Quote:
Originally Posted by Hillclimber
Yes, its to power a race car used for speed hill climbing at venues like Shelsley Walsh, Prescott etc with occasional sprints (1 lap) of Goodwood, Snetterton etc. Have used Rotax engines previously but need some more hp. I will use a CVT (Constantly Variable Transmission) like the old DAF system. Suits the 2 stroke characteristics perfectly.
There will be 6 Expansion chamber type exhausts, reworked porting, and an Emerald ECU to run the whole system. Its mappable from a lap top.
Considering sequential injection ( total of 12 injectors) with 2nd 6 coming in for above 75% throttle with methanol/oil mix for high RPM engine cooling and lubrication. Each exhaust port/pipe fitted with EGT and air/fuel ratio monitors to try and keep the rods in one piece.
After the test run, we fit the supercharger to run at 12 to 15 psi. SC powered by turbine powered 2000psi nitrogen gas so not to have any parasetic power loss.
I would be interested to hear from anyone with prior knowledge of any of these concepts or "Add Ons"
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300xs is a heavy and slower version of the 300x , it has different porting and is direct injection...suited for economy not performance due to parasitic losses caused by high injector rail pressures required.
The 300xs is a 3.2l engine which is basically the normal 3.0's just with a stroked crank which is to make up for the extra parasitic loss
All 3.0 and 3.2 l motors have a cast exhaust chest so I'd recommend 2.5 or 2.0l motor as they have removable exhaust chest covers (if your set on expansion chambers)
The outboard 2 strokes in question have no exhaust manifold as such just a collection chamber in the back of the block which would be a real challenge to fix headers/expansion chambers to.
Forced induction on 2 strokes isn't very successful as most of the charge tends to be pushed straight out the exhaust ports which remain open after the inlet ports are closed off.
Imo best option would be an 2 5l mercury f1 motor which will be the easy to get hold off, the lightest and also produce the most power. .. around 400!
Leave the exhaust chest standard, obviously there's more power to be had with correctly sized expansion chambers but I dont think the extra work involved would justify the gains.