Need bigger injectors

Skydog said:
Mine did the same thing to a tee!! Get a 2:1 adjuable fuel psi regulator and turn up the staic psi some! Then you will be able to add enuff fuel with the GEM. Make sure you are not boling the gas in the fuel rail. Mine was doing that and going lean after she got real hot under the hood.

SKydog P.S. I know you are running more boost and things are not the same but, just alittle info to look at....
Click to expand...

I agree completely with Skydog.We haven't ran out of fuel at well over 18lbs with stock injectors (12.2 Afr) and a Gems controller (sea level). The first thing I would purchase is a AF gauge. You don't need injectors or Rb3. Don't over complicate your sled and more importantly don't just throw money at it. Fuel pressure is the key, the Gems is doing its job.
 
Wildman said:
Skydog said:
Mine did the same thing to a tee!! Get a 2:1 adjuable fuel psi regulator and turn up the staic psi some! Then you will be able to add enuff fuel with the GEM. Make sure you are not boling the gas in the fuel rail. Mine was doing that and going lean after she got real hot under the hood.

SKydog P.S. I know you are running more boost and things are not the same but, just alittle info to look at....
Click to expand...

I agree completely with Skydog.We haven't ran out of fuel at well over 18lbs with stock injectors (12.2 Afr) and a Gems controller (sea level). The first thing I would purchase is a AF gauge. You don't need injectors or Rb3. Don't over complicate your sled and more importantly don't just throw money at it. Fuel pressure is the key, the Gems is doing its job.
Click to expand...

I have a A/F gauge on her, and the updated fuel pump from MPI. The only thing that is not on there now besides the injectors is the return rail to tank line. Which Pat said he has done on some larger Apex setups in the past. Like I have said in the past the sled would sputter and barely go without the new pump. It was at 17.5 on the A/F gauge. So after the install it started up and sounded good. Took a little spin, then out to the track to try it out. The lowest it would go on the track was 13.5 on the A/F. Then that is when the problem happened. They are guessing the octane isn't high enough due to the lack of fuel pressure which caused the lack of fuel. Since it was running with the meth injection. The meth nozzle was set at 300. Which we are going to switch to three nozzles directly in to the throttle bodies per Dave. Keep in mind I called Dave to ask him some questions after the problem happened. Figuring he is the master of Meth, and boost together, and he was kind enough to let me pick his brain for a few minutes. He had nothing to do with the build, or design of this. He was just helping me with some ideas on why this setup might be short on fuel pressure.
I am sure Pat was thinking if he has had stage ones with 10lb's on them working fine with the gem, how different could the two be with a pulley setup somewhere between 11-12lbs sent to him by Heath. Those setups though where on racing fuel, or mix. That is why this time we are going to set it up on race, get it right, then introduce the meth. The meth kit manufactuer is telling me we should get a minimmum of 112 octane, and have seen 116 octane with a 50/50 mix. The only other problem that could of occurrred while having the lack of fuel would of been detonation due to to high of a compression ratio. I was asked by someone, what was the compression ratio on the stroker? If it is to high the problem that occured could of happened there, in the middle of figuring out the fuel issue. I will have to find out the numbers to figure out that math. Which just adds more to the issue of the problem child. All I know is I want the fuel issue resolved so if next year I was to bump up the boost, I wont have to tear half this crap out again. Only change pulley's, fuel settings, and clutch settings. Thanks for the help guys during these trying learning times :o|

:rocks:
 
So you had the MPI upgraded fuel pump but not the fuel pressure regulator? Get a set of 430cc injectors and a adjustable fuel pressure regulator with a 1:1 rising rate at least.
 
Ah good news :-)
We got stage 4 injectors for my friends Attak powered by Poweder Lites, it already has a Malpassi 1:1 fuel pressure regulator, Vortech BOV and RB3 installed. PL stage 3 IC and stage 4 injectors with full boost......
 
So what are the major option, or function differences between the RB-3, Boondocker, attitude, and power commander units. Looks like they all can add or subtract fuel, and have some mapping technology. The RB-3 seems to be the new hot thing for a lot of guys, and is probably right from what I am hearing. Since you are supposed to be able to play with timing. Just wondering if some have too many options that I won't use for my application, and don't need to pay for, or if some don't have enough for future builds? Some dealers look like they have taken some of these, or a Gem, and just changed the sticker, and map to call it their special model for your sled. So why pay extra for that when each application is special, unless it is a good starting point? MPI would still like for me to add a version of their Prologger on this after it is together for a safer setup, and better tunability. Sounds like I will need a trailer just for the controllers.

If you could add some info why it would be nice. Instead of buy this it's right for you. Looking for the one that will leave room for future potential if I go more after this beating. Thanks for the help guys ;)!
 
You need to be able to add AND subtract fuel to make big injectors work for you.You should also be able to add and subtract timing on a decompressed engine.You add timing to the low end to rebuild the cylinder pressure and you subtract timing with boost to control your cylinder pressure.My prefference is RB3 but that doesn't mean that there aren't others that can do the job.I think that RB3 is a good ,advanced package for the money
 
HURRICANE said:
You need to be able to add AND subtract fuel to make big injectors work for you.You should also be able to add and subtract timing on a decompressed engine.You add timing to the low end to rebuild the cylinder pressure and you subtract timing with boost to control your cylinder pressure.My prefference is RB3 but that doesn't mean that there aren't others that can do the job.I think that RB3 is a good ,advanced package for the money
Click to expand...

Dave thank you for your help, it sounds like it should work great. I am going up there today to pick up my Apex, and talk to Pat. Talk to you soon....
 
Bill,

You have the upgraded fuel system which included fuel pressure regulator 1:1 and return line.
As well as fuel pump.

Like i have stated and others have at this boost level stock injectors are fine. But for somereason obviously your sled is lean. I would be curious to have your stock ones flowed to see if one has a issue and is clogged or what..
 
heath@mpi said:
Bill,

You have the upgraded fuel system which included fuel pressure regulator 1:1 and return line.
As well as fuel pump.

Like i have stated and others have at this boost level stock injectors are fine. But for somereason obviously your sled is lean. I would be curious to have your stock ones flowed to see if one has a issue and is clogged or what..
Click to expand...

Mine was lean to at 800 feet with the up grade pump and 1:1 reg. with the gems maxed at wot. Had to go to a adj. 2:1 up the base psi by about 3 psi and it was great. But then put on a RB3.. And it was even better!! ;)! :rocks:

Thank you Skydog
 
Not sure how you can flow that much fuel through the stock injectors unless your at 100 psi fuel pressure and 100% duty cycle or are my calcs off?
 
Skydog said:
heath@mpi said:
Bill,

You have the upgraded fuel system which included fuel pressure regulator 1:1 and return line.
As well as fuel pump.

Like i have stated and others have at this boost level stock injectors are fine. But for somereason obviously your sled is lean. I would be curious to have your stock ones flowed to see if one has a issue and is clogged or what..
Click to expand...

Mine was lean to at 800 feet with the up grade pump and 1:1 reg. with the gems maxed at wot. Had to go to a adj. 2:1 up the base psi by about 3 psi and it was great. But then put on a RB3.. And it was even better!! ;)! :rocks:

Thank you Skydog
Click to expand...


How much Boost were you running?
 
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