Popular Hot Rodding had an article in June 1990 highlighting Turbo City’s TPI performance system. The kit included a new y-pipe, cat back flowmaster exhaust, K&N air filters, underdrive pulleys, spark plug wires, PROM, and a TPI air foil. While they did not give specifics, the test car, a 1989 5.0TPI convertible with a T5 ran low 14’s with the kit, apparently over a 1 second reduction in ET.
Enjoy!
All Chevy featured an article in the February 1990 issue highlighting Street Legal Performance’s (SLP) TPI parts and two of their test bed IROCs.
Enjoy!
The scans below are from the September 1989 issue of Car Craft featuring four Third Generation cars in various states of tuning. There is a complete writeup and also quarter mile testing.
Enjoy!
As most of us know, the 1LE Third Generation F-Bodies was GM’s answer to bringing their cars to the racetrack and competing head to head with the likes of the Corvette, 911, Saleen Mustang, and other more track oriented semi-exotic cars.
Some data from Camaro Wikipedia’s page on the 1LE:
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A new SCCA racing class had emerged in the late 1980s called Showroom Stock. Starting in Canada, it was the first time with the Canadian Players Challenge where it would grow to include SCCA and IMSA events in the USA. This was just the class where the top-of-the-line production Camaro could excel. As sophisticated, refined, and powerful as the IROC-Z was as a street car, however, Showroom Stock racing had a way of bringing out the weaknesses in a car. The sanctioning bodies permitted changes to the shock absorbers or struts, wheels, and tires; no other changes to the suspension could be made. While racing the camaro’s they discovered that the brakes needed to be changed. They simply were not designed to go from street to track and just would not suffice.
Due to the many complaints from Camaro racers, Phil Minch, a General Motors brake engineer, set out to come out with a solution. One very important part of this solution was the use of the massive 12-inch front disc brakes off the Chevrolet Caprice as it used the same front bearing package as the Camaro. Unfortunately these calipers, Minch suspected, would end up not being up to the task. So After some research, Minch checked out and was considering the two-piston aluminum caliper manufactured in Australia by PBR. The Corvette used this caliper as they were specifically made for them. To use them for the Camaro, it required modification to bolt to the Camaro spindle. Minch worked with Camaro platform chief engineer Chuck Hughes and F-body power-train manager Ray Canale to get the car modified. The rear disc brakes that came with the original four-wheel disc brake option were felt to be adequate, since most of the braking force is borne by the front brakes. Bill Mitchell of Special Vehicle Developments was contracted to do track testing of the car. The stock front-to-rear proportioning valve was nonadjustable and did not work well with the new brake setup. It was replaced by a new proportioning valve with satisfactory results.
After all this, the the vastly improved braking revealed yet another weakness. During hard braking, the engine would suffer starvation of fuel when the fuel level fell below a quarter tank. To fix this, baffles had to be added to the gas tank as well as a new fuel pickup and sock.
These had to manufactured to ensure the tank-mounted fuel pump was constantly fed under all racing conditions.
General Motors, Chevrolet addressed other complaints from racers. Virtually the manual five-speed transmission was virtually used in all the Camaro’s raced. The overdrive fifth gear was great for mileage but too tall for the small-block V8’s torque and horsepower band. With Mustangs, which were lighter and differently geared, camaro racers were battling just to keep up with them. Another added change to the Camaro was to change the fifth gear ratio in those Camaro’s ordered with this 1LE racing component package. For weight reduction purposed and revolving mass of the racing Camaro, an aluminum driveshaft would be part of the package. An engine oil cooler was also added as insurance.
An enthusiastic and competent engineering student, Mark Stielow, assisted Hughes and Canale in procuring the pieces for the 1LE option and getting them into the production loop so they could be assembled on the Van Nuys, California, assembly line. Chevrolet’s John Heinracy, who was a frequent and very successful racer of Camaro’s as well as Corvettes, was actively involved in the entire process. This included all the way from the racetrack to the Camaro assembly line to ensure the finished product performed back on the track. To qualify for Showroom Stock, all these new items had to be available on the production car so the car could, in fact, go Showroom Stock racing as equipped.
