I have researched alot about JWT Upgrade, MAF Upgrade, Piggybacks, and several standalone units out there. I am probably going to go with a turbo kit from something like:
>XS Engineering (~ $3,400) - 228 rwhp
>Nsport:Stage 1 (~ $3,900) - 240 rwhpStage 2 (~ $5,700 ) - 300 rwhp
>Fmax, but I can't get a ~ hp rating (~ $4,000)
Most of these kits come with the Vortech FMU (link). I have never actually tuned a forced induction motor and the whole idea is still new to me. I do understand that fuel management systems have mapping points in which you can adjust the A/F ratio, does the Vortech also have this or just automatically pump more gas? And when JWT reprograms your chip how many points can they preset for you? Thanks for any links or information anyone can disperse, I am a bit confused on the matter and hopefully this thread will also clear up some confusion I have seen in this FMU process as well.
JWT ECU Upgrade/Vortech Question
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S14Zilvia
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As far as I know the FMU is just another mechanical device. It will send x more psi of fuel for each pound of boost. This seems like the weak point in those kits... I don't really see how it could be anywhere near in tune if it's just tossing a set amount of fuel when it sees boost.
I'm probably way off here though.
I'm probably way off here though.
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C-Kwik
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S14Zilvia wrote:As far as I know the FMU is just another mechanical device. It will send x more psi of fuel for each pound of boost. This seems like the weak point in those kits... I don't really see how it could be anywhere near in tune if it's just tossing a set amount of fuel when it sees boost.
I'm probably way off here though.
FMU pressure rise ratios are usually calculated a bit on the safe side. But they are effective for the price. Their limitations are really based on how much flow the fuel pump can provide at such high pressures, and how soon the injectors fail open. But for the most part, boost is roughly linear to how much more fuel you need. So an FMU is quite effective. But in now way will be in the best state of tune, but it's great for the budget concious...
Flamereka wrote:wouldn't you just be better off with the apexi afc or the hks unit?
On Stock ka injectors an safc won't do anything over 5 psi.I know because i'm was trying to run 6 psi and at 50% over stock it still ran lean.
An fmu will allow more fuel pressure and you can get more fuel from the same duty cycle of the injectors.
Duty cycle is the amount of pulses your injectors do per rpm.An FMU will allow more fuel to be spit out during that pulse.There is still a limit to how much fuel can be spit out though.
I hope that make since. It's late and I'm tired.
James Poe
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WDRacing
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JWT uses the same amount of A/F and timing points as the standard ECU that comes from Nissan. He just has them tuned for your current setup. The system will work great. It might be a tad on the rich side, but you'll still make plenty of power in safe zone.
The FMU is just a rising rate fuel pressure regulator. Each one usually comes with one setting, say 12/1. Meaning it will add 12 psi of fuel pressure for every 1 psi of boost. You can buy regulators with a variety of settings.
Like C-kwik said, the problem lies in your stock pump. It will have problems with the FMU demand. So you'll end up upgrading to a Bosch or BBK unit. It's not unusual to see fuel pressures near 120psi at full boost.
WD
The FMU is just a rising rate fuel pressure regulator. Each one usually comes with one setting, say 12/1. Meaning it will add 12 psi of fuel pressure for every 1 psi of boost. You can buy regulators with a variety of settings.
Like C-kwik said, the problem lies in your stock pump. It will have problems with the FMU demand. So you'll end up upgrading to a Bosch or BBK unit. It's not unusual to see fuel pressures near 120psi at full boost.
WD
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I am Technoman
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S14Zilvia
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matt0941 wrote:But with the reqrite you can always upgrade with a piggyback correct? So wouldn't I be better off just going with the rewrite and then possibly later getting a piggyback in order to not run rich?
That's probably the easiest, most effective way of doing it.
The only problem is that you don't want to be sending back your ecu all the time for things like cam upgrades or injector upgrades. You'd have to know pretty much exactly how you wanted your car setup before you even started the project. Of course you could compensate for this later with the piggyback. That gets in $$ though for an ecu and a piggyback.
I'm probably going to use the e-manage for the fact that it has all the features I'll ever need for less than the other options cost.