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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by dsrace on Today at 03:31:59 PM »
hmmmm interesting.
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by fabr on Today at 01:11:53 PM »
FAST has differing levels of their EFI. The ones that use the 8 injector throttle bodies all use the same 74# injectors so I believe they have that info programmed into the software. For the top of the line system that allows the use of whatever injectors wanted I am sure the info is input to the software as with your system.
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Chassis and Suspension / Re: 5 link rear sandcar suspension
« Last post by dsrace on Today at 12:19:35 PM »
so i was close
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by dsrace on Today at 11:43:40 AM »
mine is a 1:1 reg. i will have to turn it on and look at the gauge again to know for sure i do know it dropped it more than i thought it should.

it would be interesting to know how fast controls inj's w/o knowing dead times or flow rates. must be a pre set dead time setting and you just input what size inj's ? this of course is not your fuel psi issue just my curiosity on the system.
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Chassis and Suspension / Re: 5 link rear sandcar suspension
« Last post by fabr on Today at 11:05:12 AM »
just comparing gearing. mine is a 4.43 r&p with a 2.21 1st and supposedly 1.67 2nd. i have a gut feeling my 2nd is closer to 1.55 or a tad deeper as there is a noticeable jump from 1st to 2nd as opposed to 2nd to 3rd in my rail. i cannot pull any hills in 2nd unless i am atleast 3k rpm and in boost. that would be 56 mph mathematically which puts me on the edge of my comfort zone on some of the dune tops  ;D. that why i down shift and just hammer 1st most of the time. then again mathematically my 1st gear , at rev limiter (6500 rpm), tops out at 62 mph. i have never watched my gps for actual ground speed . with drag and wheel slip, prob closer to 45 to 50 mph. i know i am geared to high, the only reason it is even usable is my current turbo. your rail seems to move right along in the video's but with a n/a motor and your gear range ( 2nd 2.062 .. 3rd 1.448 .. 4.44r&p) i personally understand what you were saying about wanting 3rd deeper.  ;D
We were running 45-50 most of the time on our runs .
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by fabr on Today at 11:01:34 AM »
based on that info your on the threshold of 0 vac.Yes,a very low restriction intake tract. do you know the fuel pressure sensor reads correctly on your data log?Not at this time but is on list of things to check. i have one installed but its not stable at idle. i used the same one enemy uses and it is rock solid for him but not for myself. i have mine mounted in the same place he did as well.  also, does your fuel pump see batt voltage? Yes,but will of course double check.have you ever checked the ecu to verify that it is reading the same voltage as the batt?At this time all I can say is battery voltage is steadyacross all rpm ranges. 13.6-13.9 i had to correct my megasquirt, it red 1.5 volts less that what i saw at the batt. if the ecu thinks you have more or less voltage it changes everything.SFAIK the FAST ecu doesn't reference battery voltage but the battery and logged voltage are right on .

what i was getting at on batt volatge it that......inj dead times spec sheets show what they flow at different voltages.True the ecu needs that infor or should need that info to calculated required fuel based on available voltage. this will not cause fuel pressure to dip to 20 psi of course but if its off a bit then it could cause the inj's to flow less fuel than the ecu thinks and in turn you turn the pw up to compensate.I believe FASTs strategy is to use O2 readings to do the compensation instead of flow rates based on voltage. i would assume you needed or there is a place to add the inj deat time/flow info in the faste ecu?     i was mistaken earlier, my batt v's were only off .5 v from batt to what the ecu read.  my v gauge on my dash was off 1.5 v's.....chickity china gauge that is gone. 

