MGB Carbs on a Vitesse

[Jordon T]

Hello There,

- CAn MGB SU carbs be bolted directly onto a vitesse 2 litre mk1 inlet manifold?
- What are the advantages and disadvantages of using SU's over Stromberg's?
- My car had CD150 Stroms, so what would be the SU equivalent?

Thanks

JOrdan

[garyf]

Not sure if the MGB Carbs are a straight fit, but I had HS4 Su's on my Vitesse Mk2 when I first bought it, however I converted back to the CD150S Strombergs during its rebuild.

I can remember one of the previous owners purchasing and fitting the SU carbs back in the late 80's, they where brand new and supposedly for a Mk2 Triumph 2000, he was fed up with the Spindle wear on the Strombergs causing erratic tick over because of air leaks, he was always moaning about the choke mechanism on the Stombergs too.

I reckon the choke mechanism on the Su's is far simpler/better design than the Strombergs but apart from that and the possibilty of the diaphrams splitting on the Strombergs there's not much between them?

[piman]

Hello Jordan,

the MGB uses HS 4 which is the right size as a CD 150. I'm not sure about the flange mounting but I think they are the same?

Alec

[Nick Jones]

Flanges are not the same but holes in the carbs can be slightly elongated to make them fit.

Think MGB carbs are angled so will require mods to bring the float chambers back level (parts swap only).

Had HIF 4 SUs on my Vitesse for a while (ex-Allegro 1500) with T200o spec needles.  Worked ok.  Didn't go quite as well as the original Stroms but gave better idle, economy and hot start due to the Stroms being knackered.....

Strom is perfectly decent carb if in good shape.

Nick

[oil_on_the_carpet]

SU's ~ Easier to set up but go off tune fairly quick.

Strombergs ~ Harder to set up but stay in tune far longer.

I had an old Volvo 144S for years with twin Strombergs, other than changing the perished diaphragms once, never had to touch them. Sprint? Always fiddling with the SU's.

[Jordon T]

What other cars use Su's which will just bolt on then? Maybe a Dolomite sprint Su's?

I'm more used to SU's Rather than stroms as my maestro has an SU. And also, Su's seem to last longer!

Will Spitfire 1500 Carbs Work??

[Pete Lewis]

both carb types are often criticised for reasons of non awareness.
I allways say if you take the two apart , lay all the component parts out and look at them  the  strom is engineered the su is abag of meccano

cds strom are the easiest, proper choke valve, not the thames barrier device, easy to adjust the jet from down under like an Su

a starting valve is the best way to choke ,ut  eliminates all choke misgiving ,,
Choke on Su is just a load of bent cranked rods and levers to hopefully lower and return the jet.. this often fails on its return journey,  

there are far more needle profiles  available for SU
the su float needle valves are notorious and less tolerant of debris and leak for the least oportunity.

for ease of maintenance steer clear of any with emmision controls added in the 70s to save the planet and frustrate owners /fitters.


all rely on well fitting throttle spindles, free moving air pistons and dampers, a well maintained choke linkage, correct fuel heights
  despite the myths  that surround the two makes most test results show the strom is better in performance and economy compared to SU

and dont ask  for that to be printed off..   take forever

Peter

[oil_on_the_carpet]

peterhlewis wrote:

the su float needle valves are notorious and less tolerant of debris and leak for the least oportunity.

Peter

Often with rather 'exciting' results!

I've also heard that the Stromberg, (Proper Triumph, not a BMC device and aircraft rated), gives better efficiency and am toying with the idea of switching from HS6's to CD175's.

[junkuser]

CD had the rotating choke bar that lifts the needle to give more fuel.
CDS had the enrichment device to supply extra fuel for starting.
CDSe had the emission control bits that make them a headache.

'Tis a pity that these carburetors don't have the spindle seals as found on modern throttle bodies.

Nice to see the favorable comments about Strombergs.
They are nicely designed and very reliable, but finding someone interested in tuning them in my part of Australia is a problem.

You can use SU needles in them with a suitable shim.
I resorted to this using 2 CDS 150s on the Spitfire 1147 engine but could not find a rolling road operator interested in sorting them correctly.

[Deleted User]

junkuser wrote:

Nice to see the favorable comments about Strombergs.

Technically, there is nothing wrong with the Stromberg, it's a very good design. SU would only finally deliver a half decent carburettor with the HIF many years later, just as everyone was switching to fuel injection, (years after TRiumph pioneered FI and then dropped it, but that's another story).

A lot of people wrongly assume that as Triumph largely switched from Strombergs to SU's in the early 70's, the SU was 'better'. No, it was because BL now owned Triumph and BL owned SU.
Triumph had to keep using the Stromberg for the US market where they had to guarantee the carbs would stay in tune and meet Federal emissions requirements for 50,000 miles, something an SU was completely incapable of doing.

[Deleted User]

Tuning strombergs for go faster purposes

https://rapidshare.com/files/1106562177/Stromberg_CD_Book.pdf