Thread: Need opinions ecu

I have an 04 rxp with 140 hours. It has an A kit installed and now it is having a seadoo centre 8400rpm ecu installed. What are your opinions on retainers and valve train upgrades? Are they needed or not?

Also what hp do people think this setup will be turning? thanks

From what Ive discovered from research and speaking to people, the valve train seems to be the weakest link with the rotax. Also if your planning on upping the RPM's by using aftermarket or modifying ECU then upgraded valve train including springs, valves retainers would be a must.

The extra RPMs will give you more boost aswell as turning your prop faster giving you more speed, but other than that the upgraded valve gear really doesnt give you any more HP, just reliability and ability to cope with turning larger RPM's.

IMO unless you plan on racing why place the motor under the extra stress of having to cope with higher RPM. Spinning at between 8000 and 8100RPM at wot I personally think that poor little rotax is workin hard enuf considering the environment its in!! On the other hand Ive heard of a lot of people having great success raising RPM's. But at what cost??.

I am planning to race soon and higher rpms would really help.

I did ask the people at seadoo centre and they said that it wasn't needed. I just wanted to hear other people's experiences and thoughts. They said the same thing you said that its not needed until you go above 8600rpm.

Also this might sound dumb but what does RRFPR stand for and what does it do?

RRFPR stands for rising rate fuel pressure regulator. A RRFPR adds more fuel to the engine by increasing fuel pressure as boost rises. In other words, they raise fuel pressure proportionally in response to increases in manifold pressure.
By the way how have you liked the A Kit wheel?? Feel a major difference in acceleration and top speed??
I have finally got all my stuff in and am just waitin to get my hands on a prop tool to put in the 15/20 and Ill finally get to put it in the water!! Cant wait

Thanks for clarifing that for me. I'm sure they tune that a little through the ecu. I have told Seadoo Centre my set up and they will tune my ECU accordingly.
The A kit is awesome! It only revs to 7600 because the Skat Trak prop i put in isn't working right. So once i replace the prop should feel it even more. With the ecu they say it will give the A kit life. So can't wait to see the results once everything is running and tuned right.

What results you expecting? I'm sure it will be exciting

Pottsy is correct.

Its the rev limiter they are playing with. Make the boat capable of reving higher to take advantage of this.

140 hrs is time to have a good look over the whole train to check for sagging parts etc. Keep the charger slip in the range, and all will be well.

The humid atmosphere the system works in will take its toll in corrosion etc, which does weaken the valve stems.

The 04 has a bad rap for Cyl#3 dropping its valves.

You can put better valves in which will help performance. look to pay about $2000 to get it near done. Have the .29 cam re-profiled, and it will whizz along for you.

Best power may well be at 8150(or what ever the ECU is tailored to) shall we say, so revving past this is really just a waste of time.

Pull the RPM back down by altering the outlet of the jet-pump to this number.

Either change the valves to 07 ones, or go for performance ones.

Just a good idea with 140 hrs on it, and probably unknown history. To get an exchange short block to fix a damaged unit will set you back $3500 easily, with non-oem parts fitted to it as well..!!

You have to remember that real race engines are regularly dis-mantled and inspected. 9100 motors need lots of TLC... but you can tell immediately they are what it says on the box.

Do some hull modifications to get the edge too, it is suprising what this will give you if you are racing. I know of one A special, with all the other mods which is a brilliant CC machine. No Valve changes or ecu changes either...even uses std inter-cooler... nets 72.8 MPH everyday, with handling to suit. 8100 RPM..!!

Which prop are you using to pull the RPM so low?

Have you double checked the Charger slip, and for air leaks?

My mechanic is going to take the head apart, and check everything as he puts the new ecu in. The charger was all checked over, just 2 hours ago when the A kit was installed.

What do you mean by having the .29 cam reprofiled?

What hull modifications are you suggesting? i have already got worx sponsons and a worx intake grate, removed opas and extented the ride plate. Got pro taper handle bars with a umi finger throttle and a new jet trim seat and hydro turf mats for more grip.

I have a skat trak 13/18. It is faulty so getting a new one. Yerr everything else has been checked, so must be the new prop.

More RPM means more boost so it must be faster then at 8100rpm. Say if at 8100rpm its running 10psi boost at 8400rpm it could be running 11 or more psi of boost. correct?

Yeah the boost rises proportionally with RPM. Also the faster your engine is turning over the faster the prop is spinning thus more speed. I think Richieb was suggesting that without cam mods you will theoretically not be making any more usable power from raising the RPM. I agree with this but as speed of the craft is determined by how fast the prop is turning I can see how raising RPM will improve speed.(I look at the prop as being like a differential in a car so to speak) .
Anyway thats my 2 cents worth. Most guys here would have a great deal more experience than myself as im relatively new in the jet ski world and learning as I go.

Im hoping to see 75mph and still have a strong holeshot. As im only a rec rider im not overly concerned about squeezin every last bit out of it but since I have have always had a sickness for power and speed I will keep tuning and modding well beyond what I ever had planned!!
Attached is a pic of all the new bits installed. Had it runnin of the hose and no leaks or probs at the moment. Hopefully have the prop in today and with any luck be in the water tomorrow. Shame your so far away, would have been interesting to line em up!!IMG_0325.jpg

i hope richie b is wrong because i would be quiet disapointed. yerr it would be nice to line them up. 75 mile ha? pretty quick.....good luck

I've finally gotten around to doing my 4 inch air intake and I have a few questions about the way you did yours.

1. How did you connect the 4 inch Kanaflex pipe to the superhcarger. Did you use a reduser? I was thinking of getting an exhaust place to fabricate a 3inch to 4 inch metal pipe.

2. Did you use a piece of 4 inch metal pipe to mount the supercharger and the pod filter together?

3. Something about the oil bleed line. What is all that about?

4. How did you get the pod filter to sit in place, because seadoo centre sells a mounting bracket that screws underneath the steering. Though quiet pricey for what it is.