This may be a daft question , but it's something that has been bugging me for some time .
We all know certain engines have a distinctive `sound' - Stratos , BDA , 6R4 , to name a few - but , what is that makes a 6R4 sound like nothing else on earth ?
I think I have most of the right bits - 2.5 V6 , quad cams , 24 valve , lots of revs , short open exhausts , but mine sounds very different.......?

I'm guessing some induction noise? Plus maybe the way the gas flows out of the head and through the manifold.

Didn't toyota as good as copy the BDA head for the 4A-GE series of engines which is why they sound almost the same as one? Lending credence to the theory above, that it's down to port shape/induction noise.

Cams ?

Your cams will surely be very mild in comparison.
Engines with wild cams always sound sharper when in the meaty bit of the power.
An acquaintance of mine used to have a car with a steel xflow which was full race spec ( Phantom P75 - click here ) and it sounded absolutely unlike any xflow I have ever heard.
Your engine does pull from zero revs though, so the cams must surely be very 'soft'.

Short/long stroke and firing order will make a big difference to sound.

ATB

Simon

the angle of the V, the firing order, cams and timing will all make a huge difference

the 6R4 has a 90 deg block and firing order is 1-6-3-5-2-4

1-2-3 <-(cyl #'s)
4-5-6

were as your's is a 60 deg V6 (don't know your firing order)



[Edited on 21/2/10 by mcerd1]

Lots of compression can change the sound of an engine. We used to build 305 cu in Chevys for Formula 5000 with 180 degree cranks, ran like two four cylinder engines tied together, sounded like a Ferrari.

IIRC the 6R4 was a 270° motor which gives it the offbeat, lower frequency noise. Which was nice...

I don't know if this is the case, but using 2 sidepipes is a 2 * 3 cilinder sound?