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EA81 twin carb flanges
Posted: Sun Jul 12, 2015 10:10 pm
by Tweety
ok, this is just a talking point. Having gone from weber 32/36 to supercharger, to SPFI, 38/38 and now 32/36 I'm not going this way ok guys lol
RAM performance have these flanges for sale. $169 pair think NZ dollars.
see
http://ramengines.com/page16.php
I was wondering. All the guys here and elsewhere that want twin carb manifolds that are impossible to get, why cant they use these flanges?
I assume a steel tube would fit into the hole then a carbie base plate then bolt the carb on each side. bolt in a barb each flange for the hose and connect. The PCV is a worry. How much more hp would it roughly increase by using two single throat carbs?
Discuss away. Tony
Posted: Sun Jul 12, 2015 10:26 pm
by Bantum
Could work - lot of effort to do it though.
The trouble with carbies is they have to be vertical for all the 'plumbing' to work ...
Not that I'm any expert, just ask Willy, he seems to know all about it ...
Ciao, Bantum ...
Posted: Mon Jul 13, 2015 10:55 am
by Tweety
They would be vertical. steel round tube straight into this flange and a carbie above it. No manifold curves. All the desperate guys out there trying to find a original or limited released weber twin carb manifold...this seems the answer to me.
I'm assuming the threaded hole is for a male barb for the coolant
Posted: Mon Jul 13, 2015 6:31 pm
by Silverbullet
Would be an interesting project made very easily achievable by these thingies, although I've heard someone on this forum say the two carbies need to have their fuel/air passages connected in the middle like the factory manifold for some balance reasons...but then there's the Safari rally version with the two completely separate. Who's going to splash the cash and find out?
I'm more interested in some of the other EA81 specific goodies on that site! Wish I'd found that before I had my twin carb engine rebuilt...although it's not too late for this

Posted: Mon Jul 13, 2015 6:41 pm
by Tweety
What's that item mate?
Vw engines, twin carbs don't have a common tube. No other ones have them. think better not to have them IMO but I'm no mechanic just a magnificent fiddler of all things unusual lol.
I'd love to be the ginnea pig but cant afford it now I'm retired. but never say never. economy is what I'm chasing now that I've got the performance I want.
So if I went twin carb with these flanges I'd suggest two single throat carbs like solex's would be ok. Then there's the linkages etc. Theoretically twin carbs should be more economical than a twin throat single carb in the centre. But they never are I don't think. Maybe if we had a ea81 with two twin throat carbs with the single throats used mainly and jetted right it could be ok.
Efi ...
Posted: Mon Jul 13, 2015 7:07 pm
by Bantum
I was looking a bit further down the page & saw this :
For EFI but ... Could do something with that maybe ?
Ciao, Bantum ...
Posted: Mon Jul 13, 2015 7:08 pm
by Silverbullet
That is the bracket/sensors for a distributor-less ignition system...I think. Not sure why there are two sensors. But a toothed wheel goes on the crank pulley as well. Then with some small electrical gizmo and a coil pack you can throw your distributor away which is what I want to do so badly
I wonder if those adapter plates could be used to make a twin point (?) fuel injection system...then throw away the carbies as well!

Posted: Mon Jul 13, 2015 7:57 pm
by Tweety
an ea81 with no dizzy, no carbies ??? mmmm, simplicity, low maintenance. just got to get no adjust tappets then only got to tighten the water pump belt and oil/filter change.. This is my kind of thread.
Posted: Mon Jul 13, 2015 10:35 pm
by Subydoug
Just my thoughts but I did have two 34mm single throat webers I was going to do something similar with a long time ago. I swapped them with some other bits to Toonga. My hunch would be that it would be very little improvement over standard, it would be a lot harder to tune and keep in tune and when it is slightly out of tune the car will run like crap unless theres a a cross pipe connecting the two intakes together. Other thing that makes it a little bit tricky in our subies is bonnet clearance and things like the alternator and power steering pump. All that being said Im not against anyone going that route, just know what your getting into and be good at fabricating stuff from scratch!
No need to lash out gazillions of dollars for that Silverbullet, 5-1/4inch 36-1 ring gear fits perfectly behind the crank pulley. Only need a single sensor then with a bracked of your making.
Regards
Doug
Posted: Mon Jul 13, 2015 11:30 pm
by Tweety
My VW 1916cc engine is one example. Twin Solex's then twin 40 webers. Never was economical either of them. That's how they were set up from the factory at Panther trikes. But reckon far better to have had single twin throat carb all along.
Posted: Wed Jul 15, 2015 8:52 am
by steptoe
you would connect the two sides (great find BTW Tony ! ) air stream as a balance tube and for those of us with vacuum booster assisted brakes would need a vacuum supply without looking for a separate vacuum pump or alternator from a Diesel.
One day would really like to do a dizzy less programmable ignition on an EA or something, not an EJ as that has been done

Posted: Wed Jul 15, 2015 1:20 pm
by Tweety
Oh, vacuum for brake booster, didn't think of that for you guys.
I suppose the short tubular manifolds that would be made would be say 50mm high and off those could be a 16mm tube on each unit. Then a tube connecting them. All vac's like auto kickdown and dizzy advance could be taken off that?
Posted: Wed Jul 15, 2015 9:34 pm
by El_Freddo
Carb directly over the head = very high revving engine before you hit it's peak torque. Not nice to drive as a daily around town.
Longer runners between the carb and the head is better for low down torque. You could set them up with a stretched "x" manifold, small crossover tube/hole in the middle and you'll have a set of carbs over the heads and the longer runners too.
Cheers
Bennie
Posted: Wed Jul 15, 2015 11:24 pm
by Tweety
yeh, better idle too with longer tubes. The old vintage engines used to idle perfectly with the carb high up.
Wouldn't be hard to weld on the stretched "S" tubes toward the middle. Having heads offset you could allow the "S" tubes to rise up to mount an IDF carb?? in the centre. ?? What about off the flange is a 90 degree bend (short) then a SU per bank. Meets in the centre for a common box air filter.
These flanges I suppose could be utilised for multi point FI.
Got to have a bex