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TURBO V6 NOTES
Last Updated: 11/29/2007
NOTE - All Buick V6 information NOT specific to the Turbo V6 has been moved to the NA V6 NOTES PAGE. It is highly recommend that Turbo V6 owners read the NA V6 NOTES as well!
SEE ALSO:
NA V6 NOTES
1982 GRAND NATIONAL
NOTES
Below are some helpful facts and technical tips specific to the 1978-83 Buick Turbo V6. Please visit the Turbo Regal Web Site and it's Technical Information Articles. While not always applicable to our earlier cars, there is quite a bit of useful information here. Most of the below entries are the results of question and answers from the Message Board. If you have a question not addressed here, have additional information, need clarification or disagree with something listed here, PLEASE post a message on the MESSAGE BOARD!
What would I do if I where going to race my Turbo Buick? See the Racing the 1978-83 Turbo V6 Buick page!
DISCLAIMER - Although I believe that the following are all true, please verify them before making any decision involving the restoration/modification of your vehicle. Some entries do not apply to all years/models. Also check with Federal/State laws before modifying or removing any emissions control devices.
ENGINE BLOCK and MECHANICAL
CONVERTING A NON-TURBO V6 TO A
TURBO V6? - If
you have a normally aspirated (NA) Buick V6 and you want to add a
turbocharger to it for some easy horsepower, please read "CONVERT TO A
CARB/TURBO?" first.
It's a little long, but it should be very helpful. Also read
about an alternative to the factory draw-thru system; "CONVERT TO A
CARB/TURBO? PART II?"
TURBO V6 and NAV6 PARTS INTERCHANGE- Finding
a Turbo 3.8 in the junk yard can be next to impossible. The NA
3.8 can be a great source of parts. Blocks, heads, left side
exhaust manifolds and many accessories interchange. Just check a
parts catalog or compare casting numbers (or ask the Message
Board). Even better, is the 4.1 litre (252 ci) Buick V6. Not
only does it have a Quadrajet, but also a rolled fillet (turbo)
crack and the ESC system (1981-'84). You may also find larger
radiators and higher amp generators in 4.1 cars. Here is a list
of GM CARS WITH
THE 4.1 V6, courtesy of David Chase, Silver6.
"RWD"
BLOCKS - All Turbo Buick's were rear wheel drive (RWD) with the
exception of the Riviera. The Riviera did however use the same long block
as the RWD models - just the bolt-ons (exhaust, turbo, etc.) were
different. The Riviera's motor was place longitudinal versus the
transverse mounting of later FWD Buicks. The transverse FWD Buicks did not
share the same block (trans mounting was different). Since it shares the
same block as the RWD's, it is commonly referred to as the "RWD block"
even though it was technically in a FWD car.
LIFTER TICKING? - If you think you have
a lifter ticking, first check for a cracked exhaust manifold or
leaking gasket. These are very common problems on the Turbo V6,
and sound very much like a ticking lifter. It's worth a look and
much, much easier to repair.
ENGINE ELECTRICAL & EMISSIONS
AIR
INJECTION PUMP DELETE - First off, I don't consider bypassing or removing
the AIR (smog) pump a performance modification. The parasitic drag on the
pump is minimal. I removed mine to get some of the hard pipe and valves
out of the way. Before I did this, I purchased a new catalytic converter
that did not use the AIR tube. The model I bought was a Dynomax 15146,
which is a universal converter intended for 84/85 Turbo Regal. On my
'83 T Type, in place of the AIR pump/alternator belt, I used a shorter 10mm x
1185mm belt to drive just the alternator (Other years may have a different belt
configuration). I was able to pass IL emission this way.
