http://www.turbograndprix.com/Extensive%20Details%20and%20Differences.htm

I don't know how accurate that is, but I'd sure like to find out!

I guess if anyone has a spare TGP/STE engine and the time/whatever cash to check it all out, it might be worth it now that there is a list of things said to be different from the NA and FI 3.1's.

>The difference with a “turbo” setup over a “non-turbo” 3.1L<

>Detailed technical and general specs<



What makes the Turbo Grand Prix/Turbo STE different than a stock W-body Grand Prix?, there are many differences actually, and when you understand how many, and the research put into spec’ing out all that was needed to make it into production, you have to gain a much greater appreciation as an owner of one of these cars!



Listed here are the specs for the Turbo Grand Prix/Turbo STE setup, many items are unique that differentiate it from normal 3.1L setups, these are labeled as such: “unique”.  Some of those items that are unique to a Turbo Grand Prix might be used on other cars/as other options.



To start, parts in this engine were stated as "Select Engine Components" that meaning when they were taken from the parts bin they were checked and selected for having closer tolerances, better castings uniformities, and closer matching/machined dimensions.




Unique VIN V engine block, part number (long block) 10140528, stock VIN T block is part number (long block) 10089656 (engine complete VIN V: 10110580, engine complete VIN T: 10115768).  Though there is a “T” marking on this block, The VIN V block is a different block.  Other engines such as the VIN M have the same “T” marking yet are very different blocks.

Engine block and related specs:

Manufacturer: CPC Group, GM Corporation

Plant Locations: Ramos Arizpe, Mexico, and Tonawanda, New York

Engine assembly code: BDC

Engine option code: LG5

Engine VIN code: V

Block material: Cast iron with a 20% nickel content to improve strength, very small amount of tin for same, both additions unique to the VIN V engine

Machined weight: 107 lbs
Type: 60 Degree V6 OHV

Displacement: 3.1L/3,137 CC., 191 Cubic Inches

Cylinder block height: 9”

Cylinder block length: 17.4”

Cylinder bore: 89mm/3.503”

Cylinder stroke: 84mm/3.3122”

Bore spacing center line to center line: 4.5”

Unique lower compression ratio: 8.80 to 8.78:1 attained with larger combustion chamber.

Turbo oil feed: Open oil feed port on block at oil filter/oil cooler adapter, braided line.

Turbo oil return: Unique metal tube off of front side of oil pan, and lined silicone hose.

Oil filter model: PF52, the stated PF51 did NOT have the necessary check-valve and should not be used!



Unique rods: these forged versions are unique to the 1989-90 Turbo Grand Prix and 1990 Turbo STE only.  Stock 3.1L rod part number is 10078995/12515767, “turbo” 3.1L rod part number is 10070113.

Rod Specs:

Unique construction: C-1037 heat treated steel forging, with SAE 1050 air quenched rod caps.
Weight full assembled: 1.33 lbs

Length Center Line to Center Line: 5.70”

Small end size: .905”

Big end size: 2.474”

Racing Specs per Chevy Power manual: 7,000 rpms possible, but the rest of the rotating mass needs to be tightly balanced for this including a better crank.



Unique crank, started as a heavy duty casting number 981 as seen in the all-wheel drive Chevy Astro, but this one is unique to the 1989-1990 Turbo Grand Prix and Turbo STE, being worked on after starting as a 981 crank!  Proof; stock 981 crank part number is 10146900, “turbo” 981 crank part number is 10110549.

Crank Specs:

Material: nodular cast iron

Unique machining: Journals chamfered, with deep rolled fillets that provide residual compressive stresses for added durability

Unique Treating: Ion Nitrided with a hardened depth of .02"-.03" raising surface hardness from 30-35 Rockwell C to 60 Rockwell C.

Weight: 39.5 lbs

Unique Crank dampener, stock 3.1L part #: 14091896, turbo dampener: 10131060



Pistons: Mahle autothermic hypereutectic pistons with reinforcement bar/steel strut to add strength to the top of the piston (which is often left out in aftermarket versions!).

Piston Specs:

Composition importance: 12% silicone

Weight: 365 grams/12.8 ounces

Top compression ring: 1.5 mm

Second ring: 1.5 mm

Lower/oil ring: 4 mm

Compression height: 1.463”

Dish volume: 28 ml

Pin diameter: 22.9950 mm/.9053”


Stock 3.1L cam, as used in the 2.8L, 3.1L VIN T and VIN V.  A special “turbo” cam is not required for a good forced induction setup, though you can make a better cam for any engine.

