WEBER 45DOCE - what application if any to a 1725

[DanR]

I have a Webber 45DOCE pictured below and wonder if they would work on my 1725 ?

Any comments, suggestions, recommendations are welcome..... I know absolutely nothing about a Webber.

 

[spmdr]

Short answer: YES

Longer answer, you may not want to deal with all the variables.

to get the system working satisfactorily.

SOooo .....I'll be GLAD to test it for you.....


OR, better yet.... if Jerry agrees,

Send it to Jerry for his engine Dyno work.

Jerry is planning to test intake systems.

It may be the HOT ticket that WE All should have...??

DW

 

[alpine_64]

45dcoe was a popular setup down under and used on the lynx manifold. They worked well but the lynx was a complex cast manifold that had a flawed design with unequal length runners... So you would always have a small flatspot somewhere in the rev range.

Your fabricated manifold would avoid that... I think will be a great choice of carb for your 1725.. and with some porting and valve/ head mods.....even better

 

[alpine_64]

This is the LYNX version

 

[JackSun]

Hi Dan , I use the Lynx intake w/ a Weber 45 w/ the headers you so graciously provided . I have been more than pleased &
impressed w/ the increased performance & throttle response . I converted from the 32/36 Weber downdraft w/ a drastic , major
improvement . I have not experienced the “ Lynx intake , flat spot “ through “ normal “ driving & RPM ranges , FWIW .

 

[DanR]

SOooo .....I'll be GLAD to test it for you.....

Let's talk about it... I am impressed by the response. Sure sounds like a very nice option on my 1725.

 

[DanR]

have been more than pleased &
impressed w/ the increased performance & throttle response .

Jack, That statement really makes my day.....

 

[jumpinjan]

I have a lynx manifold like in your picture Michael. It's machined for the slanted engine.
Jan

 

[alpine_64]

I have a lynx manifold like in your picture Michael. It's machined for the slanted engine.
Jan

Jan there are 2.. one has Alpine cast as per jacks .. the other has GT or Hunter which are for the 10° motors... The one in my photo was a hunter one with the face machined to be horizontal.. they do get quite thin but works.

 

[spmdr]

I'm currently VERY excited about finding the BEST

intake system for MAX performance for an Alpine engine.


For a SBF Tiger, max RPM Carburetor HP is had

with a single plane (straightest runners)

into a plenum, fed with an adequate CFM Carb.

The most common SBF Weber individual runner intake systems

do not net max HP.


A very similar situation happens in the World of Alpines.

The very common duel 40 DCOE system is inadequate for MAX HP.

And it seems there is no other Alpine intake system to compare

with the single planes available in the SBF world.

However, this single 45 DCOE intake is getting closer, I think and hope.

I expect this single 45 DCOE system will out perform a Dual 40 DCOE

system.


I assume the best/max HP would be had with the Carb

connected to a plenum that feeds all of the cylinders.


This fantasy intake system would have the straightest runners,

no 90 deg transition from down draft carb to side port.

and a carb big enough to provide the least restriction.


As far as I know, that is Not available in the Alpine world.

YET.

DW

 

[alpine_64]

A very similar situation happens in the World of Alpines.

The very common duel 40 DCOE system is inadequate for MAX HP.



This fantasy intake system would have the straightest runners,

no 90 deg transition from down draft carb to side port.

and a carb big enough to provide the least restriction.


As far as I know, that is Not available in the Alpine world.

YET.

DW

Dan... Duel DCOE.. fighting spec

I think the ultimate alpine intske does exist... it's the straight in twin DCOE manifolds... very straight runners and no big kinks... but.. I believe it's very hard to fit to a LHD alpine due to the steering box interference.

The only disadvantage of the straight runner manifold is you either have short runners to have longer velocity stacks or longer manifold and then shorter stacks due to the distance to the wheel arch... I have seen people notch the arch to allow a longer manifold and stacks.

Assume you are cicumspect that the redline/warnerford/LYNX manifold with the goose/swan neck costs to much air speed?

 

[spmdr]

MK, Yes, you may be correct about current Practical ultimate (just/poorly) FITTING intake systems.

I'm liking the DUAL 45s I'm playing with currently, so far!

But I'd like to try my theory.

Also, the problem is ANYTHING I would come up with would NOT be applicable in the "Vintage" world.

So at this point, not likely to get much of my effort.

DW

 

[alpine_64]

MK, Yes, you may be correct about current Practical ultimate (just/poorly) FITTING intake systems.

I'm liking the DUAL 45s I'm playing with currently, so far!

But I'd like to try my theory.

Also, the problem is ANYTHING I would come up with would NOT be applicable in the "Vintage" world.

So at this point, not likely to get much of my effort.

DW

Dan,

Firstly I forgot its saoca not CAT.. so my smiley icon after "duel" didn't come up... I am captain typo... but I did think performance carbs being called "dule" was funny and appropriate.

Re the manifolds....i have a couple of manifolds that might meet your needs and are "dual carb" for your duelling pleasure....but not for DCOE...

I'll send you an email tonight... I may have the images in the forum...I'll link if I can...
But it requires different carbs... But British .. and if you believe holbay... As powerful if not more in normal conditions and maybe close in racing

 

[alpine_64]

Dan..

For your viewing pleasure... consideration....how about some BIG SU 1.75 or 2" carbs?

Manifold options.

Custom long neck twin SU manifold with balance pipe.

[URL="https://forum.sunbeamalpine.org/index.php?media/img_20190404_084338_1cs-2-jpg.4419/"] [/URL]

Period Alexander conversion manifold twin SU







Short TWM dcoe:

MKING_2xDCOE_straight_03

TWM straight twin dcoe intake top

forum.sunbeamalpine.org

 

[spmdr]

After writing the above, I realized what I am looking for is basically an AI manifold

but modified for a Side carb.

But, of course, it would be a tight fit on an Alpine.

DW

 

[DanR]

CAn it be a good possible change to rotate the mount position on the intake 90 degrees and save some space? And perchance even make a better flow???

 

[alpine_64]

After writing the above, I realized what I am looking for is basically an AI manifold

but modified for a Side carb.

But, of course, it would be a tight fit on an Alpine.

DW

View attachment 29605

Years ago I got an alloy adaptor for a DCOE carb to DGV manifold..... Iirc it was for an Alfa.. if you put it on this you could face the chokes back towards the firewall Buying you some space ... But also breathing in hot air.... Then there is the 90° turn down... Followed by a 90° turn left for the air and fuel to travel...

 

[spmdr]

DanR sent the single 45 intake system to me to check out.

I checked the setup of the 45mm carb:

- 36mm choke

- 135 mains

- 165 air

- F16

- F8 65 idle

- 9-9.8 mm float level

- 45 pump jet


I was wondering what the sizing of the custom intake

manifold was.

Looking down the carb, there appeared to be a step between

the carb and the intake manifold.




I took the carb off the manifold to check it out.

As I suspected, it looks like the manifold was made for a 40mm carb.

There were a pair of 40mm O-ring plates between the carb and the manifold,

the ID measures 39.18mm.

The manifold port ID is a nominal 36.5mm at the carb flange.

Clearly a bit small for a 45mm carb.

The custom steel manifold has tubes with 37.7mm OD.

And the manifold has a nominal head flange port size of 35mm ID.

It will be interesting to see how it works.

DW