Currently building a Terrapin ( single seater based on a Mini ) and planning in a few years time to use it for hill climbs and sprints. No intention of winning but just for fun.

In terms of class Am I right in thinking it would be

D1. Sports Libre Cars up to 1400cc

And that if I fit a 998cc mini engine and then turbo it it still falls within this class as a turbo carries a 40% increase in capacity penalty so making the 998cc engine a 1397cc engine.


Paul

It will fall into the 1600cc single seater class which is a bit competitive!

Surely with the terrapin being a single seater, then you would be in the appropriate class for single seaters of the engine size ?
(That's after applying the turbo multiplier as you correctly state).

Wouldn't have thought that Libre would have been your class.



You should maybe bear in mind that if you plan a build lasting some time then you may have to be flexible about final choice of engine.

Regs have something of a habit of changing and upsetting the apple cart.

Then there's the popularity of classes.

Years ago up here, Single Seaters up to 1600cc pretty much meant an old FF on webers slicks and wings.
Then we had up to 1100cc along with standard FF which meant either an imp engine with webers in a slicks and wings chassis or an old FF in standard spec.

Since the advent of cheap bike power, all of the above is now ancient history. If you don't have a GSXR1000/11/13 in the back then you're not there.
Car engines are nowhere now except in the bigger classes where Judds, DFVs and the very occasional Hart 420R can still be seen.

I know you said you're not looking to win, all I'm saying is that you could maybe consider the class you end up in as an empty class is never much fun.

Speak to minitici, he has done all of these things and still continues to do so.

I'll shut up now, there are far more expert than me on such matters

You could always build the Mk5 Terrapin sports racer and enter Sports Libre up to 1400cc.
Not all championships/venues use the 1400cc split for Sports Libre, some are 1700 or 1800cc to cater for old Clubmans spec cars......

If you build for Sports Libre, refer to the MSA blue book for specs for Roll Over Bar and harnesses for Sports Libre (needs bigger bar and six point harnesses).