Cam Specs:

Part number: 10118636

Material; Cast Iron

Drive; Crank via chain drive

Weight: 3.098 kg/6.83 lbs

Valve timing at .050”

Intake/Exhaust duration: 194/202 degrees (1st quote)

Intake/Exhaust duration: 196/196 degrees (2nd quote/cam doctor read but on a used cam)

Intake valve open: 13 degrees after TDC

Intake valve closed: 27 degrees after BDC

Exhaust valve open: 29 degrees before BDC

Exhaust valve closed: 7 degrees before TDC

Intake lobe center: 109 degrees

Exhaust lobe center: 109 degrees

Intake Lift: .2626”

Exhaust lift: .273”

Lobe separation angle: 112

Rocker ratio: 1.5:1

Total effective lift with 1.5:1 rocker: .4095”



Timing chain Specs:

Type: Chain

Chain Width: .64”  41/64”  16.2 mm

Pitch: .625”  5/8”  15.875mm

Center to center line spacing: 6.261”



Oil Pump, unique to the 1989-90 Turbo Grand Prix and 1990 Turbo STE.  Higher volume, cast iron body verses commonly used aluminum versions.

Oil Pump Specs:

Manufacturer (other than GM in this case): Mellings M95HV

Material: Cast iron body

Pump gear length: 1.203”

Pump gear diameter: 1.504”

Pickup: 5/8” feed tube

Output: 25% greater than stock

Oil pressure @ 1,100 rpms: 15 psi

Oil Pressure @ 2,400 rpms: 50-65 psi



Oil Filter.  An AC Delco PF52 depth oil filter was used on the turbo engine, all too often the too-short AC Delco PF47 was used on 2.8 and 3.1L motors but, there are many advantages to keeping with the AC Delco (or other brands) depth oil filter PF52 style besides more filter media and contaminant retention.  Last note, PF51 does NOT have the necessary oil drain-back check-valve!

Specs PF47:

Oil drain-back check-valve: Yes!

Oil Volume: 15.883 cu in

Thread pitch: 1.5 mm x 18

Specs PF52:

Oil drain-back check-valve: Yes!

Oil Volume: 23.03 cu in

Thread pitch: 1.5 mm x 18



Water pump Specs:

Body material: Cast aluminum

Pump type: Centrifugal

Pump material: Cast iron

Flow at 1,000 pump rpm: 12 gpm

Bearing: Ball-Roller



The stock/NA VIN T engines of 1988-1990 used 3 different casting heads that all had the same smaller more pronounced heart shaped 26 cc volume combustion chamber of later production engines.  Later production years where replaced with the 10087511 in 1991-1994 with its more open, larger less defined heart shaped combustion chamber.  Then back again for VIN M 1993-1995 and VIN M 1996-1999 with the smaller chamber and more pronounced heart shaped design (shuffling the deck a lot!).  Changing the piston’s dish volume allowed working with these different heads/combustion chamber volumes, and the 2 different head gasket thicknesses of .040” and .060” to achieve design compression rations for those engines.

But for the 1989-1990 Turbo Grand Prix and 1990 Turbo STE, used the yet unreleased at that time head casting 10087511 and its larger/28 cc, less defined heart shaped combustion chamber, with the deep dished 28 cc piston top to achieve the .1 drop in compression ratio to 8.8 (or 8.78 or 8.75 depending on what you read).



Unique for the time, the head that was used on the VIN V engine in the 1989-1990 Turbo Grand Prix and 1990 Turbo STE had a casting number of: 10087511 (other engines below to compare).

10087511 Head Specs:

Cylinder head material: Cast aluminum

Weight: 11.7 lbs

Cylinder head volume: 28cc

Port/Valve arrangement: Splayed to provide a “swirl’ air charge flow

Port type intake: Nearly rectangular

Port type exhaust: Round

Intake valve: 1.72”

Exhaust valve: 1.42”

Valve face angle: .045”

Valve seat angle: .046 degrees

Valve spring install height: 1.5748”

Valve spring pressure closed: 90 at 1.701” height

Valve spring pressure open: 215 at 1.291” height

Valve seal: Viton, press fit

Head gasket (initial) thickness: .065”

