perf-list-digest Tuesday, June 1 1999 Volume 02 : Number 132



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Ford Truck Enthusiasts - Performance
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In this issue:

Re: FTE Perf - ADMIN: MAJOR ANNOUNCEMENTS
FTE Perf - 351w pulley
FTE Perf - Back Pressure
Re: FTE Perf - Back Pressure
FTE Perf - ADMIN: FOLLOW-UP
FTE Perf - Exhaust Manifold Bolts
Re: FTE Perf - 351w pulley
Re: FTE Perf - My new web site
Re: FTE Perf - questions from a shade tree mechanic to the pros out there

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Date: Mon, 31 May 1999 06:27:19 -0700
From: George Miller
Subject: Re: FTE Perf - ADMIN: MAJOR ANNOUNCEMENTS

It's still difficult to relate the slogan 'Tried, True and Ford Blue' to
red trucks but the site looks great. Your efforts are evident in the
organization and response speed.

George Miller

Let me know what you think and please report any problems.

> Ken Payne
> Admin, Ford Truck Enthusiasts
> http://www.ford-trucks.com
>
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== FTE: Uns*bscribe and posting info http://www.ford-trucks.com/faq.html

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Date: Mon, 31 May 1999 07:48:23 -0700
From: Margit Walden
Subject: FTE Perf - 351w pulley

i am putting in a 351-w in place of a 302 in my 70 bronco. i need to
find the proper single groove crank pulley that will line up with the
water pump and alt. pulley. the 351 balancer requires a shorter
pulley. was there a early 70's car pulley that would work? if i knew a
make and model i might be able to order it through ford.thanks
bronco buster

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Date: Mon, 31 May 1999 08:11:59 -0700
From: "Chris Samuel"
Subject: FTE Perf - Back Pressure

From: "Aaron Martin"
SNIP
- -> I start to look at things a wonder how they can be reingeneered for
- -> improvements.

This is truly as it should be in the finest Henry's tradition!-)

- -> First of all, while I know what backpressure is, I only vaguely
- -> remember the explanation of why some is better than none.

So, is your definition of "Back Pressure" roughly as follows?

Back Pressure:
The difference in the relative pressure of the gasses contained in the
exhaust system, at a given measurement point (usually a point between the
junction of the Exhaust Port and the Muffler/Head Pipe joint) and the
pressure defined as one standard atmosphere.

The Basics:
As you know the infernal combustion engine is a device that converts
chemical energy into mechanical energy. In a Gasoline Engine it works by
rapidly oxidizing a blend of petrochemicals. The oxidizing gas is a mixture
of atmospheric gasses containing mostly inert gasses and some Oxygen.

Operation:
It has been shown that a mixture that contains 14 parts "Air" and one part
Fuel produces the cleanest burn or oxidization.
A mixture of 12 parts of Air to one part Fuel produces the most power in a
Piston Driven Engine.
This relatively large volume of Air to Fuel requires that the engine design
must be capable of intaking the required volume to produce the desired
output. In the case of our engines we have not yet figured out how to
completely process the Air and Fuel so most of the energy that we produce is
wasted in the form of heat and exhaust gasses (there is more but I am
"trying" to keep this simple).

Society:
As open exhaust ports have been deemed to be too noisy and dangerous by our
society, and adding a length of pipe to the port has been proven to increase
the power output of an engine we are currently stuck with having to lug
around an exhaust system.

Example:
The amount of energy that is sent out of the engine is significant, witness
the Turbocharger, a device that when sized correctly is capable of
compressing Air at a rate larger then the engines ability to process it,
hence the Wastegate.

Lawyers:
Any time that the exhaust energy is restricted from reaching the atmosphere
it will rise in pressure due to the restricted flow. Yes, this pressure is
what drives the Turbocharger, and it is also commonly called "Back
Pressure".
Any time that the exhaust is restricted, it follows that it will not escape
from the cylinder as easily as if it were unimpeded. Therefore it follows
that if the exhaust can not easily leave the cylinder, then the energy that
is contained in it can-not leave the cylinder; that is until the intake
valve opens. When the intake valve opens the exhaust energy is exposed to a
comparatively short, unrestricted passage to the atmosphere.
Whatever else happens there is a rule about pressure that is inescapable; it
flows from high to low seeking to balance itself with in the system.
Open the system to a low pressure and there you go...
Reversion! Back Flow! Intake Charge Dilution! Bad things!
I have seen both EFI and Carb systems that are black in the intake ports,
and manifold... Vary common on old tractor engines. Wonder where that came
from?
Yes, I have just glossed over this issue leaving out Inertia, and FAW, and
Sonics and, and, and....

