Weber 40 DCOE 151

[Rocketman]

I am considering fitting a pair of weber 40 DCOE 151 carburettors to my 3A with a weber manifold. Has anyone got any pictures of this manifold in situ. Does anyone have an carburettors setting for theirs.

[Drewmotty]

Idle Jet 55F9

Main jet 130

Emulsifier F15

Air Correction 180

Choke 30 mm

Aux Venturi 4.5

Float Needle 1.75

Pump Jet 45

[Drewmotty]

Produces an extra 8-10hp on my lightly modified engine but only above about 3500 rpm. Below that it just uses more fuel for no gain over twin SUs. 

[iain]

55 minutes ago, Drewmotty said:

Produces an extra 8-10hp on my lightly modified engine but only above about 3500 rpm. Below that it just uses more fuel for no gain over twin SUs. 

Andrew you answered my question :-).

Cheers 

Iain

[Malcolm Tatton]

[Malcolm Tatton]

Sorry, I thought that these images which I have were the same as your kit, and they are similar but not exactly the same

 

[Rocketman]

From what I have read with no actual experience of these set ups my initial thought ar

40 DCOE 151

32 or 34 chokes

4.5 auxiliary 

130 main

180 air

45F9 or 50F9 idle

F15 tube

45 pump

50 discharge

2.0 needle

it has 86mm pistons so 2138cc 

balanced bottom end

maxpeeding forged rods

newman PH1 fast road 280 cam

use would be road/fast road keeping below 5000rpm 

any thoughts??

[BlueTR3A-5EKT]

Just to add spice…did anyone in UK ever fit twin Mikuni 45s to a TR2-4?   The North Americans seem to be getting them to work by fitting to original inlet manifold in place of the twin SU or Stroms.

 

https://www.triumphexp.com/forum/tr4-and-tr4a-forum.7/another-tr4a-mikuni-carb-upgrade.1367107/

 

I have decided the twin 42 DCOE kit we have will not get used as simplicity of the SU remains paramount.  ( they are available for sale)
As stated, the DCOE carb give strong performance at higher rpms but as a round town and touring item the economy is not too special.

Edited March 28 by BlueTR3A-5EKT

[Motorsport Mickey]

1 minute ago, BlueTR3A-5EKT said:

Just to add spice…did anyone in UK ever fit twin Nikuni 45s to a TR2-4?   The North Americans seem to be getting them to work by fitting to original inlet manifold in place of the twin SU or Stroms.

Never heard of a Nikuni ? is that a typo of Mikuni ?

Mick Richards

[Motorsport Mickey]

54 minutes ago, Rocketman said:

From what I have read with no actual experience of these set ups my initial thought ar

40 DCOE 151

32 or 34 chokes

4.5 auxiliary 

130 main

180 air

45F9 or 50F9 idle

F15 tube

45 pump

50 discharge

2.0 needle

it has 86mm pistons so 2138cc 

balanced bottom end

maxpeeding forged rods

newman PH1 fast road 280 cam

use would be road/fast road keeping below 5000rpm 

any thoughts??

Stuart from the Watermill Carriage Company has Dellorto 40s on his car, but I can't remember whether 86 or 89mm pistons, so he may be able to give a starting point.

Mick Richards

[BlueTR3A-5EKT]

5 minutes ago, Motorsport Mickey said:

Never heard of a Nikuni ? is that a typo of Mikuni ?

Mick Richards

Spelling done!

[BlueTR3A-5EKT]

Have you found this?

http://tr3a.info/WeberDCOEinfo.htm

 

[Motorsport Mickey]

Peter Burgess at Automotive Performance Engineering in Alfreton 01773 520021 has had some Mikuni's go through his rolling road (probably on MGBs) and he rates them.

