stock Fuel Lines?? running out of fuel

[Imation]

I a 90 gtr 740cc injectors tomei fuel pump nismo fpr, stock rail. I was on the dyno last night running 20psi on gt2860r-5's I ran out of fuel at 6400rpm. leaned out to 12.4 afr at the same time my fuel pressure dropped from 60psi to 55.

So my question is what do i need to upgrade to solve my fueling issue?
Keeping in mind im looking for 480-550 whp.

I no on the stock rail, the feed tube is only 1/4" so im assuming thats where my problem is can someone comfirm.
Would i be able to get away with changing just the rail and get a new fpr or do i have to change the lines from the tank back?

Finally anyone know the size of the lines under the car and comming from the tank?

Dan

[evilgtr]

It's common to hit 600whp on stock lines,rail and fpr so I would look at your tuning and set up again. However if you are looking at upgrading you can get a twin pump set up like a few other members - dual in tank pumps. This will increase volume but your still limited to the line diameter. The most cost effective way would be run a larger diameter feed and return line with High flow filter and larger fpr. I priced everything out through summit racing and it was only a few hundred dollars - very affordable. A surge tank is is great to but it's also overkill if you don't need it and can get costly fast especially if you built it properly.
Check out summit
- dual in tank pumps (Bosch or tomei)
- larger diameter supply and return lines
- high flow filter (aeromotive make a nice one that's easy to clean and maintain)
- and a aftermaket FPR
- if you want you can upgrade the rail to, a nice aftermarket rail will only cost you about $200

[evilgtr]

At 20psi with -5's what kind of numbers did you put down ?

[jrhdohc]

stock r32 fuel rail blow!
took nissan till the r34 to get it right.

wouldn't hurt to have 2 pumps. although, it can be done with one tomei.

nismo fpr is great item. stock fuel lines and fuel filter are good too.

if you don't want AN fittings and SS lines. some aftermarket fuel rails have provisions for nismo stock mount fpr.

http://www.reimax.com/pages/products/air-fuel/index.html

or just sell the stock mount fpr and buy the AN style one.

[gtrjon]

or just buy a complete system off of evilgtr like i did

[Imation]

At 20psi with -5's what kind of numbers did you put down ?

We managed to hit 387whp on a mustang dyno at 6200 afr 11.5, meth turned off and left timing at 14 degrees to be safe until we finished tuning fuel.

[Imation]

It's common to hit 600whp on stock lines,rail and fpr so I would look at your tuning and set up again. However if you are looking at upgrading you can get a twin pump set up like a few other members - dual in tank pumps. This will increase volume but your still limited to the line diameter. The most cost effective way would be run a larger diameter feed and return line with High flow filter and larger fpr. I priced everything out through summit racing and it was only a few hundred dollars - very affordable. A surge tank is is great to but it's also overkill if you don't need it and can get costly fast especially if you built it properly.
Check out summit
- dual in tank pumps (Bosch or tomei)
- larger diameter supply and return lines
- high flow filter (aeromotive make a nice one that's easy to clean and maintain)
- and a aftermaket FPR
- if you want you can upgrade the rail to, a nice aftermarket rail will only cost you about $200

I cant see how the stock rail can handle that flow rate from a 1/4 line feed line, tuning i dont think is the issue. When we went lean we added 20% more fuel and it still went lean in the same spot. Checked fuel pressure and it dropped in the feed line.

1 tomei pump should handle 500whp. shouldnt it?
740cc injectors should also shouldnt be the limiting factor.
5/16th line comes out of the tank, so if I were to bump that to 3/8
Run 3/8 to the front of the car add a new rail and aem or aeromotive fpr and same 3/8 retune

In theory should this be ok?

[christdeyoung]

I've read a bunch of places that stock lines are good to 600whp. I have the same issue as you, looking for up to 550whp. Got on the dyno a few weeks ago, and made it to 310whp when we leaned out. Keep in mind that was the stock pump that I was expecting to flow a little more than that, and my boost was creepin like a MF. Since then, I installed a Deatschwerks in tank pump, and filter. Awaiting tune.

Change your fuel filter if you haven't already.

If you want bigger lines, use the power steering lines for the HICAS if you removed it/plan on removing it. They're quite a bit bigger than the stock fuel lines.

[GTR-Dad]

I've seen 525 awhp on OEM fuel rail with 600 cc injectors and a Bosche 044 in tank pump, so your basic setup is fine for your goal. The trick is to find the bottleneck. Check pump inlet and any restriction on the intake side. Check voltage to your pump. I know at least some fuel pump control strategies dial voltage down at low loads to save pumping excess fuel - if yours doesn't ramp up, you could be running at partial pump capacity.

Dan