ELECTRONIC SPARK CONTROL (ESC) - The
ESC system is what made the turbocharger practical for Buick's V6
application. The Achilles' heel to a turbo set up is detonation,
or knocking. Under boost, detonation increases and will damage
the engine. Most earlier and aftermarket system uses water
injection to reduce detonation. Buick engineers developed the ESC
system. The system uses a sensor to "listen" for
knocking. When knocking is detected, the ESC retards the engine's
timing to prevent it. The more knocking, the more retarding of
timing, the less performance. To avoid knocking (and therefore
maximize performance) use premium, high octane, fuel. The higher
the octane, the greater the fuels resistance to detonation. See
the KNOCK,
KNOCK page for more detailed
information.
ELECTRIC EFE - The 1981-1983 Turbo V6
uses an Electrically Heated Early Fuel Evaporation System. It
uses ceramic heater grid, incorporated into the gasket, under the
primary bores of the carburetor. It provides a "source of
rapid heat to the engine induction system during cold
driveaway" (Buick Service Manual). The system is easy to
test. Disconnect the EFE from the engine wiring harness. Check
the resistance of the heater, it should be less than 2 ohms. If
not, the heater is burned out. Next connect a test light (or
voltmeter), to the harness. With the engine cold, the light
should turn on. If not, the relay is probably bad. Check the
proper year service relay for relay location. A bad heater or
relay will not turn the SES light on. The Electric EFE was used
on many other engines besides the Turbo V6.
ELECTRIC EFE II - The Electric EFE system (1981-'83) is
designed to improve cold driveability and lower emissions. Unless
your car is driven in cold, winter climates, you may not need it.
While many engine builders spend a lot of time porting and
polishing the intake and head passages, these ceramic grids have
to be an obstruction. Since mine wasn't working and I didn't miss
it (summer driven only), I removed it and replaced it with a
normal carb gasket. Just disconnect it at the harness. It won't
trip the SES light, or confuse the ECM (it is output, not input).
While I don't know how much it helps, if it's not needed (or not
even working), why have it in the way of the air/fuel mixture? A
new electric EFE heater is very expensive.
VACUUM EFE - The 1978-1980 Turbo V6
uses a vacuum controlled Early Fuel Evaporation system. A
butterfly valve is placed between the left exhaust manifold and
the crossover pipe. A Thermal Vacuum Switch (TVS) passes vacuum
to the valve when coolant temperatures are low. The vacuum closes
the butterfly valve which blocks the exhaust path. The exhaust
then travels through the crossover in the intake manifold,
heating the induction system quickly. Check to make sure that the
valve has not seized up. Also make sure it is closing when vacuum
is applied.
VACUUM EFE II - The vacuum EFE is another system you
may consider removing or disconnecting. Disabling the valve will
keep exhaust out of the intake and therefore lowering it's
temperature. Cooler air/fuel charge will help reduce detonation.
If you have blocked the exhaust crossover passages in the heads
or intake, then the EFE should be disable, as there will be no
where for the exhaust to go. Removing the butterfly may help
improve flow through the exhaust manifold.
1981-1983 COMPUTER COMMAND CONTROL - Since
1981 (1980 in CA), the Turbo V6 has used a Computer Command
Control System (CCC) to control many engine functions. The
Electronic Control Module (ECM) monitors and controls various
systems that effect vehicle performance. The ECM can recognize
some operational problems and alert the driver through the
"CHECK ENGINE" light. A SCAN tool can be connected to
the computer by using the ALDL port under the dash. The tool will
display the output of various sensors (Oxygen, RPM, etc.) and
display trouble codes. The codes can also be retrieve by
grounding the test terminals on the ALDL port with a jumper (wire
or paper clip). Do not buy "code readers", they just
fancy (and very expensive) jumpers. This tech page from the Turbo
Regal Web Site will explain more: GN/GNX/T-Type
Malfunction Codes. Codes for Carb/Turbo
cars can be found here: 1981/83
ECM CODES
1981-1983 MAP and BARO SENSORS - On a NA engine, the
MAP and BARO are actually two sensors, but the are the same. Both are 1 bar,
blue units. With the engine off, they will read the same. (The BARO is located
near the ECM and has no hose connected to it). On a turbo V6, they will
not read the same. 0 vacuum is full scale on the NA MAP and BARO, but mid scale
on the Turbo MAP. This is because the Turbo MAP needs to go above 0 vacuum (aka
boost).
