Expansion pipe on two stroke marine engine possble ?
Hi there all,
i have a 40 hp mercury(jap spec) short shaft 3 cylinder,3 carb engine on a 3.90 mt alloy tinny.
i have done quite a few mods so far to it,jack plate,hydro foil plate,mercury ss 15 " 4 blade balanced,cupped,thinned prop,50 d2 carbs,50 hp d1 larger stinger exhaust,60 thou shaved of head,irriduam spark plugs,removed air box,disconnected rev limiter wire,lightened flywheel,carbon reeds,ram tube velocity stcks,removed 2 lighting coils,exhaust relief hole mods in leg,cut air vents in cowl,amsoil full synthetic @ 50:1 ratio,bp 98 octane fuel
future mods will be in next few months,
1 mm over size wiseco forged pistons,full race porting,balanced crank shaft.
ok,so is it possble to make/modify and fit a expansion pipe to a out board marine engine ?
i realize the expansion part of the pipe will not fit in lower leg,but i would use the smaller ,later model stinger manifold,add some pipe length to end of it,then run a cylicone adaptor pipe,cut off the old curved pipe/flange and position it so the pipe comes out of side of leg ,near where the lower 2 bushes are,then make bracket/brace to bolt the out chamber to the engine.
i have ben looking at using a jet ski 800 cc expansion pipe,the jet ski pipe shoulld work ok i beleive as the engine on jet ski are similar size,bore,stroke and rev range.
although they usually rev to 7,000 rpm.
here is what im looking at buying and modifying to suit/fit,
www.factorypipe.com
http://www.factorypipe.com/p_kawasaki.php
http://www.factorypipe.com/p_yamaha.php
http://www.factorypipe.com/p_seadoo.php
is this going to be possble some how ??
out of the pipes above,which would be the best one to choose ??
i like that kawaski 750 SX/SXi Limited
i really hope so,cause a nice decent expansion pipe would cain hard!!
i luv the sound of two stroke pipes!!
so do you reackon the perf from a expansion pipe would be be on par with say just the normal exhuast stinger or worse ?
out of the pipes from factory pipe website which one would have the most chance of working ?
you know how jet ski's have 2 or 3 cylinders,and they have only one expansion pipe for all cylinders,why is that and they work on them ?
i cant buy bigger engine ,say for example a 60 hp as they are far to heavy for my boat !!
as it is my boat is meant to have only a 25 hp size engine on it
.
but i have had my rear transom braced and modified for extra weight and power force.
i have tried doin extensive google search on this topic so far,nothing much.
do you please have any other links of info/pics of expansion pipeson small outboards ?
it is not possble to make seperate manifolds for my engine is it ?
why cant you keep bliping the throttle to keep revs up,say like shift gears??
jet ski's dont have gears either,and there power expansion pipes work dont they ??
they dont have a chamber for each exhaust port do they ??,no the ones iv seen any way!!
what is a sliding style pipe mean ?
so if the pipe does not act/perfom like it should do on a marine out board,if it was fitted,would it run worse then ?
what about the nice tinny rev sound a expansion pipe makes,will it have it ?
if i buy the centre bleed in the links above i provided,the pipe should kick in lower rev range than the end bleed pipe!!
hope to hear some replies/helpful comment or may be some links!!
cheers guys
