to put it into context:

I run 24# FMS injectors.. I've never seen the engine pull fuel on LTFT.. I've got a SCTbyHF 91 'canned' tune on it now, and my LTFT is around 3-9% above zero.. when I run the 91 -5% trim, I see around 12~17% above zero..

my engine is basically stock- I have a true cold and isolated air intake, air gap, 1.7rr's, and true dual exhaust through headers- and the 24# injectors are adequate to keep with the PCMs ability to manage..

there is something mighty funky going on with your fuel management Auggie.. I said it in the other thread- it could be fuel pressure, stuck open injectors, or simply injectors that are WAY too big.. gotta be one of those three..

 

Or I misunderstood

yeah I'm thinking maybe a bad injector because they are rated a 22.68 flow instead of 22.3x flow at 43psi (stock)... that would mean what 24-26 flow at 49psi? could that really make that much difference? I will check the plugs.. I already have an adjustable regulator on order... do you think that would be ok to use with the stock fuel pump?

 

What flavor of regulator? Is it a return style?

 

Will strait piping a v8 gain more mpg's. I have a muffler on it now but I want to take the cat off will this help or hurt the mpg's. I was also reading about the 14+3 and was thinking about putting that in. What do you guys think?

 

I lost mpg with 14x3.... Pulls hot air right inn

 

No. Exhaust behind the cat has very little effect on performance/economy.

 

none of that will really do anything for mpg's (or horse power ... mufflers can gain you 2-3 hp tops) removing the cat wont help your mpg's either... it usually hurts it unless you run a simulator and the end result would be possible hp gains in the upper rpm range at the cost of low end torque ...and since you want to save on gas you want to do most of your driving in the low end rpm range anyway.... 14x3 also has been reported to cost low end grunt Why im not sure other than its less restrictive? these things are "tuned" for power in the low rpm range... many mods just move the powerband up at the cost of some lower end power...this is bad if your like most who are just stoplight racers and like the power on takeoff and at normal driving conditions.. this is why my low hp 84 corvette is still so fun to drive and feels so powerful... its tuned for lots of torque which is what you want for the feeling of power and fast acceleration up to a point ... its also the biggest cause of breaking other things like transmissions.. HP is more important at top speed when your squeezing every last bit out for that top speed. At least thats how I understand it.

you never answered if you had a lift or larger tires? if so changing your gears can help depending on what you have now...

 

no its not... but I thoght the pump had a bypass to let some fuel back in the tank depending on the pressure and amount used?

I use a regulator on my vw with an electric fuel pump... (But im only dealing with like 4-5 psi and regulating it to 2.5psi to the carbs...

 

I don't think the external regulator will hurt anything. All it's going to do is limit pressure after it, the whole system in front of it will still act exactly the same way..... I don't see it being a problem.

 

thats exactly what I was thinking...