This represents a compilation of
what I used to know about the T series engines. Since moving to EFI, I
have since forgotten most of it.... However, I have left it
here on my page for those of you who don't want to
go into the new world, IE, fuel injection. I am definitely
not the expert here, I am just repeating what I have
either tried or what I have heard of done.
For your information: The stuff that's here has been here a
while..... Though I do notice the many
sub 8 and 9 second 3T powered monsters, many of them in the Caribbean, I don’t
spend any time at all on the 3T series motors.
Currently, my interests are in working with the 4A-GZE.
These engines could use more in the
way of fuel delivery. A lot more. The stock Aisin carb is not worth your time above
4000 rpm if you are serious about performance. Many people will disagree over
which is better as a replacement,
Weber or Mikuni, but everyone agrees that just about anything
is better than the stock Aisin unit. I have a
Weber 32/36 progressive on mine. Although a bit pricey for
my student tastes at $278., I have found that it is worth
what I paid. Below 1500rpm there is a noticeable gain, and
above 3000rpm the free-flowing nature of the
carb is very discernable. Passing at speed is greatly
helped, as is high rpm driving. This unit is a downdraft,
not a side draft; The side draught carburettors show even more gains.
The stock fuel pump can be replaced
with a higher output one for increased pressure and better reliability at
higher than stock delivery rates, but this does nothing when
you still have the stock carb. My Weber does
not require anything more than the stock pump; However the
dual Mikuni side draughts on a fire breathing
monster most certainly would. The easiest way to tell if you
need more fuel delivery capacity is to see if you
are leaning out at high rpm... If you have an oxygen sensor
(mine originally did not, but I have a manifold on
that does have a O2 sensor- from a 81 corolla) you can
measure the voltage coming from the wire. The
range should run between .15 and .8 volts; Anything
reasonably within this ballpark means that your O2
sensor is working fine; If you are getting either no voltage
or some really weird number, you need to check
your test equipment or your sensor...
The intake manifold can be given a
slight polish, but not too much. A smoother than stock finish will allow
for more fuel to reach the cylinders, but a too- smooth
polish will not keep the fuel properly atomized and it
will clump and not burn completely. The amount of polishing
to do is more an art than a science, and if you
have any experience in this field then please go ahead and
tell me about it. Supposedly the perfect intake
port looks like a lightly sandblasted tube. I plan to get an
extra stock intake and mess around a little bit and
see what happens... More later...
The addition of aftermarket headers
is probably the most beneficial thing that you can do for your engine.
The stock headers do not allow for much in the way of flow,
and they have a tendency to have too much
backpressure. TRD makes a high quality header; It is also
impossible to find anymore. When changing a
header you also are going to need to change your exhaust, as
it will do nothing alone. Of course, the same is
true of the other way around- with larger piping everywhere
but the header, you still are not going to realize
the potential of your engine. Do the whole system... I plan
to leave the stock header for a few months (long
enough for smog purposes) although in a modified form
(ported and polished) and change the entire tubing
from the current 1 7/8" pipes to a 2.25" system.
With a catalytic converter from a Nissan Sentra and a
free-flowing turbo muffler, I will be all ready for a header
set and more horsepower. The final word of
advice is this: use stainless steel, as opposed to
aluminized pipe or regular steel. While more expensive, it will
LAST. The restrictions of the stock exhaust system are most noticeable
above 4200rpm. The car seems to
lose power and no longer picks up as well; It hits a barrier
of sorts where the power output is no longer
increasing.
Basically, unless you have added a turbo or supercharger, use the stock equipment and make sure it is in good condition. If you have gone the positive displacement route, or run extremely high compression ratios, this is a waste of time for you to forgo the stock reliability for an aftermarket piece. The advantage of an aftermarket ignition unit is twofold- you gain ignition power and timing/advance adjustment.
The ignition system from Crane has
been getting high marks for its reliability and performance. I have used it on
my Triumph Spitfire for a year- it’s good for a stock replacement, if you have
points. If you have the stock ignition
system with an igniter module, the Toyota unit is IMHO better than the Crane
unit. I also would think that a good
set of wires (magnecor?) would be worth the investment since they do carry the
spark to the plugs- but only if you have significantly modified your engine.
The Jacobs system was also given high recommendations. The distributor can be
replaced; There are blueprinted units but I have heard that the 1972 2T-C
distributor was a very good one. This should be very easy to pick up in a yard
if you know what to look for. I plan to make my own system based on a micro
controller and a hall effect sensor.
