International SyTy Registry

GMC Syclone, Typhoon, & Sonoma GT History and Data

SyTySoGT FAQ

The SyTySoGT trucks have a unique past that has lead to some very interesting stories, information, and misconceptions on the trucks. Compiled here is a listing of common questions that are frequently asked among new owners or enthusiasts.

How many SyTySoGTs were made?

The total number of PRODUCTION trucks are as follows:

  • 2995 – 1991 Syclones
  • 2500 – 1992 Typhoons
  • 2200 – 1993 Typhoons
  • 806 – Sonoma GTs

How do I find the number of my truck?

The accepted method among the community and how our database of trucks is built is to use the last 4 digits of your VIN.

Example: 1GDCT14Z2M8800001 – This would be considered #0001

While the Typhoons were not built in VIN sequence, it it still accepted to use the last 4 digits of your VIN and consider that your truck number.

What is the color breakdown of the SyTySoGTs?

Production Colors are as follows:

1991 GMC Syclone

  • Black / Black

1992 GMC Typhoon

  • Black w/ Black (1262 Total)
  • Black w/ Gray (130 Total)
  • Frost White w/ Gray (518 Total)
  • Apple Red w/ Gray (345 Total)
  • Bright Teal w/ Gray (132 Total)
  • Forest Green Metallic w/ Gray (82 Total)
  • Aspen Blue w/ Gray (28 Total)
  • Radar Blue w/ Radar Blue (2 Total, test color)
  • Raspberry Metallic w/ Raspberry Metallic (2 Total, test color)

1993 GMC Typhoon

  • Black w/ Black (1,008 Total)
  • Black w/ Gray (98 Total)
  • Frost White w/ White (532 Total)
  • Frost White w/ Gray (115 Total)
  • Apple Red w/ Apple Red (77 Total)
  • Apple Red w/ Gray (101 Total)
  • Forest Green Metallic w/ Gray (210 Total)
  • Garnet Red w/ Gray (24 Total)
  • Royal Blue Metallic w/ Gray (35 Total)

1992 Sonoma GT

  • 1991 Black w/ Black (1 Total)
  • Black w/ Black (408 Total)
  • Black w/ Gray (41 Total)
  • Frost White w/ Gray (101 Total)
  • Apple Red w/ Gray (180 Total)
  • Bright Teal w/ Gray (48 Total)
  • Forest Green Metallic w/ Gray (14 Total)
  • Aspen Blue w/ Gray (14 Total)

What engine is in the SyTySoGT?

The Syclone and Typhoon both utilize a turbocharged and intercooled 90 degree 4.3L V6 engine.  The Sonoma GT utilizes the standard CPI 4.3L V6.

The common misconception is the trucks came with the 3.8L Turbo V6 engine that was in the Grand National. While there is proof of prototypes having used the 3.8L engine, the production trucks were all 4.3L.  Another misconception is the trucks were 350 V8s with superchargers. While many have done V8 swaps into their trucks, the PRODUCTION SyTySoGT only came with a 4.3L engine.

What are the differences between 1992 and 1993 Typhoons?

Aside from color availability (see color breakdown FAQ question), here are the major differences between the 92 and 93 models:

BODY

  • 92s have escutheons around the door handles, unpainted
  • 93s feature NO escutcheons
  • 92s Typhoons have silver colored decals
  • 93s Typhoons have gold colored decals
  • 92s have two tone grille – gray headlight buckets & center with matching body color
  • 93s have full colored grille that matches body color
  • 92s have a “square” style roof rack (if equipped)
  • 93s have a more “rounded” style roof rack (if equipped)
  • 92s tailgate latch are thinner
  • 93s tailgate latch are thicker
  • 92s EARLY production trucks will have black GMC letters. This was later changed back to red.
    • Recent info has lead to the information that PAS wanted to use Black GMC letters to distinguish the trucks from the standard GM line (since it was PAS who built the trucks). GM did not agree to this and forced PAS to go back to the standard red lettering.
  • 93s ALL production trucks came with red GMC letters.
  • The exhaust hangers differ between 92 and 93.

INTERIOR

  • 92s have NO overhead console
  • 93s have an overhead console

Door Panels:

  • 92s leather inserts have a pleated/bunched up look
  • 93s leather have a smoothed look with single horizontal seam (same concept is carried into the side panels in the rear seating area)

Seats:

  • 92s have leather fronts, but cloth sides and backs. Typhoon logo embroidered into the headrest. Manual lumbar via hand pump bulbs.
  • 93 have full leather “Fat Man” seats with electronic controls

Cargo Net:

  • The 92 Cargo Net mounts directly onto the tailgate.
  • The 93 Cargo Net mounts onto the body next to the tailgate.

What are the common problems and issues with SyTySoGTs?

First and foremost, realize that these trucks are 25 years old now. Common parts such as suspension (tie rods, balljoints, idler arm, etc.), hoses, and bushings are going to be worn out or prone to breakage if they are still original or haven’t been changed/maintained on a regular schedule. These types of items are no different than if you were looking to purchase any other well aged vehicle.  However, the SyTySoGT (mainly the SyTy) do have some unique if not quirky issues and problems that seem to plague both new and long-time owners.

