View single post by Esprit2
 Posted: 02-13-2020 05:37 pm
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Esprit2

 

Joined: 05-01-2005
Location: Minneapolis, Minnesota USA
Posts: 460
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The carbs in which I measured both needles dropping out at around 4.5-4.75 turns were on a stock 1979 Lotus Eclat's Federal 907.

Stop screw or no... the point is that the adjustment range is limited by the length of the thread. 3.5 turns out is very lean, and about all you can get. 1.5 turns out is richer, and 'about' where the engine will be more happy. That was with B1DK needles, and the exact setting will vary with the needles that are installed.

*~*~*~*
If you're observant about vintage Lotus cars, you might notice a trend of odd fixes used to meet American standards.

The Europa's nose was too low to meet Federal bumper and headlight height standards. Initially, Lotus simply inverted the lower control arm, which raised the nose. That got it into the country and off the dealer's showroom floor. Then all the private owner had to do was flip the lower control arms back over (all the required parts were 'right there') to lower the nose back to Euro ride height.

Another example is the dual-MOP 110 red dot/ 100 blue dot cam pulley on the later emissions 907. On the dual-MOP pulley, the geometry doesn't permit both 110 and 100 to co-exist. So Lotus simply moved the blue dot to the nearest MOP that did exist... 97 MOP. That's worse, so why would they do that? Because once the car was in the country, all the private owner had to do was remove the intake pulley, flip it over, and rotate it 3 teeth to the desired, more powerful 110 red dot timing.

There's a history of Lotus using such creative assembly to get the cars into North America... then you just re-assemble/ re-adjust the same parts to get the car to what is was really meant to be. There is no published list of such monkey business, and no insider NNWWSNM acknowledgement, but I've been playing with Lotus cars long enough to have had more than one occassion to go, hmmmm.

It wouldn't surprise me at all if Lotus used a metering needle with which the engine could be tuned to run 'normally', and then simply adjusted it extremely lean to get the car into the country. Even if setting it that lean meant leaving out a stop screw. The 1979-80 907 powered cars ran like crap rolling off the boat, but they were emissions legal. Then the private owner only had to re-adjust the Z-S metering screws, flip over the existing dual-MOP intake cam pulley to 110 MOP, and adjust the static ignition timing to 12-14 BTDC in order to convert a polished turd into a diamond. Just a Saturday afternoon.

A corporate car manufacturer or their official dealers can't modify cars out of compliance with Federal specs. But a private owner could/ can modify their cars... just look at all the custom-bult hotrods, low-riders and street-tuner cars that are running around.

But you didn't hear any of that from me.

Regards,
Tim Engel

Last edited on 02-13-2020 06:21 pm by Esprit2