Head gasket (compressed) thickness: .062

Stock head bolt rating/class: 10.9, 150,800 psi

Stock bolt type: Stretch-to-yield meaning one-time use

Rocker arm ratio: 1.50:1


VIN T Engines used from 1988-90 had stock head casting numbers: 10048651, 10048696, 14089834.
VIN T W/O/SEFI Engines used from 1991-94 stock head casting number: 10087511.
VIN T W/SEFI Engines used from 1993-94 stock head casting number: 10087511.
VIN M Enhanced Engines used from 1993-95 D-Port stock head casting number: 10154743.
VIN M Enhanced Engines used from 1996-99 D-Port stock head casting number: 24503769.
VIN J Special Emissions Spec used in 1999-? stock head casting number: 102181170.


Upper and Lower Intakes for 1989 and 1990 Turbo Grand Prix and 1990 Turbo STE, unique for their “3.1 Intercooled Turbo” engraving/raised lettering on the top.
Weight Inlet Plenum/Upper: 7.9 lbs.

Weight Intake Manifold/Lower: 12.4 lbs.
Unique 1989 Turbo Grand Prix Upper Intake Casting Number 10110556.
1989 Turbo Grand Prix Lower Intake Casting Number 10070110.
Unique 1990 Turbo Grand Prix and Turbo STE Upper Intake Casting Number 10131046.
1990 Turbo Grand Prix and Turbo STE Lower Intake Casting Number 10110432 and 10137026.
1989's had PCV line/hose run into the lower intake, 1990 had PCV into the upper intake.



Exhaust system, very different for obvious reasons. Unique rear exhaust manifold (ASC/McLaren) part number V-29X8-5988-0XXX, unique crossover pipe, turbo, unique downpipe, cat, unique mufflers and true dual exhaust finished with cast aluminum tips.

Turbo Exhaust Specs:

Exhaust cast manifold material: Nodular cast iron

All exhaust pipe material: T409 .042” thickness

Mufflers type: Reverse flow

Muffler weight: Left 9.8 lbs, right 12.2 lbs

Muffler construction: T409 stainless steel

Catalytic converter type: Ceramic monolith

Catalytic converter weight: 4.25 lbs

Catalytic converter nobel metal types: Platinum (Pt), Rhodium (Rh), Palladium (Pd)

Volume: 2.79L/170 cu inch

Turbo specs:

ASC Part Number: V24X82467BXXX

Manufacture: Garrett AiResearch

Size: T2 Frame

Version: TB02528

Cooling: Water and Oil

Lubrication oil flow: 1.2 L/m SAE 30, 90Degrees C, 2.75 Bar

Bearing: Floating sleeve

Turbo Complete Part number: 465939-2X

CHRA Number: 431876-29

Compressor  housing casting number: M24

Compressor A/R: .80

Compressor wheel trim: 70

Compressor wheel diameter Ind/Exd: 1.69”/2.02”

Compressor flow: 29 lbs/Min

Turbine housing casting number: M4

Turbine A/R: .68

Turbine wheel trim: 62

Turbine wheel diameter: 1.64”/2.09”

Wastegate: Internal, vacuum/pressure actuated by ECM control solenoid

Heat blanket; Ceramic fiber

Manufacture for Ver. I: (John) Mansville

Manufacture for Ver. II: Tig-Hitco

Part number: 379530935



Transmission/Transaxle is unique, and in a few key areas that owners would be hard pressed to duplicate with an aftermarket upgrade, that from nothing available. Larger 3/8” tranny cooling lines, and an auxiliary stacked plate tranny cooler in the fender well area with dedicated air cooling duct.  Hardened Gears and Gear Carrier Set.  Additional nested accumulator springs, other little changes to the tranny, some not listed.  The first 4T60 called the 440T4 was the first 4 speed front wheel drive automatic transaxle produced by an American automobile manufacturer.  The 4T60 was a greatly redesigned 440T4, now vastly improved!

Tranny Specs:

Manufacture: Turbohydromatic; division of GM

Plant location: Warren, MI

Case material: Cast aluminum

Weight: 192.57 lbs wet

Style: Transverse mount for FWD application

Type: 4T60=

4: 4-speed, T: Transverse Mount, 60: Production Series (engine torque range)

Maximum gross vehicle weight: 6,400 lbs.

Maximum gearbox torque: 368 lb-ft.