BARO and MAP off pressures are the same ambient air pressure, but different scale,
so the Turbo V6 scale is off by a factor of two, because it's a 2 bar sensor (or
200 kPa). 52 x 2 = ~100. NOTE: Some scan tools may correct for this.
VACUUM DIAGRAMS - The vacuum diagram
should be on the fan shroud or in the shop manual. If not, I have
most available. Here is a list of the diagrams. Some have are
links to the diagrams. If you need a diagram not listed, let me
know and I will scan it. Note "E" series is
Riviera. All others are RWD models.
EXHAUST
TURBO
EXHAUST MANIFOLDS - The 1978 exhaust manifolds do not
interchange with other years due to the head redesign in 1979.
Also Riviera maniolfds do not interchange wit the other RWD
models. Driver's side manifolds are the same as non-turbo units.
Follow this links to images of some passenger side Turbo
Manifolds; TURBO V6
EXHAUST MANIFOLDS
In 1983 Buick switched to stainless steel tubular exhaust manifolds. The size difference is significant. The '83 crossover has a 1 3/4" ID while the '82 has a 1 3/8" ID. But bigger is not necessarily better. They will bolt directly on 1979 and later heads. (I am not sure if the up-pipe will work on all combinations. If not, fabricating one shouldn't be to difficult. The '82 and '83 use the same up-pipe.) The 1984-'85 Turbo Regal uses the same manifolds and crossover as the '83. Note: Riviera manifolds also changed in 1983, but I am not sure about interchangeability.
CRACKED
EXHAUST MANIFOLDS - Prior to 1983, the Turbo 3.8 used
cast iron manifolds. Just like the later units, they are prone to
cracking between the center and rear cylinders on the driver's
side. I had one that was completely cracked in two! Check yours,
you may be losing exhaust pressure here. It may be hidden under
the thermac stove. The driver's side cast manifold is the same on
turbo and non-turbo engines and should be cheap to replace.
EXHAUST
MANIFOLD GASKETS - Buick V6 engines do not come with
exhaust manifold gaskets. Most rebuilders, however, use them.
After blowing out three gaskets, all at the number 2 cylinder
(right, front), I quit using them. Instead, I use a very thin
coat of Permatex Ultra-Copper. Just check the the mating surface
on the manifold is in plane. If not, take it to a machine shop.
More importantly, torque each bolt to proper specs and recheck
often!
DOWNPIPES -
The RWD Buick V6 engines as share a common downpipe (DP). It did enlarge
in size slightly in and gain a 4-bolt mounting flange for the converter around
1981/82. The 84/85 DP is similar, but not a direct swap. The top ¼
are different, but the 78/83 has the simpler bends. Hopefully a shop that
can do 84/85 DP's can do 78/83's as well. I would recommend a 2½"
DP. Here are the two side by side
CARBURETOR, FUEL SYSTEM, & INTAKE
ALCOHOL INJECTION - Alcohol injection is a great way
to run more boost, especially on a turbo system that can't utilize an
intercooler. ALCOHOL
INJECTION PAGE
ROCHESTER CARBURETOR NUMBERS - All
1978-83 Turbo V6 engines originally came with a Rochester
Carburetor. In 1981, (1980 in California) Buick began to use
computer controlled carburetors. Due to the complicated
emissions/vacuum system of these cars, I believe it is important
to have the correct carburetor. Follow this link to a table with
the production numbers and models used; TURBO V6 CARBURETORS
"ROCHESTER CARBURETORS" By Doug Roe- I
highly Recommend this book. It explains the operation, repair,
tuning and performance modifications of the Quadrajet and other
Rochester carbs. Covers electronic and non-electronic
carburetors. Published by HP Books, copyright 1981.
