Scooby exhaust "warble"

**kenholland** · 5-31-04, 15:46

Averyone here must be aware of the very distinctive exhaust note on a Scooby. Sort of a "missed beat" type noise due to the deliberate missmatched exhaust header lengths built-in to the design.

Well, since I've had the KLZE fitted I've noticed much the same sort of effect with my MX6! Not only has the exhaust note deepened quite a bit, it definitely warbles on acceleration...

When we fitted the new engine we had to replace the J-Spec rear exhaust manifold because 2 of the studs had sheared off. We used the UK one and Kyle manufactured a plug for it to block up the EGR port. (He actually welded a plug into the end of an EGR screw.)

I suppose that, in some small way, the difference is just enough to put the exhaust "out of phase" and produce the Scooby effect...

Just thought I'd share - I'll get me coat.

Ken

pete7 · 5-31-04, 16:11

are you sure you aint got a missfire!!!

( grabs his coat too! )

**kenholland** · 5-31-04, 16:36

If I have it only appears when I accelerate Pete - no sign at tickover or normal running. And it sure pulls like hell...

**JAP MX** · 5-31-04, 16:40

I love that sound.
Whos nicked me coat?

Jay

**Ian F Chequer** · 5-31-04, 16:55

The Subaru engine is a flat four and each pair of pistons fires at the same time so they "punch" into the crankshaft together.

So you get half the number of exhaust pulses per revolution of the crankshaft as with a straight four engine, and a very uneven exhaust note.

Careful planning of the exhaust manifold can allow existing exhaust pulses to "help" each other and aid exhaust flow and this might result in odd warbling effects.

regards,

Ian Chequer

**cruisemad** · 5-31-04, 18:49

Mine does as well so dont worry about it.

The ports are different and allow more fuel and air in hence the 200 bhp and is why the sound so different.

Kyle

**kenholland** · 6-1-04, 1:50

Don't get me wrong Kyle, I wasn't worrying about it at all.
I love the new sound...

Ken

**Russellg** · 6-1-04, 13:43

Sounds like a new breed of 6 to me...
The all new "Scooby 6"

Glad you like the sound though... I just hope it isn't as loud as most Scooby's.
One of my mates has a Scooby with the rediculously large zorst on the back...
Lets just say he don't use the radio.

**kenholland** · 6-1-04, 14:08

Quote:

Originally Posted by Russellg

Lets just say he don't use the radio.

I didn't for the first few months of Powerflow ownership either.
The first month was 'cos I couldn't hear the damn thing though...

Now I've got a new note, the radio is off again.

Ken