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You can adjust your fuel one of three ways:

1. Electronic pulse width modulation at constant(ish) pressure
2. Pressure modulation at constant(ish) PWM
3. Both electronic PWM with adjustable fuel pressure.

If you're not using a rising rate fuel pressure regulator, then you're going to have to put some serious flow through the injectors, which requires aftermarket PWM-ing software. The Apex'i SAFC will do just that, and it will also allow you to upgrade the VAM (on egts) to a MAF, i.e. the 5.0L mustang MAF.

Most people will keep the stock fuel injectors maps in their ECU and use different fuel injectors, then they'll adjust fuel PRESSURE to get the right mix. The downside to rising rate fuel pressure is that you cannot adjust the fuel pressure as a function of rpm. It is a linear relationship, which is usually about 12:1 (psi).

The positive side about using electronic PWM to get a fuel mix is that it can be controlled electronically instead of mechanically (FMU), so you can map out your settings as you please. The downside is that you really don't have constant fuel pressure, but you DO know what the pressure is at a given rpm, which is known according to the stock fuel pressure regulator. A good tuner will datalog fuel pressure as a function of rpm and adjust the PWM of the injectors accordingly.

hope that helps.
 

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siragan said:
If you're not using a rising rate fuel pressure regulator, then you're going to have to put some serious flow through the injectors, which requires aftermarket PWM-ing software. The Apex'i SAFC will do just that, and it will also allow you to upgrade the VAM (on egts) to a MAF, i.e. the 5.0L mustang MAF.

Most people will keep the stock fuel injectors maps in their ECU and use different fuel injectors, then they'll adjust fuel PRESSURE to get the right mix. The downside to rising rate fuel pressure is that you cannot adjust the fuel pressure as a function of rpm. It is a linear relationship, which is usually about 12:1 (psi).
Mabey it's because I've been drinking, but how dose this apply to a EGT? Have you even turbo'd a 2nd gen GT or are you just guessing this stuff? Is this recycled bad info from some one else that dosen't know what they are say? I'm not trying to be a butt hole or anything, but almost every thing you said makes little sence, backwards or dosen't applies to a EGT.

Denis, old school turbo EGT that helped pave the way for every one else.
 

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I'm just a junior mechanical engineer. I just know the physics behind the systems that suport turbocharging setups. I don't know a whole lot about what specific brands of products to use, but I DO know what functions you need to satisfy, and I believe that is what truly counts.

If you don't want to take my advice, then just go research it yourself. I'm not going to force it down your throat. The information is out there.
 

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fmu's are only good for forceing higher fuel pressure to get more fuel out of a smaller sized (factory injector for instance) injector under boost to help with proper air/fuel mixture. They are not nessasary with bigger injectors, but the factory ECU has no way of knowing how to control a larger sized injector. Few people here are useing stand alone engine managment systems to control fuel and timming. Others are going cheaper routes with piggy back controlers that "get the job done" but have less tuneability.
 

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gt19ho said:
How did you feel about the sds? Was it a get the job done or would you use it again, if you had to to?
It wasn't a bad systm at all. Very easy to install, drilling the crank pulley to install the magnets for the timming pick up is a little scarry, but once you under stand that it's not that bad. I was 1 degree off on timming when I did it and you can compnsate for that in the program. I decided to go with a haltech E6K because my needs were changing and I was looking for more options that the haltech could do over the SDS. SDS is easy to install and programming it is very easy to understand. You can tune on the fly which is a plus. I ran the SDS for a few years and only time I had a problem with it was if I accidently bumped the quick +/- 50% fuel adjustment knob or hit a button or 2 on the programmer. Another plus is you don't need a laptop to program it.
 

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siragan said:
onegimp- were you using EM-4D or the EM-4E? I think that engine management sounds like a badass way to tune...

can you save all the settings that you entered and switch saved profiles on the fly?
It was originally the EM-4D, then I spent a little extra cash and converted to the EM-4E, so it dose fuel and timming control. It comes with a hand held programmer so no laptop is needed (didn't have a laptop back then). You can tune on the fly, upside. Down side is you can save maps and swap them out. I use to print out tables and write down my setting so I could save what I have tried.
 

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It piggybacks the stock ECU, right? Do you have any loss of functionality over just the stock ECU setup (any sensors that you can't use, etc).

Also, did you need to purchase any additional sensors?

I'm thinking about independent management on N/A. I can't afford turbocharging. Yet.
I doubt many people think the same way I do, but I would rather have a very tunable car than a turbocharged setup that works but doesn't have much tunability.

Are you FWD?
I'm planning on buying this RX-7 you may have heard me talking about... I'm planning on dropping in a mazda miata engine/tranny and doing the whole turbo/independent management on it. I love the 12A engine that comes stock in the RX-7, but it's absolutely horrible on gas and I kinda want electronic fuel instead of carbs. I don't know of anybody who's done a BP swap into an RX-7, but I think it shouldn't be too rediculously difficult.
 

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siragan said:
It piggybacks the stock ECU, right? Do you have any loss of functionality over just the stock ECU setup (any sensors that you can't use, etc).

Also, did you need to purchase any additional sensors?
It is not a piggy back system. It is a stand alone engine management system and it comes with all nessasary sensers. Optional sensers cost more.
 
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