20R / 22R / 22RE / 22R-TE
The 20R 2200cc. / 22R
2400cc. engines were the most popular US Toyota engines.
For 20 years, 1975 to 1995, these motors served as U.S.Toyota's
dependable workhorse engine. These
engines powered the popular Celicas until 1985, and the unbreakable Pick-up
models used these engines until 1995 (in commercial models).
Turbo models appeared briefly as the 22RTE in 1985-1988 on Pick-up and
4Runners. The 22RE Fuel injection
models appeared in 1983, on some Celica and Pick-up models.
In 1985- the 22RE had a major change.
The block was taller and the head shorter, compared to the earlier
models. The engines' blocks and
heads are not interchangeable (for practical and cost purpose).
The engines are OHC
design, with hemispherical combustion chambers.
The cross-flow head was very
efficient, short of a 2 or 4 valve (per cylinder) Twin Cam.
The long stroke provided a lot of torque at a reasonable RPM range.
The engine responded well to all the tuning tricks.
The 20R head is different from the 22R heads.
The 20R had open combustion chambers and the 22R had a swirl-inducing
chamber (for cleaner emissions). The
intake ports on the 20R were round, and rectangular on the 22R.
Exhaust ports were identical round design.
The later 22RE (with the shorter deck height) had keyhole shaped exhaust
ports. There were available 22RE
models that used the earlier 22R head, in the 1982 to 1984 Celica GTS.
All 22RE from 1985 used the later blocks and heads.
The 22RTE Turbo engine was
based on the later model 22RE (short block /tall head).
This is a similar but entirely different block and head.
The block was drilled with different oil passages to accommodate the
Turbo oil requirements. The
cylinder head's combustion chamber had a different shape.
The piston was dished. Advertised
horsepower was 145. The factory set
the boost at 5.5-6 pounds, but completely stock internals survived boosts of up
to 17-22 pounds, with proper fuel injection modifications.
This is a testimony to the bulletproof bottom end design.
Nitro / Methanol fueled dragsters, producing in excess of 1100 HP- used
the original (modified) crankshafts and TOYSPORT pistons!
Toysport built the first
2400 cc. 20R, these evolved in the 20/22R hybrid engines, in the later years
when the 22R engine was introduced in 1981.
The 20R head holds a distinct advantage over the 22R / RE heads, it
flowed better. The availability of
big valves extended the tuning potential for the 20R (and all the other
engines).
There was a Japanese
version 21R 2000cc, which had both an early and late model cylinder head similar
to the 20R and 22R. These were
imported due to the big demand for used engines.
There is nothing of interest from these engines.
In 1985 Toysport raced a
22RE Toyota Celica GTS in the Macao Grand Prix.
The original plan was to use an 18RG, but since the vehicle had US serial
#'s (from Toyota Motorsport) we were forced to use the U.S. engine the 22RE!
To the entertainment of the other Toyota Teams from Japan, we qualified
at the last minute, in the last half of the grid.
The other Celicas (with their Twin Cams) were all in the top 6 positions.
At the finish the Toysport Celica placed 3rd- behind 2 BMW
Motorsport prepared 6 cylinder BMWs! This
is the highest finish achieved by the 22RE in international racing competition.
From 1984 to 1989 Toysport
prepared a Spec-Engine for SCORE / HDRA Toyota private entrants.
The winnings from the Toyota Contingency Program testify to the racing
capability of the set-up. The
engine package kit is still available, as complete engines.
This set-up won National Championships for Toyota in Class 7 and Class 7
4WD. The carbureted engines
developed 185-195 HP, but consistently out ran the 239-240 HP Ford engines in
the same class. The secret is in
the torquey characteristics of the power band.
The limiting factor of this engine is also its strongest point.
The long stroke limits RPM capability to about 6200 maximum, but the
bottom end will take a lot of abuse. The
crankshaft is forged.
Modifying
the 20R / 22R / 22RE / 22RTE Engines
BLOCK:
The best set-up is achieved by starting with a 20R head and a 22R early
block. This allows the use of the
twin-row timing chains- over the late model single-chain type.
Boring the 20R to 92mm is possible but some castings will develop bubbles
in the bores that eventually clean up at 92mm.
The high compression pistons for the 20R / 22R are forged.
The stock early 22RE piston (full crown type) can also be used under the
20R head but the block and deck must not have more than .5mm cut, if used with
big valves.
The 20R / 22R early and
22RE late model, responds well to high compression pistons.
The rods can be prepped by stress relieving and shot-peening.
The crankshaft oil galleys may be chamfered.
High Tensile bolts can be upgraded to ARP- main, rods, and head bolts or
stud kits.
The early and late style
blocks have different engine mounting bosses, so interchangeability of late
block to early chassis and vice versa may come up.
Some early and late blocks have provisions for both.
Really early and really late blocks do not have these provisions.
