Just pondering about a secondary external pump or even keep in-tank pump and upgrade it, but use a boost referenced 1:1 FPR up front.

Are there any disadvantages running these fuel pressures on C6:

40 psi while decel
43.5 psi idle
53psi at 0 Vacuum
63 psi at 10 psi boost

Tanks would be dropped to install LPE in tank FPR block offs:


http://www.lingenfelter.com/mm5/merc...Store_Code=LPE

http://www.lingenfelter.com/mm5/merc...Store_Code=LPE

I got the above values from scanning my car at decel, idle, 0 vacuum (ignition on engine off) and assuming 10 psi boost from blower at WOT max pressure.

My reasoning as most know, is to get injectors like SD 60's to still behave properly at idle/parking lot speeds, and still provide enough fuel up top, while upgrading your overall fuel system to handle the power.

This would mean that the Deka's would act like the following:

57 lb/h at decel
60 lb/h at idle
66 lb/h at atmospheric
72 lb/h injectors at 10 psi boost

(boost to fuel pressure within reason I know its not exactly linear)

Since these injectors dont do so well at 58 psi stock fuel pressure & low speeds, I'm certain they would do just fine if we could get the IPW above 1.5 at idle which using these values/pressures should be no problem.

To add to that, I'm thinking there wont be many issues with getting the correct injector data using boost reference, reason being because like on old LT1's we'd have the IFR table set to constant across the board (since FPR will vary with manifold pressure), and the voltage table would also be flat lined in reference to pressure delta, and only vary with voltage which is easy to figure out especially once you get these injectors into their linear sweet spot, which according to the injector data I found for them starts at 1.5 ms.

Not sure if I'm missing something, never had a boost referenced FPR but I'd gather it references vacuum for driving and boost at high demands.

Ofcoarse eventually I do want to get ID's or new Boschs, but I'd be upgrading fuel system as well, and for the time being I wonder if that could work, next year upgrade to some nice injectors once my pre-buy condo is built.

Also I read some regulators boost referenced don't compensate in vacuum but I think most of the nice units do, but I'll read into that a bit more.

 

Got my answer from Dave's right up on ID's site, awesome info answers my question completely:

http://www.injectordynamics.com/Stec...reArticle.html

 

You need to think about differential pressure between the intake manifold and fuel rail the point of a 1:1 fpr is that it maintains the same d/p so it's not going to make your injectors flow more or less.

 

I understand, and yes I do think of that but maintaining pressure across injectors using external FPR lets you pulse higher at lower manifold pressures while a static pressure requires the ECU to command short PW to the big injectors creating all sorts of problems.

 

With today's injectors that's not really an issue. Some are better than others, but most all pencil type injectors have very linear pulse/flow chart. The good thing about a 1:1 fpr and imo the only reason reason to use one is to prevent eating up unnecessary injector pw by having to compensate for a lower "relative fuel pressure" while in boost due to smaller d/p.

 

1:1 is preferred for any boosted system because the PCM is not set up to calculate proper delta pressure while in boost.

 

Yes I believe the ZR1 runs 36psi at idle, I'd imagine the fueling would stay cooler as well. There are FPRs out there good from 20-100 psi.

Something like this:

http://performancefuelsystems.com/De...eRegulator.htm

BTW. Dave is the man! I've learned so much just by asking him questions here and there.

 

I run 58psi base pressure on my Aeromotive regulator with an Eliminator pump, and have no trouble hitting 78psi rail pressure while at 20psi boost.

FWIW, my Aeromotive pump controller is screwed up and intermittently shuts my pump off. It has always been a piece of crap, which is why I'm just coding and building my own controller now that will blow it away. Should prolong pump life too.

 

Keep in mind when just adding an external pump you should NOT reference the fuel pressure regulator unless you pull the tanks and replace the internal factory regulator.
Failing to do so will allow the factory regulator to just bleed the added pressure off into the tank. Now, before everyone jumps in and says, oh just add a check valve on the factory feed line. Well the problem with that is now your are entirely dependent on the external pump for all the fueling which most wont keep up standalone.

 

My Elimnator is in tank. I imagine most people just go that route.

You can run whatever pressure you want. I think the pressure rating is just base. I don't think it'll have a problem.

I never liked the Aeromotive pump controller. That's why I'm ditching it in favor of my own setup. Pump speed scaled with boost? Yes please.