Fluid fill capacity from fully dry: Case/Lines/Coolers: 11 quarts, greater (unique) fill quantity over stock 4T60s.

Fluid fill capacity after an overhaul: 8.5L/18 pints/9 quarts.

Unique higher count clutch packs.

Unique valve body accumulator spring setup.

Unique channel plate arrangement.

Unique valve body and plates.

Gear count: 4 forward with lock-up torque converter, 1 reverse.

Forward gear ratios: 1st 2.921, 2nd 1.568, 3rd 1.00, 4th .705.

Reverse gear ratio: 2.38:1.

Chain ratio: 35:35.

Maximum shift speed 1-2: 6,000 rpms.

Maximum shift speed 2-3: 5,500 rpms.

Maximum shift speed 3-4: 5,200 rpms but only the early 89s allowed WOT 3-4 shifts.

Torque converter type: Fluid drive, with friction pack lock-up clutches; available in 3rd and 4th gear based on load though past 83mph is fully locked at anything other than engine deceleration, or a brake application.

Torque converter capacity factor “K”: 177.

Torque converter size: 245mm.

Torque converter stall speed: 1898 rpms.

Differential gear ratio: 3.33:1.

Unique Differential construction: hardened gears and gear carrier, with steel washers instead of bronze.

Control Type-Shift: TV/Throttle Valve cable for up shift and downshift points, and a centrifugal governor regulating line pressure for shifts as well.

Control Type-Pressure: Vacuum Modulator regulated, referenced through a vacuum line just off the back of the upper intake inlet, regulated down by an in-line restrictor to allow the check valve/bleed valve at the modulator to bleed off a boost signal coming from the upper intake.

Unique Cooling System: dual system; larger heat exchanger in the radiator end tank, and a unique auxiliary air to liquid stacked plate cooler located in the passenger front fender cavity.  Also unique larger 3/8” cooling lines.

Axle shaft manufacturer; Saginaw division.

Axle shaft type: Solid.

Axle shaft diameter left: 23.81mm.

Axle shaft diameter right: 27.06mm.

Universal joint type inner: Tripot joint, 27 sz, 66mm, ball and needle bearing.

Universal joint type outer: Rzeppa joint, fixed ball bearing.



Unique radiator and cooling system.  Larger 3 row radiator (GM replacement units after 1994/Valeo produced had 4 smaller rows), different upper (silicon) radiator hose and aluminum thermostat housing neck, larger tranny cooling line connectors, different (cleaner!) location of radiator fluid overflow tank and feed line.

Radiator Specs:

ASC part number: V29X85823DXXX

Manufacturer: Blackstone

Blackstone part number: 1002609

Dimensions: 20” x 15 3/8” x 2 5/16”

Tube Rows: 3 (many aftermarket units are 4 core and not as good)

Fins per inch: 16

Inlet header: 16 ½” x 2 7/8”

Outlet header: 16 ½” x 2 7/8”

Inlet hose connection: 1 3/8”

Outlet hose connection: 1 ¼”

Total cooling system fill: 12.5L/13.2 quarts

Unique Tranny Cooling Connections: Larger 3/8” size (stock was 5/16)

Electronics: Fluid level sensor, supposedly a corrosion sensor too but not!
Largest electric cooling fan from the parts bin at the time, for main engine cooling, 240 watt rating.

Secondary/smaller cooling fan to assist engine cooling, air conditioning condenser and intercooler air flow needs.



Unique Blackstone Air-to-Air Intercooler (similar to Turbonetics 2-113 core).

Intercooler Specs:

Blackstone part number: 1030044

ASC part number: V-29X8-7092CXXX

Width: 6 ¾

Length: 11 ¾

Thickness: 3 ½

Power at 2 psi drop: 240 hp

Rating at 240 hp: 360 cfm



Unique upgraded fuel Pump taken from the Corvette Parts Bin.

Fuel Pump Specs:

Manufacture: AC Delco/Delphi

AC Delco Model: EP375

Delphi Model FE0110

Pump Code: WES or WEG

AC Delco Pressure rating: 75-85 psi (high pressure unit)

Delphi Pressure rating: 350 kPa

Delphi rating for Relief Pressure: 450-750 kPa

AC Delco Flow Rating: 40 gal/hr

Delphi Flow Rating: 23 grams/sec



Unique size injectors.