If you are really going for all out
performance, consider investing in a aftermarket ECU. These units, made
by many manufacturers including Haltech, Electromotive and
Accel, really give you total control over your
motor. You can set timing advances, fuel maps, pretty much
everything. However, they run from $400 to
$4000 and you usually get what you pay for. This is the
ultimate mod that you can do- change your
carbureted T series (or other, for that matter) to a EFI
setup.
The engine itself can be modified,
of course. The pistons, rods and cam are all good in stock form for all but
the most serious of rebuild. The head can be replaced with a
high compression type from a pre 1974 2T-C
motor. These are supposedly Yamaha designed units, with the
same mounting locations, albeit missing smog
fittings. (Oh, shucks.) The cam from the 1972 model year 2T
is also a good one to have due to the slightly
more aggressive lobes (less in the way of smog regulations
that year). The steel piston rings can be replaced with
molybendium rings, as they will wear longer and provide more
service. Of course, better bearings than stock
can be located and if really wanted, either a prelube or a
dry sump system can be installed for the increased
oil lubrication of all moving parts. Finally, a radical cam
can be installed, which would up your performance
even more. The 272
grinds seem to be the rage these days for street vehicles, and 292 for race
only cars.
Basically, it all comes down to
what you want to spend and what kind of performance you will be satisfied
with. If you just want a mild street brawler, then stick
with a bolt on carbie and perhaps a set of headers. If
you want an all out race machine, be prepared to invest
serious amounts of time and money into a fast but
possibly unreliable machine. I personally want something in
the middle, so I am swapping a 4A-GE into my
car, and perhaps later replace that with a 4A-GZE. Something
to keep me happy and fulfill my needs
(without killing my pocketbook!!)
The front struts were replaced with Gabriel gas charged
struts. Not Koni's to be exact, but much improved
over the former lack-o-strut that I had previously. I
thought about modifying the old type of fluid shock, and
was told that I could save myself a lot of hassles by just
throwing them into the neighbors pool. They're that
good.
The car still corners too softly for my taste. The body roll
is akin to a large boat... So I am thinking about
putting a pair of stiffer springs in...
Brake rotors were ordered last week, they should come any
day now. As soon as they do, I am going to
take them into work and cross drill them... Whirl pattern,
few holes but strategically placed... Semi metallic
pads, it should be good to go.
I picked up a Mitsubishi turbocharger (TC-05) from the yard
for $30 and am going to try to put it on
something.. I have a Saab intercooler all marked out and
ready to pull... Should be about $20. I am not sure
which engine I want to use yet, either a 3T b lock or a
4A-G**... I am leaning towards the 4A since it is
DOHC and newer, as well as a longer production run... More
parts, better flowing head. The 3T does still
have an extra .2 liter though...
EFI is going to be a big concern with this new changeover...
I want to make it as bulletproof and as flexible
as possible.. The two are not necessarily compatible... But
I am going to try my best... I think that I am
going to learn how to program in C++ just for this
project... Heh heh...
Brakes... The front disk brakes were FUBAR. They still
worked, but not very well. The hoses were
replaced a while ago (they were starting to fray and that is
not a good thing to see!!!) and so all the front
hose equipment is new, stock. The rotors cam e in, and I
decided not to drill them. basically, I am not doing
much auto crossing and am not in situations where I use them
to the point that they fade. So the extra rust
weakening that I would get from doing this would not be
worth the trouble of drilling them. Illinois winters
are hell on steel. So, stock pads, stock rotors. Cost: $47.
Bitch to get the driver's side plate back enough to
fit the new pads, but WD-40 and a stubborn resolve fixed
this. My advice: GET A C clamp. I did not have
one over 2" and man, it would have been all done in an
hour if I did. Get the pistons back before you take
the old rotor off. It is easier that way. It took me an hour
and a half- an hour to get the driver's side done,
and 15 minutes to do the passenger side . Another 15 minutes
to put everything (Wheels) back on and clean
up. The car stops much better. Interestingly enough, the
passenger side was the original rotor, both rotors
were thin. Too thin. The pads on the passenger side were
metal-metal, although I didn't hear it at the time I
know that I would have soon. Like maybe a day or two. They
were that close.
Swap page!
This is a big part in the life of my car, as it changes the
basic behavior, heart and soul of the Corolla. See
the new motor part for the details of the changeover. But
basically this is the transition from fixing all the
things that are wrong to truly starting to modify the car.
Before this point I made changes when I had to, but
not out of pure desire to modify for better performance.