Well i put a vacuum line on the stock reg so it drops to 50psi at idle.

But now it wont go over 62psi even under full boost.... i think that FMU just fried my pump.


<img src="http://memimage.cardomain.net/member_images/3/web/831000-831999/831395_11_full.jpg">

Exactly!!!!!!!!! You put the vacuum on it and it drops 50 base and WOT is 60 psi or when you take the vacuum off.

Chris, you don't seem to understand the concept of proper tunning.
About 80% people here on the ORG if you ask them how to run a proper Forced Induction set up they are going to tell you to get a rising rate something and most of the time it is wrong.
People run FMU's 12:1 (god) 8:1 6:1 4:1, and FPR's and stuff and drop the pressure, but all you need is a big enough injectors and way to adjust the duty cycle and the pulse width!!! It's all about THAT!!!
Right now I am not sure if anyone is putting more HP to the wheel on a ECO than me and I am not bragging about it but I am running the simplest set up possible and it works really good.

People go and by EIC's and expensive TEC's and other fuel systems and they cannot get them to work.
I got Blazer pump, bigger injectors, non adjustable FMU, and S-AFC.
I am running 50 psi base and 60 psi WOT.
My Blazer pump won't push more then 75 psi at 10 psi but I don't need more!!!!! and noone else does people think they do, it can carry a lot more volume than it can pressure. Get it
For a long time I used to think than 1:1 is not enough, but it is if you know what you are doing, and let me tell you what one to one is.
There are 2 ways of reading it properly.
1st way is, every psi of boost you get a psi of fuel, so at WOT you have 60 and at 10 psi you should have 70 right?? Well maybe.
You have to take into consideration that when 10 psi of positive pressure that Turbo throws into your combustion chambers put 10 psi of stress on your injectors or should I say air velocity that injectors have to over come to squirt hence they lose 10 psi and you lose 10 psi of fuel.

So lets see, if you didn't have rising rate of FMU or anything and you spool up to 10 psi, if you look at your fuel pressure gauge your fuel pressure from 60 should drop to 50 at WOT just because the injectors have to push through 10 psi of air.
Now to solve the problem, you run a 1:1 to even out the psi and so that you get to keep your 60 psi at WOT and 10 psi. Most of the factory FPR's WILL take care of this alone because they are boost sensitive and so are the Aeromotive and bunch of others.
People don't talk about this much, like I said cause most of the FPR's fix the problem, but it doesn't mean it is NOT there.
Another way of rising one to one is on the top of what the FPR gives you 1:1 to fix the problem you ADD ANOTHER 1:1 WITH THE FMU.
So instead 60 WOT you have 70 WOT granted you are still at 10 psi.
In reality it is 2:1, but like I said, a lot of people don't talk about the 1st thing and they reffer to 2:1 as 1:1.
It all depends to who you are talking to.
This is the one that I am running 2:1 so at 12 psi I have 72 psi of fuel.
Sorry if I am boring someone to death, but it got me thinking one day when I spooled up to 10 psi and looked at my fuel gauge top out at 75 psi of fuel and I was still rich while I had 6:1 disk in the FMU and the fuel pressure was suppose to be like 120+ psi, but the pump couldn't push it.
I crunched up the numbers and saw that if I remove the disk out of the FMU I will get what I am getting right now, so I did it kept an eye on the EGT's and everything was fine.
Now to fix the idle and tune the fuel curve a little better I used the dyno and the S-AFC.

That is it, and trust me IT IS PLENTY OF GAS AT 2:1 or if you wanna call it 1:1.

One more thing before I leave, perfect way of doing the fuel for me would be to ditch the FMU so my FPR would take care of the lost pressure and I would still get my 60 psi at WOT, but to shorten the pulsewidth and maybe increase the duty cycle by 10% or so when it starts reading boost, so that way the extra psi of stress is not being put on the fuel pump. This is the way Subaru, Mitsubishi, Saab, is doing it and even GM with the Supercharger REFLASH. LOL I will do this later tho but for now it is FMU and S-AFC.

Sorry for a long post but I hope this cleared it out.



Best time:"""11.946""" @ 114.73 mph @17psi 1.83--60"
11 second daily driver!!!!
Race Related 727-561-9440
Shop of choice for your 11 second J body!

Also, built bottom end and or top end LSJ and L61's available.
13's ----12's ----11's ----10's

Yasmin.

I appreciate the write-up - but it's not that I "Don't understand the concept of proper tuning"... don't go assuming my knowledge, just as I don't go assuming yours.

I would much prefer to tune larger injectors with duty cycle myself, which is why I have an S-AFC, I just can't do it with boost because I don't have an emanage (it wasn't proven enough on the J-body for me to spend the $$$ and try it).

Trust me I'd rather tune with duty cycle and pulse width any day, there just is no really reliable and proven way to do it with boost.

With that said, again don't assume what i know or what I'm doing. Just because you ran a 6:1 disk in your FMU doesn't mean I didn't crunch the #'s a YEAR AGO before I got boost and about 3-4 times with Shifted (Ron)... we both came up with a max pressure for the injectors that I have at a pre-assumed horsepower rating.

What did we come up with? At about 8 psi of boost all I needed was 75 or so PSI of fuel pressure - just as you're stating. My injectors are smaller than yours so you can run more power at that fuel pressure... but my point is I AGREE with you.

I just didn't understand the "1:1".... if that makes sense. 1:1 meant 10psi over stock pressure which just isn't enough depending on the size of your injectors.

Point being is, currently I'm running about 3:1 on my FMU at 14 lbs of boost and the fuel, according to all of my calculations, should be there.

So - don't assume.

With that said, again - I appreciate the write-up as I would imagine many people on the .org will. You've been talking about "1:1" for a few months now and it didn't really make "sense"... it does now that you've explained it but as you said, it's really a 2:1 ratio.

And remember, fuel pressure ratios all depend on the size of your injector. 2:1 for you might be 4:1 for me...... going by fuel pressure alone. God forbid we throw duty cycle and pulse width into the equation.

Good luck chasing down that 12 second 1/4 mile man. You're getting close.

-Chris-



-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...