Lotus Elan

Elan +2 UK spec Stromberg Carbs vs. U.S. spec Stromberg carb

PostPost by: mcole01 » Sun Jan 09, 2022 11:13 pm


I was reading Miles Wilkins book on the Lotus Twin Cam engine and came across the following statement regarding Stromberg carbs on cars with emission equipment i.e., Federal cars. "He states, The only cure for these engines is to return to standard U.K. specifications , i.e., to fit adaptor blocks, balance pipe, 175 CDS Strombergs, four branch manifold and a distributor" (meaning, I assume, a U.K. spec distributer). I understand everything except the 175 CDS Strombergs. I've searched the web and my books but can't find such a carb. What I find is 175 CD2 carbs.
Can someone enlighten me?

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PostPost by: SENC » Mon Jan 10, 2022 12:35 am

Mike - see below for a couple good resources - the first is available from Burlens, and their website is quite useful, too. The second is a good little book that you can likely find on ebay or elsewhere on the web for not much (though I haven't looked in a long while). Essentially, the goal is to convert carbs bound for the US (CD2SE) to the same spec as carbs bound for the rest of the world (CDSE).

Martin Jay (Distributor Doctor) can set up a new/rebuilt dizzy with the right advance curve.

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PostPost by: Lotus 50 » Mon Jan 10, 2022 1:05 am

It seems like every Stromberg Lotus Elan or Plus 2 that I see has been converted to Webers, There was no claimed power difference, but was there a difference?
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PostPost by: steve lyle » Mon Jan 10, 2022 2:28 am

I sent my Federal Strombergs to Joe Curto, and he rebuilt them to UK specs. At his recommendation, the dizzy went to British Vacuum Unit, where it was rebuilt and recurved to UK spec. IIRC, Curto charged $600, BVU $100. Car runs like a scalded dog.

My understanding is that the Fed TCs also had slightly less compression, so if a Fed car has less power after the above, that would be why. Skim the head to fix that, I presume.

And oh yes, replace the iron exhaust manifold with headers.
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