These issues often include:

IGNITION SYSTEM

These trucks are hard on ignition parts and very much require a strong ignition to run correctly. Making sure you run the correct plugs, quality wires, and a brass cap/rotor is essential. Many owners upgrade from a 7mm plug wire (stock) to an 8mm. The best and most popular spark plugs are AC Delco CR42TS (best for stock trucks), NGK UR5 (stock to mild modded) and NGK UR6 (heavily modded).

VACUUM LINES

Everything from your boost, EGR, fuel pressure, cruise control and more, the SyTys vacuum system is a maze of vacuum lines running from one side to the other. Span a number of years and mix in the environment of a hot engine bay, the vacuum lines, “elbow” fittings, and bypass valves eventually dry out and either crack or completely break. Even the most minor leak in the vacuum system can disable a truck. There are now vacuum line kits available on the market that are made from high quality platinum cured silicone that are pre-assembled complete with instructions for replacing your entire vacuum system and is highly recommend as a necessary upgrade.

FUEL PUMP

The stock fuel pump was considered barely adequate to handle fuel delivery for our boosted motors. It is recommended that if your truck still runs an original pump, swap it to a Walbro 255ltr/hr pump.

DETONATION

With 8:35.1 compression and hypereutectic pistons, our 4.3L motors are very sensitive to detonation (knock). Unlike the popular 3.8L motors, the 4.3L when allowed to detonate doesn’t blow head gaskets and can easily be fixed in a short amount of time. Instead, rods become pretzels and look for exits through oil pans and cylinder walls.  Our trucks require 91 octane or higher. DO NOT use low grade gasoline. Ignition can also play a factor in detonation (see above for needing strong ignition components) as well as fueling.

TRANSMISSION

The 700R4 (4l60) is a great transmission. Unfortunately, they are a challenge to keep together when you couple them to AWD and throw more than 300 lb/ft of torque at them. The SyTys are notorious for transmission failures. There are owners with stories out there who have rebuilt their transmission 8….9…10 times or more.  Yes, we’ve even heard and read all of the “my trans builder can make a bulletproof 700R4….” stories and comments and we’ve also seem those same people frag those expensive builds too.  While there are some successful builds that have been done, the truth is that the likelyhood of a transmission failure in a SyTy is very high. Stock. Modified. It doesn’t matter. Many have gone the route of replacing the 700R4 entirely and replacing it with a 4L80E and have never looked back. This is a costly upgrade, but given the fact if you have to have your 700 rebuilt multiple times, you basically just paid for one anyhow. If you are new into ownership and plan to drive your truck on a regular basis (and by drive, we mean spirited driving on the street and racing on the track), prepare yourself for the awful day when you suddenly loose gears.

CLADDING

Initial thought is why is cladding listed as an issue?  Again, these trucks are pushing 25 years old. The cladding on the SyTySoGTs were made from injected plastic molds. On the backside of the cladding (excluding the front/rear bumper) are “tabs” that are used to help bolt the cladding to the body of the trucks. These tabs were poorly designed and are easily broken off. As time goes by, the plastic becomes dry and brittle and these tabs commonly will crack resulting in the loss of cladding while driving.  OEM cladding is not produced anymore, and while many pieces are still available both new and used, they do command a price. Fiberglass reproduction cladding has recently become available and typically is cheaper in price than OEM pieces.

What is a Marlboro Syclone?

The Marlboro Syclone was the grand prize for ten winners of The Marlboro Racing ‘92 Contest. These were production Syclones (all start as standard black trucks) that were provided to American Sunroof Corporation (ASC). With the help of Larry Shinoda Design Associates, Inc. – the designer behind the Corvette Stingray and Boss Mustang, and in conjunction with Phillip Morris, Inc. each of the 10 Syclones were customized for the contest giveaway. The Marlboro Syclone custom features include:

  • ASC converted the roof to a targa-style roof panel with mounts in the pick-up bed
  • ASC installed a slide-down rear window assembly
  • Guidon hard tonneau cover
  • Boyd Coddington “Cobra” wheels with Marlboro emblem center caps and Goodyear Eagle GS-C tires
  • PPG “Hot Licks” Red paint, with white strobe stripes provided by Graphik Concepts
  • Recaro leather seats with Simpson 5-Point racing harness
  • Custom Momo “Evolution” steering wheel
  • Sony sound system
  • PROMPaq performance chip and Borla stainless steel exhaust
  • Bell Tech suspension dropped 3 inches

All 10 Marlboro Syclones still exist today and are documented on location and ownership.  The value of these trucks range from between $65,000-100,000 (based on previous private and public auction sales spanning from 1991 to present day). The Marlboro Syclones have always been a sought after truck among owners and enthusiasts.

Why do my stock rims stick out in the front and sucked into the rear?

The stock SyTy rims use different offsets for front and rear. More than likely, they are mounted backwards with the rears on the front and front on the rears.

The rims are stamped behind the center cap with “FRONT” and “REAR” as to help with mounting position.

Can I drive without the forward propshaft?

