RX-7 FC Injectors OK to use with Greddy Kit?
#3
Somebody hasn't read the FAQ. There's some slight math to be done, and you can do it here in the third post: https://www.miataturbo.net/forums/showthread.php?t=4288
The short version is that (although some have managed) the stock ECU won't idle injectors above 330cc very well. And that's OK because with the Vortech AFPR and a fuel pump capable of over 100psi you can fuel enough for over 200whp+ with 330's... which is probably a good goal for an initial Greddy upgrade.
Just what do you hope to accomplish by upgrading the injectors? The Greddy kit with it's base boost output of 4.5-5psi is designed to work with the stock injectors and fuel pump and the supplied disc in the AFPR. As you turn up the boost, the AFPR will raise fuel pressure to the max of the stock pump at 80psi... which is why guys usually upgrade the fuel pump along with larger injectors (but 440's are too big to idle) which will give A LOT of headroom for fuel. But you can't turn the boost up without some way of getting intake temps down no matter how much fuel you dump in... so now you need an intercooler... then you get to a point in turning up the boost that an intercooler isn't enough to keep your engine from pinging at the Greddy mandated 6* of timing advance, so you need someting to manage your timing (a Bipes).
Or you could skip all that crap, keep the 440's and get a Megasquirt and Devils' Own Water Injection Setup and run 15psi on the Greddy for about 240-250whp... don't forget a clutch... might want a BOV and an upgraded crossover pipe too... and new tires... and better brakes... and maybe a rollbar... and since your girlfriend is gonna dump you cause you spend all your time working on the car, a new one of those (blondes tolerate more).
The short version is that (although some have managed) the stock ECU won't idle injectors above 330cc very well. And that's OK because with the Vortech AFPR and a fuel pump capable of over 100psi you can fuel enough for over 200whp+ with 330's... which is probably a good goal for an initial Greddy upgrade.
Just what do you hope to accomplish by upgrading the injectors? The Greddy kit with it's base boost output of 4.5-5psi is designed to work with the stock injectors and fuel pump and the supplied disc in the AFPR. As you turn up the boost, the AFPR will raise fuel pressure to the max of the stock pump at 80psi... which is why guys usually upgrade the fuel pump along with larger injectors (but 440's are too big to idle) which will give A LOT of headroom for fuel. But you can't turn the boost up without some way of getting intake temps down no matter how much fuel you dump in... so now you need an intercooler... then you get to a point in turning up the boost that an intercooler isn't enough to keep your engine from pinging at the Greddy mandated 6* of timing advance, so you need someting to manage your timing (a Bipes).
Or you could skip all that crap, keep the 440's and get a Megasquirt and Devils' Own Water Injection Setup and run 15psi on the Greddy for about 240-250whp... don't forget a clutch... might want a BOV and an upgraded crossover pipe too... and new tires... and better brakes... and maybe a rollbar... and since your girlfriend is gonna dump you cause you spend all your time working on the car, a new one of those (blondes tolerate more).
#4
Sam, do I understand you correctly- the 330 injectors will let through enough fuel for up to around 230 rwhp? at what point is the horse power high enough to require some sort of timing advance above the Greddy recomendation--how much safe power can be produced using the 330 injectors and the Vortech AFPR along with a basic fuel pump upgrade?
#5
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Sorry for jumping in here, Sam, but...
All by themselves, no. With the addition of an adjustable FPR, yes, with room to spare.
Before you start doing anything, you'll want an intercooler or a water-injection system. Or both.
It's unlikely that you'll need to upgrade the fuel pump. With 330cc injectors you'll have enough fueling for your stated HP goal without needing 125PSI of fuel.
The Vortech FPR is probably going to cause problems with 330s. You need something adjustable. That unit was designed for the stock injectors at 5 to 6 PSI of boost.
However it's quite likely that you will need some dynamic ignition retard. The Bipes ACU is one option, though for the cost of that plus a good FPR, you're in EMU territory, price-wise.
at what point is the horse power high enough to require some sort of timing advance above the Greddy recomendation--how much safe power can be produced using the 330 injectors and the Vortech AFPR along with a basic fuel pump upgrade?
It's unlikely that you'll need to upgrade the fuel pump. With 330cc injectors you'll have enough fueling for your stated HP goal without needing 125PSI of fuel.
The Vortech FPR is probably going to cause problems with 330s. You need something adjustable. That unit was designed for the stock injectors at 5 to 6 PSI of boost.
However it's quite likely that you will need some dynamic ignition retard. The Bipes ACU is one option, though for the cost of that plus a good FPR, you're in EMU territory, price-wise.
#6
Thanks so much guys; I've been reading as much as possible.
I was given a set of RX-7 Injectors in exchange for other parts I had with someone. I knew they were P&P, but now I see they aren't suitable for my application.
I'm thinking of leaning towards a Greddy kit, with intercooler, and running 6-8 lbs. I want to build a reliable, daily driveable setup that focuses on quick spool and low down torque as opposed to big numbers and highend HP.
Thanks all for the guidance so far. Much more research to do.
I was given a set of RX-7 Injectors in exchange for other parts I had with someone. I knew they were P&P, but now I see they aren't suitable for my application.
I'm thinking of leaning towards a Greddy kit, with intercooler, and running 6-8 lbs. I want to build a reliable, daily driveable setup that focuses on quick spool and low down torque as opposed to big numbers and highend HP.
Thanks all for the guidance so far. Much more research to do.
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