noboostnogo

iTrader: (4)

What would be easier to tune: 60lb injectors with a fuel regulator that increases pressure as boost increases to make them flow more

OR

80lb injectors at base fuel pressure?

i know the 60s would be easier to tune idle and cruise but how would i compansate for the higher flow at full boost with higher fuel pressure on TS?

I know the 80s would be a bit harder to tune at idle and cruise but may make it easier to tune at wot full boost?

383 stroker, victor efi, single turbo th350, ~700rwhp

oh i have water/meth too

This is my first time experiencing with TS i am going from a CSU blow thru carb to MS.

Drac0nic

If they are modern injectors it probably won't matter a ton. If you leave the regulator to atmospheric pressure only (just leaving the line disconnected) you are hurting your self for 2 reasons.

1)You are not dropping the pressure at idle. This is probably ~5-10 PSI depending on your cam's idle vacuum. This makes idle easier to tune because you effectively have slightly smaller injectors

2)You are losing capacity on your injectors. For every PSI of boost you will effectively get 1 PSI less of fuel pressure. That means you drop from 43 PSI to 23 PSI at 20 PSI of boost, effectively losing ~25% of your capacity. Not really the place we want to lose capacity at....

Now then if you're referring to an FMU unless you're doing a full race 383 the 80s should be good for you. I wouldn't bother at that point, because the less pressure you run the higher output you're going to get from your fuel pump and maximize your investment. Not to mention that the way fuel pressure to flow capacity works you'll only see a 25% gain by doubling pressure; overall not worth it considering how much harder the pump has to work.

noboostnogo

iTrader: (4)

As far as tunerstudio do u think it'll be a nightmare running the 80s with a rising rate fuel regulator?

I wouldn't mess with a fmu I'm looking at the aeromotive 13110 regulator

NufNuffZ28

iTrader: (10)

Everyone I talked to about this very subject(including diyautotune) stated that they should be boost referenced at the regulator. It cleaned mine up a lot and helped me get more out of my 80 lbers...

Six_Shooter

iTrader: (2)

The vacuum/boost reference is not to increase flow of the injectors, it is to maintain a constant delta fuel pressure, that would have predictable flow rates at all intake pressures. This applies to any size fuel injector, or EFI system.

project89

iTrader: (1)

when u buy injectors buy low -z injectors, these are easier to tune at idle as they open fatser then high -z

on a 383 u shouldnt have problems with 80's anyway

my 65# injectors idle just fine on a mild 355 with 53psi base fuel presure

anesthes

iTrader: (12)

I don't know that the responses you got were exactly what you were looking for.

A 1:1 boost referenced regulator will keep the fuel pressure ratio consistent with the raise in boost pressure, but I'm thinking you meant a multiple ratio regulator (FMU?) to actually increase fuel pressure for additional enrichment under boost.

My advise to you is to NOT go that route, but instead just use a 1:1 regulator.

In tunerstudio, you can either use a 0-200kpa MAP, or you can create multiple AFR tables for more resolution.

You didn't say what megasquirt you have, if you wired the injectors batch fire or sequential, but you have a LOT of control over the injector firing which aids in tuning the 'big injector problems' that we used to have with the OEM stuff.

The way I have mine currently setup, I just created a 0-200KPA single AFR table. I spent some time selecting which AFR ratios I want at the intersecting cells. The wideband 02 in autotune will build a VE table based on that programming over a nice long drive and completly dial in your part throttle, cruise, and WOT ranges. You'll need to then make some adjustments to youe AE (which it has a wizard for), and potentially PE.


-- Joe

noboostnogo

iTrader: (4)

Thanks a lot guys this clears it up a lot for some reason I was under the impression that with a 1:1 regulator I would get more but instead it maintains.

I have a ms2 v3.0 wih msextra code and the map sensor in the ecu. I am only controlling fuel with the ms for right now and leaving timing control to my digital programmable msd box I do t wanna confuse myself off the bat.

I've been playing with tunerstudio just a bit on the stim but its pretty basic the things you can do with just the stim vs the actual engine so I am gathering all the info. I'm looking for reliability "fuel efficiency" and performance and by fuel efficiency I mean better than what I got with my blow thru lol