will I need to upgrade the fuel system?
09-30-09, 01:56 PM
#1
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will I need to upgrade the fuel system?
What's going on guys, when I do my turbo II swap this winter I plan on doing th RBrev 2 exhaust and a front mount intercooler. I know ill need a fcd for boost creep but will I be fine with using thE stock fuel system?
09-30-09, 03:05 PM
#4
When you think about what your turbo is actually doing, you begin to realize and understand why (I know that's how it was for me). Your turbo is just a compressor, it compresses air and forces it into the engine, with more air comes a leaner air-fuel ratio so you'll need more fuel to balance it out.
Don't get an FCD if you're getting an aftermarket exhaust and FMIC, it doesn't prevent boost creep, it just lets boost creep go on about its business. To eliminate it, you need to port the wastegate.
If you're going to do something, may as well do it right. Get an Rtek and some 720cc('ish) injectors if you don't plan on running high boost.
Also, is your T2 swap S4 or 5? if it's 4 then fuel cut is 6.5 PSI (I think) and with a REVII you'll be way past that.
Don't get an FCD if you're getting an aftermarket exhaust and FMIC, it doesn't prevent boost creep, it just lets boost creep go on about its business. To eliminate it, you need to port the wastegate.
If you're going to do something, may as well do it right. Get an Rtek and some 720cc('ish) injectors if you don't plan on running high boost.
Also, is your T2 swap S4 or 5? if it's 4 then fuel cut is 6.5 PSI (I think) and with a REVII you'll be way past that.
09-30-09, 06:08 PM
#5
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The rev 2 exhaust from racing beat makes boost creep to 10psi that's why I would need a fcd. A fmic wouldn't cause more boost creep. So why would I need a rtek. And I was pretty sure I could use my stock injectors. I just want to get a little bit more power out of it without upgrading a lot of stock Parts
09-30-09, 06:18 PM
#6
Well that's a good way to blow your engine. If you are simply allowing boost creep to happen, actually INVITING it to happen; then quit now, that is no way to go about modifying sports cars. If you want more power, you MUST spend more money. You are about to spend 700 bucks at least on an exhaust? Whats an extra 200 or less for some 720cc injectors? Throw em on and run rich for a bit till you can buy an rtek. Port your wastegate to prevent boost creep.....Then get a boost controller. etc.... etc... etc.... then bam, about $1500 and a year later, you're pushing 14psi and making 280 to the wheels. Be patient.
Otherwise we are going to be seeing your next thread saying "Damn, need a rebuild" or "Man, RX-7's suck"
Sorry to berate you, but without a plan of attack, you are doomed for failure.
Otherwise we are going to be seeing your next thread saying "Damn, need a rebuild" or "Man, RX-7's suck"
Sorry to berate you, but without a plan of attack, you are doomed for failure.
09-30-09, 06:40 PM
#7
I am surprised nobody has mentioned that you need to at least run the turbo fuel pump if you are doing a swap. I don't know if you can actually run the stock NA pump, but those with more knowledge than me have said if you do an NA to turbo swap, at the least run a turbo fuel pump. I went with the Supra pump; however, the Walbro is cheaper and a good pump.
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09-30-09, 06:42 PM
#9
What I was saying is that fuel cut is there for your safety. When you get boost creep, your boost is spiking up to unsafe levels and that's what your fuel cut is there for, to prevent running too lean. If you were to get an FCD, you're letting your boost spike up there past those levels which can be a hazzard. I have a REVII exhaust and I'm not bothering to get an FCD. Why bother wasting my time and money when I can spend an extra $100 and get an Rtek, then another $200 for a safe setup with bigger injectors. But hey, if you want to get an FCD and you just plan to juice it once or twice every like second month, be my guest.
Yeah, you'll need an FC or FD pump for starters. Walbro and Supra are also good.
Yeah, you'll need an FC or FD pump for starters. Walbro and Supra are also good.
10-02-09, 03:51 AM
#13
Correction, only 720cc secondaries. From the website:
Stage 1.7
Basically Stage 1.5, but for cars with 720cc (or larger) secondary injectors. The Flood Clear option has been added back in as well. For Stage 1.7, the fuel map has been corrected to compensate for larger 720cc secondaries without the need for external fuel control, like an AFC, to keep from running very rich. If you have an AFC, it will no longer have to trick the ECU to compensate for the larger injectors. The AFC can still be used for fine tuning. This also means that you CANNOT run Stage 1.7 in a car with 550cc secondaries or you will run lean. As we have demonstrated above, the less you have to 'trick' the ECU, the better. So with Rtek Stage 1.7, 720 secondaries, and a larger fuel pump, you should have a setup that can push the stock turbo to its safe limit (approximately 12 PSI).
Stage 1.7 is slightly more complicated to install so we require you send in your ECU to us.
Stage 1.7
Basically Stage 1.5, but for cars with 720cc (or larger) secondary injectors. The Flood Clear option has been added back in as well. For Stage 1.7, the fuel map has been corrected to compensate for larger 720cc secondaries without the need for external fuel control, like an AFC, to keep from running very rich. If you have an AFC, it will no longer have to trick the ECU to compensate for the larger injectors. The AFC can still be used for fine tuning. This also means that you CANNOT run Stage 1.7 in a car with 550cc secondaries or you will run lean. As we have demonstrated above, the less you have to 'trick' the ECU, the better. So with Rtek Stage 1.7, 720 secondaries, and a larger fuel pump, you should have a setup that can push the stock turbo to its safe limit (approximately 12 PSI).
