Lotus Elan

Rev Limit?

PostPost by: andyhodg » Tue May 24, 2011 9:40 am

Hi All

I have decided to invest in an electronic rev limiter for my +2. The question I have is to what rev limit should I set the limiter. The easy answer is of course the 6,500 rpm red line. Is it safe to set it slightly higher? The engine has a standard crank and con rods. The cams have been reground (years ago by vegantune) to a 0.360" lift and the head has been converted (again by vegantune) with big inlet and exhaust valves. The cam fllowers are the lightweight thin pad buckets and the valve springs are standard (as far as I know).

Thanks in advance.

Andy
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PostPost by: Robbie693 » Tue May 24, 2011 10:12 am

Hi Andy,

I know this doesn't specifically answer your question but the Big Valve engine had a rev limit slightly higher than the SE engine at 6750rpm. The red line on the rev counter wasn't changed though. I don't know if any of the engine internals were beefed up to achieve this.

Cheers

Robbie
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PostPost by: GrUmPyBoDgEr » Tue May 24, 2011 10:32 am

Andy,

if you've got them, take a look at the power/torque curves for yours or a similar engine.
I doubt if there is anything to achieve by limiting the revs higher than 6500 RPM except for nice noises when driving through tunnels.
Your driving style will have the most influence on your final decision, bearing in mind the higher fuel consumption & reduced engine life that the higher revs bring with them.
My Weber's simply guzzle fuel at high revs & at today's prices I keep the revs down except for when the Demons take over control. :wink:

Cheers
John
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Editor: On Sunday morning, February 8th 2015, Derek "John" Pelly AKA GrumpyBodger passed away genuinely peacefully at Weston Hospicecare, Weston Super Mare. He will be missed.
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PostPost by: rgh0 » Tue May 24, 2011 12:00 pm

The bottom end is normally safe to 7000 rpm and the standard top end will run well above that. However you want some safety margin so I would not set a rev limit on a standard bottom end for road use much above the 6750 rpm of the Sprints.

You engine may get a little more power with the mods done if you pushed it to 7000 rpm but not really worth the risk - I have seen a lots of standard bottom ends come apart if revved for long even just a little over 7000rpm.

cheers
Rohan
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PostPost by: andyhodg » Tue May 24, 2011 6:24 pm

Thanks Guys

I think the 6,750 limit sounds good to me. Just enough for the boy racer in me to be let loose once in a while.

Regards

Andy
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PostPost by: SJ Lambert » Fri May 27, 2011 6:24 am

That sort of limit is good - cause it can be fun when you run into it!!

My stock standard road motor with crank at 10 or 20 under (I can't remember which) ran for years as daily transport with not uncommon bouts of running into the limiter (6500 on original rotor button) without problems!!
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