Injector Specs:

Manufacture: AC Rochester Products/Delphi

AC Model: 217-259

Delphi Model: FJ10006

AC Type: Multec Disc style spray pattern

Delphi Type: Multec1 TFP

Delphi Alcohol Resistance: E10

Coil Resistance: 12.4-12.6 ohms

AC Fuel Rating at 3 bars/43.5 psi fuel pressure: 21.9 lb/hr, tested @ 230 cc

Delphi Fuel Rating at 350 kPa: 22 Lbs/Hr



Unique fuel supply/return lines at engine bay area, in front of ABS Unit.



Miscellaneous differences and general details:

Unique hood that did have truly functional unique venting louvers, with drain pans to manage water exit.



With the unique B4M aero package, the front bumper also had a unique energy absorber.  In that same area and to further lower weight; the stock front steel bumper reinforcement beam was replaced/upgraded to a unique structural aluminum piece (option code VD6, part number 10183516), this to help return the Turbo Grand Prix to it's original stated weight class.



Unique HUD/Head-Up Display.  Designed with Huges Aerospace division of GM.  Was used in the Turbo Grand Prix as the first road going production test unit HUD, to determine reliably for future/expanded production use.  In 1989 most HUDs displayed MPH and KPH via a change-over switch, this feature was dropped and 1990s did not have this feature.  Augment to the dash display were key indicators that also showed up in the HUD display such as ; Check Engine, Low Fuel, High Beams, Turn Signals and MPH for 1990s and MPH or KPH for the 1989s.  There was a slider on the side of the HUD that adjusted display-on-windshield viewing height, and a slider/dimmer below the headlight module for the HUD display brightness adjustment.



Motor Mounts, 1 hydraulic/rubber encased fluid (engine side) and 1 solid elastomeric (tranny case side).



Unique to the Grand Prix, engine oil cooler as some Monte Z34s had, maybe others.



Unique water tap to regulate coolant water supply to the turbo center section, and unique fittings to plumb it in.


Unique coolant line take-off welded on to provide for turbo cooling water system return from turbo center section.


Unique analog gauge cluster, with battery volt gauge replaced with vacuum/boost gauge, also “Intercooled TURBO” imprinted though requires a little custom work to light up properly.



Air filter setup was totally unique, and a rather small air filter and box for this turbo setup.  With crankcase breather tube, and cold air intake duct behind passenger side headlight, and silicone flex hoses to attach to turbo inlet.  Air filter is AC Delco part number A875C.  Actual test data on the total air box induction system with a new air filter: 328 cfm flow @ 28”.  Flow capacity with used/dirty stock air filter: 290 cfm.  Flow with drop in air filter upgrade: 344 cfm.  Flow with K&N RU1390 on length of intake pipe: 497 cfm/  Flow of K&N directly on the turbo: 573 cfm.



Intercooler (as spec’d above) with unique piping from turbo outlet to throttle body.



Unique colder heat range spark plugs: AC Delco R42LTS with a .045” gap.



Unique electronics; 2 bar map, turbo solenoid, dual fan control.



ECM/Engine Control Module/Electronic Control Module, used a removable MEMCAL for vehicle specific calibration.  “MEM” standing for memory, which relates the ability to remember such things as fuel trim and idle stability learning.  “CAL” for calibration as in settings to run the engine’s systems including transmission, turbo boost, cooling fans, fueling, timing etc.  Also contained in the MEMCAL is the knock filter circuit and limp-home mode chips/netres (short of network resistors).  This MEMCAL is unique to the Turbo Grand Prix and Turbo STE with several versions being release that corrected owner driveability issues over the years.  The CAL/Calibration and program is contained on an EPROM soldered to the MEMCAL base.  This EPROM version is a 28 pin DIP M27C256 100ns, an 8 x 32k size (256k) CMOS base running at 100ns (nano-seconds) and a 5 V programming rating.  EPROMs stand for Erasable Programmable Read Only Memory, erasable through the quartz (only, glass will not allow UV light to pass) window with a UV light in the range of 253.7 nanometers (2537 angstroms).  Using 21.45KB of space for the program/calibration entailing 9,464 instructions to operate.  ECM architecture is based off a 68HC11 Motorola CPU, but with many changes for adaptation to GM’s automotive needs, some of those differences are;

Many changes to: Interrupt Vector Mapping, Illegal Instruction, Bus Reset, Watchdog Timer Reset, Clock Monitor Reset, Power On and External Reset.

