I'm looking to do a dual pump set-up on my TT 350Z and face the same problem. My solution....install a warning system that will alert you to a pump failure thru flashing lights & audible warning.

 

Good luck Greg

 

Nice data and thanks for sharing and rep+ AMS, I have a question for Chewbacca.

How about if you have a stock FPR and 60lb'ers...running ~ high 500RWHP on GT28's @1.4 bar of boost on pump. Do you feel 3.8 bar would work better or 5.0 bar of fuel pressure. Both seem to work with little ups and downs and it seems borderline.
Does the data show a better option in that range?

Thanks,

 

Why is it that the 3.8 FPR is good for more hp/flow over the 5 bar? Is it not the other way around?

 

How exactly are you sensing the failure?


As for why lower pressure but larger injectors is better for power production it's simply because as you raise fuel pressure the pump moves less VOLUME. Volume is what you want as this is truly what goes into the cylinder. So, a larger injector and normal volume flow more than high volume on a smaller injector - there's also the issue that some injectors have issues opening under really high pressures if you take it to an extreme.

 

Correct. Injectors are usually rated at 43.5psi of rail pressure. When you increase thate pressure you are increasing the amount of fuel the injectors flow when they are open. However, with the increased pressure there is more resistance to flow for the pump, lessening it's capabilities.

As far as which one is better at the 650hp level, it is kind of a wash. The lower pressure regulator would be easier on the pump, while the higher pressure one would mean a lower duty cycle for the injectors. I have not seen a significant amount of failure form the stock pump or aftermarket injectors, so in the end it's a wash. I would personally perfer the lower pressure reg, but your tuner might like tuning with the higher pressure unit.

 

Preaching to the choir - I to prefer larger injectors! In fact I have them. High pressure fuel leaks are awful and higher pressure fuel leaks worse. Never mind that many pumps take a serious dive when high pressure is asked of them as can be seen in this graph with the GTR pump(s). A marginal pump will also drop off more easily and as it goes bad flow will plummet. It's a personal decision but I prefer to keep pressure as close to factory as possible - YMMV. I do recognize that large injectors can make dialing in idle behavior a PITA but with P/H injectors it shouldn't be too bad unless a resistor box is being used to drive them and not proper drivers. Been there, done that.

Oh, it should also be noted that double the pressure != double the fueling capacity of an injector. In fact different manufacturers injectors of the same size might even fuel differently - best to get them tested IMO. It will probably also change responsiveness.

That said I would love to see a good parallel pump setup for these cars that sits in the tank and is as stock as possible. I realize the rails might be an issue etc. too but a parallel setup, assuming the return line is good, ought to support pretty decent power without tearing up too much of the car.

 

thanks Sam, It has been a long road.

 

Evoms has a great in tank dual pump set-up with the -8 or -10 return line and an external regulator. $6500-7000 for the kit

That said I would love to see a good parallel pump setup for these cars that sits in the tank and is as stock as possible. I realize the rails might be an issue etc. too but a parallel setup, assuming the return line is good, ought to support pretty decent power without tearing up too much of the car.[/quote]

 

[/quote]

+1.... I think someone needs to come up with a dual in-tank bracket like Titan carries for the Supra. I think one can do it for a lot cheaper than $6k

 

+1.... I think someone needs to come up with a dual in-tank bracket like Titan carries for the Supra. I think one can do it for a lot cheaper than $6k![/quote]

I built one for my Supra for the cost of an 044 pump and Aeromotive fittings?

 

I know for a fact that a cheap dual series set up with 850 cc siemens genesis injectors will do 850 rwhp using 3.8 bar fpr

 

Hey mark, how many lbs is an 850cc? And do you mean the second pump will run is series after the factory?

 

Just so you are aware, those injectors are no longer rated at 4 bar operating pressure. I wouldn't recommend running them at anything other then 3 bar.

We have seen multiple failures running them at pressure higher then 3.8, 4, and 5 bar.

The division of Siemens that made those injectors was bought out by continental and quality took a big hit at the same time.

This is the main reason we discontinued the use of this injector.

 

80.9lb