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This special package was known in Chevrolet Engineering as 1LE, but it was not an offered as an official ordered RPO feature. The 1LE Special Performance Components Package was triggered when the G92 Performance Axle option was ordered, G80 Limited-slip 3.42 rear and the C60 air conditioning option was not ordered. If only the G92 option was checked, the buyer had to select from the B2L 350ci V8 with automatic or the LB9 305ci V8 with 5-speed manual. (The standard V8 in the IROC-Z was the 170-horsepower LOS 305ci V8-not enough power for the SCCA Showroom Stock competition.) The G92 package included the engine oil cooler, four-wheel disc brakes, dual converter exhausts, P245/50ZR16 Goodyear Eagle tires, a 145mph speedometer, and 5,500rpm tachometer. Air conditioning could be ordered in these cars. If the camaro was ordered without air conditioning, the 1LE option code was then automatically triggerd. This included an aluminum driveshaft, heavier duty front disc brakes and calipers, fuel tank baffle, specific front and rear shock absorbers, and unique durometer jounce bumpers. The 1LE option added nearly $700 to the car’s price tag.
In mid 1988, the 1LE Special Performance Components Package became available but was virtually unknown to most Camaro racer-types. The result, only 4 1LE equipped IROC-Zs were built at the Van Nuys plant that year. (However anecdotal evidence suggests 4 RPO 1LE’s were exported to Canada which seems to suggest the possibility of actual 8 were produced. However this is not official.) However, by 1989 the word of the 1LE started to circulate. Eager buyers were now with checkbooks in-hand for the 1LE racing performance package. For 1989, the dual-catalytic exhaust system was added to the package; a total of 111 IROC-Zs were ordered with this package. And the buyers were not disappointed. Chevrolet writes, “In 1989, Chevy’s F-body swept the Sports Car Club of America (SCCA) and International Motor Sports Association (IMSA) Showroom Stock series. Camaro’s won every race in the SCCA Escort Endurance Championship, and captured the ‘Car of the Year award in the IMSA’s Firestone Firehawk series.”
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In 1988, the secret showroom stock racing 1LE option (option level 0 IROC-Z) was first available; however, only 4 were produced. Then in 1989, the option became more well-known as 111 were produced that year. The package was obtained by ordering the following:
Level 1 IROC-Z with 5.0 TPI engine (LB9) with 5 speed or 5.7 TPI engine (L98) with 4-speed automatic. These Camaro’s had 145 mph speedometers and 5500 rpm redline tachs. Optional axle ratio (G92) (305/3.45, 350/3.27) and its required options G80 Limited-Slip rear axle
Package consisted of (G92 Was Ordered With A/C) [Street Vehicle]:
engine oil cooler 4-wheel disc brakes Performance exhaust system (N10) (dual catalytic converters) Tires P245/50 ZR16 Goodyear Gatorback
Note:
G92 ordered WITH A/C was classifieds as a Street vehicle.
G92 ordered WITHOUT A/C was classifieds as Race series.
Package consisted of (G92 Ordered Without A/C) [Race Vehicle]:
Aluminum driveshaft (JG1) (part # 10085375) G80 Differential with limited slip with 3.42 posi rear G92 Rear axle performance package Big front brakes adapted from the Corvette Larger (11.86 inch) front rotors (part # 18016035) Larger front spindles (part #’s 18016737 / 18016738) PBR front, dual-piston aluminum calipers (part #’s 10132827 / 10132828) Special swinging fuel pickup in gas tank and special 18 gallon baffled fuel tank for fuel pickup down to .5 gallon reserve to prevent fuel starvation in hard cornering specific front and rear shock absorbers Lower control arms (part # 10164151) Special deflected disc shocks Air conditioning delete (C41) (standard heater) (weight savings and better air flow to the radiator) Fog lamp delete (to release the air intake located behind) T-Tops delete Power accessories delete Aluminum spare wheel with smaller spare tire (N64) A Few RARE ones came with special 16″ x 8″ light alloy mesh wheels (XWL).
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1988
Chevrolet built 4 “1LE” 1988 Camaro’s for the SCC A Showroom Stock racing series. The reason only 4, virtually unknown to most Camaro racer-types at the time.
