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2x 1 1/4" su's on standard 998 too big???
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Author:  bigfella [ Wed Oct 13, 2004 10:07 pm ]
Post subject:  2x 1 1/4" su's on standard 998 too big???
picked up a set of twin 1 1/4 su's just asking the guru's if this would be too big for a stock 998 (with extractors only) obviously with a jet change????

im new to carbs, brought up on efi :)
cheers for the help
cam
Author:  Mini Mad [ Wed Oct 13, 2004 10:10 pm ]
Post subject: 
I wouldn't think so, they ran twins on 998 coopers, so can't see why not.
Author:  drmini in aust [ Wed Oct 13, 2004 10:30 pm ]
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It'll be OK- they were fitted to many 850s too (Sports 850, and aftermarket kits). :wink:
Author:  998_Clubman [ Thu Oct 14, 2004 11:40 pm ]
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i had twins on my 998, had extractors and a bit of a pipe, ran a lot better with them on, drank a bit more motion potion i think, but well worth it..

id think they'd be safe :wink:
Author:  TheMiniMan [ Fri Oct 15, 2004 10:43 am ]
Post subject: 
No problem what so ever,,,easy-peasy

Just everyone have a little think here for a minute,,,(i know it might give you all a head ache, but bear with me 4 a min) :-)

when one piston from an engine sees --->(sucks through) a carby hole,,,lets say a single 1&1/4su for this example,,, that means that they all have to suck through that same carby,,,a single 1&1/4 right?????????????

well,,,now lets put a set of twin 1&1/4 SUs on then,,,,each piston is still only sees (sucks trough) a single 1&1/4 SU hey???

the difference being a much straighter un-interupted manifold flow.

simple as that.!!!!!!!

that balance tube/pipe on the twin manifolds is simply that, a balance tube,,,very little (if any at all) extra air/fuel mixture is able to move through that tube with any given response to actually creat more air avaliable to any particular cyl in such a short time that it has per stroke.

The handsom little 998 engine came out with a single 1&1/2 SU fitted to the later leyland minis right?????????,,,so there`s absolutely no reason why it can`t run quite happilly with a pair of 1&1/2 SUs hey??? & they do so quite admirably i might add :-)

so,,,remember what i said here when this topic arises in the pub again ok???


there`s no more "extra" comming from twins as there is from a single,,,just the manifold is way way way better.
Author:  Anto [ Fri Oct 15, 2004 10:46 am ]
Post subject: 
Yes that is all well and good, but when your at the pub, you earn so much more respect using the buzz words 'twin carb'. Just the same as how a Weber is a sidedraught carb and is hence better than an SU..... :lol:

I'd personally always go with the bigger single SU because it's easier to tune. But then, I always go with the theory that if you want economy, go a single SU, and if you want power, go a Weber/Dell'orto. But that would just be my opinion :wink:

Cheers,
Anto.
Author:  J_A_M [ Fri Oct 15, 2004 11:11 am ]
Post subject: 
Good and valid points from Matt and Anto..... 8)

It made interesting reading....
Author:  drmini in aust [ Fri Oct 15, 2004 11:52 am ]
Post subject: 
If you want to make the twin HS4s or 2s go properly, Vizard reckons the BMC manifolds need a bit of a tickle inside. Put a nice radius in the top of the port on the engine side of the balance pipe. It is bloody sharp there normally.

I've always wondered how twin SUs would go if I filled the dirty big balance pipe with epoxy, or a plastic tube, with a smaller hole down it.
Wouldn't be hard to do.

The Maniflow one which is now supposed to be the best (according to KC) has only what looks like a 1/4" balance pipe there. 8)
Author:  J_A_M [ Fri Oct 15, 2004 12:36 pm ]
Post subject: 
Kev I can't wait to pick your brain when I am building my new motor.... :D ..and the time is rapidly approaching!
Author:  zippytheclown [ Fri Oct 15, 2004 3:03 pm ]
Post subject: 
Anto wrote:
Yes that is all well and good, but when your at the pub, you earn so much more respect using the buzz words 'twin carb'. Just the same as how a Weber is a sidedraught carb and is hence better than an SU..... :lol:

Cheers,
Anto.
Author:  zippytheclown [ Fri Oct 15, 2004 3:06 pm ]
Post subject: 
oops. wrong button. Every time I tell someone I have a mini, the first thing they ask is 'does it have twin carbs?', even non mini people. If you were to say something like 'nah, it's got a weber' they would go 'ooh aah'. It's like verbal 'bling'
Author:  TheMiniMan [ Sat Oct 16, 2004 9:18 am ]
Post subject: 
Image

oops ,,,how did that get there

:-)

not much out there like this tho hey?

a nice big single 2",,,,

but i try to tell everyone that it`s 8inches
Author:  min13k [ Sat Oct 16, 2004 9:51 am ]
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thats freaking big
makka
Author:  TheMiniMan [ Mon Oct 18, 2004 8:27 pm ]
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Thanks Makka,,,that`s what all the girls say...

:-)
Author:  drmini in aust [ Mon Oct 18, 2004 9:17 pm ]
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Nah, Matt- that carb's no good- not made in Italy.... :lol: 8) :P
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