I agree with the cast pistons verses forged pistons. I would never put a
cast piston in a racing or any high compression engine.
What about the factory connecting rods? Are they strong enough to
handle around 200 horsepower? This around what a U20 is capable
of normally aspirated. Plus or minus 20 horsepower.
I was just brainstorming about competition U20's. I was trying to see if it
was
feasible to build a high compression engine using flat tops. It would be
much
cheaper I guess to go to the mod class and use a VG or SR then try to
build horsepower into a U20.
Thanks,
Mike
No money, so I am doing some leg work and taking notes for a race car.
Jim Tyler wrote:
> For a real competition engine, any of the OE cast pistons are totally
> unacceptable. Decking the block with flat tops doesn't help much,
> if you run at the piston at zero deck height that only allows
> about .050 (gasket) of clearance which you must have. To get
> 11.5 or more you must have a dome. The R16 piston is way to wimpy
> for sustained revs over 7k.
>
> Probably the best choices for custom pistons are Venolia or JE.
> Even after you get a set from them, consider that a starting point
> since you will usually have to machine various portions for optimal
> performance and clearance.
>
> If you want to get really serious about it, I have a set of Cosworths
> around here some where I'll sell at a good price. They came out
> of Studdards program. They are the lightest/strongest.
> They can't be used for street since the under side of the dome is
> relieved (meaning you can't cut some of it off to lower the
> compression. They are all out racing pistons.
>
> Jim
>
> Mike Poorboy wrote:
> >
> > List,
> > After Stephan's use of 1600 domed pistons in his U20 it
> > had me wondering what the race car engines that are running
> > 11.5 to 1 or higher compression ratio's are using for pistons.
> >
> > NISMO catalog shows an Arias .40 over piston, but it doesn't
> > mention if it is domed or not. The standard U20 piston is a flat
> > top cast piston. I am thinking there are at least two ways to increase
> > compression in the U20 one is use the flat top style piston and deck
> > the block. the other is using dome top or pop up type pistons.
> > I realize that the engine would have to be run on racing fuel.
> >
> > I am just trying to get an idea what has been done out there to
> > accomplish
> > this on the U20 race cars.
> >
> > Thanks,
> > Mike
> > 2 69 SRL's part cars.
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