected to. This produces a further large variation in the spectrum of harmonics which lend character to sound, which is why engines, even of similar configuration all sound different. Formula One teams record eachother's engine notes and work out what they can rev to by working out the fundamental of the engine note. Link to comment Share on other sites More sharing options...
elie boone Posted March 20, 2002 Share Posted March 20, 2002 sjwb, The Hemi is 426 cid and the finest from uncle sam. The BRM H16 must have sounded magical if it did'nt exploded. Link to comment Share on other sites More sharing options...
sjwb Posted March 21, 2002 Share Posted March 21, 2002 Elie, Absolutely correctblush.gif, I was confusing the other (nominal) 7 liter of the time - the Ford as in Mustang and Cobra. 426 cid = 6980.889 cc 427 cid = 6997.276 cc BRMquestion.gif Have you heard the Into The Red CD which accompanies the book of the same name? I play it in the workshop (flat out) teeth.gif. Neighbours look very worriedconfused.gif Steve B Link to comment Share on other sites More sharing options...
Andrew Russell Posted March 21, 2002 Share Posted March 21, 2002 SJWB The BRM on that cd is the V16 rather than the H16, but both sound even better in the flesh!!!!!!!!!! Sometimes being of a certain age does have benefits as I been around long enough to hear both in their hey-day, although the V16 was being driven by J.Y.Stewart rather than by Gonzalez! But then, come to that I saw Gonzalez drive the V16 at Goodwood a few years back but that doesn't count, does it? Andrew Link to comment Share on other sites More sharing options...
elie boone Posted March 21, 2002 Share Posted March 21, 2002 sjwb, Hemi is a Mopar engine ( Chrysler and has the same mytical status as the BD engine made by Ford ), i know that the sound from the "bullit" Mustang was from a GT40 but i am not sure. Edited by - elie boone on 21 Mar 2002 18:47:45 Link to comment Share on other sites More sharing options...
Chelspeed Posted March 23, 2002 Share Posted March 23, 2002 Another odd sounding engine is the Scoobie doo impreza. A flat four engine but with the turbo on one side. The primary pipes from the drivers side are short but those from the passenger side are much longer. Apparently at certain revs the pulses all arrive at the turbo together leading to a very odd flat sounding engine. Doesn't seem to affect it though, it still goes bl**dy quick. Link to comment Share on other sites More sharing options...
sjwb Posted March 24, 2002 Share Posted March 24, 2002 Elie, I was in fact refering to the Dodge Charger cool.gif wot the baddies drove for the sound, even though I got the displacement wrongblush.gif. I reckon the hemi was more mellifluous. And yes, you are correct about the GT40 bit. Here's one for you old ones - Triumph Daytona Three, as in Mike Hailwood (memorial run today), Percy Tait etc. Steve B Link to comment Share on other sites More sharing options...
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