23 replies to this topic

[greggy50]

Hello

Currently I have a 3" Play Mini Duel Exit Exhaust fitted to my 998 Mini

 

However I am pretty sure it is loosing me a lot of power as I believe it is 3" system all the way through? And I heard that 1.75" is what you should have?

 

I wondered whether if would be possible to purchase a better manifold and then 1.75" link pipe and just keep the backbox at all as believe I would recoup most of the lost power then? And if so what would I need to buy?

 

This is my system it is stainless steel all the way to the manifold

 

 

 

[Alex_B]

I think it is actually better to keep the exhaust diameter the same from the manifold to the exhaust tip, 


The system you have is far from efficient, especially as its twin 3" exit, and changing the system up until the backbox would be a little bit pointless as that backbox is the worst part of the system so either swap the whole system for performance or just be happy with the sound and not worry too much about the hp youre loosing :) 

[Cooperman]

Sorry, but that is just about the worst system you could have on a 998.

For a 998 revving to up to around 6500 rpm the ideal system is a 1.625" internal diameter system, this diameter to be constant from the end of the ex. manifold to the final exit point.

Only then will the exhaust system be efficient.

[Anthony30]

Maniflow 1.75'' twin box side exit, with cooper freeflow manifold. IMO.

[greggy50]

How much power would people say this system is loosing me?

 

As will help me decide whether to ditch it or keep it...

 

Thanks

[KernowCooper]

Maniflow 1.75'' twin box side exit, with cooper freeflow manifold. IMO.

Better than whats on there now, maniflow dont make a 1.625 system and the 1.3/4 being their smallest

[HarrysMini]

How much power would people say this system is loosing me?

 

As will help me decide whether to ditch it or keep it...

 

Thanks

A noticeable amount, I don't know for sure an exact figure, but I would have thought around 7hp.

[greggy50]

 

How much power would people say this system is loosing me?

 

As will help me decide whether to ditch it or keep it...

 

Thanks

A noticeable amount, I don't know for sure an exact figure, but I would have thought around 7hp.

 

 

Okay well if it was over 3/4 would consider changing as probably a good 10% on this engine

 

I would quite like a system that has like a twin exit in the middle can you get that in a 1.75" size?

 

Thanks

[Alex_B]

The closest would probably be the Miglia style exhaust which is a central twin exit but still a bit big for overall power :) 

[cradley-heathen]

im certainly not aware of a centre exit exhaust that has a sensible bore size but with two tailpipes.

 

its a case of function, or style really im affraid (assuming your into the monster exhaust thing)

 

ok, im going to say, its mean, but i feel i must...... the existing exhaust looks really silly, and i bet its really loud too. please take it off! lol

[greggy50]

Actually quite like the look of this one

 

http://www.maniflow....58&product=1181

 

Presume this would be a lot better?

 

And exhaust was on when I purchased the car not my choice! Was 16 at the time but to be honest is too bloody loud now!

[Cooperman]

It's the twin exit which causes the problem. If you want a twin exit on a 998 the diameter of each final exit pipe should be about 1.2".

For optimum efficiency it is vital that the final exit is the same cross-sectional area as the rest of the pipe from the end of the ex. manifold in order to keep the molecular velocity of the exhaust gas the same at the exit as at the end of the ex. manifold. If the final exit is larger, the velocity is reduced and the pressure increased. Think of a hose pipe and think what would happen if the very end was made a larger diameter. The water would not exit efficiently or cleanly. It is basic physics.

 

I am surprised at Maniflow selling that final exit box. It is vital that the final exit cross sectional area is the same as the main pipe. The science is called 'Bernoulli's Theorem' - check it out if you wish.

Edited by Cooperman, 06 March 2014 - 12:03 AM.

[cradley-heathen]

sorry mate didnt intend to be harsh! its just massive lol!

 

youll find it will drive much better with something like an rc40 or maniflow equivelent on it. and because its not going to be so loud you wont mind getting your toe down a bit more!

[greggy50]

Okay the one I linked is a 

1 3/4" BOXTER SINGLE BOX CENTRE EXIT EXHAUST SYSTEM (LS01B/B)

I understand this may not be perfect but it must still be a lot better than the huge twin 3" thing I currently have fitted whilst still having a bit of noise to it?

 

Also what else would I need presume a new manifold as well 

 

But will I need a new downpipe or is that part of a system like the one I linked

[greggy50]

sorry mate didnt intend to be harsh! its just massive lol!

 

youll find it will drive much better with something like an rc40 or maniflow equivelent on it. and because its not going to be so loud you wont mind getting your toe down a bit more!

 

Its okay current  I agree the exhaust is too big!

 

It sounds really nice revving it stationary (I think) but after about 5 minutes on the road you just have a headache

 

I had a graduate meeting I was running late for a couple of weeks ago so had to go about 75 (normally sit at 55 on mway) and the noise really was unbearable had a terrible headache upon arrival!