Fuel System Upgrade Info - Something Doesn't Add Up

[pneumo]

That's a good start, you can also drill out the banjo bolt slightly bigger.

 

[habitatguy187]

That's a good start, you can also drill out the banjo bolt slightly bigger.

I thought about it, and was headed to the bench-vice, then remembered that I don't own any drill bits.

 

[sbiggi]

Seems like a waste of time to modify the banjo bolt.

Really if you are the point where you need more fuel then a upgraded pump can provide, then you should probably come up with a more extensive solution then modifying the banjo bolt.

And if you arent making 400+ whp then you really dont need to worry about the stock lines and rail anytime soon.

 

[habitatguy187]

Seems like a waste of time to modify the banjo bolt.

You really think that 15 mins of work isn't work it? Just look at the stock banjo fitting and see how small that inside ring is, there's no way this isn't helpful, and it's way easier than a fuel pump rewire.

Really if you are the point where you need more fuel then a upgraded pump can provide, then you should probably come up with a more extensive solution then modifying the banjo bolt.

I'd much rather have upgraded or "modified" lines than just throw the bandaid of a high pressure fuel pump on the car. Granted if I wanted to do it better I'd put a -6an fitting at the top of the fuel filter, but for a free "mod" I don't see how you could beat it with a stick.

 

[9!'clipseDOHC]

There's 2 things wrong with the Stevetech article: like you said, the filter can flow more than 2lph if there's a good pump behind it.

Second, the injectors are fed evenly regardless of fuel pressure. There is no mechanism present in the fuel rail that limits flow or pressure to an individual injector while allowing greater flow/pressure to another. The stock fuel rail is a large open tube, if pressure drops then it will drop evenly in the whole rail.

The only good thing about the Stevetech article is that it shows how to build and install high flow fuel lines.

I don't see how the stock filter could only flow 2 liters per hour, maxxed out stock injectors flow almost 2 liters per minute. I have maxxed out 1000's on the stock filter which is 4 liters per minute. So even if you mean to say liters per minute, over liters per hour, i have flowed double.

If y'all read from the beginning, the article in question says that the factory filter flows 2 liters per minute (lpm), therefore 120 liter's per hour (lph).

As far as drilling out the banjo bolt, it seems like a good idea and the price is definitely right. I can't see how it would hut anything. I also like how you lined up the holes to provide straight flow into the feed line.

 

[dsm-onster]

The stock filter system OBVIOUSLY flows more than 120litres per hour. Look at the multiple results with those over 500whp with the stock fuel lines.

 

[9!'clipseDOHC]

I agree. It's already been established that the tests in the VFAQ article were with the factory fuel pump. I was just clarifying the lph/lpm issue.

 

[diambo4life]

I know it's digging up the crypts but this is just my own experience with my old Talon. The facts below are with the stock FPR, Bosch 044 in the tank and stock fuel line and E85. My car was right around 3150-3200lbs with me in it. Those are the constants.

1. 541fwhp (dynodynamics dyno) and 128mph in the 1/4 mile...2 days later. Same tune. Nothing touched. Done with the stock fuel lines INTACT! boost was about 30psi IIRC.
2. More boost. 38-39psi'ish. 10.56@136 & 10.8@138mph. Stock fuel line INTACT to the STOCK fuel filter. I only upgraded the section between the fuel filter and the rail. I only got rid of the banjo. My IDCs were maxed. This was still with the single Bosch 044 in the tank. The newer Walbro 400/450s should do even better.
3. Numerous mid 10 and 139mph traps were with a proper AN fitting at the fuel filter. Adding the inline Walbro did reduce the IDC by about 20% and kept my AFRS in the mid to low 12's where I like it.


Basically...I had reached the maximum capacity of my fuel system for airflow/boost. But at least you know what you can get away with.