on another note lol i forgot to reconnect my alt wire back to my batt after working on something before the fall dune trip. i turned the engine on and could not figure out why my afr gauge was reading low 15' to low 16's at idle! my alt keeps my v at 14.1 to 14.8 while running. usually 14.1 to 14.4 but after a few more cold start cranks than normal i will see 14.8v for a bit. so my pump running at 11.5 vs 14.1 reduced fuel flow. not your issue but worth checking if there's a v drop??I don't believe I have the issue but will check.
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by fabr on Today at 10:23:08 AM »
you are correct, they are for vac/boost reference.  i know on the passenger vehichles i have worked on the vac reference is usually a 5 psi diff. in my case i set 43.5 psi with vac hose disconnected reconnect and it drops. i have 21" vac at idle. i read that article you posted the link too......very good article! i just would't have thought one would require such a large swing on psi but i can see why now.  your right, it must be your pumps or in the fueling system.
I have read that 2"vac =1psi.  with a 1:1 rate regulator I would expect to see your43.5 base without vac connected lower to approximately33psi. Is that what you see or do you use a rising rate regulator?
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by dsrace on Today at 07:39:04 AM »
based on that info your on the threshold of 0 vac.Yes,a very low restriction intake tract. do you know the fuel pressure sensor reads correctly on your data log?Not at this time but is on list of things to check. i have one installed but its not stable at idle. i used the same one enemy uses and it is rock solid for him but not for myself. i have mine mounted in the same place he did as well.  also, does your fuel pump see batt voltage? Yes,but will of course double check.have you ever checked the ecu to verify that it is reading the same voltage as the batt?At this time all I can say is battery voltage is steadyacross all rpm ranges. 13.6-13.9 i had to correct my megasquirt, it red 1.5 volts less that what i saw at the batt. if the ecu thinks you have more or less voltage it changes everything.SFAIK the FAST ecu doesn't reference battery voltage but the battery and logged voltage are right on .

what i was getting at on batt volatge it that......inj dead times spec sheets show what they flow at different voltages. the ecu needs that infor or should need that info to calculated required fuel based on available voltage. this will not cause fuel pressure to dip to 20 psi of course but if its off a bit then it could cause the inj's to flow less fuel than the ecu thinks and in turn you turn the pw up to compensate. i would assume you needed or there is a place to add the inj deat time/flow info in the faste ecu?     i was mistaken earlier, my batt v's were only off .5 v from batt to what the ecu read.  my v gauge on my dash was off 1.5 v's.....chickity china gauge that is gone. 

on another note lol i forgot to reconnect my alt wire back to my batt after working on something before the fall dune trip. i turned the engine on and could not figure out why my afr gauge was reading low 15' to low 16's at idle! my alt keeps my v at 14.1 to 14.8 while running. usually 14.1 to 14.4 but after a few more cold start cranks than normal i will see 14.8v for a bit. so my pump running at 11.5 vs 14.1 reduced fuel flow. not your issue but worth checking if there's a v drop??
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by dsrace on Today at 07:16:46 AM »
you are correct, they are for vac/boost reference.  i know on the passenger vehichles i have worked on the vac reference is usually a 5 psi diff. in my case i set 43.5 psi with vac hose disconnected reconnect and it drops. i have 21" vac at idle. i read that article you posted the link too......very good article! i just would't have thought one would require such a large swing on psi but i can see why now.  your right, it must be your pumps or in the fueling system. 
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Motor and Drivetrain / Re: Soooooo How To Stop The Waterworks
« Last post by fabr on Yesterday at 08:47:15 PM »
so that it impressive and on fuel pressure do you have a vac line connected to the fuel reg? if so disconnect that, it's only used for forced induction.Uh,no,that is incorrect.The regulator is for vac and/or boost referencing. It should be used whether N/A or boosted.See link below. no matter what dripping down to 20 ish psi is an issue This is correct for sure but I don't have enough vac under WOT or mid throttle to pull it anywhere near that low. I believe I need to pull the pumps and do some investigating the supply side.but again that could be vac doing that. just for example....my rising rate fuel reg is rated for up to 100 psi. wasn't easy finding one that actually put a rating on it! mine raises fuel psi 1 lb per 1 psi boost up to 25 psi then it drops to .75 lbs per 1 psi. i run 130 lb inj's also. i tried an actual walbro 450 pump but it began failing quickly or it couldn't move the fuel it was rated for. either way i went to the a1000 which is over kill for myself. the walbro worked correctly for the first several runs but by the 3rd day at st a it started dropping to the point it wasn't supporting 18 psi boost.  i did read a post that load/kpa mirror each other up to 100 at sea level and at altitude that changes but seems to part ways by 80 at altitude. so no matter what your motor moves some air n/a!
https://www.enginelabs.com/news/video-how-a-fuel-pressure-regulator-works-with-efi-university/
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