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Fuel Rail Modification (Fast guys, I'd like your input)

Old Jun 21, 2004 | 11:14 AM
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DRAGRACR's Avatar
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Fuel Rail Modification (Fast guys, I'd like your input)

Just was curious to know if there is any power to be had in modifying the fuel rails on my 92 Corvette. They are designed basically the same as the 93 Camaro. This is currently supplying my 445RWHP 357 ci automatic LT1. I drilled the end of the fuel rail out and pulled the tube out, and then heliarced the hole back up. It just seems that the tube is restricting the fuel flow a huge amount. Let me know what you think.
Old Jun 21, 2004 | 11:18 AM
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that might work, i would try and bore it out to a larger size and see if that makes any difference. i dunno my Z is stock so i cant help you with experience issues. sorry!


*Eric*
Old Jun 21, 2004 | 12:05 PM
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I don't mean to oversimplify, but unless it's lean, it's getting enough fuel. I used stock lines, regulator, and rails to make over 600rwhp, as have others. Why fix what isn't broken?

Rich Krause
Old Jun 21, 2004 | 01:37 PM
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Originally posted by rskrause
I don't mean to oversimplify, but unless it's lean, it's getting enough fuel. I used stock lines, regulator, and rails to make over 600rwhp, as have others. Why fix what isn't broken?

Rich Krause
Well right now im fishing for some hp that i am down. I feel that my motor should make 470+ to the rear. Also, do the 95 rails have the tube inside them?? I know that they do have the crossover on the front, so I am just curious. I did find out this past weekend that my opti was coming apart, and only had one screw holding the rotor in.........
Old Jun 21, 2004 | 02:28 PM
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why are you down power?

is it because you are running lean? when the car is on the dyno, what did the wideband read?



because if its not running lean, you're barking up the wrong tree.
Old Jun 21, 2004 | 03:02 PM
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Originally posted by MrDude_1
why are you down power?

is it because you are running lean? when the car is on the dyno, what did the wideband read?



because if its not running lean, you're barking up the wrong tree.
Well Im not sure of why I am down on power, but mainly I was looking at the duty cycles of my injectors. I am at 85+ % at 7800 rpms, and a 42lb injector at 45lbs pressure. Just made me think that it may be starving for fuel. I know that it can't hurt.
Old Jun 21, 2004 | 03:37 PM
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Originally posted by DRAGRACR
Well Im not sure of why I am down on power, but mainly I was looking at the duty cycles of my injectors. I am at 85+ % at 7800 rpms, and a 42lb injector at 45lbs pressure. Just made me think that it may be starving for fuel. I know that it can't hurt.

if your injectors are close to being static, and your fuel pressure on the rail is stable, a new fuel rail wont help. you need larger injectors.
Old Jun 21, 2004 | 11:32 PM
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Either way there is a nice write up in GM High Tech this month on how to do it up good
Old Jun 22, 2004 | 08:03 AM
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Thanks for the replies, but I'm still looking for some people who have modified their rails.
Old Jun 22, 2004 | 08:17 AM
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Originally posted by DRAGRACR
Thanks for the replies, but I'm still looking for some people who have modified their rails.
ok.

well, the early manifolds have the crossover in the back, and when you use the LT1 manifold on a SBC, you cant have it cross in the back because the distrib gets in the way.


we solved it by getting some generic fuel rails, cutting them to length, milling the holes for the injectors, and tapping the ends to a NPT pipe size... we then ran SS braided hose with AN fittings on it.

athough, a new manifold, with the new fuel rails is cheaper then what he paid for the hose.
Old Jun 22, 2004 | 11:25 AM
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You should be fine N/A. I made a cross over on my rails due to #7 going lean on the Gas!

Email me and I can shoot you a few pictures.


BTW thats good pwr so why do you think your down any?
Old Jun 22, 2004 | 02:36 PM
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On my webpage you can see how i modified my fuel rail.
basically i just modified the with -6an fuel fittings that i had welded on. and the return is on the front i welded a 90 degree fitting.
www.96z28ss.cz28.com

Last edited by 96Z28SS; Jun 22, 2004 at 02:39 PM.
Old Jun 22, 2004 | 03:00 PM
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Nice setup, thanks for the pics. Have you put your car on the chassis dyno yet? If so what did it make on motor??
Old Jun 22, 2004 | 04:07 PM
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I took my stockers, chopped off the OEM fittings and welded -8AN bungs on the back and the top of the front. I then removed the x-over and TIG'd it shut. I had heard about the tube on the inside of these, but didn't mess with it. Even with the tube, you can move a LOT of fuel.
Old Jun 23, 2004 | 01:10 AM
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Is the tube steel? If so its probably there for structural integrety. granted the rails are pretty solid aluminum extrudions, but that's the only thing that comes to mind. Porous aluminum at high psi maybe?

I dunno.

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