Thread: A/F Ratios on Standard Skis
01-10-2012, 05:40 AM #1
A/F Ratios on Standard Skis
Just out of interest has anybody ever had a O2 gauge on a standard RXP or RXP-X or T ski with no mods? if so what are the factory A/F ratios like at idle, mid and WOT.
01-10-2012, 09:46 AM #2
Skoepp did it. He posted the results in a thread somewhere.
01-10-2012, 09:54 AM #3
01-10-2012, 10:17 AM #4
I have readings on T-x.
I will see if can find thread.
01-10-2012, 10:20 AM #5
X boats are alot leaner then you would think top end, but then its only 10psi and the ECU is cleaver it has knock ect ect. That is why some people post gains from running high octane fuels, all the fuel does is stop the knock and let the ECU run full timing.
I have tested a RXP-X with 4 inch front air and it was in the high 12s WOT, stock ecu and injectors. Some re-maps are worse then that. This was done with a innovate LC1 and it is known that they read richer then true.
01-10-2012, 10:40 AM #6
01-10-2012, 11:07 AM #7
High 12s low 13s from what i have seen.
01-10-2012, 12:23 PM #8
Here are my findings.
I would expect for anyone at sea level or lower rad then myself to be leaner.
Hope this helps.
Conditions and mods listed at top.
70 air, 77 water, 29.8 pressure, 59 dew, 2,200 ft = 3,800 ft RAD
added 84 ring and saw exact same speeds, no change, 10.0 psi boost at 8,060 with flashes of 8,080 rpm.
So was better RAD and going from 85 to 84 same rpm with same speed.
72.5 to 73.5 mph. I did notice that the prop almost wants to come on hooked with this ring, not sure tho, as i tried to repeat and it hooked good. It felt faster top end but GPS says no.
my mods for any that want to know when looking at AFR:
4 inch front air without filter, no filter in manifold, relocated X ic, j pipe with gibson. stock ecu and X sc.
AFR readings ( 2 different recordings)
warmed up ski good, then 1st recordings:
idle - 12.9-13.1
2,500 rpm - 12.1
3,000 rpm - 11.9
3,500 rpm - 12.0
4,000 rpm - 12.5
4,500 rpm - 12.8
5,000 rpm - 13.2
5,500 rpm - 12.9
6,000 rpm - 13.1
6,500 rpm - 12.5
7,000 rpm - 12.4
7,500 rpm - 12.1
8,000 rpm - 11.7
8,060 rpm - 11.5
After that recording i made some speed runs for a good while and noticed that it was starting to lean out more with some high 13,s to even low 14,s when cruising say 60 mph.
So i let the ski cool down a bit ( 5 minutes) and did another recording.
idle - 13.3
2,500 rpm - ?
3,000 rpm - 12.5
3,500 rpm - 12.7
4,000 rpm - 13.1
4,500 rpm - 13.6
5,000 rpm - 14.1
5,500 rpm - 13.8
6,000 rpm - 13.8
6,500 rpm - 13.1
7,000 rpm - 13.1
7,500 rpm - 12.9
8,000 rpm - 12.6
8,060 rpm - 12.4
I am pretty sure that the sensor was not messing up as after riding it still was calibrated correct.
01-10-2012, 03:08 PM #9
I saw very similar AFRs to Skoepp's second set of numbers before my ECU was re-flashed, idle high 12 to 13s, mid high 13's, and WOT 12.2-12.5. This was on a cool day, stock ECU, up to 8100 rpm. I was a little surprised how lean it ran.....
01-10-2012, 05:33 PM #10
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