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

I wouldn't think so, they ran twins on 998 coopers, so can't see why not.

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Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484

It'll be OK- they were fitted to many 850s too (Sports 850, and aftermarket kits).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

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

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GTi Turbo'd mini, abused daily

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.

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

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.....

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

Cheers,
Anto.

Good and valid points from Matt and Anto.....

It made interesting reading....

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.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Kev I can't wait to pick your brain when I am building my new motor.... ..and the time is rapidly approaching!

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What was god thinking when he created minis without round noses??
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MY99 Subaru WRX
1967 Mini Delux
2002 Mitsi Mirage
1993 Honda Prelude

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'

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What was god thinking when he created minis without round noses??
____________________________________________
MY99 Subaru WRX
1967 Mini Delux
2002 Mitsi Mirage
1993 Honda Prelude

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

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

thats freaking big
makka

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Anonymous moderation means the agro that is built up towards the mods isn't aimed at an individual (fewer "Makk" attacks). Less stress for mods means less moderator "retirements".

Thanks Makka,,,that`s what all the girls say...

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Nah, Matt- that carb's no good- not made in Italy....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.