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Riva's sea-doo

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Hi there

i will be tuning a riva vipec V88 on sea-doo this will be my first on this type of equipment i really appreciate is anyone can give me some direction on that my big concern is how do apply engine load on that and there is kind of dynamometer for this do i need to do of the job in the water.

Thank you .

If you don't have a Jet ski dyno setup then it is possible to tune the engine on the water, however this can be quite time consuming if you're starting from scratch.

You will find the load/rpm range of the jetski motor will be a lot more narrow than that of the street car. What I mean by that is you will find you will have a lot of "Dead spots" in the fuel map where you will never access or transition through really quickly.

I would basically just start by doing some some runs on the water and logging what it is doing, and make adjustments as required.

The only thing which can be difficult is tuning ignition timing, trying to achieve MBT will be basically impossible.

Start very conservative.

I would also recommend doing the "Road Tuning Course" available, although I know you won't be tuning on the road, the principle is the same and I think you will find it quite helpful in getting the same/or very similar result as you would on the dyno.

I haven't had the opportunity to tune any PWC, however I have tuned a number of jet boats and the techniques I imagine would be quite similar. As Chris mentions, you're only going to operate across a pretty narrow band of the fuel and ignition maps. You can basically take the idle area operating region in the bottom left of the map and the WOT/high rpm operating region in the top right and then draw a line between these points and that covers the area you will move through (ok so it's a little wider than this but not too much). This in many ways makes the tuning quite simple, particularly under WOT operation since the engine will end up almost operating in steady state conditions in a very small region of rpm and load.

I'd start by keeping the timing conservative and getting the fuelling correct and then move on to timing. While it's not as good as a dyno, you'll actually get a lot of feedback from a jet unit in terms of when the timing is optimal out on the water. Perform a test and note the max rpm, make a change to the timing and then see how the rpm is affected. If you make more torque, the engine rpm will increase - simple!

If the engine is heavily modified or you're expecting some large gains in power then you also need to consider the jet unit. A jet unit will have a specific rpm range where it delivers maximum efficiency (I can't speak for PWC, however in the Superboat-class competition jet sprint boat I tune for example, this is about 6000 rpm). If you make a significant increase in power it can often require a change to the blades in the jet unit to effectively load the engine harder or you can end up effectively running into cavitation. I understand PWC are probably running to 7000-8000+ rpm but thought I'd mention it anyway.

I have to tune one jet sky soon to with Riva package you should get a base map to start with.most tuning I consider using the logging and work out from there.

If you have a base map that is close enough to let you ride the ski and perform logging then your life will be much easier. It's understandably going to be harder working from scratch. Data logging is your friend :)

Hi there

there is anyway that i can get a base map that get me close enough to let me ride the ski to star my tuned from there, what are you recommendation for that or do i need sent a email to vi-pec to help me out.

I would talk to Riva and ask what the map supplied with the ECU is. I wouldn't be surprised if this will be enough to get you started as most vendors will sell Plug & Play ECUs with some kind of base map. Of course if you've made dramatic changes to the engine configuration then the base map might be way out.