Lotus Elan

More power from QED420 spec' engine

PostPost by: holywood3645 » Fri May 11, 2018 7:53 pm

Ok, Yes its fine and probably more than enough for a road going elan. But I feel the need!
Presently a 1700cc QED 420S spec motor, Sprint Valve head, mildly ported, 83.5mm pistons, 711M block & decked bottom Lucas CE ignition and 40DCOE151's (145 to 155hp quoted) hardened and balanced rods etc

Now that I have the suspension nearly where i want it to be, I would like another 20 or so hp, without sacrificing torque and drive-ability. Any ideas, where I can gain performance without throwing the baby out with the bath-water?
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PostPost by: rgh0 » Sat May 12, 2018 2:57 am

Whats your compression ratio you may be able to go a little higher.
1.625 inlet valves and some more porting ( or new head)
I would also try the McCoy .44 lift 285 seat to seat duration cams. Depending on how your current head was built you will probably need new valve springs and followers.
What exhaust do you have, the TTR system will help

If you have not had it on a dolling road dyno then finding someone good with Webers and spending some time optimizing the carbs chokes and jetting and ignition timing will give you a boost also.

Doing the above in 1700cc engine should give you around 170hp at 6500 rpm.

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