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ms3 prc heads and out of injector?

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Old 02-06-2006, 11:16 PM
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Default ms3 prc heads and out of injector?

just got my ms3 cam and prc heads install finished and when i went for a tune the car ran lean as hell (15:1) and i had a 98%+ injector duty cycle... i did'nt think i needed bigger injectors for a h\c swap but its lookin that way....

BTW EVEN OUT OF TUNE THRUGH A 3500 STALL (UNLOCKED) I PUT DOWN 400RWHP .... IM PRETTY CONFIDENT THE CARS GOT ANOTHER 20-30 HP WHEN I GET THE FUEL

BUT DOES THIS ALL SEEM RIGHT OR AM I MISSHNG SOMETHIN??
Old 02-06-2006, 11:20 PM
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i would like to know as well i have the same set up goin in soon
Old 02-06-2006, 11:29 PM
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I just had my car tuned h/c auto and I was hitting 100% duty cycle at about 410 - 420rwhp unlocked and it went to 115%. I just swaped in some 30#ers which should do the trick.
Old 02-06-2006, 11:31 PM
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i just got my ms3 and prc heads combo tuned wit hstock injectors i was at 117 percent duty cycle we stepped it up to a 42 lb injector and now im at 61 percent duty cycle
Old 02-06-2006, 11:31 PM
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Ok Cool Go Up On Injectors And Retune Hopefullt 430 Unlocked In In My Future
Old 02-07-2006, 12:11 AM
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Its not uncommon to max out stock injectors with a nice H/C setup.

and why are you yelling?
Old 02-07-2006, 05:51 AM
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Are these the new LS6 PRC heads? Also, if i ran AFR 205's with an MS3 am I going to have to bump up my injectors? Don't wanna hijack the thread or anything but I'm thinking now.
Old 02-07-2006, 06:31 AM
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Another way to do this is to install a fuel pressure regulator at the rail with a return line.
Your injectors can handle ~450rwhp but AT 58 psi.
With stock system, psi drops to 52/53 at WOT and that is why your injectors are maxing out early.
Old 02-07-2006, 06:55 AM
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What causes psi to drop? I know that there is a reason why it would, but I just wanted to know the technical side. Is it for safety reasons or what?
Old 02-07-2006, 07:34 AM
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Originally Posted by PREDATOR-Z
Your injectors can handle ~450rwhp but AT 58 psi.

I thought it would be about 450rwhp im a m6 car. Which would be around 420 on a a4 car anyway
Old 02-07-2006, 08:25 AM
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im just gonna get a set of 42's and call it a day ... i was just a little concerned but hell since its common for this to happen its all good .. hopefully ill have real numbers in a week and ill post em up
Old 02-07-2006, 08:35 AM
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Originally Posted by Jpr5690
im just gonna get a set of 42's and call it a day ... i was just a little concerned but hell since its common for this to happen its all good .. hopefully ill have real numbers in a week and ill post em up
If you do not plan on spraying in the future, 30 lbs SVO are better. They are 34.54 at 58psi
Look, keep in mind you'll have to upgrade your pump. Racetronix + harness is a nice PnP upgrade, and look at a fuel rail regulator, you'll feel the difference.
Old 02-07-2006, 11:16 AM
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My cam only car hit 105% at 4500.
Old 02-07-2006, 11:48 AM
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Originally Posted by stang killer
My cam only car hit 105% at 4500.
That is because you have 26 lbs injectors
Old 02-07-2006, 12:00 PM
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I went with some SVO 30# injectors myself with the ms3/prc combo...
Old 02-07-2006, 07:22 PM
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Originally Posted by PREDATOR-Z
If you do not plan on spraying in the future, 30 lbs SVO are better. They are 34.54 at 58psi
Look, keep in mind you'll have to upgrade your pump. Racetronix + harness is a nice PnP upgrade, and look at a fuel rail regulator, you'll feel the difference.
whats the dif. between the 30lb svo and like a 42 lb injector? thanks for the help
Old 02-07-2006, 07:33 PM
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Originally Posted by 35thls1ss19
whats the dif. between the 30lb svo and like a 42 lb injector? thanks for the help
I'd be interested to know this as well as I was planning on going with the 42's with my small bore AFR 225's and 231/231 cam.
Old 02-07-2006, 07:41 PM
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interested in these numbers...I am thinking about this set-up myself
Old 02-07-2006, 08:31 PM
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Originally Posted by 35thls1ss19
whats the dif. between the 30lb svo and like a 42 lb injector? thanks for the help
12

Old 02-07-2006, 08:53 PM
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At 408/390 Na my stock injectors were at 90+ % percent duty cycle, I went with the Ractronics in tank pump and RT's 37lb injectors for my 100 dry shot. Definetly dont want your injectors going static at any time.



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