Thread: Fully Modded RXP-X
06-14-2009, 01:07 PM #1
Fully Modded RXP-X
It has been about 7 months since posting my original thread regarding the Riva X-Charger upgrade and the HKS SSQV v.2 BOV.
The updated mods are the Riva waterbox, Bosch 55lb injectors, Riva rear air intake w/pre-filter removed and vent screen installed in its place, R&D Extender for O2 sensor, boost gauge, Innovate LC1 AFR with a Dynotune Digital Square Display (blue), supercharger slip set to 13.5lbs (I check about every 10hrs to maintain correct slippage), Engine Ice, Riva thermostat, RIVA Pro-Series O.P.A.S. Block-off Kit, and Garmin Etrax Legend Cx GPS and mounting cradle.
All mods are as follows:
Solas R-Series Concord Impeller 15/22R (virgin)
RIVA 2° Pump Wedge
RIVA RXP-X VTS Extension Rod
RIVA RXP-X Pro-Series Reduction Nozzle
R&D Intake Grate (original)
RIVA Pro-Series Power Filter Kit
RIVA X-Charger Pro-Series Impeller & Housing
Set Supercharger Slip to 13.5lbs
RIVA Intake Manifold Upgrade Kit
RIVA Valve Train Upgrade Kit
RIVA OEM Intercooler Upgrade Kit
RIVA Pro-Series ECU (2007)
Bosch 55lb injectors (from Porsche)
RIVA RXP Pro-Series 50lb Fuel Injector Kit (replaced w/the above 55lb injectors)
HKS SSQV v.2 BOV w/Greddy type adaptor
RIVA Pro-Series Aluminum Water Box
RIVA Thermostat Kit
Engine Ice Coolant
RIVA Stainless Steel Replacement Wear Ring
RIVA Pro-Series O.P.A.S. Block-off Kit
RIVA Intercooler Water Strainer
R&D Extender for O2 sensor
RIVA/Jettrim custom seat cover
RULE 500 GPH bilge pump
Innovate LC1 AFR with a Dynotune Digital Square Display (blue)
AutoMeter Liquid-Filled Boost Gauge - Model 5401
Garmin Etrax Legend Cx GPS and mounting cradle
Kanaflex w/ RIVA/K&N Filter for Kawasaki Ultra 250X (ocean riding setup)
This setup produces unbelievable performance from a few bolt-on parts and for a recreational x-boat its smoke'n.
As for the manufacturers, RIVA has produced a comprehensive kit for the X-boats (and others) and provides a level of customer service that is beyond reproach. As I have said in my original post (http://www.greenhulk.net/forums/show...ght=rxpxseadog), several manufacturers should take a page or two from RIVA's customer service - their customer service is bar none, the best in the industry! Given these accolades, RIVA is not perfect, but damn close.
As for my opinions, as a forum member I share my results and they are not intended to be conclusive. More importantly, these mods are done to meet my own personal riding conditions and performance expectations.
A few months back, forum member 'Danny' provided some awesome bench flow testing that provided some surprising results as it related to both the Riva rear intake (see: http://www.greenhulk.net/forums/showthread.php?t=85309) and the Riva waterbox (http://www.greenhulk.net/forums/show...y+flow+testing). The biggest surprise was the negative numbers that resulted from the Riva rear air intake with the pre-filter installed. Danny also provided results for Riva's rear air without the pre-filter installed. Danny’s test results demonstrated that Riva's rear air intake without the pre-filter had excellent air-flow. However, I suspected that Riva had designed its performance kits, including the X-Charger upgrade kit, around the restrictive airflow created by the pre-filter. I also suspected that the less restrictive exhaust that created less back pressure would cause the engine to lean out a bit.
My suspicion proved to be quite true: to test it, I installed an Innovate LC1 with a Dynotune digital gauge (see attached photos). The AFR numbers with all the above kit installed was alarming. The AFR numbers ran between 13 and 17. At WOT, the AFR numbers were in the low 14's and as high as 17 (air temp 74, water temp 67). Because of these frightening numbers, I immediately stopped testing with Riva's 50lb injectors. Ski ran a top speed of 80.5mph with a full tank.
