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Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 9:49 am
by evonaut
out of interest, seeing as there a lot of opinions about what is a good set up and not, any views on this set up......

i have twin HS4s on my 1275 cooper s engine, they came with the car when i bought her in the 80s, the engine has been bored +0.040 to 1310cc, and I elected to use an SW5 cam instead of the 731 originally in the car, mainly for drivability in and around london which is where i live. i have a standard crank, 12G940 11 stud big bore head, and standard forged rockers etc.....

be gentle with me, please ;o)

evonaut

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 10:06 am
by rich@minispares.com
evonaut wrote:out of interest, seeing as there a lot of opinions about what is a good set up and not, any views on this set up......

i have twin HS4s on my 1275 cooper s engine, they came with the car when i bought her in the 80s, the engine has been bored +0.040 to 1310cc, and I elected to use an SW5 cam instead of the 731 originally in the car, mainly for drivability in and around london which is where i live. i have a standard crank, 12G940 11 stud big bore head, and standard forged rockers etc.....

be gentle with me, please ;o)

evonaut

I think that twin hs2 would be a better carb for town driving with a 'soft' cam, the twin hs4 are more for hard driving where the engine would benefit from the extra air/fuel at top end

I think you would get a little more mpg and much more low speed flexibility with the hs2.


just keep the hs4 on the shelf 'just in case' :lol:

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 10:12 am
by evonaut
thank you rich.

unfortunately i am not in a position to purchase a set of HS2s so will have to tolerate the lower mpg...... i will however ensure that the car gets a decent run out every now and again to take advantage at higher revs!

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 10:15 am
by rich@minispares.com
evonaut wrote:thank you rich.

unfortunately i am not in a position to purchase a set of HS2s so will have to tolerate the lower mpg...... i will however ensure that the car gets a decent run out every now and again to take advantage at higher revs!

sounds like a plan!

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 10:43 am
by Spider
evonaut wrote:thank you rich.

unfortunately i am not in a position to purchase a set of HS2s so will have to tolerate the lower mpg...... i will however ensure that the car gets a decent run out every now and again to take advantage at higher revs!
Find someone who has a set of twin HS2's and wants to swap ;)

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 11:01 am
by mikep
carbon wrote:
Vegard wrote:Twin HS4s are equally stupid on that spec.
I'm with Vegard on this one. A pair of twin HS4s would be better matched with a longer profile cam with more valve lift, as the real benefits only kick in at high rpm.

The OP's engine spec is a good tractable fast road unit.

I would recommend sticking with a single HS4, fully vizardised inside, with K&N filter (pref not cone) and good stub stack (not rubbish cheap one from ebay). And spend the money on a good flowing inlet manifold similar to Oselli Torquemaster, getting flow from good shape not large ports.

With this set-up you won't be giving away many horses as compared to twin HS4s or Weber.
If going to a single would be better of with HIF6 on a metro inlet, they are cheap and work very well. Not very sexy but solves the problem. Another idea may be to try and find a good 11/2 fish carb never ran one on a big engine but were second to none on small blocks.

Re: Twin SUs or Weber 45 DCOE?

Posted: Fri Jan 16, 2015 11:03 am
by evonaut
nice idea, and in fact my late father had a pair of HS2s ready to fit, can't find them anywhere - have searched my mums house high and low!

gonna give the HS4s a go........will just have to keep the revs up a bit :D