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what can you do to get around boost cut??
-hks fcd/ greddy bcc (safc or similar recomended)
-upgraded ecu (mines, blitz, ect.)
-jdm mk4 map sensor (right?)
- what all are these good for? how much do they cost? where can you get them?
- use in conjunction with safc or similar (correct?) (an safc alone will not fix boost cut)

sorry i this question seems stupid or obvious, i just want to be clear. thanks
 

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the SAFC can tune out some of the boost cut if the car is rich at the boost level you are trying to run. If you take fuel out then you are lowering the voltage signal from the map sensor to the ECU. ex: The map might see 16psi and send a 5v signal which equals boost cut. However, if the car is rich at this 16psi and you take fuel out then you are lowering the voltage signal to the ECU. This is how the fuel computers work-change the voltage to the ecu and it changes the map in the computer to whatever direction you want it to go. Less voltage will put the computer into a lower map that tells the injectors to slow down.
Going to the 2jz map sensor is a good idea because it will get you to around 18psi before it sends a 5v signal. Now if you want to run 20 psi then you need more fuel-do this with a fuel pressure regulator! Then take the fuel out with a SAFC or something like it. What sucks is the stock computer only has a ignition map in it for about 16psi. This means as you raise the boost you are going to loose whp per lb of boost. At 20 psi you might make 24whp per lb. but at 25psi you might only make 19whp per lb. If you could advance the timing(stand alone) then you could maintain that 24whp per lb.

Simple questions sometimes have complex answers. Hope this helps to guide you.....Wes
 

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harwewe1: I know what you mean by the drop in power per lb of boost. I know a guy who made 360rwkw on a dyno dynamics dyno using a GT3540 and 28psi of boost. So that is higher on your dynos. I don't think he increased it one lb at a time so he doesn't know the power per lb but there is no doubting that that is some serious power and shows that the stock ecu can do some crazy shit. Although I personally wouldn't do it. BTW not using SAFC but is using FPR.
 

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Ultimately the problem with using voltage clamp style FCD's is that no matter what boost youre running the map sensor will never output a full 5 volts. Meaning once it hits like 1.03 bar it wont register anymore pressure, even pressure from boost spikes etc, so no fuel will be added to compensate for such events, and you havent reached the failsafe map for the stock ecu yet either, where it KNOWS the map sensor has maxxed out so goes super rich to compensate. The ideal way to eliminate fuelcut is to change the voltage scale with larger injectors and a fuel controller, or use a reflashed ECU with limiters removed.
 

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anorexicpoodle said:
Ultimately the problem with using voltage clamp style FCD's is that no matter what boost youre running the map sensor will never output a full 5 volts. Meaning once it hits like 1.03 bar it wont register anymore pressure, even pressure from boost spikes etc, so no fuel will be added to compensate for such events, and you havent reached the failsafe map for the stock ecu yet either, where it KNOWS the map sensor has maxxed out so goes super rich to compensate. The ideal way to eliminate fuelcut is to change the voltage scale with larger injectors and a fuel controller, or use a reflashed ECU with limiters removed.
agreed!
 

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what would be a good fuel controller to get for this motor.my car is rich and i would like tolean it up a bit
thanks keith
 

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an SAFC works well for basic stuff, but if you plan on boosting over 1 bar or running larger then 440cc injectors look to something more advanced. The Emanage or an SAFC with a reflashed ECU (flashed for no limiters and larger injectors) would both be good.
 

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i have a set of jdm 440's(at least the guy that sold them to me said they were)not yet installed.i was going to stick with the twins for now,with a y-pipe if somebody starts making them.i also have a fpr i installed when i did the swap.so you think the safc would do the job for tuning this set up?is ther any info about wiring it up?
thanks keith
 

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I made 482whp at 23 psi with a SAFCII and Jwcatto made 506whp at 24psi with the SAFCII, both had stock computers. Both cars where on US 550's which is damn near the samething as a 440 high impedience.
 

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near the same thing? how do you mean? dont the 550's flow much more than 440's?
 

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harwewe1 said:
I made 482whp at 23 psi with a SAFCII and Jwcatto made 506whp at 24psi with the SAFCII, both had stock computers. Both cars where on US 550's which is damn near the samething as a 440 high impedience.
Ive heard its difficult to get the off boost map lean enough with a sensor bender like a SAFCII and 550's. Did you have any problems running rich off boost?
 

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No it wasn't rich out of boost, of course I tuned the low throttle to where as most people just guess at it.

Injector duty cycle? I know this is going to sound bad but I don't know what % they were at. I know that those injectors can handle 500whp on a single 2jz like it aint shit. So to get a high 400whp on a 1jz should be fine. Hell, I did this for a solid 9 months.

Man I've seen the 440 high impedience injectors work and they tune like the low inpedience 550's. We had 2 sc300's with all the EXACT same mods and boost. However, one had us 550's and the other was running the jdm440's. I tuned the first car with the 550's got it all around 11.8:1. I put the other car on the dyno with the 440's and set the SAFC to the same settings as the first car and damn, wouldn't you know it 11.8:1. The af% lines between the 2 cars damn near layed right on top of each other. Not to mention that one made 375whp and the other made 378 @ 19psi(both using us ct12b's-the jdm engine had a bad rear turbo so we put a spare set of us ct12b's on)
 

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harwewe1 said:
I made 482whp at 23 psi with a SAFCII and Jwcatto made 506whp at 24psi with the SAFCII, both had stock computers. Both cars where on US 550's which is damn near the samething as a 440 high impedience.
what turbo do you have?
 
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