NOYDB

Here is my setup:
LQ4 bored and stroked to 408
Procharger D1SC with 12-13 lbs boost
Stock rails and line
Upgraded injectors

This is my first venture into boost so I don't have a lot of experience with fuel system upgrades. The stock fuel pump is good up to 4500 rpm but after that it cannot keep up. Injectors are well within the duty cycle so I think I am good there and with the rails. This is a daily driver so not necessarily looking to make 1000 hp just want to prevent lean conditions. Is the Walboro F90000267 450LPH upgrade going to get me where I need to be? Will the stock line be enough? Any other suggestions?

G Atsma

The bigger pump should do it.

NOYDB

Thanks, will give it a try.

NHRATA01

iTrader: (10)

I would search around the forum threads - the Racetronix 255 is more of a plug n' play with the stock rails and in tank regulator, and good for about 600rwhp. The upsized 340 kit available has a few more mods and conversion to the C5 regulator setup, I want to say good for ~800rwhp but again likely still a simpler install than a 450.

Perhaps someone who's dropped in a 450 will be able to give you some good direction.

NOYDB

Okay that may change things. I am already good up to 500 hp before pressure drops below the threshold (58 psi I think) so not sure I want to go through dropping the tank and not get it done with a sufficient safety margin. Sounds like I should consider switching to a return based system with new rails, front end regulator, etc.

Any ideas on the best approach there?

NOYDB

Has anyone tried removing the stock pump bucket and running 2 fuel pumps (Thinking 2 walboro 450) off a Y fitting with the stock hat? Would just run them both hot and use a regulator up front. Or a Hobbs switch and run one over 3 -4 pounds of boost.

dlandsvZ28

I agree with NHRATA01.

IMO the simple solution is the Racetronix 340 kit along with the C5 filter/regulator kit. Kits come in two flavors (98 kit and 99-2002 kit) dependent on model year (assuming you have an fbody).

Dependent upon your rwhp will determine injector size. A 6an line is sufficient up to 1000 hp. The RXP341 is good up to about 750-800 (gasoline only of course)

My setup will be about the same except for a TSP 370 instead of a 408. Some think that my 60s won't be enough injector and that I will have to upgrade to 70-80's. What size are your injectors?

If I do have to upgrade to a larger injector, then along with the 340 kit I also plan on upgrading to the Racetronix fuel rails, lines, and regulator instead of the c5 kit.

Won't know until we put it on the dyno and test if I will need more injector. Pulley combo will be 7.65 and 4.00 with Aster Bracket. The 370 is built for boost up to 1000 rwhp. My goal is only 700 rwhp. Bob at Brute thinks I might have to go smaller with a 3.90 pulley to reach 700.

Keep it simple - really don't think you will need duals or a 450.

NOYDB

Thanks for the input. I have a 2005 Sierra so I am not sure the kit works for me. I have heard the wally 450 will fit in the bucket, and heard it will not so not sure. My injectors are 60lb and the fuel line is the stock 5/16. I am looking to make 700 at the wheel, but since it is 4 wheel drive that takes about 850 at the crank. I am not sure the line is going to be big enough.

The injectors were well within the duty cycle at 59-62% and we don't think they are going to be the issue. I am really more interested in torque than total HP to get this heavy *** thing going. If I get anywhere close to 700 hp I will call it done. Getting to the pump in the truck is a pain, it is under the bed so I really only want to do it once.