09-07-2010, 09:45 AM #1
Fuel Presure Drop at WOT ,is this situation normal ?
I try set fuel pressure at 55psi @idle as Riva suggest on Stage III+,
fuel pressure not same at idle ,it begin decreasing when near and WOT,
(i will check for number tomorrow)
1000CC duty circle not above 100%,around 80%
MAP sensor max i can see is 218 kPa (16psi?)
Top speed 75GPS
so might have another question ,why such that much boost ,but so low top speed
09-07-2010, 10:01 AM #2
There is no way those injectors should really be at 80% dc. I would check the config file and or send it off to Pete along with a log.
09-07-2010, 10:02 AM #3
09-07-2010, 02:08 PM #4
09-07-2010, 02:12 PM #5
You are probably going to have to log the voltage to your fuel pump to make sure it is correct.
09-07-2010, 09:21 PM #6
Any other clue to make Fuel pressure drop while in WOT?
I'm going to replace stock Fuel Pump with R&D High Flow,
but has no anyone mention at all about stock fuel pump limit,
except Fuel Regulator.
Thank for every reply and suggestion,
i'm try to join 80mph+ club ,but unable yet
09-07-2010, 09:23 PM #7
09-08-2010, 06:01 AM #8
Your fuel pump voltage drops as your rpm increases try setting up your fuel reg to raising rate
09-08-2010, 09:54 AM #9
Many people have a tendency to increase injector flow volume when they see high injector duty cycle in their log files. This is like putting the cart before the horse. A good fuel system starts with a good fuel pump -- one that has sufficient flow volume to hold pressure at any injector duty cycle. So, if you have installed a set of 1000cc injectors, a properly matched fuel pump should deliver and hold a steady 55spi at 4000cc flow rate per minute (1000cc X 4 injectors @ 100% duty cycle)..... anything less is a compromise and will require you "tweak" your tune file to provide for fuel system design issues.
The bottom line is 1000cc injectors are a patch for lack of fuel pump flow volume in most cases for ski's setup for up to 16psi boost. This boost level requires no more than 750cc injectors @ 80% duty cycle when properly fed with 58psi fuel pressure and where engine speed does not exceed 8,800rpm.
09-08-2010, 10:22 AM #10
very good explanation desperado, thanks for sharing.
the online store here lists 2 different fuel pumps one is 255 lph high pressure fuel pump, and the other is 255 lph LOW pressure fuel pump, whats the difference??
wich one would correct the issue teerayoot is having ?
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