None of the original HC11 I/Os are present.

Relocation assignment of on-chip SRAM.

Bits 7 and 6 of the CCR are assigned locked values of 1’s.

$CF/STOP, $8F/XGDX and $18 8F/XGDY instructions are removed.

CPU is run as the Master and all off-loading worker chips are set as slaves via an SPI (Serial Peripheral Interface) system strategy, this is done to off-load some of the work the CPU might have to do, as well as off-load slower and/or less mission critical sections of programs.



Something one would hope to turn up on eBay would be an IM/Instrumentation Interface Module and specific HUD display.  That’s right, a special HUD used to display data from the IM as you monitor and/or modify system operation to facility development i.e. engine tuning/calibration adjustments.  This device plugs directly into the ECM via a 50-pin connector attached to the GBAM (General Buffer Auxiliary Memory).  And yes this is a form of real-time tuning via emulation as most real tuner shop now use.  The IM also provides output to a strip (print) chart recorder.



Detailed technical date not necessarily unique to the Turbo Grand Prix/Turbo STE:



Suspension front; Coil springs, one-pieces “A” configuration lower control arm

Suspension Specs:

Type: McPherson struts

Make: Delco

Feature: Nitrogen charged

Full jounce: 75 mm/2.95”

Full rebound: 95 mm/3.74”

Strut piston diameter: 35 mm

Strut rod diameter: 25 mm

Coil spring material: hardened spring steel

FE3 spring code range: FUZ or FWW

FUZ load rating: min 3,480, max 4,928 lbs

Sway bar diameter: 30 mm

Steering ratio: 14:1

Turns lock-to-lock: 2.25/2.3

Steering type: Rack and Pinion

Manufacture: Saginaw Division

Turning diameter curb to curb: 39’

Lateral Gs: .87



Suspension Rear; Tri-Link independent with single transverse leaf spring, large lateral wing attached to body cross member.

Suspension Specs:

Type: Chapman tubular struts

Maker: Delco

Feature: Nitrogen charged

Full jounce: 107mm/4.21”

Full rebound: 95mm/3.74”

Leaf spring material: Fiberglass

FE3 spring code range; RHH or RDM

Sway bar diameter: 12 mm



Anti lock brakes, standard on the Turbo Grand Prix and Turbo STE, available first and optional on 167 1988 W-Bodies which were sold and unbeknownst to the owners; only as a test-bed run/guinea pigs.  Delco Moraine was the only servicing entity for that short run, later service work was done by appropriate dealers and outsourced venders.  Optional on other W-Bodes cars till 1991, and on some Lotus Turbo Esprits though those owners said with horrible programming.  It is also worth mentioning that this unit was designed by a talented and diverse team of engineers from; Delco Electronics, GM Hughes (that did the HUD/Head-Up display), Packard Electric, Delco Remy, Saginaw Division, New Departure Hyatt, GM Advanced Engineering and Delco Moraine.  This unit is an integrated master cylinder and boost assembly controlling a 4 Wheel Disc with a 4 Sensor/3 Channel ABS system, Electro-hydraulic pump for pressure source of power assist.  An accumulator pressure container, and a unique heat shield to offset heat-soak from the turbo and exhaust downpipe.  Separate relay and fuse block, and rear proportioning valve.  And last an electronic control unit under passenger’s seat that provides extensive monitoring, data logging, reporting and testing procedure abilities.  There is also a low fluid level sensor in the master cylinder reservoir.  Other than needing to replace the one wear item; the accumulator, owners who maintain this item on a typical 2-4 years fluid flush schedule can many years of trouble-free service.  Though there were some casting issues with the aluminum mounting part for the accumulator, pump and pressure switch, which was addressed by Prior Reman in their now expensive "rebuild" unit .

Brake Specs:

Manufacture: Delco-Moraine

Model: Powermaster III

Pedal arc ratio: 3.5:1

Brake pedal travel with 100 lbs foot force: 2.91”

Heat shield manufacture: John Mansville, part number 24314



Front brake rotors: Composite vented disc

Rotor size: 267mm/10.51”

Rotor thickness: 26.3mm

Effective area: 169 sq cm

Sweep area: 44 sq cm

Caliper: 2 piston cast iron body

Piston diameter: 2 @ 42mm

Pad type: Semi metallic, integrally molded

Pad size: 119.4mm x 38.1mm

Pad thickness: 12.19mm



Rear brake rotors: Composite sold disc

Rotor size: 256.5mm/10.1”

Rotor thickness: 12.5mm

Caliper: Single piston cast iron body, integral parking brake

Piston diameter: 1 @ 35mm

Pad type: Semi metallic, integrally molded

Pad size Outboard: 83.8 x 33mm

Pad size Inboard: 102.9 x 33mm

Pad thickness: 8.64mm



Charging/Starting System.  Unique Alternator, was the highest output for the rather small CS130 model unit, though there was one other of this rating, part number is specific.

