Lexurf VIII

[Balllsy]

Looks great as per... can't wait til it's ready for the test run

[Growler]

That is looking just gorgeous Vince

[yoshie]

Class again Vince.
I love seeing these lumps on the floor, I would like to photoshop a picture of them all lined up.

[si tate]

Is it me or are you transforming these lexurfs alot quicker "now that your a dab hand at it"

[flounderbout]

Is it me or are you transforming these lexurfs alot quicker "now that your a dab hand at it"

I was wondering that. Looking epic as ever Vince - nice one yet again!

[legendgamesmaster]

All blue, now with new plugs and leads and some polished bits...

trouble with ALL these lexurfs is that you lot now need clear Perspex bonets to show em off!!!

[Paul1566]

cured with blowtorch


I did the wifes exhaust down pipes on her motorbike with that stuff and i must say its lasted well, little dull right against the clamp, but the rest is fine.

[Kwakka666]

I got to see the (near) finished product yesterday...
Baz you won't be disappointed!

[Bazcam]

Hey Vince, I see the down pipes from the manifolds start off in 2 1/2"
and then reduce to 2". Is there any paticular reason for this?
Does the V8 like a bit of back pressure?

I ask because a local custom exhaust place has given me a very good price
on a 2 1/2" stainless system.

[BUSHWHACKER]

Hey Vince, I see the down pipes from the manifolds start off in 2 1/2"
and then reduce to 2". Is there any paticular reason for this?
Does the V8 like a bit of back pressure?

I ask because a local custom exhaust place has given me a very good price
on a 2 1/2" stainless system.

The idea is to give the restrictive manifolds something to dump into as that was the I.D. of the deleted Cats. It then steps down to 2" as thats what the factory exhaust size is.

2.5" will be fine, but ask then to install an 'X' pipe as close to the downpipes as possible, or 'two 'Y' pipes, so that the downpipes merge into a single 2.5" pipe then split into two again at the back.

By merging the two banks of cylinders smooths out the exhaust flow and gives a little more power at the same time reducing the noise level at high RPMs.

The V8 doesn't need any back pressure.

[Bazcam]

Thanks for that mate, I,ll have a chat with them in the week and work
out the best way to go.

[BUSHWHACKER]

Forgot to add, don't go bigger than 2.5" or you'll lose low end torque.
I went for 3" on mine from the downpipes all the way to the back and had to rev the engine quite high to get any oomph out of it.

I fitted 2.25" to Lexurf III and that seemed to be the optimum size for maximum torque/horsepower, I fit 2" now as it's easier/cheaper to find parts/tube.

[Wolfracer]

The V8 doesn't need any back pressure.

Forgot to add, don't go bigger than 2.5" or you'll lose low end torque.
I went for 3" on mine from the downpipes all the way to the back and had to rev the engine quite high to get any oomph out of it.

I fitted 2.25" to Lexurf III and that seemed to be the optimum size for maximum torque/horsepower, I fit 2" now as it's easier/cheaper to find parts/tube.

Excuse my ignorance, but why would a more free flowing system decrease torque/hp output if the engine doesn't need back pressure?

And if "open headers" are the optimum for V8's then why would a larger than standard exhaust system be detrimental?

Or is it because you would you need to alter the tune for the larger pipes?

[BUSHWHACKER]

It's all to do with Scavenging, Harmonics and Energy waves.
Inertial scavenging and wave scavenging are different phenomena but both
impact exhaust system efficiency and affect one another. Scavenging is simply gas extraction. These two scavenging effects are directly influenced by pipe diameter, length, shape and the thermal properties of the pipe material (stainless, mild steel, thermal coatings, etc.). When the exhaust valve opens, two things immediately happen. An energy wave, or pulse, is created from the rapidly expanding combustion gases. The wave enters the exhaust pipe traveling outward at a nominal speed of 1,300 - 1,700 feet per second (this speed varies depending on engine design, modifications, etc., and is therefore stated as a "nominal" velocity). This wave is pure energy, similar to a shock wave from an explosion. Simultaneous with the energy wave, the spent combustion gases also enter the exhaust pipe and travel outward more slowly at 150 - 300 feet per second nominal (maximum power is usually made with gas velocities between 240 and 300 feet per second). Since the energy wave is moving about 5 times faster than the exhaust gases, it will get where it is going faster than the gases. When the outbound energy wave encounters a lower pressure area such as a second or larger diameter section of pipe, the muffler or the ambient atmosphere, a reversion wave (a reversed or mirrored wave) is reflected back toward the exhaust valve without significant loss of velocity.

[Wolfracer]

Hmmm, think I've read that before somewhere....

Nice to see you've changed you viewpoint on H/X/kiss pipes now!