12 replies to this topic

[montyc]

Hi guys,

I know there are lots of questioms on this already and have had a good trawl through but still have some questions.

I have a '89 998 mini city standard engine as far as i know apart from a drilled airbox and k&n filter, and am looking to fit a stage 1 kit soon.

Looking at minispares what they have is a twin box side exit in one kit (c-stn17) and a large bore side exit single box (c-stn17b) both out of stock at the moment so will need to wait anyway.

Question is what would the difference be between the two? Am looking to get a bit more from the engine and make a better noise without it being deafening whilst in use as its my daily driver but would like it to be noticeable.

Both are in budget but would i be better off asking if they can do the normal bore but with a single box rather then double?

Sorry if the question has already been asked

Cheers

[Dusky]

You can do a normal bore with single box. But don't think it makes more BHP than a twin box. + You will have lots of more sound , then again mini's are always loud ;)

[Mighty made]

Hi

 

I think you are on the right lines, the trick is to increase the flow through the engine, with just enough back pressure

to help.

 

So you are looking for an exhaust system that has better flow characteristics than

the standard one.

 

I have a twin RC40 on,  with a freeflow manifold, new inlet, K&N in the standard box

and a modified needle to get the mixture right. A single box would be even noisier

 

On the rolling road 20% uplift from standard....

[montyc]

cool, from reading what others have put i think i'll go for the twin box rc40 from minispares with all the kit that it comes with in the set.

 

i have limited tools here, but i'm guessing itll fit on easily enough with just having the car up on ramps without taking the engine out or anything like that?

[Harrison541]

I've just swapped from a noisy single box to a quiet twin box. The twin box produces quite a breathy sound where as the single box had a definite raspy tone and more of a bassy rumble.

If it was a weekend toy and you like the noise I'd probably recommend a single box, correct diameter exhaust, however if you're using it everyday it's far nicer to have a quiet twin box. Can't really hear the exhaust sound with mine, more just engine noise and wind noise.

[montyc]

cool, its probably unachievable but ideally something which i can put up with whilst driving but which others would turn their head to look at. but from what others have put on here i think i'll be going for the twin box rather then the single, but i suppose the only way to find out is to try both which i can't fun at the moment but probably will in the future

[KernowCooper]

I had a twin box RC40 on mine and it was to quiet and to the point if you like a old Cooper S type of exhaust note you need the single box. I replaced mine with a 1.75 single side exit maniflow and its not that noisy unless you rev it a bit

[montyc]

so you would reccomend the large bore single box rather then the twin box? i suppose its difficult to say which would be too noisy in the actual car as i'm driving as all minis are different as far as soundproofing goes.

as far as i can see the only soundproofing etc that ive got is a bit of foam behind the bulkhead, but can comfortably listen to music and audio books with tiny speakers on the motorway with standard exhaust etc

[montyc]

also, why is the large bore more expensive then the twin box kit?

[Yams]

Read a few topics where some people had stated that the twin box RC40 produced about 2bhp than the single box. However 2bhp wouldn't be noticeable.

 

As to why the single box is more expensive, i'm not sure, but i use it and i think i get a far nicer exhaust note than my friends who have double box RC40s.

[timmy850]

There is the large bore single and the small bore single. If you got:

 

RC40 Small Bore Single Back Box:

http://www.minispare...c/C-STR809.aspx

And Long Pipe:

http://www.minispare...nge/AN180V.aspx

 

Is cheaper than the Large Bore Single:

http://www.minispare...e/RC40-012.aspx

And Long Pipe:

http://www.minispare...nge/AN180V.aspx

 

It is also cheaper than the twin box RC40:

http://www.minispare...isers/RC40.aspx

Short Pipe:

http://www.minispare...e/RC40-001.aspx

 

[KernowCooper]

You need to avoid the large bore systems on a 998 they will cost you bhp/torque which you dont have a lot of to start with, you can use a 1.75" single box system side outlet, but the optimum size is for a 998 is slightly smaller but I dont know anyone making a single box system for it. The 1.75" RC40 single box will work just avoid the silencers with big tail pipes that sound like a vulcan bomber

[montyc]

cool, ill wait for the twin box to come back into stock with the kit. 

 

cheers for the help