ross02ss

iTrader: (1)

Ok so we got the car back together in February this year.
Setup is
Ls3 418, afr heads
Stage 2 snow meth kit
D1sc
Stage 7 flt 4l65
Moser 12 bolt.
So we strapped it on Geoff dyno at eps after build.
Car made 660 rwhp at 6200 rpm. With air/fuel 11.4 with meth 18*. That was on 9 1/2 -10 lbs of boost. Stock converter. 93 pump gas.


So last week we installed FTI triple disk billet converter,10.5" 3000!
And drop down from a 3.4 pulley to a 3.2 on blower.
So last weekend I got her back on dyno. Made about 12 lbs of boost and at 4700-4800 rpm the fuel pump couldn't keep up. Car made 650 rwhp at 4,700. Same air/fuel .

I built the whole fuel system on car except at the tank. I was told it was dual pumps when I bought car from Colorado speed, and that was all. So I always assumed it was 255s. With my fuel system( 8an feed line, 6an return, rails, boost regulator, 60lb injectors) I should have enough fuel if its 255s.
My next step is drop the tank and find out exactly what's back there.

My question is what's some good in tank pumps? I was told aeromotive 340s?? Goal is to be around 720ish

ls1curt

iTrader: (31)

Twin 255's should have no issues at your power level. Sounds like you might just have one 255 or only one is working.

lemons12

iTrader: (71)

I would run 1 feed line to 1 rail and another feed line to the other rail... Highly recommend.

ross02ss

iTrader: (1)

That's why I was thinking one must be getting weak. I have it on a hoobs switch. But during pull fuel stays around 58-60 and as soon as we hit 4700ish pressure drops to 40 quick! Pumps are getting close to 8 yrs old.

The Alchemist

iTrader: (19)

If it's a dual pump kit from Lonnies, I know I can switch which pump is primary, and which one is secondary. If you can do that, it might indicate if one is weak. It almost sounds like the second pump isn't kicking in.

I personally have Lonnie's twin in tank 255s, and I'm having the issue where I'm maxing out my 60's injectors due to using the factory regulator. I need to switch over to a 1:1 boost refererenced regulator at this stage, but my at-rail pressure stays in the high 50's low 60's throughout the rpm range.

ross02ss

iTrader: (1)

Good suggestion @alchemist.
My next step is to get the tank out and see exactly what I have back there. Cars been at 10 lbs for years and fuel has always been enough after I did lines and rails etc...
Now at 12 lbs and pump issues...Just trying to get some options on pump choices . One day I may upgrade to a f1a so

ross02ss

iTrader: (1)

The 1:1 boost reference regulator helped my duty cycle out a lot on my 60s. I was maxing them out before hand

The Alchemist

iTrader: (19)

Good to know... It's on my list of to-do's over the winter. Right now I just want to drive it this summer and enjoy it. It's working, so I'm going to leave it be.

Gonoma

iTrader: (15)

I'm going to be running one walbro 255 and a racetronix's 340 pump they have its around $130

Blown06

iTrader: (32)

That sounds dumb. What if one pump is weaker than the other?

lemons12

iTrader: (71)

I know very few people that recommend not running individual feed lines on higher HP FI builds.

How smart does it sound to feed on rail/injectors and then cross over to the other side with whatever is left? That is why you see a lot of cars go lean on one side and no the other side.
FPR location/issues can also cause the same situation.

The Alchemist

iTrader: (19)

So are you saying to run two separate fuel lines from the tank, one for each rail? I've never heard that before.

I think it would make sense to run one larger line to the FPR, then use a 'y' and feed each rail.

Currently, I'm running off the factory fpr in the tank, then I come into the back of the driver's side rail, cross over in the front, then feed the passenger side. I have my fuel pressure sensor at the back of the passenger rail, so it sees the lowest pressure. I guess I should switch my wideband over to the passenger side to make sure I'm not running lean.

ajrothm

Definitely run two feed lines and a 1:1 regulator.

Here is my setup:

*First off, use a fuel log/fuel block to tie fuel feeds together. Mine is a 5 port log.
*LPE 225 lph intank pump (primary) on a hot wire kit, using the stock fuel line that is feeding one port on the fuel log.
*Bosch 044 external, running on a KB Boost a Pump and Hobbs switch. It is feeding thru its on -8an line to the fuel log.
*Each fuel rail is fed on separate lines from the fuel log and they cross over to each other up front
*The last port on the end of the fuel log goes to the fuel pressure regulator, then out of the regulator back to the tank.




I'm also using an Alky control kit with dual nozzles so I do get some fuel supply from that but... With both systems in place, I made 900rwhp (with the stick) and only 78% DC on the Fic 1000s. Fuel pressure is 1:1 referenced. At 7000 rpms I see 77 psi of fuel pressure.

No doubt I could easily feed 1000-1050rwhp with this setup.. It's very simple and very reliable.. Runs around on one single, intank pump like stock.

TheLS1Lover

Seems like more work than is needed, would something like -10AN split to -8AN not be sufficent?

ls1curt

iTrader: (31)

Here's my setup. Makes 850 thru a th400 on mustang dyno. 2 walbros with -8 feed that y's to feed each rail. Then a y on the other end of the rails and into the regulator with the factory feed as return or a -6.

I8UR4RD

iTrader: (16)

so are there two pumps in there or not?

Blown06

iTrader: (32)

You guys are missing the point.........its one feed line that y's into the rails.

I hope you guys aren't recommending a separate fuel pump and line for each side. Lemons: show me one high powered car that has that setup.....

lemons12

iTrader: (71)

I either worded it wrong or it was taken wrong.

It was 5AM when I posted it though!

Y it into the rails.

Blown06

iTrader: (32)

got it........didn't want anyone doing it wrong and ******* their **** up.