How much boost?
Using the info in the DIY thread I figured out that for 220 hp at 80 psi of fuel at 80% duty cycle I need 293cc min injectors . My question is how do you figure out how much boost you need in corolation to injector size and fuel pressure?
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there are formulas that will get you close, but it's still a variable.
a small turbo will have to run more boost to match the HP at redline of a larger turbo due it it's inefficiencies. |
So how do I figure it? I would like to run 10 psi.
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220BHP x 12:1 AFR x .00916 = 21.18 CFM
BHP x AFR x BSFC/60 = REQ CFM (CFM x CONSTANT X (460 + AIT) / VE X RPM/2 X CID) - 14.7 = PSI 21.18 x 639.6 x 550 / 3500 x 97.7 = 21.78psia - 14.7 = 7psi like i said, it gets you close, but there are many other factors involved. |
lol, is there a thread in here where I can learn what all the abreviations mean?
I should just buy a wideband, shouldnt I? __________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
yep. then you just log, turn up the boost, see how much fuel you have.
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Ok, so just so I know, when I get a wideband and I get my fuel pressure correct with my 1.8's at 7psi. Which it should be already. When I swap to larger injectors like 330's this should cause me to go rich right? and then i could just turn up the boost to correct the afr?
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In theory yes. What FP are you gonna run an dwhat rate on your FPR the rate might overrichen you on tip in and cause you to lose power. with a rrfpr and a healthy pump capable of 80 psi 220whp should be doable on a mid to small size t28 before you hit 10psi if you have the right cooling and timming in place. If not you can blow to 15 psi and you still won't make the power you want just a bunch of silent knock.
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Originally Posted by levnubhin
(Post 155471)
and then i could just turn up the boost to correct the afr?
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Originally Posted by Atlanta93LE
(Post 155492)
No. With a rising rate fuel pressure regulator setup, you would have to turn down the pressure rise per psi in order to have the same fuel flow rate at a given boost level. Remember, with a RRFPR, increasing the boost also increases the fuel pressure up top.
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yes
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Phil!!!
The stock ECU can idle 330's? Wow..... something tells me the exhaust gasses at idle will be flammable lol |
Originally Posted by DropTopDrifter
(Post 155505)
Phil!!!
The stock ECU can idle 330's? Wow..... something tells me the exhaust gasses at idle will be flammable lol |
Originally Posted by DropTopDrifter
(Post 155505)
Phil!!!
The stock ECU can idle 330's? Wow..... something tells me the exhaust gasses at idle will be flammable lol the AFM has an idle-mixture screw. you can still achieve a perfect 14.7:1 AFR at idle. ...then you start to get into the realm of open loop mode with higher fuel pressures |
Yeah i got 460's to idle just fine with a safc and rx7 afm 300's is easy. Given you have a 1.8 and run 265 cc/min injectors anyway the change will not be as drastic for you as it is for us 1.6 guys at 212 cc/min.
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Jesus, just buy a megasquirt. I don't know why anyone would dick with FPRs, RRFPRs, lean/rich tip-in, trying to idle injectors, new fuel pumps, and then trying to figure out how to correct the timing in all that mess.
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Originally Posted by Savington
(Post 155612)
Jesus, just buy a megasquirt. I don't know why anyone would dick with FPRs, RRFPRs, lean/rich tip-in, trying to idle injectors, new fuel pumps, and then trying to figure out how to correct the timing in all that mess.
Bandaids fucking suck. Never again. |
wheeheeehee... i had my megasquirt for about 3-4 months now and STILL didnt install it :)
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Originally Posted by Savington
(Post 155612)
Jesus, just buy a megasquirt. I don't know why anyone would dick with FPRs, RRFPRs, lean/rich tip-in, trying to idle injectors, new fuel pumps, and then trying to figure out how to correct the timing in all that mess.
Any donations will be gladly accepted.:) __________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
Originally Posted by levnubhin
(Post 155681)
Any donations will be gladly accepted.:)
You can probably make the 330s work on the stock ECU if you are so inclined. However it's a bit like kissing your sister- you can do it, but why on earth would you want to? |
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