safc and 720 secondaries
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#10
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who said u dont need 720's for a stock turbo?? with intake and complete exhaust and even without a street port... or fcd the car will run very lean on the high end..those 55O's gotta go.. specially with a street port
#11
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Originally posted by 13B2QuIcKNy
who said u dont need 720's for a stock turbo?? with intake and complete exhaust and even without a street port... or fcd the car will run very lean on the high end..those 55O's gotta go.
who said u dont need 720's for a stock turbo?? with intake and complete exhaust and even without a street port... or fcd the car will run very lean on the high end..those 55O's gotta go.
The higher the manifold pressure, the higher the FPR pushes up fuel pressure. The stock pump can't flow enough to maintain the required pressure at boost levels past ~10psi so the engine runs lean. This has nothing to do with the injectors. The pump needs to be upgraded well before the injectors do.
If you upgrade the pump you fix that problem but if you run high boost on the stock turbo (which you shouldn't anyway) the ECU's maps may not be suitable. This is when you use a fuel controller to enrich any areas running lean. You only need to upgrade the injectors if this tuning causes injector pulsewidths over 85%.
Your comment about the effect of the FCD isn't completely correct. On S4's the MAP sensor has very little to do with fuel delivery, but it does control ignition timing. On S5's though the MAP sensor does have an effect on fuelling. In either case, this is again a control issue than can be tuned using a fuel controller. But since you have no control over ignition timing, running more than 2-3psi higher than 8.6psi with an FCD is risky because the timing isn't being retarded as manifold pressure increases.
The turbo's efficiency drops off past 11-12psi anyway, so if you do run high boost on the stock turbo (with an FCD), then you'll have problems with high intake temps and over-advanced ignition, both of which will cause detonation. Detonation can be suppressed with rich mixtures, but that kills power and increases fuel consumption. Basically it's a very crude and inefficient way to "tune" an engine.
Again, injectors don't need to be upgraded unless you can't get safe mixtures without exceeding 85% duty cycle. Sort out fuel pressure and fuel control first. And if you're running high boost because of boost creep then fix it!
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"The higher the manifold pressure, the higher the FPR pushes up fuel pressure."
"Your comment about the effect of the FCD isn't completely correct. On S4's the MAP sensor has very little to do with fuel delivery"
So is the S4 from 1986-1987? And the S5 is 1988+?
If so, then hondahater's fuel delivery is controlled by the MAP sensor right? What controls the fuel pressure on the S4's, the MAF sensor? or does the fuel run a closed loop fuel map?
oh yeah, wut is an FCD? And can the ignition timing be adjusted by tweaking the crank angle sensor? If so, will this cause the car to run on closed loop?
"Your comment about the effect of the FCD isn't completely correct. On S4's the MAP sensor has very little to do with fuel delivery"
So is the S4 from 1986-1987? And the S5 is 1988+?
If so, then hondahater's fuel delivery is controlled by the MAP sensor right? What controls the fuel pressure on the S4's, the MAF sensor? or does the fuel run a closed loop fuel map?
oh yeah, wut is an FCD? And can the ignition timing be adjusted by tweaking the crank angle sensor? If so, will this cause the car to run on closed loop?
#13
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Originally posted by oregano
oh yeah, wut is an FCD? And can the ignition timing be adjusted by tweaking the crank angle sensor? If so, will this cause the car to run on closed loop?
oh yeah, wut is an FCD? And can the ignition timing be adjusted by tweaking the crank angle sensor? If so, will this cause the car to run on closed loop?
Jarrett
#14
its 86 to 88 is s4 and 89 to 91 is s5. I don't think I need the injectors like nzconvertable always tells me but thats what I got so I gotta live with it. Hey nz I got a question for you. At what rpm does your secondaries kick in? And when they kick in should I tune the a/f ratio down to compinsate for the 720's over fueling for my setup? THanks.
#15
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All secondaries kick in at 3800 (assuming stock ecu). And although NZ cautions against it, I am also running 720 secondaries. Actually, I will be going to 800+ secondaries and 720 primaries on a stock turbo (in preparation for the aftermarket turbo of course). But the SAFC is going to be turned WAAAAY down. And I also have a walbro, so fuel isnt a problem..Ever.