TURBO
V6 INTAKES - Because of
the draw-thru arrangement, the Turbo V6 intake manifolds are very
different than their non-turbo counterparts. Follow this link to
some images of an early and late Carb/Turbo intake; TURBO V6 INTAKES. There are no
aftermarket intakes for the 1978/83 Turbo V6.
INTAKE MANIFOLDS - The cast iron intake manifold used
on the 1978 and '79 Turbo V6 weighs about 31 pounds. The aluminum
intake on later engines weighs only about 11 pounds. Before
swapping to the aluminum intake, make sure you are prepared for
other changes also. The aluminum intakes do not have provisions
for knock sensors, are not compatible with 1978 heads and may
need the matching carburetor plenum.
SPECIAL MANIFOLD BOLT - "On those
Buick V6 engines equipped with the large diameter HEI integral
coil distributor, a clutch head bolt (Torx) is used for clearance
purposes under the distributor. This bolt is readily seen once
the distributor has been pulled." The Buick Free Spirit
Power Manual by John Thawley, copyright 1980.
CARBURETOR POWER SYSTEM - Non-electronic
carburetors use a Power valve to enrich the mixture during
acceleration or high speed operation (to prevent detonation).
This system is modified for Turbo applications. (One reason a
Turbo carb is different than other carbs.) The power system works
off manifold vacuum. Low or no-vacuum situations open the release
(open) the power valve. Most carbs get this vacuum signal from a
port with the carb. In a draw-through turbo set up, the
carburetor is separated from the intake by the turbocharger.
Releasing the throttle when the engine is under boost will
produce vacuum within the plenum. However the intake will still
be supercharged. The plenum vacuum will close the power valve and
lean out the mixture and cause detonation. To correct this, the
power system needs to be connected to the intake manifold down
stream of the turbo. It also needs to be protected from boost
pressure. (When the intake is pressurized, the power valve should
receive no vacuum and no pressure). This is accomplished with a
Power Enrichment Control Valve (PECV) or Turbocharger Vacuum
Bleed Valve (TVBV).
AIR CLEANER
THERMOSTATIC AIR CLEANER (THERMAC) - The
air cleaner is design to provide an incoming air temperature of
about 115 degrees (F). A temperature sensor is in the carburetor
elbow and is used to control a vacuum actuated damper door in the
snorkel of the air box. This door on the snorkel blends incoming
air with air heated by the right side exhaust manifold, via a
very narrow duct. This improves winter weather driveability.
Warmer climate and summer only driven vehicles can do without
thus system. During WOT acceleration, the (carburetor) vacuum
drops to zero and the door will slowly open to allow unblended
air through the snorkel alone. There is an inline delay valve
which could be remove for quicker opening of the damper door.
AIR
CLEANER ASSEMBLY - On the 1978-81 Turbo V6, the complete
air cleaner assembly was red with a gold "Turbo 3.8"
decal. The air cleaner assembly on 1982 and '83 models consisted
of a chrome elbow with V6 logo, a black duct and black air
cleaner box. The openings on each end of the accordion duct are
3" inner diameter. Check your duct's pleats for cracks
and rips, which will allow unfiltered air in.
AIR CLEANER ASSEMBLY II - The stock air cleaner assembly is
very restrictive. While replacing the filter with an OEM style
K&N will help, the real problem is the air box. The snorkel
opening is tiny. Replacing the air box assembly with a K&N
cone type filter will remove this restriction. The trade off is
the loss of the Thermac system. To keep the K&N cone away
from the engine's heat, place it between the fan shroud and inner
fender. Then use some flexible duct to pull fresh air from behind
the grille (or under the bumper), through the opening behind the
headlights and to the cone. Remember to plug the Thermac's vacuum
source. Hot Rod magazine (6/81) reported a 0.13 sec decrease in
quarter mile times by just removing the AC duct (breathing warm,
underhood air) on an '81 TR. The K&N cone should provide
similar results.
