Sea Doo VE Table

Hi Everyone,

So, I have recently gotten a hold of a sea doo spark engine that is going into my mini jet boat and was trying to figure out what is going on inside the stock ecu. The tunes offered for these machines lead me to believe brp has likely left a lot on the table in terms of performance with these engines. I started looking through the stock file and when I came across the VE table it was unlike anything I have ever seen before. I was hoping someone would be able to tell me what is going on with this. According to the table, at 100 kpa it does not even reach 50% VE and for some reason the table only starts at 60 kpa. I have done a lot of thinking and so far the only things i could come up with is that this is either the worst flowing engine in the world, or I am missing something. I did also find another table under electronic throttle that shows airflow as a function of throttle opening and RPM. Could they be using that as their main airflow calculation? I do have a suspicion that they could be using a combination of speed density and AlphaN as there is a table for interpolating between the two but it is all set to 0. Either way I have no idea what is going on and would appreciate any help. I have attached the HPT file for those that would like to take a look.

Do you have a target VE table as well?

Does wideband logging suggest target VE is being matched with those VEs?

What is MAP at idle?

What induction system and exhaust are you running?

If they are cammed/ported/manifolded to make power at 8000rpm without emissions concerns VE will be pretty low at idle.

I cannot seem to find anything related to target VE but I find most other tables such as ignition timing and power enrichment seem to be using engine load expressed as a percentage for the Y axis, but I can't seem to find where that is being calculated. It is also entirely possible that HP Tuners has not yet made all the tables available for this ecu.

As for logging and data, I have not run the engine yet and am not able to do that right now as it is currently winter over here. I will not be able to do any significant data logging until spring. I do have a wideband but not sure exactly how to mount it into a water cooled exhaust. Might be able to tap in somewhere before exhaust and water mix.

The exhaust and intake are all stock. It does have water cooled exhaust though, not sure what kind of back pressure a person can expect from something like that but I guess it could bring the VE down a bit.

What I find interesting is that the VE table actually looks very normal until you look at the numbers on the load axis. I am starting to think the load calculation is done mostly off of throttle position in the following table.

I can send you a picture tomorrow of where to put a Wideband O2 Sensor and a 900ace (Spark) Engine

Thanks Matt. That would be much appreciated.

Where the red X is

sorry pics isn't closer

Do you usually just drill and tap it or weld a bung on?