How does one know...

Gotta have the MAF matched to the injectors (this is not the way it works technically but we don't want to confuse the thread). If you change the injectors to a different size, the MAF transfer curve needs to be adapted (either with a 'calibrated' MAF or via a tune.

If you like to tinker, I'm sure the guys are goin to suggest to use big squirters, an LMAF and an RT. Then you can dial it in perfect, rather than having stuff that should work but having no way of adjusting the bugs out.

You can do a lot with the trans (Wes is great with assistance!) with an RT as well.

Good luck.

Here is what I'd do if I was you
and
Seeking the knowledge you ask about

First thing is ... Don't buy anything else
until
You take advantage of peeps knowledge on these boards that have
successfully done what you seek to do :Word:

You can find a few on this forum
but
I'd focus in on the power adder forums

I assure you ...
You'll find plenty of reading material to educate yourself
The fuel needs of a blown street combo have been throughly thrashed

If you wanna tune as Ford did with a FMU-less setup

In a nutshell ...

You go with a big in tank pump & maybe an in line pump as well
You go with inj's of 42lbs or maybe even larger
You go with a meter that will handle the blower's additional airflow
You go with a way to adjust the pcm to make it all come together

The ability to adjust things with the pcm is gonna be W A Y more
accurate than that Mickey Mouse mechanical FMU method :Word:

No ... You won't be able to go with a meter caled for 42's
and matching inj's without SOME drivability issues with
OEM pcm values

Grady

HOLY DUAL GRADY TYPERS!!!!!!!!!

Your opening a big ol can of worms...

After rounding up suitable parts to replace the FMU .....

You'll have to make the decision to Self or Pro Tune

Lets break it down to money & ability

MONEY

Self tuning with a Tweecer will set you back at or a bit over 1 Grand
550 interface
200-400 laptop
200-300 wide band
50-100 misc software

You can get a Pro to do it for less

ABILITY

A Pro should have the ability
but
You'd be wise to get references

You as the tuner will take some time
cause
You basically teach yourself as you go along

Here is where I would say your choice in forced induction can be a
bit of a disadvantage cause A forced combo is much more critical of
mistakes or misunderstandings than a NA combo :Word:

I'm not saying you can't learn to tune your forced Stang

I am saying you'll need to be focused and careful ... thats all

I don't see how anybody can tell you if
You should ... or ... should not ... Self Tune

You can dig up old threads where myself and others have tried to
describe what its like

I some how think most peeps who have taken to it
and
Have found satisfaction from the whole process

Well ... they just know before they even get started

Its Gonna Be A Hoot

btw ... there is some basic Tweecer self tuning stuff on my site
its done with older software
but
the info is accurate and still valid

Maybe you can get some insight from that stuff

Grady

toyman said:

Okay let's take this one step at a time

Rounding up suitable parts

That's where I am looking for input/advice

We know that the fuel pump, injectors anf MAF meter need to be changed but it's here where one gets a wide range of opinion

So, if I'm going to keep boost in the 6-8 psi range on an otherwise stock engine my take on the various posts would indicate that a 190 lph pump, 30/36 lb inj and a matched MAF meter should, with a tune, work well together

By working well together I mean that all the componets are not being pushed to their operating limits if that makes sense

Or are we dealing with matters where bigger is generally better

If I can help it I would just like to do the job once

We do know that with the current setup the FMU is forcing the FP and injectors to work in a way they were not designed for

Click to expand...

I'll be happy to give my thoughts and input on each Q or concern
but
Its gonna have to be later this afternoon

Grady

Knowing that forced induction engines need more fuel than your standard na engine combo it's better to go a little bigger than needed on your fuel system. Here's what I would recomend for any basic forced induction combo as a bare minimum.

42lb. fuel injectors
255lph high pressure fuel pump (walbro GSS340)
80mm or larger maf cal'ed for 42's or a 90mm lightning maf.
Some sort of tuning everything.

I wouldn't run this setup without tuning because even if the engine seems to be running fine it doesn't mean that it is safe timing and A/F ratio wise. The lightning maf will also have to have a custom tune in order to work.

The 36lb. injectors and 190lph fuel pump might work but they will be slightly taxed and I would rather know that these components are going to be able to handle the fuel requirements.

toyman said:

Okay let's take this one step at a time

Click to expand...

Fine by me my friend ... We'll not skip a one

Rounding up suitable parts

That's where I am looking for input/advice

Click to expand...

I'll give you mine and I hope others will chime in as well

We know that the fuel pump, injectors anf MAF meter need to be changed but it's here where one gets a wide range of opinion

Click to expand...

Lets talk about those ... Opinions

Opinions are great
but
1) Some are are nothing more than that
and
2) Some have the fruit of successful experience and results behind them

You can get all bogged down in
this guy said this and that guy said that

I've found the most reliable info comes from the #2 kind of peeps :Word:
thus
Thats why I pointed you to the power adder boys hang out place

You just have to look at all data and see ........
Which info is just being passed along
and
Which info is based upon actual experience

So, if I'm going to keep boost in the 6-8 psi range on an otherwise stock engine my take on the various posts would indicate that a 190 lph pump, 30/36 lb inj and a matched MAF meter should, with a tune, work well together

Click to expand...

