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Except on returnless cars where the pressure drop across the injector is measured and kept as close to 40 as possible.
2001 Lincoln LS8
1994 Lexus GS300
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Joined: Aug 2001
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Hard-core CEG'er
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Hard-core CEG'er
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It really is irrelevant for returnless or return style. The rating by the injector designer can be at any pressure differential but the software in the car will calculate flow delivery based upon pulse width and pressure.
The only requirement is that the pressure be kept within an acceptable range so that injector spray pattern remains as intended.
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
See My Mods
'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black
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Joined: Mar 2001
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Hard-core CEG\'er
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Not what I was getting at. You will not see higher than advertised on a returnless system. It will not go to 55psi.
2001 Lincoln LS8
1994 Lexus GS300
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Joined: Aug 2001
Posts: 5,810
Hard-core CEG'er
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Hard-core CEG'er
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Oh. That makes sense.
So when you guys tried different fuel pumps were you still limited to 55psi?
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
See My Mods
'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black
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Joined: Mar 2001
Posts: 1,860
Hard-core CEG\'er
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Unless it is commanded in the softwaret the fuel pressure will not rise above the value entered. The factory value is 40psi. Even under WOT.
2001 Lincoln LS8
1994 Lexus GS300
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CEG\'er
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OP
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Wired pump to get power directly to the fusebox, and grounded it to the chassis. Now getting full voltage to the pump. Only using the thin stock wire to handle the signaling. Picked up a PLX R500 wideband O2 to monitor the AF and see how much boost we can run. http://www.plxdevices.com/R-500_productinfo.htm  Fuel pressure up to 55 psi, and AF remains at 11.2:1 or below at 13 PSI at 7000 rpm. Went to an airfield with a magazine (not sure I can name them yet). It was 103 degrees F, absolutely horrible for turbocharged vehicles. It ran 0-60 in 3.6 seconds, quarter mile in 12.2. Pretty disappointing, but not too surprising. Next up: more boost.
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CEG\'er
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CEG\'er
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Originally posted by gotapex:
It ran 0-60 in 3.6 seconds, quarter mile in 12.2. Pretty disappointing...
Wish I could be that disapointed. 
Nice to hear! You know after posting all this duartec candy over the past few months, you're now obligated to visit each ceg members area and provide them with rides didn't you?
Cheers!
John.
96 LX 3.0L MTX - Black/Tan
K&N; 12lb F/W & uprated clutch
2.5" Pipe; SVT bits; Mystery Mod; Pull-tie Mod;
UN-tuned Mod; 3rd Gear Synro-Crunch Mod
280K on the Shell, and 40ish on the Motor... 1/4 mile??
Yeah, it's a fun daily driver...
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Joined: Aug 2001
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Hard-core CEG'er
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Originally posted by gotapex:
Wired pump to get power directly to the fusebox, and grounded it to the chassis. Now getting full voltage to the pump. Only using the thin stock wire to handle the signaling.
Picked up a PLX R500 wideband O2 to monitor the AF and see how much boost we can run.
http://www.plxdevices.com/R-500_productinfo.htm
Fuel pressure up to 55 psi, and AF remains at 11.2:1 or below at 13 PSI at 7000 rpm.
Went to an airfield with a magazine (not sure I can name them yet). It was 103 degrees F, absolutely horrible for turbocharged vehicles. It ran 0-60 in 3.6 seconds, quarter mile in 12.2. Pretty disappointing, but not too surprising.
Wow! Nice if you asked me. You may want to raise that fuel ratio though to at least 12.0-12.2:1
Unless those heads are significantly different than ours, the combustion properties should be the same and 12.2 to one will yield significantly more power and still be detonation resistant if your intercoolers are working properly. I ran 12.0-12.2:1 just this weekend at 14+ psi of boost and nothing happened to the engine but gargantuan amounts of power! 
I wasn't ready for that much boost yet so I turned it down but the point is I have stock everything in my 3L block with 10:1 compression, and nothing happened but the tires spinning out at 65-70mph when the boost came back on.
Tune it slowly during the lean out process of course and try 11.5, 11.8, 12, 12.2 and see how it goes. Should do it on a dyno so you can see if the torque levels start to fluctuate or get jagged as a sign of getting close to preignition.
You shouldn't get anything until 12.5:1 or higher in my experience.....on this engine that is.
Good luck with it.
Former owner of '99 CSVT - Silver #222/2760
356/334 wHP/TQ at 10psi on pump gas!
See My Mods
'05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red
'06 Mazda5 Touring, 5spd,MTX, Black
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Joined: May 2003
Posts: 5,600
Addicted CEG\'er
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Addicted CEG\'er
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That is an impressive piece of equiptment (the little computer). Wish I had some extra cash layin' around. 
#4559 of 6535 born on Feb 17, 1998
Black 1998.5 CSVT
FOR SALE [cleaning house]: SVT rear swaybar. Reasonable offer and its yours!
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Originally posted by warmonger:
Originally posted by gotapex:
Wired pump to get power directly to the fusebox, and grounded it to the chassis. Now getting full voltage to the pump. Only using the thin stock wire to handle the signaling.
Picked up a PLX R500 wideband O2 to monitor the AF and see how much boost we can run.
http://www.plxdevices.com/R-500_productinfo.htm
Fuel pressure up to 55 psi, and AF remains at 11.2:1 or below at 13 PSI at 7000 rpm.
Went to an airfield with a magazine (not sure I can name them yet). It was 103 degrees F, absolutely horrible for turbocharged vehicles. It ran 0-60 in 3.6 seconds, quarter mile in 12.2. Pretty disappointing, but not too surprising.
Wow! Nice if you asked me. You may want to raise that fuel ratio though to at least 12.0-12.2:1
Unless those heads are significantly different than ours, the combustion properties should be the same and 12.2 to one will yield significantly more power and still be detonation resistant if your intercoolers are working properly. I ran 12.0-12.2:1 just this weekend at 14+ psi of boost and nothing happened to the engine but gargantuan amounts of power!
I wasn't ready for that much boost yet so I turned it down but the point is I have stock everything in my 3L block with 10:1 compression, and nothing happened but the tires spinning out at 65-70mph when the boost came back on.
Tune it slowly during the lean out process of course and try 11.5, 11.8, 12, 12.2 and see how it goes. Should do it on a dyno so you can see if the torque levels start to fluctuate or get jagged as a sign of getting close to preignition.
You shouldn't get anything until 12.5:1 or higher in my experience.....on this engine that is.
Good luck with it.
I absolutely agree. We're running too rich right now. I'd ideally like to be right at the 12:1 mark or so. I'd say a little bit rich is ok just for safety, especially with this horrible west coast 91 octane gas.
Next up, we need to tune the boost levels up. Twin GT28R turbos can definitely operate higher than 13 psi before efficiency issues.
The shop that's doing the tuning is getting a dyno in soon. All the dynos I can possibly stomach are coming. 
I'm guessing the next issue will be the tranny. Apparently, during heavy sustained roadracing, torque levels about 400 lb/ft become an issue.
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