Fuel System Max Out Question

[nlowell]

I just spent the last 90 minutes searching and reading threads. I didn't find my answer so I am going to ask in a new thread.

With the Kraftwerks C30 kit on e85 I have maxed out my fuel system at ~6,800 RPM (as logged by Bill at DeliciousTuning). I have purchased new plug-n-play Grams injectors (550cc) and fuel pump (265lph). After seeing how the fuel pump is not a direct replacement, I am now questioning whether or not I want to install it.

I have read (and proven) that the stock fuel system maxes out at ~300hp.

DW has nice graphs of the stock fuel component performance - but I can't translate this into which one maxes out first and when:
http://www.ft86club.com/forums/showt...highlight=fuel

Questions:
Is it just the injectors maxing out or the fuel pump as well?
Is it required to install an upgraded pump when installing larger injectors?
If not, at what HP (approximately) does the fuel pump get maxed out?

Thanks in advance!

[rb6freak]

See a few details here: http://www.ft86club.com/forums/showt...51#post1569851

Also talk with @mkivsoopra who has been through a lot of this.

Me personally, stock fuel pump but 770cc injectors. I think (off the top of my head) I only use maybe 15% give or take of the injector duty cycle so I'm certainly not needing new fuel pump. 240ish whp mustang.

[mkivsoopra]

Originally Posted by rb6freak

See a few details here: http://www.ft86club.com/forums/showt...51#post1569851

Also talk with @mkivsoopra who has been through a lot of this.

Me personally, stock fuel pump but 770cc injectors. I think (off the top of my head) I only use maybe 15% give or take of the injector duty cycle so I'm certainly not needing new fuel pump. 240ish whp mustang.

Haha.. that's funny, because I did the opposite and started off with the Denso pump (265lph) with stock injectors. I maxed out the stock injectors shortly after 290 whp (dynojet) on E85.

OP, what fuel pump did you get? Both DW and Denso pumps are pretty straight forward to install. If you'll be running E85 and already have the pump, you might as well install it too. I don't know when the stock pump runs out though.

[s2d4]

Originally Posted by rb6freak

See a few details here: http://www.ft86club.com/forums/showt...51#post1569851

Also talk with @mkivsoopra who has been through a lot of this.

Me personally, stock fuel pump but 770cc injectors. I think (off the top of my head) I only use maybe 15% give or take of the injector duty cycle so I'm certainly not needing new fuel pump. 240ish whp mustang.

You are perhaps using only 115cc of it?

[rb6freak]

Originally Posted by s2d4

You are perhaps using only 115cc of it?

Well, I wouldn't exactly call it that. I am only using a small portion of the injectors full capacity. Better to not wear out injectors at 100% duty cycle all the time and also have room for growth.

I just double checked, I am using anywhere from 0-20%.

[ptuning]

You do not need to replace the factory in-tank fuel pump if you stick with properly sized larger port injectors. The fact that the port injectors run off of a return-less style fuel system will be your limiting factor when running really high levels of boost, not the in-tank fuel pump.

Remember, the DI system generates its own pressure and only needs to be fed fuel flow from the in-tank pump. That leaves just the PI system needing flow and pressure. Flow is easy for the average fuel pump to generate. It's high flow and pressure together that is difficult to achieve with a stock fuel pump. Since the PI system on average would only account for about half the fuel volume on a car making around 400whp. At 300 to 350whp, the stock in-tank fuel pump is barely breaking a sweat.

- Toan

[nlowell]

Thanks Toan! That's what I wanted to hear . I don't plan to go above 350 as I start to worry about the longevity of my auto transmission and engine internals above that.

[s2d4]

Originally Posted by rb6freak

Well, I wouldn't exactly call it that. I am only using a small portion of the injectors full capacity. Better to not wear out injectors at 100% duty cycle all the time and also have room for growth.

I just double checked, I am using anywhere from 0-20%.

ok, that is like 154cc.