In anticipation of this lean condition, I had bought a set of Bosch 55lb injectors designed for and sold by Porsche. After installing the 55lb injectors, pulling the LC1 O2 sensor and resetting it (free air reset) to ensure an accurate reading and installing an 81mm ring into the Riva reduction nozzle to bring the RPM's down, I tested again. My AFR readings went from low 13's with the 50lb injectors at idle, to 11.8 to 12.2 (1780 to 1820rpm). At 5000 rpms my AFR was in the 14's with 50lb injectors and with 55lb injectors my AFR numbers were between 12.4 and 12.7. The AFR numbers with 55lb injectors remained constantly in the 12's (unless the pump unhooked and the rev limiter leaned the engine out). At WOT the AFR numbers with 50lb injectors were in the high 13's and with the 55lb injectors 12.3 to 12.6.
With this setup, boost at WOT and 8500rpms is pushing or slightly above 14lbs of boost
The above testing was done with water temp at 71 and air temp at 76.
With the 81mm nozzle the ski ran (on GPS):
Full Tank: 80.6mph
Half Tank: 81.3mph
On the Buzzer (really on the buzzer - empty): 82.2mph (there is at least another .5mph in this setup)
While the AFR numbers at WOT are still of concern (see: skoepp’s AFR work: http://www.greenhulk.net/forums/show...postcount=1364 ), I believe as the air and water temps rise a bit the AFR numbers will be dead-on. We'll see what happens. As a consequence, I’ll restrict my WOT use and consider putting in a slightly larger fuel pump.
Lastly, I would be remiss not to thank the forum for always providing excellent information. Ahh yes, special thanks to RIVA for delivering awesome products with exceptional customer service.
***photos taken with Riva 50lb injectors***
Last edited by rxpxseadog; 06-16-2009 at 05:50 PM.
06-14-2009, 01:31 PM #2
06-14-2009, 04:50 PM #3
I noticed the 4"rear was restrictive too.
i looked at the way it flares nicely, then restricts at the inlet, then the filter really holds air back.
I made mine wider than the top, and drew air in from the bay also. this seemed to help.
06-14-2009, 05:54 PM #4
- Join Date
- Oct 2005
Cut some holes in the grab handle for the rear air. I just did this yesterday.
Last edited by RXP-REX; 03-26-2010 at 11:32 AM.
06-14-2009, 06:23 PM #5
If you look at the photo below, you can see the replacement vent screen used in place of Riva's prefilter. Here in the US you can buy a roll of vent screen for $10 at Home Depot (it will last a lifetime).
06-14-2009, 06:32 PM #6
forgot to attach the photos - pffff
06-14-2009, 07:57 PM #7
06-14-2009, 08:51 PM #8
Just been reading up on your lean conditions at WOT and noticed you arent using a RRFPR.
I would put the 50's back in and use a rising rate fuel reg as you will get your AFR numbers back in to the safe zone no prob at all. You should also get better fuel consumption as well compared to the 55's.
Im using the 50lb injectors and rising rate and im safe as at 17 PSI with perfect AFR's right through the range.
Just a thought.
06-14-2009, 09:51 PM #9
While I have considered a RRFR and have debated it extensively, my belief now is the Bosch 55lb injectors are perfect for this kit.
In fact, if you look at skoepp AFR work (see link above), you'll see the 55lb injectors compare quite favorably in fuel delivery at low and mid range rpms. While the AFR numbers are a bit high at WOT, I believe they'll drop by .4 or .5 with higher air and water temps.
As far as fuel consumption, it is actually pretty damn good. On the day of testing I travel more than 100 miles (GPS) on a tank.
But you're certainly right, an RRFR is an excellant option and the only option when running 17lbs of boost.
As an aside, VERY impressive numbers you have generated with your mods!
06-15-2009, 04:40 AM #10
If you ever go bigger boost, you'll need the RRFPR and a walbro fuel pump. I'm testing out a new Rude charger (Thanks Nils---RUDE 3.875 )at 18lbs of boost at 8500rpm and found that we needed to upgrade to a walbro pump to be consistant with AFR. We have the RRFPR set at 60psi with 50lbs injectors and AFR numbers seem to be inline. I contemplated going with 55lbs but once the RRFPR and new pump installed the AFR numbers were pretty easy to tune in. I'm running a simular setup including the rear air and riva waterbox but testing out a few different modded intake grates/ pressure relief valves, with a steap modded Jim's open loop plate. So far speeds in excess of 84mph but we are trying to figure out the overstuff issue. Watch out for the buck, we still can't get it resolved completely. It's enough to extend the range where it stuffs, but not 100%completly cured. We still have more testing to do.
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