Is anyone out there using twin 1.5" su's on an 1100 engine ?

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That's why it's good to be.............ME

I Don't know of anyone.

But I am looking for a specific type of 1 1/2's and have a spare set 1 1/4's

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I'm thinking you should maybe do some work on your engine to match the carbies

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"Show me the Mini!"

If a std 998 can run an 1&1/2 quite well,
then an 1100 can run twins with no problems at all... true

each piston inside the 998 sees a single 1&1/2 (one at a time)

so a set of twins is simply better because of less restriction in the manifold
& far better (more even) distribution across all 4 cyls

they work extreamly well if set-up well for the intended purpose

so even with twin 1&1/2 carbs,,, each piston is still only seeing a single, just a far straighter , more direct, less restrictive path

same-same , just less restriction & more even distribution
no more inner 2 running slightly rich & outer 2 running slightly lean

simples

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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.

except for the stop-start of the air flow down each throat because of the 2-1--3-4 firing pattern

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did I tell you that I won a trophy?

That effect is minimised by the balance tube, usually pretty big on twin SU setups.

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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.

Yes I am.

What is your engine spec , needles and springs.

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That's why it's good to be.............ME

I ran twin HS4s on a 1098 back in 1967. It was bored to 1218cc (68mm Imp pistons), ran a ported 1100S head with stock valves, a C-AEA544 cam and stock 1275 rockers. Exhaust was a Sonic LCB.
It ran mid 16s at Castlerealgh drags, blew my mate's 1275S away.

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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.

Motor was build in the mid 1990's so memory of exact details is vague.
It's an 1100 plus 60 thou
Modded 202 head with a lot (I now think to much) decked of it as I struggle to get head gaskets to seal.
Russell engineering cam (I can't remember what he was doing back then, 1993 or 4 or what it was called)
LCB exhaust with single RC40
Twin H4 SU's (I will check the needles and springs and let you know)

and it pulls really well and was a great replacement for my tired 1360.

Thanks for that , yes my engine was built a long time ago (2 owners) and the guy who built it could not remember the exact details !

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That's why it's good to be.............ME

I think the springs are blue and the needles are E3.

I will pull one out and have a look when I get a chance (may not be till the weekend).

that will be interesting, thanks

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That's why it's good to be.............ME