Stage 1.7 is slightly more complicated to install so we require you send in your ECU to us.
10-02-09, 12:49 PM
#15
I don't want to advocate poor tuning, but with how rich RX-7's run stock, there is probably a little wiggle room to raise boost. I ran a motoria exhaust (a virtual clone of the racing beat) with an FCD, Walbro pump (rewired), and heavily ported wastegate on stock 550's for 3 years. This was an S4 TII. My car would boost to 9psi in gears 1-3, and would start creeping up to 10-11psi in the higher RPM's of 4th gear. I would always back off the throttle if I saw boost going this high. By that time, you are going faster than you should on the street anyway.
Long story short, my engine compression was just over 100psi on each rotor when stock, and had the same compression after running this setup for three years. I can't guarantee your engine will hold up the same, but again, it seems there is some margin for safely increasing boost on stock injectors. You definitely need to at least get a TII, Walbro, or supra pump. A pump rewire is optional since your car was NA to start, being that it doesn't drop voltage to the pump at cruise like the way stock TII's are wired. Some people also drop in 680cc secondary injectors, "firehosing" extra fuel in under boost for added security. These injectors can be found in 1st gen GSL-SE models, and are direct fit into S4 cars with low impedance injectors.
So again, you can ghetto tune with a setup similar to my old one or what others are recommending, but realize these are still poor choices compared to getting an Rtek or some other aftermarket EMS for proper tuning.
Long story short, my engine compression was just over 100psi on each rotor when stock, and had the same compression after running this setup for three years. I can't guarantee your engine will hold up the same, but again, it seems there is some margin for safely increasing boost on stock injectors. You definitely need to at least get a TII, Walbro, or supra pump. A pump rewire is optional since your car was NA to start, being that it doesn't drop voltage to the pump at cruise like the way stock TII's are wired. Some people also drop in 680cc secondary injectors, "firehosing" extra fuel in under boost for added security. These injectors can be found in 1st gen GSL-SE models, and are direct fit into S4 cars with low impedance injectors.
So again, you can ghetto tune with a setup similar to my old one or what others are recommending, but realize these are still poor choices compared to getting an Rtek or some other aftermarket EMS for proper tuning.
10-02-09, 01:01 PM
#16
I'll put it very simply since there's a lot of guessing in this thread.
Fuel cut is at 8.6psi. Without an FCD or Rtek chip, you will not be able to exceed approx. this boost level.
Porting the wastegate is absolutely essential with a fully open exhaust. Combining an open exhaust with an FCD (which is the hack way to go) WILL blow your engine.
When upgrading the fuel system to run more than stock boost, the fuel pump is the weakest link. The stock TII fuel pump flows very poorly with increased fuel pressure. A walbro or other larger pump is a crude, but simple fix. But this is not a guarantee that the engine will not blow running 10+ psi. 550cc primaries max out before 3800 RPM @ high boost, which can eventually lead to engine damage. Rtek 1.x chips move injector staging to 3500 RPM to help.
Fuel cut is at 8.6psi. Without an FCD or Rtek chip, you will not be able to exceed approx. this boost level.
Porting the wastegate is absolutely essential with a fully open exhaust. Combining an open exhaust with an FCD (which is the hack way to go) WILL blow your engine.
When upgrading the fuel system to run more than stock boost, the fuel pump is the weakest link. The stock TII fuel pump flows very poorly with increased fuel pressure. A walbro or other larger pump is a crude, but simple fix. But this is not a guarantee that the engine will not blow running 10+ psi. 550cc primaries max out before 3800 RPM @ high boost, which can eventually lead to engine damage. Rtek 1.x chips move injector staging to 3500 RPM to help.
10-02-09, 02:21 PM
#17
I don't want to advocate poor tuning, but with how rich RX-7's run stock, there is probably a little wiggle room to raise boost. I ran a motoria exhaust (a virtual clone of the racing beat) with an FCD, Walbro pump (rewired), and heavily ported wastegate on stock 550's for 3 years. This was an S4 TII. My car would boost to 9psi in gears 1-3, and would start creeping up to 10-11psi in the higher RPM's of 4th gear. I would always back off the throttle if I saw boost going this high. By that time, you are going faster than you should on the street anyway.
07-20-10, 12:29 PM
#18
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when you port the manifold get the flapper door taken off and go to a junk yard and find a exhaust valve from a vw and cut it and use that for your door, youll be able to get a much bigger wastegate hole and the vw exhaust valve is coated so it wont come apart.. just porting the hole to the stock flapper is still pointless and youll still get alot of boost creep.
i have one sitting around my shop that i can post if anybody needs to realy see it.
i have one sitting around my shop that i can post if anybody needs to realy see it.
07-20-10, 01:58 PM
#20
Yes, the S5 is better at controlling boost. The stock S5 wastegate has 5 times more area than the S4 version, and it connects to both passageways in the turbine housing (2 ports).
http://fc3spro.com/TECH/HOWTO/KWG/kwg.html
http://fc3spro.com/TECH/HOWTO/KWG/kwg.html
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