Yamaha HPDI ECU Mods

[lance]

I have Yamaha 3.3L with Hydro Tec Phase III mods. I see that Simon Motor Sports mods Yamaha ECUs as well as other outboard ECUs. I'd like to raise the 6150 rev limiter on mine and see if there is any more performance to be gained with ignition/fuel changes.

I have yet to see a post where someone has had their Yamaha ECU reprogrammed. Anyone had this done?

[Jamescole]

i am also very interested in doing this with my 3.3 as well... with the mods done to mine i am also wondering if there would be benefits changing the fuel curve... Any thoughts on this ?

[dentguy]

The 3.3L ecu's are extremely difficult to read. Eric Simon has spent a lot of time trying with not much success.. As far as the rev limiter is concerned he was doing some "clocking" a few years back to get them to rev to 6350 and I ran one with good results. But that involves cutting the back of the ecu apart and replacing a part.. I think once someone gets the ecu stuff figured out on the 3.3 liters they will really come alive!

[Superbender]

I agree if we just knew some computer geeks,to help us get in there.

[Superbender]

Easy there tough guy,anybody can go and make a merc go fast.

[Superbender]

I've always had to do things the hard way,I blame my parents,sorry to high jack your thread.

[Jamescole]

any one have Fuel curve Thoughts?

[DoktorC]

any one have Fuel curve Thoughts?

To make an extreme HPDI you're going to need fuel management for sure..but the whole system is so complicated that messing with the fuel curves is going to need a lot input from the other end to tune the thing. Buy an OX66 if you want to make big power...fuel makes power....so your fuel savings will go out the window anyway.

with the mods done to yours changing your fuel curve won't get you far..considering its basically a 300...you could always try a 300 ECM and see if you pick up any rpm...

Or...how about a 3.3L OX? Up the displacement and lose the two power sucking fuel pumps...

[Jamescole]

To make an extreme HPDI you're going to need fuel management for sure..but the whole system is so complicated that messing with the fuel curves is going to need a lot input from the other end to tune the thing. Buy an OX66 if you want to make big power...fuel makes power....so your fuel savings will go out the window anyway.

with the mods done to yours changing your fuel curve won't get you far..considering its basically a 300...you could always try a 300 ECM and see if you pick up any rpm...

Or...how about a 3.3L OX? Up the displacement and lose the two power sucking fuel pumps...

i think fuel management will make power with out any porting.

[DoktorC]

i think fuel management will make power with out any porting.

It absolutely could...but you'll have to add something to the equation (more than you have now) whether it be compression, porting, magic...to see APPRECIABLE gains.

Hydro-tec has made more power out of the HPDI than you have in your motor...with the stock box...which tells us it's not starving for fuel until it gets to wherever they got to with the motor. If you're talking about adding a HP here or there buy finitely tweaking the fuel curve to run on premium..than yes there are probably some maginal gains to be had BUT given how HT operates and the HPDI system is an open loop I would say that there is enough fuel there to make whatever they can make with the phase III...or 4 or 5 whatever they call the ported/high compression version of your motor. Just remember...Lean is mean...and that motor is expensive to tune by plug chops and EGTs...

That being said you could just have it ported and pump the compression (the next phase...22?) and add more power for less money....then start thinking about fuel curves, timing, and rev limiters...

[Jamescole]

It absolutely could...but you'll have to add something to the equation (more than you have now) whether it be compression, porting, magic...to see APPRECIABLE gains.

Hydro-tec has made more power out of the HPDI than you have in your motor...with the stock box...which tells us it's not starving for fuel until it gets to wherever they got to with the motor. If you're talking about adding a HP here or there buy finitely tweaking the fuel curve to run on premium..than yes there are probably some maginal gains to be had BUT given how HT operates and the HPDI system is an open loop I would say that there is enough fuel there to make whatever they can make with the phase III...or 4 or 5 whatever they call the ported/high compression version of your motor. Just remember...Lean is mean...and that motor is expensive to tune by plug chops and EGTs...

That being said you could just have it ported and pump the compression (the next phase...22?) and add more power for less money....then start thinking about fuel curves, timing, and rev limiters...

so.... Fuel management is useless?

[lance]

Regarding Dentguy's post, the Simon Motorsports website states they can raise rev limiters and do custom tuning on most Yamaha Outboard ECU's 2003 & UP HPDI 200, 225, 250, 300, so they certainly imply they have the computer figured out. I guess I'll call them and see what service they provide. BTW Keith, the Yamaha I bought from you 2 years ago is still running great!

I seem to remember seeing several posts on a Hydro Tec dyno test where a 3.3 HPDI, ported, phase III, had the rev limiter raised and the horsepower kept going up well past the stock 6150 limit. I don't remember the specifics.

Another thought... the ECU takes inputs from several sensors including atmospheric pressure and air intake temp. I wonder if the electrical signals from these sensors could be changed slightly and therefore change the fuel curve? For example have the air intake temp tell the ECU it is actually at a lower temp and therefore more fuel would be added. I'm assuming the ECU works something like that?

[DoktorC]

Another thought... the ECU takes inputs from several sensors including atmospheric pressure and air intake temp. I wonder if the electrical signals from these sensors could be changed slightly and therefore change the fuel curve? For example have the air intake temp tell the ECU it is actually at a lower temp and therefore more fuel would be added. I'm assuming the ECU works something like that?

I'm not sure why we haven't seen some sort of external programmer that can do all of this. The Power Commander guys have all the bikes and sleds figured out. It would still be a pain in the ass to build maps but I know for the bikes/sleds they have timing control and the ability to move the limiter.

[dnelson964]

I like the way you're all Thinking !

[Mitchie]

James I never knew you to be so sensitive. My understanding is the ht ox66 have very, very mild porting. Richard is right. They are far from crazy.... Clearly the 300xs is making more power up top.