What Fuel Injectors Are You Running?

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yamahaSHO

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Yes, it's extremely high. After looking at the file name at the top, the date of it was 1 Jan 08... That's when Chris and I were doing some tuning and it was about 20F out. My BOV would vent boost at 14-15 PSI and start to lean out a little. With the BOV not venting at that boost level (take it up to 16 or 17 PSI), it ran a little safe. I bought the high pressure version of the 255lph pump as well as the newer style injectors as I knew I would be bumping the fuel pressure.
 

AutoSHO

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The car was running GOOD that day too. :)

Need to get it tuned where you're at now... One of these weekends!
 

MerkXRTurbo

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holy crap 95%? im no tuner but im trying to learn and from what ive understood that means your injectors are pretty much maxed out. i dont know about you but id like alittle room for safety.

Not just that there's little room for safety, but injectors will overheat and die with prolonged use at high duty cycles. For safety, you generally shouldn't go above 80% duty cycle with high impedance injectors (as SHOs have), although low impedance injectors are said to be able safely run at over 90%.
 

sho_sc

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Not just that there's little room for safety, but injectors will overheat and die with prolonged use at high duty cycles. For safety, you generally shouldn't go above 80% duty cycle with high impedance injectors (as SHOs have), although low impedance injectors are said to be able safely run at over 90%.

The other thing is that once you get above 90% there isn't enough time for the injectors to open and close. They will stay open most of the time. Can't do too much tuning that way. On a postive note: when they are "static" they do get plenty of fuel for cooling. But, the real danger is right before 90%, they will overheat and stay shut.
 

texantony

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I installed 65lbs injectors on mine. I haven't tested them yet, but I'm putting my fuel pressure at 63 to 65. I'm going up to 25 to 26lbs of boost pressure so I hope I have enough. Also, I've got Josh's big fuel lines and I'm still running my boost-a-pump.

When I was running 20 lbs of boost pressure I had 48lbs injectors. The only problem with that was @ 6500 rpms The injectors were already at 98% and I't was going lean. Now don't know if it was that I was running out of injector or my fuel lines were too restricted.

The current engine I'm going to run is pretty much for test purposes because I don't know how long It will last. And I don't think the 100 shot of nos will help any.


So if you run your turbo at moderate levels "intercooled" I don't think you will have a problem running your 48 pounders. But there are so many variables to consider.
 

Sho Amo

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damn the matador is back with some serious info. i guess that 638 isnt gonna be a myth after your done.
 

sho_sc

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I installed 65lbs injectors on mine. I haven't tested them yet, but I'm putting my fuel pressure at 63 to 65. I'm going up to 25 to 26lbs of boost pressure so I hope I have enough. Also, I've got Josh's big fuel lines and I'm still running my boost-a-pump.

When I was running 20 lbs of boost pressure I had 48lbs injectors. The only problem with that was @ 6500 rpms The injectors were already at 98% and I't was going lean. Now don't know if it was that I was running out of injector or my fuel lines were too restricted.

The current engine I'm going to run is pretty much for test purposes because I don't know how long It will last. And I don't think the 100 shot of nos will help any.


So if you run your turbo at moderate levels "intercooled" I don't think you will have a problem running your 48 pounders. But there are so many variables to consider.

O.K. now you have my attention ..... what/how/what means are you going to run 25 psi of boost?
 

Lupo

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The other thing is that once you get above 90% there isn't enough time for the injectors to open and close. They will stay open most of the time. Can't do too much tuning that way. On a postive note: when they are "static" they do get plenty of fuel for cooling. But, the real danger is right before 90%, they will overheat and stay shut.

Could you up the fuel pressure, and the injector scalar so that the same injector isn't hitting 90%? How far do you think you can can go with fuel pressure with the accel #48s?
 

sho_sc

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Could you up the fuel pressure, and the injector scalar so that the same injector isn't hitting 90%? How far do you think you can can go with fuel pressure with the accel #48s?

Orginally, I was running a set of 48# with the stock fuel system. My SHO would go lean above 6500 RPM and ran 14:1 by 7200 RPM. So, after a lot of figuring and realizing that I wanted to run more boost, I put together my own fuel system from tank pickup to rail using an external pump. I had to raise my fuel pressure to nearly 70 psi static to keep the injectors below 90%. Injectors do have a limit on how much pressure they will take .... that is when I went to the bigger injectors.

So the anwer is yes, but I wouldn't raise the pressure much above 60 psi.
 

yamahaSHO

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Too many damn secrets... I'd like to learn from other's mistakes before I duplicate them....
 
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