This is a guy off the fordnatics email list. He's a bright guy who built a killer Fox body. Lots of GOOD tech info included! I put this on the general tech board before figuring it would probably be better suited here...
Well my Mustang is finally driveable.
Ian and I took it out for a spin last night. To the race pump and back home,
naturally. Along the way I lost about half the diff fluid-- top fill plug on
the back cover was missing, a small amount of oil from an AN fitting leak ..
and all the lug nuts were only hand tight. This is the unfortunate side
effect of a project 2 years in the making; you forget what you did and
didn't do.
This is also why I didn't really get on it much or drive it far before an
inspection. Today, I drove it to work and tossed it up onto the lift for a
safety check of all the suspension and brakes. It's all good.
So, tonight on the way home I finally drove it like I stole it. I hammered
on it. And let me tell you, it's freaking fast. First gear- useless. I take
off slow, give it WOT and it just nails 7k rpm like nothing was there. I
shift it into 2nd, give it WOT and it pulls very hard until about 5000 rpm.
At that point it keeps accelerating but the rear end dances around a bit as
it's breaking the tires free at around 50 mph! It's very smooth and the
power delivery is linear. Plenty of low end torque above 2k rpm. The sweet
spot starts at about 4000, with the peak somewhere around 5500 rpm, and it
seems to pull just as hard to 7k.
The Tremec TR3550 is very nice. I dunno wtf people are talking about when
they say it's a notchy transmission. It's very smooth and positive. I'm
running ordinary ATF in it, per the recommendation for the first 500 miles,
with the stock "short throw" shifter from Tremec and a Steeda Tri-Ax shifter
handle. Feels very strong.
Some interesting observations:
My cooling system. Whatever you want to call the design that I built, it
works amazingly well. Temps hold a rock solid 180 degrees- what the
thermostat is. I've got a 192 degree tstat to put in, I've just not done it
yet. I'd prefer it stay at 192. No matter how hard I got on it.. no matter
how much stop and go I tossed at this- it stayed right at 180 degrees. Oil
temps were 200 entering the cooler(s), and 180 leaving. I suspect that the
spread will get wider as the temps get higher than 180 entering- that's when
the temperature differential of the oil to water heat exchanger does it's
magic. I'll probably have 240 entering and 200 leaving on the track between
the two coolers. It's overall just REALLY nice. My last combination which
made a lot less power ran way hotter, with the temps flucuating all over the
place, requiring my Taurus 3.8L fan to sit on high a lot of the time. Now it
just sits on low and hardly ever goes on high.
I need to spend a weekend taking pictures and documenting the entire
project. I'm planning on doing that this weekend, and I'm going to do it
WELL and RIGHT. I'll try to describe the cooling system just to perhaps
spark your interest on my ingenuity.
Essentially, I wanted a cooling system that's much like the german imports-
where there really is no overflow tank. Air is purged into a continuously
recycled surge tank, and the small volume of air in that compresses to take
up the minimal expansion the coolant itself has. From there BMW/Volvo/Audi
usually has it dump to the ground in the case of overheating. I used a stock
coolant recovery tank there- to collect an emergency dump.. which is very
appropriate for on the track. The surge tank is from Moroso. It's aluminum,
and holds about 2 quarts. Now, plumbing this into the stock mustang system
took some thinking.
I -also- wanted to address the hot spots problem with Windsor V8's.
Basically, coolant tends to circulate much less in the back of the block.
Despite the head gaskets now utilizing larger coolant holes the further the
water passages are in relation to the front of the engine, unbalanced
cooling still occurs. Stick a thermometer in the back of the head, you'll
see the difference. Coolant enters the block at cylinders 1 and 5. It makes
its way to the back at cylinders 4 and 8, all the while passing up into the
heads.. with larger holes in the head gaskets requiring less static pressure
to produce flow into the head, where it then joins in the intake manifold...
and circulates forward, to the T-stat housing. This design rather sucks IMO.
Air and steam builds up in the back cylinders, especially at the water
jacket openings. Many heads do not encorporate steam pocket release holes.
Look at a new Fel-Pro 2-1011 head gasket for a Windsor 351/302 and you'll
see the holes I'm talking about. Most heads don't have them, because most
blocks don't either. I remedied this- by marking the holes in the heads and
block and carefully drilling them. The heads required close attention, and I
worked with Trick Flow Specialties [the makers of the heads I use] to
determine what was BEHIND the areas I wanted to drill. A water passage was
available in all cases except for the drivers side, where an EGR passage was
underneith one hole. I skipped that one, but was able to use all the other
steam pocket holes using the head gasket as a template.
The issue of things being too hot in the back I addressed with
simultaneously providing a method of plumbing in the surge tank. The surge
tank requires a small amount of coolant pressure, and a large drain tube
that must be hooked to the inlet side of the water pump in some fasion.
Note- it's because of that last part that my first fear when filling the
cooling system would be that.. as the engine runs and I pour coolant into
the coolant tank, it'd just keep emptying it until it sucked in a bunch of
air. The surge tank has a hose directly to the inlet of the water pump,
after all. This is in fact impossible. Where would the extra coolant go?