COOLING
PLENUM COOLANT - The plenum (adapter between carb and
turbo) on the earlier, 1978-81, turbo engine uses engine coolant
to heat the air/fuel mixture and improve cold start/cold weather
drive-ability. At normal temperatures, however, this heat hurts
performance. Try using a lower temperature thermostat. (160
degree units are available at most parts stores.) Another trick
is to disconnect the coolant lines, or better yet, install a
shutoff valve. Opened in the winter and closed in the summer. Source:
Sunday Driver Part 2, Hot Rod Magazine, June, 1981.
THERMOSTAT - Changing to 160 degree thermostat
will help the engine run cooler and this may help reduce
detonation.. Running without a thermostat on the computer
controlled car ('81 and up) will cause the ECM to stay in the
"open loop" configuration and not run as efficient. A
160 thermostat should be available at a local parts store. I
believe it is the same unit as the SBC uses.
TURBOCHARGER
TURBOCHARGER INTERCHANGE - The Buick
turbo did not change much throughout the Carb years. This page
lists part number to help identify which parts are the same and
which can interchange. TURBOCHARGERS
"TURBOCHARGERS" by Hugh MacInnes - A
highly recommend book about turbocharger design. Not Buick
specific, but lots of great information. Published by HPBooks,
copyright 1984..
TURBOCHARGER
INSTALLATION - According to a TSB issued in April, 1982,
"The turbocharger primary support on any installation has to
be carried by the turbine housing, otherwise the turbine end
bearing carries most of the load, causing the turbine piston ring
seal to wear; allowing the exhaust gases to penetrate the center
housing rotating assembly, and promote coking." . Basically
start with the turbo support bracket to the intake, then the
bracket to the turbine, next the compressor to intake, followed
by the plenum brackets and finally the EGR pipe/manifold.
TURBOCHARGER
GASKET/SEAL KIT- FEL-PRO has a turbo
mounting gasket kit that has the following gaskets:
Downpipe/Elbow Seal, EGR valve, EGR chamber to intake and plenum
(x2), Plenum to turbo compressor, turbo compressor to manifold,
and oil pan drain connector. The complete kit number is ES 72507
(1978-83 year) and was picked up at my local auto parts store for
$19.44. "We found it looking through a new FP catalog. It
was not in their computer." Thanks to Trent - Buicksandrail
on TB.com.
DOWNPIPE TO TURBO SEAL - You may have a hard time finding a GM part
number for the doughnut seal (gasket) used between the downpipe
and turbocharger elbow. It is not pictured in some of the
Illustrations catalogs. All RWD Turbo V6's use the same seal,
from 1978 to 1987. It is GM part number 1262500, Group 3.611. All
Rivieras use GM # 25504003. This part is NOT Turbo, or even V6,
specific. Local parts stores should carry it, but bring in the
old one to match it up. If you tell them what it is for, they
will give you the old "Dealer-Only" line.
INCREASING BOOST - ADJUSTABLE
WASTEGATE ACTUATOR - Adjusting
maximum boost may be accomplished by changing the rod length of
the actuator. For all years, except the 1981 model, shortening
the rod will increase boost. The factory boost level is 8-9 psi.
Increase the boost as much as possible without causing the engine
to knock. Use high octane fuel to prevent knocking (read about
the ESC). If your turbocharger or actuator has ever been
replaced, it should already be adjustable. If it is not, this
tech page from the the Turbo Regal Web Site has directions for
converting a non-adjustable rod to adjustable. www.gnttype.org
Adjustable Wastegate
BOOST CREEP - I have heard several people comment that they can get up
to 10, 11, and even 12 psi by "keeping their foot into
it". I was seeing this also. If I removed my exhaust and
replaced the air box with a K&N cone, I could get up to 12+
psi with no problem. This isn't what is supposed to happen! The
stock wastegate actuator should limit boost to 9 psi and no more.