Alternator Specs:

Manufacture: Delco Remy

Model: CS130

Output rating idle in drive: 38 amps

Output rating max rpm: 105 amp

Output rating idle in neutral: 54 amps

Ratio of revs relative to crank: 2.75:1



Battery Specs:

Manufacture: Delco Remy

Model: 75 (75B-72)

Voltage: 12 DC

Amps at 0 degrees F: 525

Reserve capacity: 90 minutes

Amp/Hrs-20 hour rate: 54 amp/hrs



Starter specs:

Manufacture: Delco Remy

Current drain @ -20 degrees F: 350 amps

Power rating: 1.4kw/1.9hp



Ignition System, newly designed distributor-less ignition system or DIS.  A rather stout system with a rating higher than that for the DIS used on the infamous Buick Grand National.  Uses 3 coils to fire 6 spark plugs, 1 coil fires 2 spark plugs with the compression cylinder spark plug getting approx 90% of the power and the waste cylinder spark plug getting approx 10%.  The crank has 7 notches, 6 are 60 degrees apart and reference the position of the pistons while the 7th notch being 10 degrees off, starts the reference of crank location's true starting position for ECM reference.



Ignition Specs:

Manufacture: Delco Remy

Theoretical max rpm range: 10,000+

Output Volts: up to 40k volts

Current Limit: 9 amps

Rise-time for Limit: 3 msec (milli seconds)

Rise-time Energy: 9.87mJ (milli Joules)

Total timed output: 102 watts times current limit duration

Inductance: 3.5mH (milli Henry)

Primary Resistance: .34 ohms

Secondary Resistance: 5.6-5.8 ohms (new, little less when older)



Body details general, glass.

Glass specs:

Windshield exposed surface area: 9,700 sq in.

Side glass exposed surface area: 1,710.96 sq in.

Backlight (rear window) exposed surface area: 7,389.09 sq in.

Total exposed surface area: 18,800.05 sq in.

Windshield glass type: unique highly polished for best reflective properties for the HUD, windshields had their reflective properties measured and the better samples were used on HUD equipped vehicles.

Windshield glass type/other: Curved-tempered laminate plate.

Side glass type: Curved-tempered glass.

Backlight glass type: Curved-tempered glass.

Windshield sloop angle: 62 degrees.

Backlight sloop angle: 66 degrees.



Specific/additional weight specs of optional equipment:

10-way power seats: 11 lbs

Side power door lock system: 4 lbs

Power Window system: 4 lbs

Sound/vibration insulation: 4.4 lbs

Floor mats: 4.4 lbs

Air conditioning: 36.6 lbs

Center console w/shifter: 15.4 lbs

Mirrors-LH/RH remote: 3.5 lbs

Sport suspension: 6.6 lbs

Brakes front/rear anti-lock: 11.7 lbs

Cooling system engine oil: 4.5 lbs

Fan (2) engine cooling: 4.4 lbs

Cruise control: 1.4 lbs

Dual exhaust: 6.8 lbs

Higher capacity batter: 5.4 lbs

Radio with cassette, eq, clock, amp: 6.6 lbs

6-way Speaker system: 10.6 lbs

Power antenna: 2.7 lbs

Moonroof: 84 lbs



Weights as measured on a 1990 Turbo Grand Prix with a moonroof and a full tank of gas:

Left front tire: 1,174 lbs 2301

Right front tire: 1,127 lbs

Left rear tire: 596 lbs

Right rear tire: 594 lbs

Total actual weight: 3491 which is very close to the 3450 quoted by Pontiac

Actual weight distribution % F/R: 64/36

Pontiac quoted weight distribution % F/R: 65.9/34.1



General data, Dimensions, capacities, test ratings

Wheel track width front: 59.5”

Wheel track width rear: 58”

Overall length: 193.9”