Jarrett
Jarrett
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Originally posted by oregano
...then hondahater's fuel delivery is controlled by the MAP sensor right?
...then hondahater's fuel delivery is controlled by the MAP sensor right?
What controls the fuel pressure on the S4's, the MAF sensor?
or does the fuel run a closed loop fuel map?
And can the ignition timing be adjusted by tweaking the crank angle sensor?
If so, will this cause the car to run on closed loop?
Originally posted by hondahater
At what rpm does your secondaries kick in? And when they kick in should I tune the a/f ratio down to compinsate for the 720's over fueling for my setup?
At what rpm does your secondaries kick in? And when they kick in should I tune the a/f ratio down to compinsate for the 720's over fueling for my setup?
Originally posted by J-Rat
...although NZ cautions against it, I am also running 720 secondaries.
...although NZ cautions against it, I am also running 720 secondaries.
Actually, I will be going to 800+ secondaries and 720 primaries on a stock turbo (in preparation for the aftermarket turbo of course).
#20
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This is all true, but honestly, my turbo is spinning to 14 PSI. Do we all know that its bad for the turbo? Yes. Do we know its bad for the motor? Yes. Do I care? Not really. I am just buying the stuff as I get money, and installing it. Its not tuned, but it will be in the new year. So what am I sayin? I know its probably overkill, but I dont care.......
But since I have your attention, what would you recommend for a TO4B? 4x720s? 2x550/2x720?
This would affect my decision.
Jarrett
But since I have your attention, what would you recommend for a TO4B? 4x720s? 2x550/2x720?
This would affect my decision.
Jarrett
#21
if you're going stand alone why not go the stock primary large secondaries (1200cc etc...)
It depends on your power goals. 4 x 720 is a lot of fuel and would probably do fine for lower - mid 300 rwhp. I remember tony was at 385 rwhp and running the injectors at an injector duty cycle of 99 percent.
It depends on your power goals. 4 x 720 is a lot of fuel and would probably do fine for lower - mid 300 rwhp. I remember tony was at 385 rwhp and running the injectors at an injector duty cycle of 99 percent.
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"Fuel pressure is controlled by the fuel pressure regulator. It is a purely mechanical device than is not controlled by the ECU. As manifold pressure goes up, fuel pressure goes up by the same amount. This is to keep a constant pressure differential accross the injector, so that fuel flow when the injector opens is constant regardless of load."
Really? Did not know that it was mechanical. Could you elaborate on how this device works NZ? Fuel pressure is created by the fuel pump, right? So is it a mechanical sensor that tells the fuel pump to create more pressure?
"If so, will this cause the car to run on closed loop?"
"Again, seperate issue. Closed loop isn't affected."
That's true. But while we are at it, I'm still curious. How sensitive is the rx7 to little tweaks like that? In other words, how easy is it to throw the car into closed loop? I know my mom's protege is running closed loop cuz the O2 sensor is busted
Really? Did not know that it was mechanical. Could you elaborate on how this device works NZ? Fuel pressure is created by the fuel pump, right? So is it a mechanical sensor that tells the fuel pump to create more pressure?
"If so, will this cause the car to run on closed loop?"
"Again, seperate issue. Closed loop isn't affected."
That's true. But while we are at it, I'm still curious. How sensitive is the rx7 to little tweaks like that? In other words, how easy is it to throw the car into closed loop? I know my mom's protege is running closed loop cuz the O2 sensor is busted
#25
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Originally posted by J-Rat
My HP goal is 350. So I believe the 4x720s would probably do the job.
My HP goal is 350. So I believe the 4x720s would probably do the job.
Originally posted by oregano
Could you elaborate on how this device works NZ? Fuel pressure is created by the fuel pump, right? So is it a mechanical sensor that tells the fuel pump to create more pressure?
Could you elaborate on how this device works NZ? Fuel pressure is created by the fuel pump, right? So is it a mechanical sensor that tells the fuel pump to create more pressure?
S4 turbos and all S5's have an ECU-controlled system that reduces the voltage to the fuel pump unless the engine's under load, to increase pump life. This has the effect of reducing fuel pressure. The ECU's fuel maps are programmed to account for this.
...how easy is it to throw the car into closed loop?
Mods should have little effect on when the ECU goes into closed loop.
I know my mom's protege is running closed loop cuz the O2 sensor is busted