Thread: 05 RXP too lean or too rich
06-17-2008, 11:50 AM #1
05 RXP too lean or too rich
Ok so hereís what Iím up against. I live in Idaho and my elevation on the lake is 2500 ft above sea level.
I have the following mods:
2005 RXP,Custom Paint and fiberglass work, UMI Steering, highrise hood fresh 5" air intake, Riva exhaust, RE block off, Reverse gate mod, Riva Racing Stage III Supercharger, Jerry's SC rebuild,Piranha IC, Piranha Front Engine mount,Stock Injectors, Stock ECU, Boost gauge, Solas 3 blade 14/18, 2 degree wedge, Riva grate, Rotax 158* thermostat, Pro series Race nozzle,Finger throttle, GH Waterbox,Worx Sponsons, Gator Grip,74.6 MPH at 8150 rpm's - 2500ft above sea level
I just switched to the 42lb injectors and my ski that usually runs at 8100 Ė 8150 rpmís with stock injectors is now running at 7400 RPMís off the start. If I make a long run WOT then the ski feels like it opens up a little and the rpmís get up to 7900 rpmís for about 5 to 8 seconds then back down to 7400 rpmís. I switched injectors because I was afraid of running to lean but now I think Iím too rich and want to get back to stock injectors.
I did have a problem the first run big run I did with stock injectors and the newly installed GH waterbox, I ran WOT for about 90 seconds and when I stopped I was smoking, the waterbox housing was melting towards the front of the hull. I had this happen last year and upgraded to the stainless steel exhaust manifold, I donít want this to happen again.
06-17-2008, 12:01 PM #2
I would say your exhaust was melting from being lean. I would go back to stock injectors and add a rrfpr. Also sound like you may have slipping sc clutches. I would check the slip.
06-17-2008, 03:00 PM #3
06-17-2008, 08:49 PM #4
- Join Date
- May 2005
With that setup you should be close to 265 hp. That would require a stock fuel regulator (58 psi) with 42# injectors. You could also get the same fuel flow with stock injectors (38's) and a rrfpr set at 66 psi base pressure, resulting in 69 psi fuel rail pressure at wot. Both setups would flow the same amount of fuel at wot. Stock injectors with a stock fuel regulator would be way too lean. It's possible that with the increase in fuel flow with the 42's you are making more hp. Could your supercharger be slipping?
06-17-2008, 09:10 PM #5
Well it sounds like the popular vote is the rrfpr, it makes sense so I'm going to go back to the stock injectors and pick up a rrfpr form Jerry.
Thank you for all of your feedback.
06-17-2008, 09:17 PM #6
The other reason for a melting waterbox could be insufficient water flow... Might have a clog somewhere..?
06-17-2008, 09:58 PM #7
Instead of having everyone guess at what your problem is and it costing you a lot of money why don't you invest in an AFR meter??
It would be way cheaper than a hole burned in a piston
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