Thread: Vtech Logger / Tuning Question
03-27-2015, 05:04 AM #1
Vtech Logger / Tuning Question
Just installed the Vtech 1100 injectors and hooked up the Vtech logger. I have a few questions about getting this ski all tuned up.
I have the fuel set at 58PSI static and it ran lean so I increased PSI to 68 and AFR's looked pretty good. Now when I'm in the map editor I see a Lambda Map option.
Is this the target AFR map? If so, it looks like upper range at high boost is at 12.5 AFR. Shouldn't this be around 11.9? I attached both logs if someone could take a look and see if anything looks bad. Wasn't sure if autotune modified anything else besides the AFR table.
First Log @ 58PSI https://www.dropbox.com/s/gug9qo078f...58PSI.csv?dl=0
Second Log @ 68PSI https://www.dropbox.com/s/2j0x8728sg...68PSI.csv?dl=0
03-27-2015, 06:03 AM #2
turn the fuel psi back down
you will burn up that wimpy stock fuel pump
all you need is 43
03-27-2015, 07:29 AM #3
You have the data logger and now have the ability to adjust fuel maps, so why are you trying to adjust the very crude way by adjusting fuel pressure?!?!
Put fuel pressure to 58psi (static, at idle) and start logging then either manually adjusting fuel map based of your findings or use the "autotune" feature. You will find the "targer AFR" map once you go into autotune (not "Lambda map 1" map option). I (we) have no idea what mods you have done to ski but from looking at your logs (a hair under 74mph @ 13.5psi boost), I may suggest between 12.2 and 12.4 wot afr as a goal.
skidoochris, what you failed to mention to him was he MUST connect the vac/boost line on his FPR (as a 1:1 rising rate) with what you suggested. Still, the VT11 injectors need higher pressure in order for them to work properly. Not going to say it can't be made to work but I generally suggest to stick to static fuel pressure as a rising rate can add complexity where not needed. We have quite a few (new) fast RXPX's down here and all are running static FP with tweaked maps.
03-27-2015, 07:59 AM #4
yes 11.9 is much safer than 12.4 on pump fuel
sandfish sounds like he does tuning but contradicts himself
says the vt1100 needs higher fuel psi and the runs them static ie lowering fuel psi under boost
the truth is they dont need any higher than actual 43
a static 58 psi and 15 psi boost is only 43 psi actual fuel psi
where 43 rrfpr with 15psi boost is also 43psi actual fuel psi
I bet vt1000s can only max flow about 900cc at 43psi
Last edited by skidoochris; 03-27-2015 at 08:26 AM.
03-27-2015, 08:58 AM #5
Thanks for the replies. Is there anything else in the logs that I would need to adjust? Like timing or reset throttle?
03-27-2015, 09:02 AM #6
03-27-2015, 09:11 AM #7
Et137+4, Riva valve springs, adjustable RR, Walbro 255.
03-27-2015, 09:30 AM #8
But to be honest, no point in talking about details yet, you need to "tune" your fuel map.
What VT tune are you using?
You did flywheel bolts?
03-27-2015, 09:34 AM #9
Sorry I also have the intercooler from 2010 RXPX. I wasn't doing a full run for too long since the afr was lean. I'm installing the updated vt11 401 8900 now to test.
03-27-2015, 09:43 AM #10
I think you will find that tune you mentioned is pretty decent but will be rich everywhere, but lean in the mid section. It's an easy fuel map to get adjusted.
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