05-01-2009, 09:59 AM #1
Rude 1 question about air fuel ratio
I'm reading the forum here and now got to thinking, first heres my set up,
Riva ECU, 50# injectors, valve train upgrade, Sea Doo X Series IC, Green Hulk waterbox, 4" Kanaflex intake, there are more mods but those pertain to the engine, my question is, should I be running a larger fuel pump? Should I take it by my dealer and have him check out the A/F ratio? Can I check it and how do I do it? I do know I can get my exhaust temp warning light and buzzer to go off in hard use, but I'm hopeing thats a issue with the sender?
05-03-2009, 11:59 AM #2
Mike, your dealer won't be able to check your air fuel ratio. You will need to have a bung welded in your J pipe and then buy one of these. http://www.dynotunenitrous.com/store...?idproduct=150
You do not need an after market fuel pump for your application.
If you are getting an exhaust temp warning while holding wide open throttle for a while then you have a water flow problem to the exhaust. Probably due to an intercooler that needs cleaning. This link will help you
Other sources of poor water flow to the exhaust are the three pisser holes in the end of the J pip clogging up and also putting the clamp too low on the coupler that holds the J pipe to the water box. If you put the clamp too low you can pinch off water flow to the water box and cause a H-Temp alarm.
05-03-2009, 05:51 PM #3
On the bold, tried all of that more than once.
I have a 2007 RXT with basically a Stage 2 set-up, Metal washers, ROTAX RACING external intercooler, ROTAX RACING 10 pound s/c wheel, 14/19R prop, RIVA grate, RIVA 2 degree wedge, NOPAS, strainer, 4" air up front. I kept getting the P-1544 hot exhaust warning buzzer coming on to the point where I purchased another sensor and strapped it to the outside (yeah I know not the best idea) . I checked my intercooler, strainer, even the 3 pisser holes in the J-pipe, went as far as to install the YELLOW-O-ringed larger restrictor washer from an RXT-X, buzzer still comes on once and a while, especially after 1 minute or so full throttle, then goes off after idling for about 15 seconds. If the water is DEAD CALM it usually won't go off.
Since the ROTAX RACING intercooler has 5/8" fittings on it, I ran 5/8" heater hose from the outlet side of the intercooler to the front of the exhaust manifold. The stock hose was 3/4" , hokey plastic step fittings were included with the external intercooler, didn't trust them so I replaced the stock 3/4" hose with 5/8" hose and replaced the 3/4" stock fitting in the front of the exhaust manifold with the smaller 5/8".
I ride the usually rough waters of Lake Michigan.
I'm open for suggestions??
05-03-2009, 06:01 PM #4
- Join Date
- Sep 2006
- winchester va
05-03-2009, 06:48 PM #5
I have the extra stock restrictor and have drilled it out 1 size.
How big is too big??
How much pressure is coming out of that pump and how much can the intercooler handle??
Forgot to mention that I have the cooler 158* t'stat as well.
Open for suggestions.
05-03-2009, 07:05 PM #6
Hey all, I bought an Innovate LM-2 for $460 Australian dollars, it has data logging on it too with memory card etc.
Now put this to $US, and it has to be a bargain.!!
Really helps me get the mixture right, no fooling about as I can see where the weak spots are in the rev range.
But to me the exh overheat sounds like lack of water-flow through the J-Pipe to the box. I actually opened up the water jets at the base of the pipe with 3 more holes of similar dimensions, and never had a problem yet with overheat.
I took out the yellow restrictor by 2mm as well to ensure full flow, as the bleed on the I/C is an extra burden on water-flow. You have to remember that fast flow thro the cooler is not ideal, but it should not be too fast, nor too slow. Now this is where trial and error come in, as the restrictor is part or the way that flow speed is regulated through the whole system. So don't over-do it either, but keep it real enough. I am told the pressure is sub 70psi, as most water/air intercoolers don't cope with pressures over this.
Remember there are no set figures or settings at this stage, as mst of the work you do is pioneering stuff..!!, just always go on the safe side. This is one point I have been trying to put accross in the tuning forum, as if one is not careful, the information we put on may not apply to all builds as each motor is different, and could cause damage... with re-percussions unknown!, just be careful.
Last edited by Richieb; 05-03-2009 at 07:12 PM. Reason: more info..
05-03-2009, 07:23 PM #7
Are you saying that you now have 6 holes in the J-pipe ???? (3) original stock holes PLUS (3) more new holes (same size??) ????
On the restrictor, 7mm is stock if I remember correctly, so you're saying you're @ 9 mm??
Thanks for the quick feedback.
Always wanted to visit your country, I'll have to get around to that sometime soon.
Suggestions on time of year (I'm told January) is best and or areas to stay @ and see???
05-03-2009, 07:40 PM #8
Yes, thats right, I have 6 on my pipe at present... all this does is cool the exhaust gasses down
I have the yellow to 2mm OD larger, but it isnt full flow though. Not too much, not too little.
Our country is tops for ski water access where we live. You should have a look one day for sure. January is pretty good all-round weather.
If you do then give me a shout, I can let you take the ski for a ride, as I have 2 here. It really depends on what you are looking for here, as we have a good mix of everything. Breath-taking scenery... spread over long distances, ocean and rivers galore in Sydney area, but I have to admit I have not had chance to explore the rest of Aus, as it is huge, and would take a lifetime.
05-03-2009, 07:57 PM #9
Can we go out shark hunting???(for pictures only)
That breath-taking scenery you're referring to, is thata S-L-O-W ride past the scenery on the beach (Bikini tops still not allowed?)?? You gotta love it.
Gettin back to the ski, 3 new holes in the J-pipe same as the stock ones??
Yellow O-ringed restrictor (From an X- Boat right??)
When you say it isn't full flow through, you mean don't open it up to like, 14-15mm, right??
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