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Well thats the plan

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Ians engine rotates.JPG


small is beautiful

The engine is made by Derbi, a relatively small Spanish company, who actually have a long history of small capacity road racing.

Based on the Minarelli AM6 engine, it is the D50B model, an improvement on the AM6 with better cooling channels and a stronger set of crankcases. The gear ratios etc are just the same.

To this has been added a lovely TRTeam 2FAST 100cc big bore and stroker crankshaft kit.

Using standard ignition this made 29 bhp on the BoostBusters dyno. That is down on the claimed 32 bhp, but from my experience of the 70cc AM6, i know that a full Stage 6 race ignition will add the rest.

To this is added a full race expansion chamber from TRTeam, a 34mm Dellorto carburettor and significant porting to both the crankcase inlet and transfers, plus the addition of a Honda CR85 V-Force reed block for better breathing.

Testing in this 



I have a Non-Disclosure Agreement in place with BoostBusters, so some information will be kept confidential, I'm sure you'll understand.

Part of the joy of this process is the people you meet and the places that you get to go to.

I shipped 2 complete engines out to BoostBusters in Stockholm Sweden where Lennarth is based so that he could couple the engine up to his dyno and complete the turbo system design and implementation.

Having a spare engine was deemed cheaper than Lennarth having to strip it down should some unfortunate event happen to the crank or similar.

The turbo system uses a Borg Warner turbo from a small Volkswagen car and runs at up to 1 bar pressure.

Due to the 2 stroke nature of the engine it require the provision of a separate regulated oil supply.

Additionally, the carburettor requires adaptations making to it to cope with boost pressures going through it venturi and into the float bowl. I'll let you work out what was needed.

On the dyno, we revved the engine to 13,800rpm and achieved a peak bhp of just under 43 bhp.

Now that is more power per litre, nearly 3 times, that of the Bugatti Veyron, not bad for a moped.

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