Apex injectors

[stone88]

Does any one know how much boost or power the stock injectors on the Apex are good for?

 

[kinger]

IIRC it was around 14 psi or 280 hp before they run out and you need to increase the pressure.

 

[mbarryracing]

Are you asking when used with the stock fuel pump and fuel pressure alone? Or with a supplimental / high pressure fuel pump?

 

[kinger]

Good point my fuel pump ran out at 11 psi and I had to go upgraded and I run about 246hp on ulmers dyno.

 

[stone88]

Are you asking when used with the stock fuel pump and fuel pressure alone? Or with a supplimental / high pressure fuel pump?

This would be with a high pressure pump.

 

[JLR]

Injectors

I've run up to 17lbs of boost with stock injectors.

 

[HURRICANE]

We have found that the stock Apex injectors are to small for boost over about 10lbs at sea level.We will then resize the injectors.The resizing proccess works well at both idle and high boost

 

[mulot30th]

We have found that the stock Apex injectors are to small for boost over about 10lbs at sea level.We will then resize the injectors.The resizing proccess works well at both idle and high boost

I have successfully dynoed up to 290hp (and there was still fueling left) using stock injectors on a turbo apex...

I had a msd fuel pump though....

I dunno hp limit, but I would bet 300hp is doable.

 

[mbarryracing]

I run a Walbro pump inline with the stock in-tank pump and have dyno'd to over 25lbs boost with the stock injectors, well over 300HP at 10:1 AFR before running out of turbo...
Again this is only because of the additional fuel pump and a fuel controller program that corresponds to that higher rising fuel pressure (using pressure to increase flow rate which is arguably considered taboo), otherwise I agree you'll be limited to around 10 psi... after that doesn't matter what controller or program you have when the stock injectors are maxed out with the stock fuel pump capacity...

 

[mulot30th]

I run a Walbro pump inline with the stock in-tank pump and have dyno'd to over 25lbs boost with the stock injectors, well over 300HP at 10:1 AFR before running out of turbo...
Again this is only because of the additional fuel pump and a fuel controller program that corresponds to that higher rising fuel pressure (using pressure to increase flow rate which is arguably considered taboo), otherwise I agree you'll be limited to around 10 psi... after that doesn't matter what controller or program you have when the stock injectors are maxed out with the stock fuel pump capacity...

So the first limiter in stock fuel system is the stock FUEL PUMP....

 

[stone88]

I run a Walbro pump inline with the stock in-tank pump and have dyno'd to over 25lbs boost with the stock injectors, well over 300HP at 10:1 AFR before running out of turbo...
Again this is only because of the additional fuel pump and a fuel controller program that corresponds to that higher rising fuel pressure (using pressure to increase flow rate which is arguably considered taboo), otherwise I agree you'll be limited to around 10 psi... after that doesn't matter what controller or program you have when the stock injectors are maxed out with the stock fuel pump capacity...

So I take it that with an aftermarket pump no problem with 380 plus hp ?

 

[zross1]

I've never had my sled on a dyno, but running 97g of weight 100+mph track speed @ 20 psi at 10500 ft elevation up a mountain I think it's making decent power. With a Walbro 255 I'm seeing 12.5 a/f ratio. I've never had it over 20 psi but I think I could to at least 22 with the stock injectors. I'm going to find out over the weekend just how much boost I can run before running out of injector

 

[HURRICANE]

There is a big difference in what you can get away with between 10000ft and sea level.Not that you are not making good power but but we cant use stock injectors at sea level with 20lbs boost at reasonable fuel pressure.Also,we found that the walbro pump falls off at 400hp on the dyno.I think that it's great to about 380hp

 

[mulot30th]

so at about 19-20 psi is about max for the walbro 255 pump?


I do have a walbro 396 pump how much is this one rated for?

 

[powderlites]

Stock new fuel system on some will go to about 300hp
With pump and and bigger injectors at seas level I have seen 363 HP on stage 1 turbo.
18 psi boost
It was the end of making anymore power and I don't think stock motor would take much more.
Used sled come in with stock pump and can't get 270 hp !!
Seems like pump gets weak over time.