1989
Chevrolet built 111 “1LE” 1989 Camaro’s for the SCC A Showroom Stock racing series. But 1LE wasn’t ordered like other RPOs. Ordering the RPO G80 Limited-slip rear axle & G92 performance axle with an IROC-Z Coupe triggered the 1LE RPO. Here’s how it worked: When G92 was ordered, it forced several other options including engine oil cooler, 4-wheel disc brakes, dual converter exhaust and P245/50ZR16 tires. A 1989 Camaro with G92 had to have either the 350ci (RPO B2L) engine with 4-speed automatic transmission, or the 305ci (RPO LB9) with 5-speed manual. These Camaro’s had 145 mph speedometers and 5500 rpm redline tachs. If RPO G92 was ordered with air condition ing, the cars were built as street vehicles. If air conditioning was not ordered, Chevrolet added 1LE equipment for the race series. This included aluminum drive shaft, big front brakes adapted from the Corvette, fuel tank baffles, specific front and rear shock absorbers, and different jounce bumpers. Also, fog lamps were deleted for weight savings and better air flow to the radiator.
1990
Chevrolet built 62 “1LE” Z28 Coupes for the SCCA Showroom Stock racing series with RPO G80 Limited-slip rear axle & G92 RPO G92 performance axle triggering the build. RPO G92 required one of two engine combinations, the 305ci LB9 V8 with 5-speed manual, or the 350ci B2L V8 with 4-speed automatic transmission. When ordered with air conditioning, RPO G92 included engine oil cooler, 4-wheel disc brakes, and dual-converter exhaust. When ordered without air conditioning, RPO G92 added heavy-duty front brakes adapted from the Corvette, aluminum driveshaft and spare wheel, special shocks and fuel pickup, and gas tank baffle. Fog lamps, normally included with IROC models, were deleted for weight savings and better air flow to the radiator. Option cost for RPO G92 equipment with air conditioning was $466.00. The cost when air conditioning wasn’t ordered was $675.00.
1991
Chevrolet built 478 Z28 Coupes with “1LE” equipment for 1991. As in 1989 and 1990, Ordering the RPO G80 Limited-slip rear axle & G92 RPO G92 triggered the build. RPO G92 required one of two engine combinations, the 305ci LB9 V8 with 5-speed manual, or the 350ci B2L V8 with 4-speed automatic transmission. When ordered with air condition ing, RPO G92 ($466) included engine oil cooler, 4-wheel disc brakes (except for a brief period when 4-wheel discs were deleted with a $287 credit), and dual-converter exhaust. When ordered without air conditioning, RPO G92 ($675) added heavy-duty front brakes, aluminum driveshaft and spare wheel, special shocks and fuel pickup, and gas tank baffle. Fog lamps were deleted for weight savings and improved cooling.
1992
Chevrolet built 705 Camaro’s with “1LE” special performance components equipment for 1992. As in 1989, 1990, and 1991, Ordering the RPO G80 Limited-slip rear axle & G92 RPO 1LE was triggered by RPO G92. RPO G92 required either the 305ci LB9 V8 with 5-speed manual, or the 350ci B2L V8 with 4-speed automatic transmission. When ordered with air conditioning ($466), RPO G92 included engine oil cooler, 4-wheel disc brakes, and dual-converter exhaust. Without air condition ing ($675), RPO G92 added heavy-duty front brakes, aluminum driveshaft and spare wheel, special shocks and fuel pickup, and gas tank baffle. Fog lamps were deleted for weight savings and better air flow to the radiator. Available for Z28 Coupes only.
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I have never driven a 1LE myself, but have seen them at the autocross, quarter mile drags, car shows, and road race events over the last 20 years. As they are rare and sought after by enthusiasts and racers, prices for used (and sometimes abused) 1LE cars can be very high, giving the 1989 Turbo TA a run for it’s money in resale value. Speaking of the Turbo TA, many of the 1LE parts made their way onto that ultimate Third Generation Trans Am as Pontiac wanted some of Chevy’s racing parts thunder on their cars, not to mention the “borrowed” Grand National powerplant and transmission.
In my opinion, Chevrolet did the right thing by introducing a special, hard to get racing version of the IROC and Z28 as their lack of high performance race resistant brakes and unbaffled gas tanks made it difficult to compete on the track. SLP took the concept a level or two further with their Firehawk which featured a 350hp 350ci engine, 275-40-17 tires, and Brembo brakes (part of the competition option), but costing $40K for the base model.
The legacy of the 1LE cannot be emphasized enough – many have added 1LE (factory or clone) front brakes to their third gens, some have changed their fuel tanks to the larger capacity baffled one, and others have replaced their factory steel driveshaft with the aluminum 1LE one (factory or clone).
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