Mick Richards

Edited March 28 by Motorsport Mickey

[Rocketman]

6 hours ago, BlueTR3A-5EKT said:

Have you found this?

http://tr3a.info/WeberDCOEinfo.htm

 

Yes thanks, i have been reading that as it’s simple and informative for the TR owner. The weber manual is a bit deep and confusing 

[BlueTR3A-5EKT]

2 hours ago, Rocketman said:

Yes thanks, i have been reading that as it’s simple and informative for the TR owner. The weber manual is a bit deep and confusing 

There is more reading to be found in David Bees 'Bonanza' thread in our forum's general technical. 

https://www.tr-register.co.uk/forums/index.php?/topic/71447-bonanza-collection-tr-articles-books-updated-20-march-2022/

 

[Drewmotty]

10 hours ago, Rocketman said:

32 or 34 chokes

I’ve tried 33mm chokes in place of the 30mm ones. As expected main jets larger than the 130s were required. 
The larger chokes provided more of the same, small gains at the top end at the expense of a less smooth roll on at low/medium throttle and slower starting (I don’t have starting enrichment fitted).

I reverted to the 30s and the car felt quicker on the road.

Accept that whatever you start with will only ever be a starting point and you will need to use rolling road data and considerable road testing to refine the setup to your personal requirements. 
Saving grace is that it takes me much less than an hour to change from Webers back to SUs now that the SUs are converted to cable operation. 

[Hamish]

Rocketman

the above is a good starting point for chokes and jets etc but a starting point, all cars seem different and rolling road time is needed imo to get things right  

i won’t share mine as it would just muddy the waters as I have 45’s on mine and it’s a slightly warmed up 89mm now.

but I would say the SU’s are just wonderful on my last engine which was an old tuned 87mm  setup with H6 and long later intake manifold they were set and forget. With about 120hp at the flywheel. 
 

i tried tinkering around at the edges to improve things and loved the look of the webers but found you need to do the whole hog to find performance

i now have around 160 + hp and 45 webers that I have had to try and learn via putting out a fire and had the rear carb flood to scary degrees due to the modern floats sticking when car left un used for a while. 
all good now.

I don’t have the start choke system, a few throttle pumps and it starts well. 
its tickover is great at around 800

and deals with traffic well but the pure joy is full throttle on and off. 
 

my question is do you REALLY need the webers ??!!

 

on the road with 45’s

 

on track a few days later

And just to be fair the old engine and SU’s

 

 

[Drewmotty]

My car today. 
Read into that what you will. 

[Andy Moltu]

4 Mikuni carbs sound like a lot of hassle when it comes to balancing.

Webers were a contemporary modification but if you are considering a quad carb setup it would seem more like logical to go efi perhaps?

Well set up Weber’s are not necessarily that thirsty but time and effort to do so as well the expense of a rolling road and the cost of swapping to the optimum internals rather than best adjusting what your Webers came with.  I was once advised that it could cost nearly as much to get a good second hand pair set up as to buy new with the right set up.

[BlueTR3A-5EKT]

Why not....go fuel injected?

https://www.jenvey.co.uk/

 

Or better still ask the people who built the splendidly finished car you have what they would suggest, if you are seeking more 'umph.

Looking at the photos of your car it is finished to a high standard with many trick features, that suggests the builders knew what they were up to.

[Motorsport Mickey]

53 minutes ago, Drewmotty said:

My car today. 
Read into that what you will. 

+1 for the stub stacks, not as impressive looking as 3" ram pipes but about 50% more effective.  Mick Richards

[stuart]

Yes as Mick stated I have Dellortos fitted to mine, now running 89mm so I did have to alter the original settings from when it was on 87mm and up to 34 chokes as well, properly set up it will just tootle around at very low RPM in quite high gears  but as some of our local group will attest it leaves most standing and will keep with a tripe Webber TR5 up to over the ton. Gets a bit light on the front at 115

It does take a lot of setting up to achieve what you want and unless you are going to actually use the performance then SU`s do a great job anyway.

FWIW if anyone is interested I do have a full EFI kit for a 4 cylinder with Webcon throttle bodies injectors and air filters and an Omex brain with corresponding loom and coil pack to suit that I will be listing for sale soon.

Stuart.

[BlueTR3A-5EKT]

51 minutes ago, Motorsport Mickey said:

+1 for the stub stacks, not as impressive looking as 3" ram pipes but about 50% more effective.  Mick Richards

The ram pipes look even better if poking through the bonnet.  

[ianc]

As Stuart states, a pair of HS6s do a very good job and are very easily set up on a rolling road by a tuner with a good supply of needles.

And most of us driving road cars don't get to 5000 very often.   When given a Hill entry, I get to 5500 on Kop Hill, but the rest of the time I use 3000 to 4500 across country.

Ian Cornish