Can a Rocket III take down the establishment, and rule this island

[wjb]

I'll bet they don't have many customers who order only 3 pistons!
Are they off the shelf pistons or custom ordered?

 

[R-III-R Turbo]

I'll bet they don't have many customers who order only 3 pistons!
Are they off the shelf pistons or custom ordered?

Well full disclosure I ordered enough for 2 sets and a spare, because race bike.
Completely custom made.

For enquiring minds, the stock combustion chamber volume I measured was 69cc, and the stock pistons 25cc dish;

 

[Gerald]

Small update here, got a handful of custom turbo pistons on order, 8.0:1 targeted.
Taking a step back to lower compression in order to take 2 steps forward by being able to cram twice as much air in there.

Are these forged units, who's the manufacturer?

 

[R-III-R Turbo]

Forged 2618-T61 aluminium alloy, from my ever helpful friends in CP-Carrillo.

Some good reading from JE Pistons on material choice (LINK)

 

[Gerald]

Forged 2618-T61 aluminium alloy, from my ever helpful friends in CP-Carrillo.

Some good reading from JE Pistons on material choice (LINK)

Either one is a good choice, forged is the key. I remember when Forged True was the industry premium. I owned several sets for different engine gassers I was running. Bought a set of JE`s from Neville for my bike.

 

[Neville Lush]

I am wondering how you are going to get more boost? You can't spin the blower faster, as you are doing 9000 engine rpm anyway. The rotrex charger has a defined rev limit. Are you fitting a larger charger? If the compression is let down to stock ( which is 8.7) , then you will need different cam timing to avoid it being a complete and utter slug under 5000rpm. Mind you, that may help getting it off the line. I suggest you buy several sets of clutch plates and practise the launch a lot.

 

[R-III-R Turbo]

I was running a small custom made crank pulley, to spin the blower slower since the pistons were high comp, and maxing out around 7-8psi.
Switching to a 100mm crank pulley now which should run the blower at it's max of 100,000rpm assuming no belt slip. Aiming for 14-15psi.

 

[Neville Lush]

The stage one kits from Richard do 17psi at 7200engine rpm on a stock rocket. First time I measured one I got a surprise.

 

[R-III-R Turbo]

Good to know, I think they're a 100mm crank pulley too so might get a few more psi from the 9000rpm engine. Although the 2.5L will consume a little more volume and counteract pressure increase.
I won't say no to more boost anyway..

 

[Neville Lush]

You won't need as much boost as you think, if the thing is set up well. It is possible to top 300hp easily with 12-13psi. Getting it to not explode will be fairly important.