Subject: [Healeys] Weber question

From: Wilko2 <[email-masked]>
Date: Wed, 4 Dec 2013 21:40:57 -0800

I've not even finished building my engine yet (15 years on...)

I was wondering about Weber Carbs for a street driver Healey and about the
45DCOE being used for all the kits and such.

Weber recommends a 40 DCOE and supplies them with 32mm chokes for many very
successful 2 liter cars. That's a 40mm carb with 32mm choke for each 500 cc
chamber.  Why then would a Healey need a 45 with a 35mm choke?

Am I going to be ok for my moderately-built 3 liter Healey using the 40 DCOE
with 32mm chokes?

Thanks,
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]
http://autox.team.net/mailman/listinfo/healeys

---

From: Mark J Bradakis <[email-masked]>
Date: Wed, 04 Dec 2013 22:47:38 -0700

> Am I going to be ok for my moderately-built 3 liter Healey using the 40 DCOE

Yes, you will be fine.  Depending on what cam you use, what exhaust and such
you may want to go with 33 chokes, but 32 is a good starting point.

mjb.

[email-masked]

---

From: Wilko2 <[email-masked]>
Date: Wed, 4 Dec 2013 22:04:24 -0800

One thing I was thinking is that a larger bore with a smaller choke gives a
better venturi effect.

Supposedly the Healey can have a velocity problem anyway, so I figured the 40
would be fine as long as the chokes/venturis aren't too big in relation to the
bore. There must be some ratio that is ideal.

On Dec 4, 2013, at 9:47 PM, Mark J Bradakis wrote:

> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
> Forums: http://www.team.net/forums
>
> [email-masked]
> Unsubscribe/Manage:
http://autox.team.net/mailman/options/healeys/[email-masked]
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]

---

From: Austin Healey <[email-masked]>
Date: Thu, 5 Dec 2013 07:28:40 +0100

I dont have personal experience with Webers on Healeys, but with minis
(1.3l, approx 100-110ps we always used  40s instead of 45s).

Just my 2 cents: on the road the SU is somewhat better than the weber. We
always had significant increase in consumption, and probles with takeoff
from idle with the webers. engine response and allout power is better thoug
(and the induction sound is marvelous).

Gergo

2013/12/5 Wilko2 <[email-masked]>

> http://autox.team.net/mailman/options/healeys/[email-masked]

[email-masked]

---

From: Mark J Bradakis <[email-masked]>
Date: Wed, 04 Dec 2013 23:41:34 -0700

Wilko2 wrote:
>   There must be some ratio that is ideal.
>
>

Somewhere in the incredible mess of my office I have a formula or two 
that takes into account
bore, stroke, max RPM, etc. to come up with a close starting point for 
carb size, chokes
and jets.  Wonder if I'll ever see it again.

There's a lot of trial and error involved with setting up Webers on a 
particular engine, and
a LOT of trials to get to the "ideal"  But it isn't that difficult to 
get pretty close.

mjb.

[email-masked]

---

From: Ray Juncal <[email-masked]>
Date: Wed, 4 Dec 2013 23:02:46 -0800 (PST)

The 40/32 is a good start but you need to get on a dyno with a good weber guy
to get the jets and emulsion tubes dialed in.  The S.U.s are a more flexible
street set up.
Ray

On Wednesday, December 4, 2013 10:42 PM, Mark J
Bradakis <[email-masked]> wrote:
 
>   There must be some
ratio that is ideal.

Somewhere in the incredible mess of my office I have
a formula or two 
that takes into account
bore, stroke, max RPM, etc. to come
up with a close starting point for 
carb size, chokes
and jets.  Wonder if
I'll ever see it again.

There's a lot of trial and error involved with
setting up Webers on a 
particular engine, and
a LOT of trials to get to the
"ideal"  But it isn't that difficult to 
get pretty close.

mjb.
_______________________________________________
Archive:
[email-masked]
http://autox.team.net/mailman/listinfo/healeys
http://autox.team.net/mailman/options/healeys/[email-masked]
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]

---

From: Chris Dimmock <[email-masked]>
Date: Fri, 6 Dec 2013 00:58:27 +1100

I have triple 45DCOE webers. With 34mm chokes. (34mm is 1.338 inches, and you
get 6 chokes with triple webers).
Do the maths. A 2inch Su is 50.8mm. You can have 2 or 3 of them.
Plus you get almost infinite adjustment with webers.
Triple 45's with 34mm chokes are fine for a road car. Probably 36's too. 38's
on a full serious high rev race engine.
But your definition of road car might be different to mine.
I've never seen triple 40DCOEs on a Healey. The magic barrel dia formula is
choke x 1.25 So a 40mm Dcoe can't be the correct answer, even with 34mm
chokes...
Best
Chris
Sent from my iPhone

