if you wanted to run 2 fuel pumps then just run make a hanger assembly and hang it next to the oem pump, you would want them run in line instead of t'd off and parallel.

now i wouldnt recommend that at all though as its not going to solve a high boost lean issue and it would be a waste of time to do that alone.

both Woody, Paul and myself have been tweaking the design for a long time now for the new fuel system. it has come a long way and does work well. the leaning has been solved, we are just trying to get the fuel curve perfectly dialed in on the low end which has been taking longer then expected.

as stated above, we do have a return system on our car with a dead head rail. if we dont run out of pressure we cant run out of fuel. with the new regulators we are running pressure dropoff isn't a problem.

between the 3 of us i bet we have tried over 100 revisions to tweak the design to the point we have now. i imagine there will be another dozen more changes before all is said and done.

here is a screen shot of the zeitronix on xrays car this past weekend. at this point the low end could be dialed back with a reflash to hold a flatter afr curve but with a few more tricks up our sleeves i think we will get it even closer without needing a reflash.

ill dig up a 17:1 afr datalog from when thsi issue first started later tonight so you guys can see how far we have come.

 

It is a barely used 13101. It also includes 2 an-06 fittings.

 

That fuel looks great at redline right where it should be. Why not just reflash and adjust the fuel in the lower rpms? seems like it would be easier.

 

Man-O-Man-O-Man...

 

What lol? its not off by that much if the RRFPR is adjusted to the same pressure at vaccum. Idle should be no different with the stock FRP vs the new one. its going to richen up the bottom 1.5k-3k because these twin screws make boost down low. and bring the top where it should be 12.1 at redline at 20lbs.

I dont see how you can avoid the bottom getting rich with the rising rate regulator without removing some of the fuel at the injector.

Is there a side effect of doing it that way?

 

There is a way around it, but its kinda complex.

You can use something like a nitrous window controller to control a solenoid, so at a certain rpm it sends the boost signal to the fpr, causing the fuel pressure to rise. That way you dont have the richening problem down low

 

I have designed a differential regulator (fluidic computer, all mechanical ) that has an adjustable start point so that there is a stand-off below which there is no FPR adjustment. Like Rob said, there is a lot of testing going on so that there are no oops out of the box..

Here is my results at Carlisle last summer and the HP curve to address the resulting gains.

If there are others that believe you have a good approach, please post your dyno results so we can all collectivley benefit.

Woody

 

Mayhem you are correct the rich issue that occurs just after the gear changes is do to the lag of the fpr bleeding down the boosted pressure. We are trying to work out a solution that does not require a retune but that maybe what has to happen. What is nice about this system is once it is fully dialed in you can control your AFR's without having to get retuned so based on weather and location you can dial in your car for optimum performance.
Just to clear up the fpr sits at atmospheric pressure and only see's any kind of boost until certain parameters are hit such as rpm and boost along with tp. If any of these three parameters are not hit it does not boost.

 

Doesn't matter. In both cases, the rail is supplied with regulated pressure, end of story. Having also owned a Buick GN, there is no real difference. the bottom line is that the regulator will control fuel pressure the same way in either case.

 

Your terminology is vague and ambiguous. Higher pressure through an orifice (injector, fuel line, etc) results in more flow. That's simple physics, more push (pressure) will result in more flow - there's an equation for that.

However, when referring to a pump that has limited (fixed) capacity, asking it to deliver more pressure will result in decreased flow.

 

2 fuel pumps are usually run in parallel as double-redundant systems using check valves.

Usually 2 fuel pumps in series is simply replaced with a single, more capable fuel pump. The purpose of double-redundant fueling is to prevent a potential lean condition.

 

thats basically what I was trying to say. I was just really really tired when I did

 

Why not have the fuel pressure regulator use closed-loop wideband O2 correction instead of an open-loop scheme? That way it adjusts itself based on actual AFR.

 

We have tried using the afr as the trigger but it works better using the boost because of the lean condition happening at the same boost pressure every time which allows us to more accurately bring on the additional fuel when it is needed.

 

well, you could run the fpr with no fancy gadgets, with just a boost reference line to the regulator.
You would have that mid rpm rich condition, but you ould easily fix that with tuning by cutting back the injector pulsewidth

 

Yhis would be more difficult than you think since you would be going from a vacumn condition to a boost which would swing the FP in a huge arc from low to hi.

 

We run our turbo cars like this all the time.
Tune the ECU to compensate, its not hard.

And its 1:1 for the fpr, every lb of boost raises fuel pressure 1psi, ts not that hi

 

If you set the starting pressure at 60 psi this happens with a negative pressure. if you go from -10 to positive 20 you are talking a 30lb diff when you only need 16 to 20. I agree that with most cars tuning is probably the easy way to do this but since our options for tuning are so limited I prefer the option of adjusting it myself.

 

i dont think you're familiar with fpr's. Vacuum doesnt lower the fuel pressure, you set base pressure, in this case, 60psi, and it runs that all of the time its in vacuum. when the fpr see's boost it raises fuel pressure 1psi for every psi of boost.

 

Exactly if you are at -10 in vacumn and go to plus 20 under boost you will raise pressure 30lb's. When you go from -10 to -9 you have added 1 pound of pressure even though it is still negative it is a raise in pressure. If you set your pressure under vac and then disconect the vacumn so it is at atmospheric pressure the fp increases.