129 replies to this topic

[Noah]

My Gawd, there are some serious power-sapping noise-boosting exhausts on here .
My son works in F1 design and apparently they are concerned that the noise takes power from the engine and they are now doing 'acoustic engineering' to try to improve the power by better 'noise management'. That is in addition to optimising the exhaust gas flow velocity at the peak revs by having the pipe size exactly correct. They are losing a bit of power due to the exhaust now blowing over the rear aerofoil to get a bit of extra down-force which screws up the pipe exit a bit, but the downforce they gain outweighs the slight power loss.

Yeah but my Mini's not a F1 Car

[Cooperman]

My Gawd, there are some serious power-sapping noise-boosting exhausts on here .
My son works in F1 design and apparently they are concerned that the noise takes power from the engine and they are now doing 'acoustic engineering' to try to improve the power by better 'noise management'. That is in addition to optimising the exhaust gas flow velocity at the peak revs by having the pipe size exactly correct. They are losing a bit of power due to the exhaust now blowing over the rear aerofoil to get a bit of extra down-force which screws up the pipe exit a bit, but the downforce they gain outweighs the slight power loss.

Yeah but my Mini's not a F1 Car

As was trying to say. If someone is into getting the best performance out of their Mini, or any other car really, they will go for parts which optimise the power and give best acceleration or best top speed, or best lap times, etc.
If noise and perceived appearance is more important, then each to his/her own. I'm an engineer, so I guess that anything which detracts from the efficiency of the engine is strange to me, but obviously not to others. What I can never understand is when someone on here asks meaningful questions about heads, best valve sizes, carb set-ups, light fly-wheels, cam timing and so on in the quest for better power, then fits a totally inefficient exhaust which loses a good percentage of the gains for which hard cash has been spent. I'm sure there must be an explanation, but I just can't see what it is. Even going back to my first Mini, when I was about 21, I still tried to make it as efficient and powerful as I could without it being noisy.

[Midas Mk1]

Its not all about "maximum power', its also about the aesthetic, tone etc....

The majority of us have road cars, which WE drive on the roads, therefore how loud or what tone our exhaust makes is up to us. If it loses 1-2hp so what, my rc40 is never going to replace my Playmini / minex setup.

I mean, you could say the same about colour schemes, as a designer, it baffles me why people choose red and white..... but then, I don't constantly moan about it.

Oops, sorry I forgot this was a picture resource , not moan about performance thread....

[PaddyShepherd]

Isn't this getting a little off topic?

[Noah]

Honestly, its different peoples preferences. Getting the right exhaust note from a car is a big part of it for me, that is probably from my musical stuff, I spend hours setting up my guitars to sound just right, I love the way the exhaust on My Mini sounds and to be honest I wouldn't change it.

My car will never be a rally car (though the previous owner was building into one), it will never be a drag racer. But it will always, in my owner ship be a road car, a point at which the fastest it will go is 70mph, he says distinctly lying through his teeth.

Now I agree with you on losing power and all of that but, for me those few BHP that I loose are made up for in Smiles Per Gallon. You don't have to be going fast to have fun.

[scotty_1987]

my custom "bozo" pipe



Nathan

[PaddyShepherd]

my custom "bozo" pipe



Nathan

One thing i've always wondered, does water not get into these pipes easily when parked/driving in the rain? or even when washing the car?

[Cooperman]

I thought there was a ' re-inforcing skid' under the rear box, but it's a bicycle wheel in the background. Doh!!

[JustSteve]

My Gawd, there are some serious power-sapping noise-boosting exhausts on here .
My son works in F1 design and apparently they are concerned that the noise takes power from the engine and they are now doing 'acoustic engineering' to try to improve the power by better 'noise management'. That is in addition to optimising the exhaust gas flow velocity at the peak revs by having the pipe size exactly correct. They are losing a bit of power due to the exhaust now blowing over the rear aerofoil to get a bit of extra down-force which screws up the pipe exit a bit, but the downforce they gain outweighs the slight power loss.

Cooperman, the noisiest car I have ever heard has got to be the V12 Lotus type102... and that was about the fastest thing I've ever seen too

It's not a beautiful sound like the 101 made though. The 102 may be much faster, but I'd take the 101 any day.. just to listen to


poor video, but here we go..

[scotty_1987]

my custom "bozo" pipe



Nathan

One thing i've always wondered, does water not get into these pipes easily when parked/driving in the rain? or even when washing the car?

Yeah its a pain in the rear but it does sorta get blown out when you rev it!! haha
also cooperman i dont plan on drifting it haha...it is quite confusing though looking at it now that you mention it :)

[joewf10]

heres mine :) still in restoration not far left now though hopefully Twin exit







Sorry for the large picstures. ive tilted the pipes so they point up a little instead of straight out, can see on the angled picture

[PaddyShepherd]

my custom "bozo" pipe



Nathan

One thing i've always wondered, does water not get into these pipes easily when parked/driving in the rain? or even when washing the car?

Yeah its a pain in the rear but it does sorta get blown out when you rev it!! haha
also cooperman i dont plan on drifting it haha...it is quite confusing though looking at it now that you mention it :)

Maybe you could mitre it to reduce it? so that the face is vertical as normal but the pipe isn't?

[hobnob888]

I thought there was a ' re-inforcing skid' under the rear box, but it's a bicycle wheel in the background. Doh!!

you say that, but on my middle box i have metal plates to stop it catching as ive pulled it off twice getting it into our workshop...

[james962]

Maniflow centre exit 1.75"

[scotty_1987]

@paddy Yeah could do or I can fashion one of these covers which tractors have that pivot when you rev so that it'll open and close :)!! I'll have to do something though as it rains a lot here

Nathan