Now ... You have concerns about pump, inj's, and meter
and
You talk about staying at a conservative 6-8 pounds of boost

PUMP

I have concerns about that 190 pump

You may need to
Go to a larger 255 pump
or
Add an inline pump along with that 190 pump

My bottom line here is ... the 190 alone is not enough

N E V E R scrimp on fuel

Especially if forced as it helps to keep the charge temp cooler
thus
You need MORE of it than a NA combo :Word:

INJECTORS

30's or 36's are not enough
Here are just two reasons for you to consider with that statement

1) Those formulas you find all over the net talk about amount of hp
to determine the inj size.

They deal in flywheel hp and not in rear wheel hp
and
Consider the hp it takes to drive the blower as well
which means
Drive train loss is not the only loss with blower combos :Word:

2) You're gonna custom tune
thus
You most likely are gonna tune with pressure set at 39 lbs
henceforth
The inj is gonna act smaller than those who tune with elevated pressures

Once Again ... N E V E R scrimp on fuel

I'd go with lime green Ford 42's

METER

I could write a book here ... but I won't
Lets just say ... IMHO ... its so critical on our 94-95 Stangs
and
All the more so than on the older Fox Stangs
cause
Our pcm's are load based and it is the meter that sets up the load

The meter and the t curve in the pcm M U S T jive :Word:
and
If the meter is not all that accurate
You'll never be able to build a t curve that is worth a dam

I prefer the meters that use an electronic calibration method
as opposed to
Those that use a mechanical cal

Having said that ... I'd consider a ProM/PMAS or Lightning meter

By working well together I mean that all the componets are not being pushed to their operating limits if that makes sense

Or are we dealing with matters where bigger is generally better

Click to expand...

Your comment about everything working well together is a wise one

I can't be certain here Richard ... but ... I some how think you may
have seen some older thinking based upon tuning with mechanical
methods like back in the Fox hey day as opposed to working with
the pcm as is more common these days

I can assure you ... a 190 pump and 30's or 36's
will not only be pushed to their limit
IMHO ... they will be pushed beyond it

Application is also important and you have stated yours plainly
so
It is not like you are gonna need .........
sumped tank
larger fuel lines
larger fuel rails
etc

Soooo ... Nooooo ... Bigger is not ALWAYS better

If I can help it I would just like to do the job once

Click to expand...

Again ... Wise thinking

You just gotta look at all the opinions/info to determine which is
valid and which needs to be weeded out

We do know that with the current setup the FMU is forcing the FP and injectors to work in a way they were not designed for

Click to expand...

This is so true ... but ... Many have done it for years

I will say that over the years I've been on these boards, I've seen on
more than one occasion peeps who have suffered catastrophic events
when something with that tuning method fails

Hope I made some sense to ya Richard
and
If I wasn't clear on some points ... feel free to ask more

Grady

toyman said:

Okay Grady, I'll take your advice and over the winter I'll quietly assemble the necessary parts as suggested

Click to expand...

Please ... Be sure to take my thoughts here and stack them up against
those folk that have done forced combos

Make sure they follow the major trends of those who have successfully
done what you seek to do with your Stang

But I must admit that I'm baffled

If the 190 lph pump and 36 lb squirters will be maxed out how can the FMU make a 95 lph pump and 19 lb injectors deliver the fuel required

Aren't we doubling the flow for all practical purposes with those higher volume parts

Click to expand...

Well ... the fmu thing is all about working things at mega high pressures
and it really is no more complicated than that as I see it

I see your thinking and I'll give you the way I look at a fuel supply
which
Is all the more compounded when you go forced

I see the whole fuel system deal as two trains of thought

1) Volume
2) Pressure

Volume

You can have a bunch of pressure but if the volume is wimpy
you're gonna run into trouble

I see the pump and its ability to keep on supplying fuel under A L L
possible conditions as what the volume is all about

Forced or NA ... Stop and think about it

Maximum Load being placed upon the fuel system at WOT
A long WOT pull in say third gear

You are really sucking down a bunch of fuel
and
You are really doing it in a very short time frame

You gotta be able to feed those injectors

Pressure

Again ... tuning with the pcm is N O T about high pressure

You select inj size based upon ...
The amount needed to feed the combo
and
Working at that lower OEM pressure

You See
If the proper size inj is selected
Its gonna pass adequate fuel without the need for all that pressure

I don't know about you Richard but my Common Sense tells me ...
This method should produce a more stable result

If this kind of thinking is not valid

Why don't we see fmu's on Lightnings Ford offers to the general public

Now it occurs to me that you are suggesting that when it comes time to "tune" I won't have to leave potential hp gains on the table and that to maximize the benefits of a forced induction system I'll need the larger capacity

Is that correct

Click to expand...

In a nutshell ... You got it

I do feel the mechanical fmu tuning method is very sloppy

One could tune the fmu for the best WOT results
and
Possibly not pick up much peak power with a Custom Tune

Two things to keep in mind is

1) there is the possibility
AND
there is the reality
of what happens with forced folk
when most of them go from mechanical to pcm tuning

Most of the time ... B I G gains are to be found with this kind of thing
simply because the tune is S O far off with the fmu and tiny inj's

2) there is W A Y more to tuning than just ... foot flat on the floor :Word:

You just don't have enough flexibility with mechanical tuning to
chase away all those drivability gremlins you are gonna have
when running big injectors

Tuning with the pcm opens up a whole new world of possibilities

You get the pcm values all squared away to match the additional
airflow and fuel demands of the blower and you can obtain stock like
or V E R Y close to stock like drivability

Grady

Hello Mods

This is some heavy stuff here :Word:

Seems like it belongs in tuning or tech

Not In ... TALK

btw ... A thread title change would not hurt as well

Grady