When preparing an engine, make sure that the block has the correct
mounting boss- or else you will have to deal with modifying them mounts.
The 22RTE with forged
pistons will survive 25 lbs! A
metal head gasket is required.
CYLINDER HEAD:
It is mandatory to port all the heads.
Big valves are also necessary to achieve and maximize the flow.
Avoid cutting more than .50mm since valve clearance may be a problem with
some piston combinations. Tri-Y
headers work the best because they complement the wide torque band of these
engines. If you are converting into
the 20R head make sure that the 20R head has provisions for power steering (if
you have power steering).
The choice in camshafts
from many sources, must be carefully considered.
High lift and long duration cams may affect the rocker arm geometry (and
oil spraying function of the oil feed). Unless
you take the time to ensure that the rocker arms are repositioned correctly
(modifying the rocker assembly) do not even attempt.
The long stroke / low RPM design of the engine dictates very mild cam
lift and duration. You cannot
redesign an engine with camshafts!
Mild cams up to about 280 duration will work with the EFI with some
adjustments to the AFM (air flow meter).
Stiffer valve springs are
a safeguard from valve-float, but will not enhance performance since the best
cam profiles will run fine with stock valve springs.
An adjustable camshaft gear will allow the most accurate setting
(remember that a Celica is totally different from a 4WD Pick-up).
There are no TwinCam heads
available for these engines.
The 22RTE head chambers
can be opened to lower compression and increase the flow.
Big valves should also be considered, but not obligatory since this is
forced induction.
FUEL SYSTEM:
Twin side draft carburetors are a natural choice, but the EFI system will
work excellent if the vehicle is originally equipped with one. (Some manifolds
for the dual carbs have poorly designed water outlets that may cause
overheating.) Long duration cams
will seriously affect EFI engines, since combustion pressure drop dramatically
even with high compression pistons. A
fuel pressure adjuster may be needed. The Weber 32/36 or 38DPS are good upgrades
for single carb set-ups. For
carburetors, use a low pressure, high volume fuel pumps.
Do not try to regulate lower fuel pressure with an adjuster because
volume will also decrease. A fuel
return line is mandatory to allow the fuel pump and carburetor to function
properly. For any kind of
performance do not rely on Toyota's mechanical or electric pump, they do not
have enough volume. The 22RTE with any upgrade will need a higher output pump.
The fuel pressure regulator should also be upgraded.
TURBO UPGRADE:
The 22RTE needs forged pistons for any serious performance upgrade.
The CT26 Supra Turbo (not the MR2/AllTrac) can be installed with minor
fabrication. With boost controller,
upgraded fuel delivery, 3" exhaust system, and intercooler- the 22RTE will
put out in excess of 350HP, at about 25 psi!
Normally aspirated 20R /
22R engines can be turbocharged without too much problems.
The stock pistons have to be replaced with low compression forged units.
IGNITION SYSTEM:
The basic ignition unit was designed for low revving conditions.
The electronics must be updated to the performance level intended for the
engines. EFI engines converted to
carburetors must use carburetor style distributors.
Ignition amplifiers and knock sensors must be used to avoid high RPM
misfires and detonation.
Some
Recommended Set-ups:
For
stock configuration- the 20R /
22R / 22RE engines are very easy to work on.
Due to different emission requirements for the different model years, try
to work on the original engine. Porting
the head will increase breathing and will not hurt emissions- so basically to
stay legal and improve performance- the cylinder head must be ported.
The early 22RE pistons can be used to upgrade the 20R to 2400cc.
For
modified configuration- the 20R
head on top of early 22Rs will instantly give higher compression.
All heads must be ported with big valves installed.
Be careful of camshaft choice, just remember that all slow modified 20 /
22R / 22RE engines have been over-cammed. Do
not try to install cams with duration over 280 on single carb or fuel injection
models. Twin side carburetors are
the best way to go. For limited
budget use the Weber 38 DPS. Headers
installed with 2 3/4" exhaust will be optimal.
A heavier flywheel will help 4WD models, that should also have the gear
ratios changed to compensate for tire sizes.
For
racing configuration- basically
these engines are truck engines. For
off-road truck racing and high performance street use (both pick-ups and Celicas)
the Toysport Spec SCORE / HDRA set-up is reliable and impressive.
See the parts list for the 20R / 22R engines.
Although
we have successfully used the 22RE in circuit racing and rallying, and truck
off-road racing- the only reason these engines were used was because of the race
regulations. The handicap is the
block configuration- which was built for torque and longevity- meaning slow and
heavy. The cylinder head
modifications, if properly done increases head flow by up to 200%.
For
turbo set-up- forged pistons,
ported head with open chambers, big valves, TO4 or CT26 turbo, 3" exhaust,
mild cam, Carillo Rods, boost controller, blow-off valve and keep the boost
under 25 psi!!
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