fuel injectors, pressure, power, and tuning
I'm going to the dyno hopefully for the last time tomorrow. Currently I'm at 67% duty at 12psi with 550cc injectors, walbro 255 in-tank and unknown fuel pressure...and not sure how much power thats making but not much. My goal is 250whp with some head-room, I'd like to see a 300whp pull so I can crank up the boost when I get the 6-speed in.
will I need more fuel pressure? |
You got a 190HP? If so, you got the fuel system for 300whp. But that's the upper limit. With rich AFR's, you may not hit 300whp. A RRFPR in conjunction may be needed.
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you should have enough fuel to see 300rwhp.
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Originally Posted by Braineack
(Post 364333)
you should have enough fuel to see 300rwhp.
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With injectors, it's like:
Duty cycle..... Actual duty cycle 0...................0 10..................10 etc.... 75....................75 80....................80 83....................83 84.....................84 85....................85 86....................86 87.....................100 88.....................100 100.....................100 You reach a point where it can't open and then close, and it just stays open. 80-85 is the limit. I would tune for higher than 80% as to still have a spec of headroom. You don't want to tune it for 90% duty cycle (really 100%) and then on a warm day it runs 86% and fuel actually falls to 86%. |
Originally Posted by patsmx5
(Post 364344)
With injectors, it's like:
Duty cycle..... Actual duty cycle 0...................0 10..................10 etc.... 75....................75 80....................80 83....................83 84.....................84 85....................85 86....................86 87.....................100 88.....................100 100.....................100 You reach a point where it can't open and then close, and it just stays open. 80-85 is the limit. I would tune for higher than 80% as to still have a spec of headroom. You don't want to tune it for 90% duty cycle (really 100%) and then on a warm day it runs 86% and fuel actually falls to 86%. I think I need to do some logs tonight because after about 500-miles on the new pump, idle AFR went from 14.7 to 12.8:1. Apparently there's a break-in period for Walbro pumps./ |
i'm seeing ~85% duty on rx7 550's at 6800rpm, if that helps. thats at 320whp/325ft-lbs, mid 11's AFR.
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Originally Posted by therieldeal
(Post 364350)
i'm seeing ~85% duty on rx7 550's at 6800rpm, if that helps. thats at 320whp/325ft-lbs, mid 11's AFR.
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stock FPR, walbro 255 pump. if i prime the pump with the engine off it stays at 43 psi as it should.
i have a fuel pressure gauge on the rail, but i forgot to watch it when i had the thing on the dyno... so i dont know if it's running at exactly 1:1 but it seems to be. i'm running 23psi of boost. |
Originally Posted by therieldeal
(Post 364359)
stock FPR, walbro 255 pump. if i prime the pump with the engine off it stays at 43 psi as it should.
i have a fuel pressure gauge on the rail, but i forgot to watch it when i had the thing on the dyno... so i dont know if it's running at exactly 1:1 but it seems to be. i'm running 23psi of boost. |
it also put down 275whp last fall at 18psi with a slightly less agressive timing map. the VJ23 is fairly comperable to the 2860... my compressor wheel is 65mm at the exducer. i dont recall the trim at the moment.
i think you will be just fine |
Originally Posted by therieldeal
(Post 364359)
stock FPR, walbro 255 pump. if i prime the pump with the engine off it stays at 43 psi as it should.
i have a fuel pressure gauge on the rail, but i forgot to watch it when i had the thing on the dyno... so i dont know if it's running at exactly 1:1 but it seems to be. i'm running 23psi of boost. Built motor? |
its a 95 escort gt with a 323 GTR motor. it's "built" from the factory, i'm sure most of you guys have heard of it?
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ok i remembered wrong...
i just opened up the logs from my dyno runs, on both runs i saw a peak of 74% duty cycle. |
258kPa gives me a boner.
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yeah, its a good time :) lol. i just desperately need a stiffer wastegate spring - as you can see in that log my wastegate control sucks even with an EBC.
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Originally Posted by therieldeal
(Post 364697)
yeah, its a good time :) lol. i just desperately need a stiffer wastegate spring - as you can see in that log my wastegate control sucks even with an EBC.
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i do have a dual port external gate (tial 38mm) with a greddy EBC
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Is it setup using the dual port? What spring you running? From my research, a dual port setup and stiff WG spring is the best setup for best spool.
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Originally Posted by therieldeal
(Post 364839)
i do have a dual port external gate (tial 38mm) with a greddy EBC
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