my unit #13301 has what i thought was a VAFPR similar to the GM unit.

now i find out it is suitable for boost only @ 1/1. they state "fuel pressure rises at 1/1 ratio" is that the exact opposite of the design of the GM unit some of us used?

what does 1/1 mean?

 

1/1 means that the fuel pressure rises 1 lb per lb of boost.

 

Unless I'm completely confused here, I'm pretty sure that works just like all other vacuum adjustable FPR when not under boost. All MPI setups need the vacuum reference to compensate for the fact that the injectors see manifold vacuum. The vacuum reference is used to cancel this out and make the injectors act like 24 lb/hr or whatever size they are at all times. We use this same feature to make our injectors act smaller at idle and bigger at WOT, completly opposite of why MPI setups use them.

 

Monte: so manifold vac is read if the line is attached to a vac source with no boost? and with presence of boost there is no vac and a positive pressure in manifold results.

like in -1.00 = vac and +1.00 = boost.

both provide the same amount of fuel?

reason i am asking is that i just added EBL and it supports the VAFPR. i used one(GM) 3 yerras ago as a substitute for tuning and as you would expect was a failure. now with my large inj's(80) at 25 lbs FP i could possible drop down to say 15 lbs FP and have adequate fueling up top. may result in better tune. maybe not.

 

Your correct, whith a MPI system that FPR would give the motor the same amount of fuel at all times uner vacuum or boost.

You might run this by Rbob, I think he has the VAFPR table setup to work well with the stock GM regulator. You can still retune that table to fit your FPR, it might just be an extra step. Judging by the fact that Rbob made this adjustable I assume that every brand of regulator works a little different.

 

Yes, will work with different regulators. The regulator I am using isn't quite a 1:1, although it is supposed to be. Eh, it was inexpensive.

Ronny, if you'd like email your current BPC for the setup. This would be for the injectors and fuel pressure that you are using. I'll run the numbers are email you back the table values to use.

Using a VAFPR with the EBL does make a difference. I was rather surprised at how much better the engine was at idle and coming off idle. Just be sure to use a full time vacuum port for the regulator.

RBob.