> On 5 Dec 2013, at 4:40 pm, Wilko2 <[email-masked]> wrote:
>
http://autox.team.net/mailman/options/healeys/[email-masked]
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]

---

From: Oudesluys <[email-masked]>
Date: Thu, 05 Dec 2013 15:59:11 +0100

40mm side draft carbs with 35 mm chokes and short stacks should be fine 
for a road car or rally car. It will give you more power in the higher 
revolutions area, not so much low down torque. For 45's you would need 
another cam and you cannot potter around on country lanes. Ultimately 
they will give more power, but that will not be any good during day to 
day driving. OK for racing. You also need to port and polish the head 
and inlet manifold and reduce the back pressure of the exhaust (proper 
spaghetti exhaust manifold and big bore exaust system).
Better to go for the DellOrto's, they are more stable than Webers. They 
may be easier to get hold of second hand, Alfa, Fiat, Ford, Lotus.
A very good book about setting up your car with Webers or DellOrto's is:

How to build & power tune WEBER & DELLORTO DCOE & DHAL carburettors by 
Des Hammill
ISBN 1-901295-64-8

These can easily be found at Ebay.co.ik or Amazon.com

The important thing is to choose the correct chokes and assortment of 
jets and emulsion tubes, great fun. Best to use a rolling road, but that 
can turn out to be very expensive.

The main advantage is "The looks".

Kees Oudesluijs

Wilko2 schreef op 5-12-2013 6:40:
> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/[email-masked]
>
>
>
> -----
> Geen virus gevonden in dit bericht.
> Gecontroleerd door AVG - www.avg.com
> Versie: 2014.0.4259 / Virusdatabase: 3658/6891 - datum van uitgifte: 12/04/13
>
>

-- 
Kees Oudesluijs
Dorpsstraat 183
2995XG Heerjansdam
T: 078-677 1233
E: [email-masked]

Technische commissie Jensen Healey en GT
Het Jensen Genootschap Holland
www.jensenholland.nl
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]

---

From: [email-masked]
Date: Thu, 5 Dec 2013 10:27:52 -0500 (EST)

Speaking of Webers, is anyone using them on a street prepared 100,
successfully? By street prepared I mean under 10:1 compression, something
close to a "M" cam, perhaps a good exhaust header, etc.
Assuming well thought out engine design (I.E. not too radical for street use)
& well sorted out Webers Vs. SU's why would the Webers get lower fuel economy?
That would seem to indicate that they are not well sorted out.
While I am asking, what is a reasonable average MPG for a 100 as described
above with SU's when traveling on the two lane roads at about 60 MPH +/-?
Gary
_______________________________________________
Archive: http://www.team.net/archive

[email-masked]

---

From: Austin Healey <[email-masked]>
Date: Thu, 5 Dec 2013 18:18:44 +0100

Hi Gary,

I always set my engines up "scientificly" (wide band lamda sensors,
ignition maping, rolling road), still I get lower fuel economy on webers vs
SUs. Please forgive me if I dont explain the reason, but my english is not
that good.

G

2013/12/5 <[email-masked]>

[email-masked]

---

From: Austin Healey <[email-masked]>
Date: Thu, 5 Dec 2013 18:40:04 +0100

"Do the maths. A 2inch Su is 50.8mm. You can have 2 or 3 of them."

We have HD6s, which are only 1.75in (44mm) for 2 or 3 cylinders, if You fit
a 45dcoe, You will DOUBLE, that. Bigger is not always better. You need gas
velocity for a good, stabile mixture.
As a guideline, one 1.75 SU is enough to feed 90-95 hps, and even good up
to 100 with not much loss. Our Healey is very overfed with the stock engine
and 2 HD6s.

Gergo

2013/12/5 Chris Dimmock <[email-masked]>

[email-masked]

---

From: Michael Salter <[email-masked]>
Date: Thu, 5 Dec 2013 13:30:47 -0500

Hi Gary,
Not so easy because the 100 head has siamesed inlet ports so the best you
can do is one 45DCOE or install an "S" head!!
We have 2 x 45 DCOEs on AHX12 and although they are, as mentioned, great
for getting the most power at higher RPM they are not a lot of fun around
town.
I would pick SUs any day for a road car, but when it comes to show Webers
sure take the prize. It's a bit like golf: Drive for show; putt for dough.

Michael S

On Thu, Dec 5, 2013 at 10:27 AM, <[email-masked]> wrote:

> http://autox.team.net/mailman/options/healeys/[email-masked]
>
>

-- 
Michael Salter

[email-masked]