S3 Build need advise

[Bdpotter03]

So I’ve been doing this build for going on two years and am finally getting everything dialed in and am trying to squeeze every last drop of power out of this engine I’m running a 2017 Gtx limited 230 on a 1500 Ho platform, which is essentially a 1503 engine with a couple upgrades seadoo did from 2016 to 2017 high flow head spray in sleeves etc.My mods will be listed below I am currently running 83.5 with 52-60 degrees outside no wind water 55 degrees F at around 8960 rpm touching 9000 at times on a 15/19R my afr’s are around 11.9-12 at WOT.I’m looking for more speed, trying to match my gp1800 in acceleration and speed and believe I’ve met acceleration and am only down 2-3 mph in speed and am extremely close, was thinking about going over to Cp pistons and running E85 type setup to maybe push it over the top,and trying a 15/20 prop but I’m trying not to loose any acceleration, any help is greatly appreciated.

Mods
68-140 le extreme charger water cooled housing
Riva Racing 300 Racing camshaft
built Ported head(bronze valve guides,riva valves,riva valve train upgrade kit, viton seals and ported intake and exhaust)
Riva stage 4 kit gtx limited 260 parts in link (https://rivaracing.com/i-17815446-gt...age-4-kit.html)
Riva SS intake grate
Fizzle Intercooler
Riva water box
Riva Rear Exit Exhaust
15/19R Impeller
custom 84mm Venturi nozzle
exhaust manifold spacer

[jpt7779]

IMO you need a lot more pitch on the trailing edge for more speed. You are running very high rpm to obtain only 83 mph.

I would get the new 15/25: https://www.4-tecperformance.com/ind...pkv3tpj76s9516

Are those PRVs I see in the 3 rd picture?

[Bdpotter03]

Yeah with the speed I was running had to go to prv’s to avoid buck what rpm range should I be shooting for to be in the powerband the jetski is really responsive close to 9000 as I push more prop will I begin to loose a lot of that rpm and fall out of the powerband or will the charger compensate for the extra edge it’s pushing,thanks again don’t know much about how the bigger chargers react to impeller pitching.

[Bdpotter03]

I’m also at 1060 elevation which will effect what my pitch has to be vs somone at sea-level

[jpt7779]

Opinions are like A-holes, everybody has one! 8800 rpm seems to be the consensus for the engine rpm sweet spot and pump efficiency, which I agree with completely.

If you just don’t want to install the 15/25 or even a 15/22, then experiment with a Lucky 13 cone.

[Bdpotter03]

Can I run a 9:5:1 piston with the 68-140 and stay on pump gas with the map tuner adjusting the fuel timings with AFR?

[Bdpotter03]

Also I’ve tried the lucky 13 bored out the nozzle to 87mm and even pitched but never had any luck with it not to say it doesn’t work read the forums
and alot of people have had huge success just didn’t work
for my setup,thanks again really appreciate your help.

[1tommygunner1927]

Can I run a 9:5:1 piston with the 68-140 and stay on pump gas with the map tuner adjusting the fuel timings with AFR?

It depends on what the ignition timing is. If its too high the ecu will pull timing out (due to knock) slowing your ski. If using straight pump 93, use 30* of ignition timing.

[Bdpotter03]

Sounds perfect thanks you again what rpm and boost are the stock cylinder good to if my heads built up already?

[1tommygunner1927]

Sounds perfect thanks you again what rpm and boost are the stock cylinder good to if my heads built up already?

Stock block, pistons/rods, and the 68/140....max rpm should be in the 8800-8900. You'll need to check/rebuild the S/Cer more frequently than 100 hours.