7 replies to this topic

[blister]

Model:City
Year:B
Description of problem (please be as in depth as possible):
no problems at all just want to no what will be best


Any non-standard parts that might be involved with the problem?
maniflow exhaust system
race clutch

i want to increase the performance of my mini by changing the cam shaft and the carb

i already have a bp255 camshaft and i was after putting on a webber DCOE twin choke 40 with swan neck manifold and short ram pipes

so first question is what performance increase would i get from standard 998 - to 998 with maniflow system 40 webber and bp255 cam

i know that a 40 is not the best idea but i will also be doing more engine modifications such as head work and flat top pistons etc.

next question is what is best upgrade after this step when all carb and cam are on.

[mike.]

You'll get more by installing a cooper head/stage 3 head than just a weber and you won't get much more by installing a weber over an SU. You might get 5-6bhp right at the top of the rev range with a weber but not much else. Also webers are a pain in the arse to set up!

Also I'm not sure how well the swan neck manifolds flow - It might defeat the object of fitting a weber in the first place.

Bare in mind that really you'll need to take the engine out to fit the new cam whereas you won't with a head/carb so it might be an idea to get that put in first. This is assuming your slowly modding the engine as you get the parts - If your putting them all on in one go then it doesn't matter.

Once you've done head, cam and carb, i'd go for a lightened flywheel assembly or if you've got the cash rebuilding the engine with lightened and balanced internals will help the engine rev higher and accelerate quicker but it'll cost alot. If your doing that much work then you may aswell get it bored out with new pistons...

Edited by minimadmike, 25 November 2008 - 12:25 PM.

[blister]

i understand where you are coming from but i dont think i would use a cooper s head i would prefer using a 1275 head and getting it machined to fit at a later date.

so you recone i will only get 6 bhp on my engine extra by just putting the webber on what about the cam? and the exhaust etc?

[mike.]

The cam and head will make most of the difference. Not sure how much extra though.

By the way its the block that needs machining to acceptthe 1275 head not the other way round.

and yeah you won't get much more by fitting a weber, you'll only get a small amount of power right at the top of the rev range because webers can flow more air than an SU.

[blister]

oh sorry i meant block work not head work

[blister]

oh and minimadmike your car looks lke mine lol just different colours

[Ouster]

A decent head and exhaust system, set up on the rollers, will work wonders. HIF38 is all you need carb wise unless you're spending thousands on a fire breathing, track-day-only engine.

[blister]

going twin su's now sorry about all that

last time i tried to put twin carbs on my mini the manifold was sitting on the top of the exhausts does anyone know why this is?