Carbs and type

[Jens]

Just skimming through the forum again an all of a sudden I realize that I haven't got the faintest of a clue as to wich type uses wich carb.
I just kmow that there are some cars fitted with Stromberg, some with DellOrto and some (like mine with Webers.

Could someone help me out so that I can stop wondering?

Thanks!

//Jens

[peterako]

VERY loosely....


First phase of cars were on Webbers....

Then Lotus wanted to get into the US and found it hard to meet emmission requirements with the Webbers....

So Stombergs make an appearance.

Some of the non-US cars also have Strombergs at the same time.

Then later moved back to Webbers/Dell'Ortos, with a sweet deal on price allowing Dell'Orto to steal Webber's wind (so to speak).....

Then Webber again



Some decisions made on technical basis, some on commercial....some on 'what's lying around?'.

I'm sure other members will have a more detailed description

Peter (Dell'Ortos in my 1973 +2)

[CBUEB1771]

Then Lotus wanted to get into the US and found it hard to meet emmission requirements with the Webbers...

Lotus had been selling to the US since the 1950s. Elans sold in the US through 1967 had Webers. The emission laws which came into effect in 1968 did force the transition to Strombergs. I think Strombergs then appeared in other markets primarily to reduce manufacturing costs.

[trw99]

Then later moved back to Webbers/Dell'Ortos, with a sweet deal on price allowing Dell'Orto to steal Webber's wind (so to speak).....Then Webber again

From my web site re the Sprint:

On the Big Valve engine Weber 40 DCOE 31 carburettors replaced the S4?s Stromberg products. In conjunction to the work carried out on the cylinder head, the jets and chokes fitted to the Weber?s were different to those fitted to previous versions of the twin cam engine.

In turn, the Weber carburettors were replaced by Dellorto DHLA 40?s in about May 1972. A service bulletin detailing the changed specifications was issued on 9 June 1972 so Dellortos must have been fitted to Sprints in the factory by May 1972. Dellortos were fitted by Lotus to the Twin Cam Europa from December 1971, so clearly Dellorto was a factory supplier by then.

One reason for this change was that Dellorto had been quicker and more willing to change their designs to meet the new European regulations that were due to come in force. They may also have been cheaper than Webers too. Dellorto DHLA 40Es were used on all ECE 15 engines, which were really the same as domestic engines but had different carb jets and ignition settings to meet euro specs. Some of the last Big Valve engines for the domestic market had European specification carbs.

Tim

[Jens]

Then, next question.

Are there any significant differences in performance or "willingness" to be tuned between the three?

//J

[peterako]

Miles Wilkins Twin book is an excellent source to answer this question

The quick answer is....yes.

The not so quick answer.......sort of....etc.

Even the Stomberg engines could produce close to the same power as the latter Big Valve Webber/Dell'Orto engines when used with higher compression (the main difference between a Big and non-Big valve engine ).

Major differences are probably more noticable in WHERE the power is.

Lads and Lassies....care to fill in the blanks?

Peter

[Ross Robbins]

As an owner of both types, I think Peter is quite accurate.

For all out full throttle performance the Weber (one B, by the way as Hamlet queried...wait for it: Two B or not two B, that is the question ) seems to flow more air and fuel and produce a rush above 5,000 rpm. On the other hand, Weber's are fluffy and tend to stumble at part throttle and cruise, while the Strombergs are smoother. Also, the pull from low rpm seems stronger with the 'bergs, though I have no real way to measure that. Either one brings a smile, nay, a grin to my face every time though, so who cares which you have. Just stuff your foot into it and enjoy!

Ross

[paddy]

I've heard anecdotally that the Strombergs are *much* more economical- if you're worried about that. Also, if building an engine from parts, the Stromberg heads seem to be quite a bit cheaper on ebay.

Paddy

[Jens]

Frankly, I don't think that people dricing classic sportscars really are into the MPG thing. But apart from that ofcourse it's interesting when you are driving long distances in the middle of the night when no gas stations are open.

Ross, what do you mean with "fluffy"? Is that a new name for "responding badly" or for "responding slowly an inaccurate"?

Greets

J - Just been doing a nightly rallye with an old Saab 96 Monte Carlo 2-stroke.

[Ross Robbins]

Jens,

Fluffy is an American slang term that roughly means that the response is soft when the accelerator pedal is pushed; perhaps hesitation would be another way to say it. It also sort of misses and stumbles a bit at a steady throttle opening almost as if it is too lean. Then as soon as the throttle is opened enough it clears and pulls strongly. I notice it on both my Weber cars even though they have both been tuned by qualified people and pass emissions tests easily.

I can picture you looking like Eric Carlsson in your SAAB Monte Carlo ...sounds like lots of fun.
Ross

[ElliottN]

.... and of course you can't fit webers/dellorto's to a stromberg head or vice versa.