Apologies & Conclusions:
So, there you have it in just a few words. Ok a Bunch of woyrdz!
Please forgive me for making a case, but... The design goal for ANY and ALL
Internal Combustion Piston Engines should be ZERO BACK PRESSURE, if Power
and Economy are the primary goals; and you can not use the Back Pressure IE:
Turbocharger, and even then lower is better.
This is due to Physics and some unbreakable laws there of.
Not because "I" said so.
Anyone that believes that Back Pressure IS necessary is welcome to that
belief but fact is they can-not "prove" it!
To do so would be breaking several Physical Laws.
Yet I know people that do honestly believe it.

Freewill is both a gift, and a curse.

Wholly Cow Days More:

- -> How will my hp and torque change as back pressure is reduced,
- -> and where will they go in reference to my rpms.

If you reduce your Back Pressure to ZERO (nearly impossible legally), all
things being equal. Your power will increase everywhere. But will show more
of an increase as you process more Air. Simply put you will have roughly the
same shape power curve, just more area under it.

- -> Second, I was looking at the air intake and it appears as though
- -> a well placed hole behind the grill on the upper right hand side
- -> would help create a ram air effect.

You obviously are thinking of the engine as an air pump:
More air in = more O2 in = more fuel in = power out!
True! But more air in generates more exhaust, more exhaust requires a less
restrictive system. This is generally bigger, though not always. It just
depends on how bad the factory, or existing system is.
Back to Ram Effect...
You more likely to make more power with this type of modification due to the
cooler temperature of the air rather then the "Ram Effect". The Ram Effect
available at legal speeds is negligible in reality, but, the cool air more
then makes up for it! No I am not saying it is not there, it is just not
that big of an effect is all.
Look for a location that will allow you to get cool air with out the added
water and bugz. The cowl has both relatively high pressure air at speed (Ram
Effect) and offers a path that water and bugz find difficult to travel. The
added benefit is that you don't have to worry about getting a 'Big Gulp'
should you get into the pond too deep!

SNIP

Having just reread this I realize that I am tired and spent too much time
under the weld hood so far this weekend and I'll be there all day today! I
should probably let this sit a day but what the heck here go'ez...
Oh well :-)
Race Day wait for no one!

Have a good Holiday and remember why we have it!
Thanks!
Muel


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Date: Mon, 31 May 1999 13:06:34 EDT
From: CPortlock AOL.COM
Subject: Re: FTE Perf - Back Pressure

There is a lot of rhetoric and and explainationof back pressure and engine
output. If you have ever experienced an clogged muffler or a catilitic
converter going bad you should be able to recoginize the effects of back
pressure

Bud
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Date: Mon, 31 May 1999 15:49:54 -0400
From: Ken Payne
Subject: FTE Perf - ADMIN: FOLLOW-UP

This is a follow up of the announcements I made earlier.

I just want to make it clear that as always, FTE is free
and shall continue to operate as a free service. Membership
in the club (AFTE) is not required to be a member of FTE.

Additionally, the club is completely independent of FTE.
FTE merely licenses its trademark names to AFTE and also
provides Internet services for AFTE. I do not sit on the
board of AFTE for obvious conflict of interest reasons.
I'm sure Don Neighbors, the president of AFTE will make
some sort of announcement on behalf of the club later on.

Ken

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Date: Mon, 31 May 1999 14:07:39 -0700
From: "Danger"
Subject: FTE Perf - Exhaust Manifold Bolts

Would it be ok to use grade 8 bolts found in most hardware stores to
bolt the exhaust manifolds back on with lockwashers and anti-sieze, or are
there special bolts for high temp that should be used? The local automotive
stores have header bolts, but they are only 1" long (need at least 1 1/4").


