beetledon

I have my 1600cc 72 super beetle with dual solex carbs and headers. It's fun to rev it up thru the gears to get up to speed, but how many rev's can I go (4000 -5000) without damaging the power plant or the trans?

beetledon
72 blue super
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How is it handling it now? The reving it up.

 

4 to 5K is a little high.

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Ryan

The tranny will be fine.  On a stock engine the limiting factor is your valve springs and the non-counterweighted crank.  The springs will likely start floating around 4500 rpms and the crank will start flexing around 4k-ish.  Crank flex will pound out the bearings and the case saddles in time, and floating the valves can lead to all kinds of problems.

When built for it, these engines can rev pretty high.  My rev limiter is set to 6500 and that's still considered mild in some crowds.  --Ryan

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beetledon

Thanks for your concern Wiggins, she's running great, thanks for the info Ryan, since your input I've set my rev limiter on the tach to 3500 rpm's. I want this super beetle to last many years and have fun at the same time. Will be going on our http://www.mvvc.net color tour next Sunday and then probably put the bug to bed for the winter according to Wayne's instructions. Too bad we don't live in Tucon or Fresno where you probably keep your bugs running all year. Our kids and grand kids live here. They like the bug too. Aufwiedersehen, beetledon

beetledon
72 blue super
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beetledon

Ryan, what is a "rev limiter". When you mentioned it, I thought it was the little red pointer that can be adjusted on the tach. Is that correct or is some gizmo that limits the accelerator cable travel?  Thanks, beetledon

beetledon
72 blue super
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Ryan

A rev limiter is an electrical device that keeps the engine from passing a pre-determined rpm limit.  Mine is part of my MSD 6AL ignition box.  When I reach my limit, the box will start dropping cylinders.  That means I can put my gas pedal all the way down in neutral and the engine will not rev beyond the set limit.

On modern cars the device is called a governer because it can shut down fuel injectors as well and will generally limit you to a top speed, not an rpm limit.  --Ryan

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