If it goes much higher, then the boost is "creeping
up". At 9 psi, the WG flapper opens and relieves exhaust
pressure away from the turbine. If the hole is too small, then
not enough pressure is relieved, and boost continues to rise.
This is boost creep. I am starting to think that this is a common
problem. Or at least on all 82/83 cars, since in '82 the turbine
was made smaller than previous years. The cure is to enlarge
(port) the WG hole just a little. Unfortunately this requires
removing the turbocharger. While higher boost is good, creeping
boost is not reliable or consistent. A ported WG hole should give
rock steady control, insuring the boost goes up to and not beyond
where it is set.
LOW BOOST? - I have found that the most common source of low boost is the
Quadrajet's secondaries failing to open. When then don't open, boost is
limited to about 6 psi. Check the NA notes page for a procedure for
checking the secondaries in the carb section titled "Secondaries Not
Opening?"
TURBO
POWER SWITCH - The "Turbo Power" switch
controls the yellow and orange indicator lights. The yellow light
turns on at about 3.5 psi and the orange at 6 psi. They can be
adjusted by turning the screws. The switch is located on the left
inner fender or fire wall. The 1978-'79 Buicks use two switches
GM part number 1259745 and 1262154, which have been discontinued.
The '80-'83 pressure switch is the same switch that is used on
'84-'87 Turbo Regals with the digital dash (RPO U52) option. It
is still available from GM (part# 25503871). The original switch
is green, but replacements are black For non-operating lights,
see TURBO POWER
LIGHTS DIAGNOSIS.
AFTERMARKET
BOOST GAUGE - The
stock boost ("Turbo Power") gauge only uses two lights
and is unreliable. An aftermarket boost gauge is very useful for
tuning the Turbo V6. Changes in maximum boost can be the result
of various things (plugged converter, cracked manifold, bad
actuator, etc.). "Seat of the pants" won't always tell
you when you've lost a few psi. Stock set-ups run about 9 psi and
an easy way to up performance is to increase the maximum boost
(see "adjustable waste gate actuator"). I recommend an
Auto Meter Ultra-Lite 4301. It measures 30 In. Hg Vacuum and 20
psi Boost. (It is unlikely that you will run more than 20 psi of
boost, so don't lose scale with a 30 psi gauge.) It also matches
the Turbo Regal's stock gauges well. See the LINKS
page for Auto Meter.
1981 WASTEGATE ACTUATOR - For 1981, Buick changed the wastegate actuator
from a normally closed design, to a normally open design. It was
an attempt to improve fuel economy that was quickly abandoned in
1982 in favor of increased performance. (The NC design has more
precise boost control.) The 1981 unit can be identified by the
use of only one vacuum hose (instead of two). To accommodate this
change, the wastegate lever on the elbow was rotated 180 degrees.
A conversion is as simple replacing '81's actuator and elbow with
'82/'83 units. If the turbocharger has been replace, this may
have already been done.
RWD Vs. FWD TURBO ID - The
1978/83 RWD turbos can easily be distinguished from the FWD
(Riviera) turbos. The RWD turbo will have the three mounting
bolts on the compressor outlet each spaced 3 inches apart. The
compressor outlet will also have a 90 degree turn at the end to
meet the intake manifold.
BUICK Vs. PONTIAC TURBO ID - The
1978/83 Buick V6 RWD turbos appear very similar to the 1980/81
Pontiac V8 turbo. They do not interchange. They can be identified
by the three mounting bolts on the compressor outlet. The Buick's
form an equilateral triangle each spaced 3 inches apart. The
Pontiac's are 3", 2.5" and 2.5" apart. The Buick's
compressor A/R ratio (stamped inside the outlet) is 0.42. The
Pontiac uses a 0.60 compressor A/R.