Danger
danger csolutions.net



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Date: Mon, 31 May 1999 17:19:41 -0500
From: William S Hart
Subject: Re: FTE Perf - 351w pulley

>i am putting in a 351-w in place of a 302 in my 70 bronco. i need to
>find the proper single groove crank pulley that will line up with the
>water pump and alt. pulley. the 351 balancer requires a shorter
>pulley. was there a early 70's car pulley that would work? if i knew a
>make and model i might be able to order it through ford.thanks
>bronco buster


No promises on how the alignment works, but Mom's 69 351W 'Stang has just a
single groove pulley on it ... if you don't have p/s or any of that stuff
all you need is an alternator as you're finding out, hers was equipped this
way, I would guess a 70 would also have the same thing ... once you get
past about 71 power steering was a mandatory option, so finding a single
could be much tougher then ...


Just my 2cents

wish

Links http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/links.html
'73 1/2 ton 4x4 Ford http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/truck.html
'96 Mustang GT http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/mustang.html
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Date: Mon, 31 May 1999 17:23:53 -0500
From: William S Hart
Subject: Re: FTE Perf - My new web site

>I am starting to put together a personal web page. I am just starting so
>the content is a little sparse. The links page doesn't work yet but I
>will get to it. Let me know what you think. The racing page is the only
>one working so far.
>

Hey it looks great, glad to see you finally saw the light and got a blue
oval for SCCA racing :) Some info on one of my latest auto crosses is up on

http://www.ford-trucks.com//lc/lc.php?action=do&link=http://ranger3.cc.iastate.edu/autocross.html

And you're not alone racin that little ranger, there's a guy in the Quad
Cities running a 5.0L Ranger that's been lowered and handles AWESOME! He's
always runnin for time against a guy in a hopped up 4cyl stang ...
something like 180 hp out of a 2V 2.3L !!! That's 2V as in 2bbl carburetor
... no fuel injection, no turbo or super either ... the thing is a ball to
drive too :)

Good luck, and the pages look great too :)


Just my 2cents

wish

Links http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/links.html
'73 1/2 ton 4x4 Ford http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/truck.html
'96 Mustang GT http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/mustang.html
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Date: Mon, 31 May 1999 17:28:49 -0500
From: William S Hart
Subject: Re: FTE Perf - questions from a shade tree mechanic to the pros out there

> How will
>my hp and torque change as back pressure is reduced, and where will they go
>in reference to my rpms.

As long as you stick with stock manifolds, or some moderate headers, you
won't have to worry about losing power. These motors like to rev a bit,
and have a fairly flat torque curve. Opening up the exhaust will only make
things better, as long as you're not running straight pipes directly from
the motor you should be fine ... I don't know that anyone currently makes
headers for the V10 either, but they can be made by taking the 4.6 shorties
for a 'stang and adding on another curve ... as someone has swapped one of
these into a 'stang already, and it looks mean ... haven't gotten to see it
in person yet, but they are out on the net (mustangworld.com has a pic on
their fun ford weekend pages )


Second, I was looking at the air intake and it
>appears as though a well placed hole behind the grill on the upper right
>hand side would help create a ram air effect. I'm sure I could expect more
>bugs in my air cleaner, but I'm more concerned about driving in a heavy
>rain. Could I suck in enough water to damage the engine?
>
I suppose you could, but if this hole is at least partially shaded I think
you should be okay, there are several guys running this type of thing on
the 'stangs, some have problems, most don't. One suggestion was a small
screen to at least keep the cats out ... the other is to drill some
smallish holes if there is a curve, that will let the water run out without
hurting the ram effect too much ...

>Besides the search for "free" power I am planning to add a K&N air filter,
>modify the exhaust, and likely add a chip.
> I'm open to all suggestions, my main restrictions are
>the thing still needs to tow 8,000 lbs around and appear stock (read that as
>no dual pipes out the back, or anywhere else).

A chip would probably be a good idea as soon as you start tinkering with
things, they can do some wonderful things with those these days, the
absolute best way is to throw it on a dyno and have a chip tuner work
things through ... its a bit pricey, but it will be tuned exactly as you
want/need it ...


Just my 2cents

wish

Links http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/links.html
'73 1/2 ton 4x4 Ford http://www.ford-trucks.com//lc/lc.php?action=do&link=http://www.public.iastate.edu/~wish/truck.html....


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