Wheel base: 107.5

Height: 52.8”

Luggage capacity: 15 cu ft

Drag coefficient: .31 or .299

Interior noise levels: 51 db @ idle, 68 db @ 60 mph and 69 db @ 70 mph, 78 db @ WOT

Power to weight ratio: 16.8 lbs per hp

EPA Mileage estimates city/highway: 19/27

Gas tank capacity: 16.5 gallons

Power steering system capacity: 1 pint pump only/1.5 pints complete system

Stopping distance: 30-0/42’, 60-0/134’, 70-0/173”, 80-0/233’

Manufacture engine power quotes at 8 psi of max boost:

205 hp @ 4,800 rpms/220 lb-ft torque @ 3,200 rpm

153kW @ 4,800 rpms/290 Nm @ 3,000 rpms

Top speed: 128 mph

Magazine tested engine power quotes:

205 hp @ 5,200 rpm/225 lb-ft @ 2,400 rpms

Top speed 134 mph

Acceleration zero to thirty/0-30 mph: 2.5 seconds

Acceleration zero to sixty/0-60 mph: 7.0 seconds

Acceleration zero to one hundred/0-100 mph: 20.6 seconds

Acceleration quarter mile: 15.3 @ 89.5 mph

Accelerating 30-50 mph: 3.2 seconds

Accelerating 50-70 mph: 5.0 seconds

Road horsepower at 30 mph: 7 hp

Road horsepower at 50 mph: 17 hp

Road horsepower at 70 mph: 36 hp

1988 Grand Prix Turbo Concept Car specs:

305 hp @ 4,800 rpms

220 lb-ft torque @ 3,000 rpms

Acceleration zero to sixty/0-60: 6.3 seconds

Acceleration quarter mile: 14.05 seconds

Modified setup with reprogrammed chip/12 psi boost, 160 stat, air filter upgrade, 92 octane:

Zero to sixty: 6.05

Quarter mile: 14.2

Top speed: 151 mph

Changed to a 100 octane chip, results with 15-17 psi boost and cool enough weather:

Zero to sixty 5.09

Quarter mile: 13.6

Top speed: 167 mph



General data other, air conditioner:

V-5 A/C Compressor that is a variable displacement unit that better matches the load with less (noticeable) on-off cycles on the engine.  2.25 lbs R12 full charge.



Some information and specifications were quoted from the following sources as well as hands on/visual identification:



MVMA-Motor Vehicle Manufacturers Association

EPA/Environmental Protection Agency

General Motors

CPC-Chevrolet-Pontiac-Cadillac, Division of General Motors

Pontiac Historical Services

Pontiac Sales and Marketing

Pontiac Performance Network

Chevy Race Shop

Price books and forms, Inc

GMSPO/GM Service Parts Operation

GMSPO Engineering Division

ASC/American Specialty Cars

McLaren Performance Technologies

Helm Publications

Motorola Inc

STG/Service Trade Guild

ERA/Engine Rebuilders Association

GM Powertrain, Division of GM

Road and Track Magazine

Car and Driver Magazine

Automobile Magazine

Sports Car Illustrated Magazine

Automotive Industries Magazine

Automotive Trade Magazine

Pontiac Magazine

Pontiac Action Track

Hot Rod Magazine

Turbo and High-Tech Performance Magazine

Delco Moraine Technical Service Tranny Manual

ATSG/Automatic Transmission Service Group

ATRA/Automotive Transmission Rebuilders Association

STS/Service Technicians Society

ASA/Automotive Service Association

ASE/Automotive Service Excellence

iATN/International Automotive Technician’s Network

SAE/Society Automotive Engineers



Author Jim Walterscheidt
Copyright © [J&W Auto Studios] 1995-2009

All Rights Reserved.

That information has been posted for several years now. The sticky at the top of the TGP section over @ w-body has a copy of most of that text if I remember correctly.

As far as I'm concerned, there's not enough of a difference in an NA vs. TGP engine to worry about. Plenty of people have made a lot of power out of formerly NA engines and ran them for years reliably. Josh's(RIP) old turbo cutty had a high mileage engine in it that was making around 300hp on the stock turbo and it's still running fine a few years later(current owner posted recently on the w-body board).

I keep trying to tell people that, but they seem very concerned over the possible differences that I over look and shrug off.  I didn't know wbody has that, if it is already posted here, sorry, didnt see that either.