Hello fellow Honda owners, am from another forum for owners of Honda jetskis, in particular the Honda Civic 10th gen L15B7 INTO HONDA JETSKI
F15X 1500 cc models.
These have a 1500cc engine, turbocharged and around 200 hp.
Honda Civic 10th gen L15B7 INTO HONDA JETSKI 15x engine
uses a dry sump oil system, tank is on the front and also contains a watercooled oil cooler. Square thing on the back is a watercooled intercooler.
It looks like a tight fit but isnt too bad to work on in ski.
These were made from 2008 to 2011 then discontinued, parts are now scarce and some not available for these engines.
A few of us have decided to look at a replacement engine and the 10th gen L15B7 seems to be the best choice.
Important for a jetski engine is a flat torque curve, L15B looks good, WOT RPM is 7000 RPM, limiter is 7400, which seems to be getting to the upper end of a L15B stock, but if we can get more torque and power can run at lower RPMs to feed the 155mm jetpump.
above some typical jetskis and jetboat power requirement curves, there is a bit of science matching a jetpump to an engine and vice versa, You can see in the upper range the pump power requirements go up very steep with all the models listed.
Our aim is to achieve the black curve, which is a Kawasaki 300 ULTRA, also 1500 cc engine. This uses a bigger jetpump at 160 mm. Think of the jetpump as a constant load like manual transmission gearing, bigger pump lower rpm like higher gearing.
L15B with built in watercooled exhaust manifold is a big PLUS for our selection as on the jetski engine this is separate, now discontinued, has a high failure rate from corrosion and price was $1700 USD when they were available. Have found a L15B7 here in Australia with 89000 KMS for the same price as a new exhaust manifold.
2nd problem was the IHI MG8 turborcharger running ceramic ball bearings, replacement internal parts are just becoming available now and retrofitting was difficult as exhaust housing was water cooled, the turbo wasnt.
Tuning is almost non existent as the ECU is potted and sealed and has an unusual K line interface and baud rate (no can bus), similar to motorcycles from that era, but can be flashed on the machine, but no custom tunes are available.
Dual balance shafts are fitted, but have become problematic and sometimes spin bearing shells, normally we delete balance shafts and plug oil galleries as a set of replacment crankcases is over $5000 USD if you can find them.
Previous owner of my F15X ski developed a conrod bearing issue, reputable shop completed rebuild with new bearings rods,rings (not pistons), head rebuild valves etc . Cost came to $8000 USD, adding a turbocharger rebuild, engine mounts and steering cable, total was $10000 USD. About twice what the ski is worth in the USA.
Would value your opinions/ caveats any advice to pursue this retrofit. Any actual dyno curves you have around the 250 HP range I would appreciate viewing particularly if they gave big torque increases.
Turbo upgrade also am interested in and differences between the B model variants.
Above power/tq curve is ideal but would like to see some actual WHP tunes from owners here.
Normally would use WOT where the power and torque curves intersect, need this to be more like 5500 RPM to ensure engine longevity.
thanks and regards
OZTRAX
L15B7 SWAP INTO HONDA F15X JETSKI
L15B7 SWAP INTO HONDA F15X JETSKI
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