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Twin SU carb
https://ausmini.com/forums/viewtopic.php?f=5&t=28818		 Page 1 of 2
Author:  cookie720 [ Sun Mar 04, 2007 5:29 pm ]
Post subject:  Twin SU carb
Hey all,
Im thinking of installing twin su 1.5' carbs onto my stock 1100 motor, can this be done? Would would it do?
Cheers. Thanks in advance.
Author:  Morris 1100 [ Sun Mar 04, 2007 5:43 pm ]
Post subject: 
You could save a lot of time and effort by keeping your existing carby and just pulling the choke out. :wink:
Author:  cookie720 [ Sun Mar 04, 2007 5:45 pm ]
Post subject: 
how would that do anything? please explain
Author:  Morris 1100 [ Sun Mar 04, 2007 5:50 pm ]
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You would use more fuel and it would run rough, just like fitting twin 1½s to a stock 1100. :wink:
Author:  cookie720 [ Sun Mar 04, 2007 6:30 pm ]
Post subject: 
Would twin carbs suit the engine if i had an exhaust system?
Author:  1360 LS [ Sun Mar 04, 2007 7:03 pm ]
Post subject: 
twin 1 1/4 at the most on a 1100. Personally I'd go a single 1.5. Without or without extractors and an exhaust setup. You'll get a smoother ride and the power increase you're clearly looking for.

Please correct if I'm wrong but this is what I'm led to believe.
Author:  poeee [ Sun Mar 04, 2007 7:36 pm ]
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Twin 1.5's are too big for a standard 1100. Maybe a HOT 1100.

Twin 1.25" would be ok. Single 1.5 or 1.75 should do ok.
Author:  cookie720 [ Sun Mar 04, 2007 8:02 pm ]
Post subject: 
Do any of you know what kind of carburettor my 74 clubman has? is it 1.25"?
Author:  willy [ Sun Mar 04, 2007 8:04 pm ]
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Probably has a Holley 950 double pumper
Author:  cookie720 [ Sun Mar 04, 2007 8:09 pm ]
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i wish
Author:  drmini in aust [ Sun Mar 04, 2007 8:16 pm ]
Post subject: 
cookie720 wrote:
Do any of you know what kind of carburettor my 74 clubman has? is it 1.25"?

If the float bowl is on passengers side it's an HS2 (1-1/4) if on drivers side it's an HS4 (1-1/2).
mounting flange on HS4 is diagonal.

1098 had an HS2, 998 had an HS4.
Author:  slinkey inc [ Mon Mar 05, 2007 3:05 pm ]
Post subject: 
1100 had an HS2?!?! :shock: Talk about lack of breathe!

Twin 1 1/4s are fine, tuning is pretty easy, but rebuilding cost twice the price as it's double the work. For cheapness probably a single 1 1/2 would be fine with a LCB system, or a 3 into 1, go extractors though.
Author:  drmini in aust [ Mon Mar 05, 2007 3:09 pm ]
Post subject: 
Yep, the 1098 motors all had an HS2, except the Morris 1100 automatic which got an HS4. All automatics got it, even the 850 auto in UK. It gave a couple of HP (in conjunction with 9:1 C/R) to offset the power losses in the auto.
Any 1098 breathes a little deeper if you bung an HS4 on. 8)
Author:  cookie720 [ Mon Mar 05, 2007 9:57 pm ]
Post subject: 
I might be getting a HS4
Author:  Besser [ Tue Apr 03, 2007 7:26 am ]
Post subject:  twin 1x1/2" ok
Running twin 1x1/2's should be ok but you either wan to do it for looks or your chasing the last little bit of power.

There is almost no cross flow between the balance tube on a twin setup and so the engine will only consider you ever have one carby even if there is two. So the advantage in a twin setup is not extra fuel but the air flow path.

On singles the air races around a bend and may unevenly fill the outside cylinders compared to the inners. Using twins the air flow is straight in (in theory) The problem with twins is the manifold, they are poorly designed with the intrusion of the balance tube forming steps and there turbulance.

If your going twins, get the Visard tuning A series book and you will have a good chance of gaining the extra power you may imagine a twin setup would give.

PS I just love the looks of Twins.
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