Series 3 Exhaust system improvements

In my life Before land rover, I improved performance with better exhaust systems- Now I was thinking how "farty" my 109 sounds on its stainless system- rather like the original Morris Minor systems- which were constrictive. In the past I have resorted to going to a maker and asking for a standard system to be made slightly larger and it works well.
Has anyone else worked on exhausts or improved matters by say- putting a 110 system on a 109?
Ideas on a postcard please!

The Steve Parker system are bigger bore than the standard ones. No idea what it does for performance though.

I once got 42mph out of a 3 by taking the manifold off completely.

Hmmmmmm.

There's a correlation between the size of the exhaust bore and the engine valves. If you increase the exhaust bore it's simply a boy racer effect. More noise and less power.

What is the correlation? is there a design process we can follow?
C

It's more complicated than just bore size due to the fact that exhaust is not a flow but a series of pulses. So exhausts are designed so that bore restrictions reflect pressure that are timed to arrive at the valve at the right time to improve scavenging. But that only works at specific revs and at other Rev ranges can actually make it worse (megaphonitis). This is why cam timing is linked to exhaust design.

Having said that, I've no idea whether that's ever been applied to older landrover engines.

Bobsticle said:

I once got 42mph out of a 3 by taking the manifold off completely.

Click to expand...

No
I thought it was not possible to breath in a series at over 35 MPH

John S said:

There's a correlation between the size of the exhaust bore and the engine valves. If you increase the exhaust bore it's simply a boy racer effect. More noise and less power.

Click to expand...

true in theory but when it came to the 2.5 lr just fitted a wider bore

SpringDon said:

The Steve Parker system are bigger bore than the standard ones. No idea what it does for performance though.

Click to expand...

On my 2.25 with 2.5 manifold and the parker exhaust worked well...for a while. Well made and a lot heavier than normal. I couldn't swear that it was any quicker but sounded nicer and quieter, for a while. Then when changing gear on the motorway it let out a pop and has sounded like a wet fart ever since. I suspect the stuffing has shifted in the back box somehow, its certainly not leaking. Well made exhaust but very pricey for what has turned out to last less time than the last Britpart effort! Next time round I will be looking to adapt a later defender exhaust.

The Rimmer Bros stainless thing got chucked in the corner after two days as it was just ridiculously noisy, a horribly brassy racket.

Fatter pipes don't have to mean noisier, a decent baffle and they can sound nicer, as the SP one did for the first couple of months.

D

raywin said:

No
I thought it was not possible to breath in a series at over 35 MPH

Click to expand...

Ok, Ok. It might have been 35 but it sounded like 42

Bobsticle said:

Ok, Ok. It might have been 35 but it sounded like 42

Click to expand...

In my TD5 35 sounds like Mach 2, but not grumbling happy that its moving.

ACR do performance parts

http://www.automotivecomp.com/prices/#performance-parts

Some interesting thoughts here- We all know the accepted wisdom or practice is to increase the inlet valves and tract- but we rather expect the exhaust to look after itself. I hear what is said about tuning and negative pressure wave but in the absence of real data it is hard to plan these things. Certainly the first expansion chamber is critical in a tuned system but from the noises my vehicle makes - something is amiss.

Someone must know more about this?

But Who? I didn't know the 2.5 had a bigger bore. I have a 2.8 on I think a standard 2.25 bore- hence Farty Trumpetting!

Just found an exhaust place in Redditch- might pop over.

Hello , sometimes ago i 've rebuild the exhaust line of my 88" . The original sistem is ok for 70bhp but with some upgrades i see it like a trap for horsepower and a cause of overheating .
The extractors are from Ashley exhaust (they did not fit at all , i must cut and weld)
The pipes are 53mm internal bore , the absorption silencers from WV golf II 1800 16v , the "umbrella handle" from diabolic tweeks lol
My goal was mostly down torque . Goal scored . At 1000 rpm in low range it purrs like a big cat and if you press the right foot ^ ^ she is pretty alive
Pictures time :

That looks just like what is needed!

Do you get any bother with the carb freezing/taking ages to come out of choke after getting rid of the exhaust manifold heat-up?