If you are speaking of the 6 driving team PPG pace cars they has a original suspension that was modified. Fred should be able to give the details but I know they were lowered and the shock and struts were changed along with bushings. They were for sure not stock but they were also not 1988 either but they all started off as the original suspensions.
I have flyer with the changes but I would have to dig it out.
The 88 was in development when the pace cars came out and was not used for these or the Indy Pace Cars.
[This message has been edited by hyperv6 (edited 03-05-2017).]
For these GTPs to perform professional track exhibitions for thousands of spectators, Autostyle and KONI engineers worked on suspension enhancements. They strengthened the front crossmembers and control arms and mounted them to the frame with high -durometer bushings. They installed KONI adjustable gas shock absorbers and coil springs, plus a 1.00-inch front sway bar.
In the rear of the car, the engine cradle (mounted to the space frame with specially designed bushings), lower control arms, and driveline were reinforced.
The factory parking brake was swapped out for a mechanical-over-hydraulic-disc parking brake. In addition, the brake rotors, calipers, bearings, knuckle assemblies, and axles (which came from the Chevrolet Chevette) were upgraded with heavy-duty components from the 6000 STE. KONI adjustable gas-filled struts; stiffer springs; and a rear-mounted, 0.875-inch sway bar tighten up the rear’s capabilities.
The PPG cars started life as 85 GTs, so would have started off with WS6 suspension, I think. Likewise, the 84 Indy replicas were SEs and had the WS6 option standard with that package, I think.
The biggest fix was to get the rear cradle more solid so the bump steer is removed.
Styleauto also had to mount a fuel cell in the nose for track use so this had to be tuned into cars handling.
I do remember the Koni shocks and struts.
They were 85 cars.
The greatest issues with the car per the team manager that let me nose around the cars was the heat in the engine compartment. But that is another story.
If I remember I will try to find the book I was given and see if it has any more details.
I wonder if there's any benefit to making similar changes to our suspension.
Having done so, I can certainly say there is benefit. Especially when some of the components are probably 30 years old and never been changed.
I went full poly bushings, new performance KYBs for shocks/struts, and ST Suspension lowering springs, along with new dogbone that had poly, and the car was a totally different animal. And that's nowhere near the changes that the real pace cars had.
If I ever get the time and energy to do the restoration of my car, I'll be going way beyond even what was done for the pace cars; but it'll have an LS then too.
Stiffer bushings or even in some solid bushings cut down on deflection.
Just I'm yer back you have sub frame bushings and control arm bushings deflecting along with a tie rod that changes toe.
Herb Adams went to solid bearing bushings on his set up. Others rely on the sub frame in solid or poly.
The key is to remove deflection but as you take steps to do this you will pick up some harshness. This is why if you go solid with one you go poly on the other.
Originally posted by tshark: How would one of the pace cars with an SD4 compare to a modern car, in terms of acceleration and handling?
I'm just wondering what the Fiero would have been like if they'd been able to make the car they wanted to make.
The real SD4 in the real pace car would have been plenty quick, with 230+ HP. The engine itself wouldn't have really affected the handling though.
The accessories that were sold to make the standard 2.5 look like the SD4, didn't really do anything for power. This is what the replica cars you could buy at the dealer had.
Remember, the V6 was meant to be a turbo car, too. And the 89-90 prototype car had a 3.2 DOHC V6.
How would one of the pace cars with an SD4 compare to a modern car, in terms of acceleration and handling?
I'm just wondering what the Fiero would have been like if they'd been able to make the car they wanted to make.
I have an SD4 in my 84 SE. The engine shaved 4+ seconds off the 0-60 time. But that isn't saying that much. Now days a Toyota Camry with a V6 can hit 60mph in the low 6's. It takes a lot of money or effort to make a Fiero handle like a Corvette or other modern performance car.
You guys would not want the set ups for the pace cars for everyday driving on a street Fiero. There is more to it than bushings, springs and shocks. These cars were not intended to drive in a straight line at low speed. The real Indy pace cars are set up to turn left which involves staggered camber and toe settings to keep the tires flat under load at high speed going left on a banked curve. The car drove like a dream at 80mph at IMS. The GTP cars are set up for the driving team maneuvers which were often performed between 60 and 80 mph. The cars are set up with 1.5 degrees of negative camber on all four corners and caster set just a tenth of a degree positive from zero. They steer really easy and require the driver to be up on the wheel at speed to keep the car straight.
I found it interesting that the pace cars used the "milder" tune of the SD. Using a TBI, no less. My Automoda had what I would consider a mild tune SD. Had the cast iron "775" SD head, instead of the "801" max performance head that everyone seems to want. I always guessed that it was making around 200 HP, with the carb installed "out of the box". It felt about as quick as my 4.9. Unfortunately, I sold it before I had time to do any tuning on it.
[This message has been edited by Raydar (edited 03-28-2017).]
I found it interesting that the pace cars used the "milder" tune of the SD. Using a TBI, no less. My Automoda had what I would consider a mild tune SD. Had the cast iron "775" SD head, instead of the "801" max performance head that everyone seems to want. I always guessed that it was making around 200 HP, with the carb installed "out of the box". It felt about as quick as my 4.9. Unfortunately, I sold it before I had time to do any tuning on it.
One of my life goals to get an SD4! Read some interesting info about it:
25 mpg at speeds up to 125! That's really impressive. I averaged about 100+ for 50 miles with the 2.8 and used half my tank. What is that, like 9 mpg? :'(
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