For quite some time, it was considered that driving without the forward propshaft would eventually damage the transfer case (specifically the viscous coupling) and should only be done so in limited distances.

Over time, we have a better understanding of the mechanics of the transfer case and have deemed that you CAN in fact safely drive your truck without a propshaft and not risk TC/VC damage from it.  If you would like to read an in depth conversation on the mechanics of how your TC/VC works, visit this thread.

My boost gauge reads all kinds of craziness. Is that normal?

Yes, it is normal it is widely known that the factory boost gauge is inaccurate. It is HIGHLY recommended that you install an aftermarket boost gauge to read accurate boost PSI levels.

It sounds like there is a motor or something running under the rear of my Typhoon, what is it?

Typhoons were equipped with Electronic Level Control (or ELC), which is a system of a compressor and two air shocks for the rear. The sound is the air compressor running to fill the shocks back up to proper ride height, which is normal.

What makes the SyTy engine different form the other GM 4.3Ls?

  • Compression is 8.35:1
  • Differences:
    • nodular iron main caps
    • better headgaskets
    • lower comp. hypereutic pistons.
    • cam is same as same year NA 4.3

What celebrities have owned a Syclone or Typhoon?

This list includes both current and past owners of SyTys.

  • Clint Eastwood – Has owned multiple Typhoons (red/gry & green/gry). Currently still owns a 93 Green/Gray Typhoon
  • Jay Leno – Syclone (currently still owns, featured on Jay Leno’s Garage Show)
  • Tim Allen – 1993 Black/Black Typhoon (sold)
  • Sean Kemp – 1993 White/White Typhoon (sold, last owned by Richard Le)
  • Rob Vanwinkle (Vanilla Ice) – Typhoon (sold)
  • Randy Travis – Syclone (sold)
  • Lou Ferrigno (Incredible Hulk) – Typhoon
  • JFK Jr – Typhoon (Stolen and recovered in 1997. Sold in estate auction after death?)
  • Ken Griffey Jr – Typhoon
  • Allen Houston – Typhoon
  • Brian Cox – Typhoon
  • Jimmy Spencer – Syclone
  • Rohan Marley – 2 Typhoons
  • Ziggy Marley – Syclone
  • Bob Adam – Typhoon
  • Sterling Sharpe – Typhoon
  • Steve Yzerman – Typhoon
  • Shawn Palmer – 2 Syclones (Pikes Peak Syclone)
  • Michael Strahan – 93 Typhoon
  • Rik Smits – Typhoon
  • Stephan Johannson – Typhoon
  • Bill Bixby – Typhoon
  • Eddie Van Halen – Syclone
  • Royce Clayton (St. Louis Cardinals) – Typhoon black.
  • Bubba McDowell (Houston Oilers) – Midnight blue Typhoon.
  • Keenan McCartle (Cleveland Browns) – White ’93 Typhoon. Runs High 12s.

Unconfirmed Ownership claims:

  • Michael Jordan – Syclone or Tyhpoon ?
  • Scottie Pippen – Syclone or Typhoon ?
  • Tim Hardaway – Syclone or Typhoon ?
  • Latrell Sprewell – Typhoon ?
  • Yancey Thigpen – Syclone or Typhoon ?
  • Sammy Sosa – Syclone or Typhoon ?

Has a Syclone or Typhoon ever been on TV or in a movie?

  • Lethal Weapon 3 – 1992 Aspen/Gray Typhoon is scene parked on the side of the road.
  • Lethal Weapon 3 – A Syclone is parked on the side of the road
  • Seinfield – Parking Garage episode, Kramer drops an AC Unit on the hood of a Syclone.
  • Absolute Power (Client Eastwood) – There is a scene where a Typhoon is used in a nighttime chase scene.
  • Falling Down (Michael Douglas) – A teal Typhoon and Syclone are parked in traffic underneath the bridge after Michael Douglas gets out of his car and starts walking.
  • Jackass – One of the episodes where Preston is chasing Weeman in their underwear, there is a Blk Ty parked on the side of the road.
  • Baywatch S03EP06 Part 2/5 – There is a very quick shot of the front of a Syclone or Sonoma GT.
  • I <3 Huckabees – A Typhoon is parked in the street in the beginning.
  • Bon Jovi Lost Highway Video – 93 White/White Typhoon appears in the parking lot.
  • SuperCars Exposed TV Series – 93 White / White Typhoon appears parked in the background.

Why does my truck cut out doing a boost launch?

This is more common on Syclones than Typhoons. If you are experiencing cut out on a boost launch, most likely you do not have enough fuel in your tank and you are experiencing what is known as “fuel slosh”. The Syclone’s fuel pump is located towards the front of the tank. When you suddenly accelerate, all the fuel in the tank moves towards the rear and starves the fuel pump due to the lack of baffles in the gas tank.  It has been commonly said since the beginning of SyTy time to not do a boost launch under 1/2 tank of gas. This still holds true today. Not only is it embarrassing (especially if you are racing), but it can lead to permanent damage from fuel starvation if you keep at it.

What fluid and how much do I use in....

All your fluid types and capacities can be found on the Maintenance Page.