DRIVETRAIN
TRANSMISSION
- All Turbo V6 Buicks, regardless of year or model used
used an automatic transmission. In 1983, the RWD transmission
gained an overdrive gear (200-4R).
REAR
AXLE - All 1978-83 A/G body use the 7.5" rear. The
8.5" wasn't introduced until 1984.
REAR
AXLE RATIO - The rear axle ratio was lowered (raised
numerically) through the years until 3.42 in 1983 (which used a
overdrive 4-speed automatic). To check the ratio on RWD cars,
jack up one wheel, rotate it two times, and
count the number of time the driveshaft turns. The RWD cars
should have a 2.41, 2.73, 3.08, 3.23 or 3.42.
POSITRACTION
- Not all RWD Turbo Buicks have positraction, if fact
most, it seems, don't. The turbo's lag seems to be built in way
to "ease into the throttle". You may not need a posi
rear - many 1984-'87 owners simply use air bags (which go into
the rear spring) successfully to aid traction. To check, jack up both
wheels, turn one and the other will turn in the same
direction if it is positraction. Also, look for a tag bolted to
the differential. Please note that Positraction is Chevrolet's name for
limited slip differential.
MCSS
REAR
AXLE - The 1983-87 Chevrolet Monte Carlos SS came with
either a 3.42 or 3.73 rear gear and many had positraction. These are
relativly cheap and easy to find. It's likely that swapping the complete
rear axle will be much cheaper and easier than purchasing and installing a new
ring/pinion and limited slip differential. Don't pay the premium for a
8.5" rear unless it's really needed. The 7.5" can take some
abuse.
BODY CHASSIS & EXTERIOR
1983
HYDROBOOST II BRAKE SYSTEM - In 1983, the Turbo Buicks
switch from a traditional vacuum-assisted power brake unit to the
Hydroboost II. This system is borrowed from diesel applications
(low engine vacuum) and uses the power steering pump to assist
the brakes. It is also found on all 1984 and some 1985 Turbo
Buicks. Here is a link to a diagnostic diagram from the www.gnttype.org website: www.gnttype.org/techarea/brakes/hydroboost.jpg
TURBO HOOD ORNAMENTS - I believe all
Turbo Buicks, with the exception of the Riviera, use the same
ornament. The base is different depending on models. GM sold the
ornaments with the base, so each has a different part number.
Finding the right ornament, with the right base may be difficult.
Try looking for an ornament with the turbo top and another with
the correct base and then combine.
1983 REGAL T TYPE EMBLEMS - The fender
and decklid emblems on the 1983 Regal T Type differ from the
'84-'86 models. The "T" is vertical and not slanted.
For some reason, the Buick parts catalog has the same number for
the '83 emblem as the 1984-'86 emblem. The correct GM part number
for the 1983 T Type emblem is 25509699. It was also used on the
1981 Riviera and 1982-'85 Skyhawk.
MISCELLANEOUS
REGAL
"SPORT COUPE" VS. "T TYPE" - Turbo
Regals from 1978 through 1982 used the Sport Coupe name. In 1983,
it became T-type and continued until 1986. Other Buicks also used
the Sport Coupe and T-type designations. It is common for all
Turbo Regals that are not Grand Nationals to be referred to as T
Types, regardless of the year.
RIVIERA
"S TYPE" VS. "T TYPE" - Sport model
Rivieras with the Turbo V6 standard used the S Type name for 1979
and '80. In 1981, it became the T-type and continued until 1985.
The name continued after '85, but the turbo engine did not in the
Riviera. The car was downsized in 1986.
. 1982
REGAL GRAND NATIONAL SPORT COUPE - This name refers to
the few 1982 Regals that came with both the
Grand National (RPO T2E) and the Sport Coupe (RPO W11) packages.
The majority of the '82 Turbo Regals are not Grand Nationals and
the majority of '82 Grand Nationals are not Turbo Regals.