It's a closed system. Coolant in, coolant out. The most the water pump can
suck in, is how much is entering the surge tank. Thermostats don't allow
coolant out so much as they allow the water pump to DRAW IN new chilled
coolant. Entering the surge tank is a measily 1/4" line, it isn't much. And
the surge tank is being filled as fast as it's being emptied. So, you can
safely remove the cap when the system is not pressurized, with the engine
running. As air is purged out through the surge tank fill line, coolant will
be drawn in to take it's place. You just keep filling it as air keeps coming
out. No more air, no more fill. Cap it up and yer done.
How to plumb in the surge tank and solve the problem of hot water staying in
the back of the block? Hmmm. Read carefully cuz I'm going to write it as it
is:
There's these neat water ports that are normally plugged off at the back of
the intake manifold. I unplugged them, ran 3/8" pipe extensions, and joined
both of them together via a T .. then I route the coolant- most of it, to
the heater core in the passenger compartment. Using a nifty 1/2" / 1/2" /
1/4" T/Elbow available in the "Help!" section at the parts store, I routed
1/4" of that coolant to the surge tank. Most of the air in the engine
collects back there normally, now it gets eliminated at the surge tank. The
heater core needs an inlet to the pump- Mustang pumps typically have two
inlets aside from the huge one from the bottom of the radiator. I route
coolant from the heater core directly to one of them. Since the heater core
no longer draws water from the stock EFI hardline and since I don't even
have an EGR spacer to cool, the hardline gets thrown away. The port it
attached to in the front of the EFI lower intake (1/2" NPT) gets plugged
with my Autometer gauge temp probe.. giving that gauge razor sharp accuracy.
The EFI system needs a reasonably accurate sending unit location and a
reasonably inaccurate sending unit location for the dash gauge. The EFI
sender gets stuck into the 3/8" drilled hole of the thermostat housing. Some
may already have the hole tapped for 3/8". The stock gauge sending unit
stays where it is- drivers side front coolant port of the intake manifold.
Ok, coolant enters the pump from the heater core via one of the inlets. The
surge tank ALSO needs a direct inlet to the pump. I routed it so that it
goes directly to the second inlet of the water pump. The thermostat bypass
however normally goes there- it doesn't now. Instead, it gets routed to the
1/4" NPT opening of the bottom input side tank of my radiator- where the
drain normally is. I plumbed in a T to retain drainage capability. Bypassed
coolant now gets chilled before entering the water pump.
SO- that solves ALMOST all the problems. The last problem is the never
ending quest to get rid of all the air out of the radiator. With this
system, it's a piece of cake!
I purchased an ordinary Stant 16lb radiator cap. Then I cut out the
vent/reclaim pressurized spring retainer portion. Basically, I turned it
into a flat radiator cap with no other seal besides the pressure of the top
rubber ring against the radiator rim itself. This outer ring is capable of
holding pressures in excess of 50 psi, so you don't have to worry about
coolant spilling out. Coolant WILL however spill out the coolant recovery
tank tube port. But instead of going to a recovery tank, it goes off to a
nifty 1/2" / 1/2" / 1/4" elbow from the heater core return line... right
before it enters the water pump.
Not only does this evacuate all air from the top of the radiator-
constantly, it provides one more small path for hot coolant to get into the
water pump via.
So, summarized: Air/Steam pockets drilled, Air/Steam collection areas in the
back of the intake vented and allowed route back to the water pump to be
blended with normal coolant, surge tank added, recovery tank eliminated-
converted into a catch tank, radiator air pockets eliminated, and the
mechanical gauge increased in accuracy.
Just in case anyone is worried that the ECU will now only see water after
the t-stat has opened... my thermostat has a 1/8" drilled hole in it.
Warm-up also happens so fast that.. well, when it's cold.. it's appropriate
to think that the engine is cold.. and when it's hot, it sees that it's hot.
The granularity in-between is still accurate with the t-stat partially open.
Other things I'm going to write up on my website are how to build the
adjustable air dam, how I shrouded my radiator, how the hell I wired
everything, what to use to utilize that nice 1/2" NPT port off the diff as a
diff cooler return line such that cooled fluid passes over the pinion as it
makes it's way through the diff housing at speed, where I routed my dif
cooler hoses, how I plumbed in my oil coolers and how I mounted them without
being in front of the radiator. What I did to get a stupid power steering
rack to clear my Canton T roadracing pan with a 351 and no washers under
ordinary FMS HD Engine mounts .. how I made a heated defroster yet yanked my
entire HVAC, what I did for the roll cage install, brake line mounting, etc,
etc, etc. There's a crapload that went into this car .. and I'm hoping that
my ideas will be of some interest. Comments and criticism are very welcome.
Keman
1990 Mustang GR40 5.8L "Vroom!"
2001 Audi S4 Avant "Vrroosh!"
http://pages.prodigy.net/keman/mustang.html
[addsig]
Today
