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| 84-87 vs 88 front suspension (Page 1/10) |
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fireboss
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JUN 01, 09:21 PM
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We all know that the 88 had the better suspension...
A lot of 88 cradles have been swapped.
and some have swapped the front suspension.
My question : is the front suspension that much better? Other than the brakes which can easily be changed...
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Bloozberry
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JUN 01, 09:25 PM
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Are you looking for subjective seat-of-the-pants opinions or objective numbers?
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fireboss
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JUN 01, 09:38 PM
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Just if the pre 88s could be upgraded at a reasonable price instead of what all is involved in swapping the 88 in.
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Bloozberry
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JUN 01, 10:35 PM
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If you compare the small performance differences that were measured by the different magazines in the day between the '88's and the earlier cars, I think any reasonable person would be hard pressed to justify the expense to convert an earlier car with '88 suspension. Especially since to achieve the same results you'd need to swap in both ends, not just the front. Besides, the rear end is where most of the improvements were made anyway, IMHO.
The early cars perform just fine for anything except at the extreme limits of performance, and certainly I believe an early car with new bushings and shocks would give a stock '88 with tired bushings a run for it's money. Again, IMHO you'd be far better off investing in renewing the suspension's key parts than in swapping in '88 sub frames.
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fireboss
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JUN 01, 11:24 PM
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Thanxs Blooz...
One more thing.
Its O/T but....does the pre 88s have slightly more room in the engine bay between the strut towers?[This message has been edited by fireboss (edited 06-01-2014).]
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lou_dias
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JUN 02, 12:21 AM
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yes because the strut towers moved inwards... With the '88 strut tower adapters you need to switch to 2.5" ID springs... You don't need an 88 cradle to benefit from that change though...
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Raydar
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JUN 02, 05:57 AM
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George Ryan, a Fiero autocrosser from back in the day, said that he thought the earlier car, with the 88 rear suspension, made the fastest car around a track. Better turn-in and cornering, etc. Of course, that's a very narrow set of parameters. There's a lot more to be considered.
Personally, I don't like the amount of kick-back in the earlier front end setups. I actually traded in an 85 GT that I had bought new, because I got tired of how it steered. ------------------
Raydar
88 Formula IMSA Fastback. 4.9, NVG T550
 
Praise the Lowered!
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lou_dias
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JUN 02, 08:50 AM
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| quote | Originally posted by Raydar:
George Ryan, a Fiero autocrosser from back in the day, said that he thought the earlier car, with the 88 rear suspension, made the fastest car around a track. Better turn-in and cornering, etc. Of course, that's a very narrow set of parameters. There's a lot more to be considered.
Personally, I don't like the amount of kick-back in the earlier front end setups. I actually traded in an 85 GT that I had bought new, because I got tired of how it steered.
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Yeah, I think it's even worse on my HELD Slalom front suspension... Has anyone ever discussed how to improve the pre-88 front end?
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Bloozberry
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JUN 02, 01:14 PM
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The kick-back in the steering is due partly to the scrub radius and partly due to the amount of caster. Since the caster settings between the '88 and earlier cars is the same (+5 deg), then the difference in kickback must be due to the difference in scrub radius.
Scrub radius is the distance between the centerline of the tire contact patch and an imaginary line extended to the ground drawn between the upper and lower ball joints (king pin angle), as viewed from the rear of the car. The larger the distance between those two points on the ground, the greater the kick back. Here's a drawing of an '88 to illustrate what scrub radius is:
On the '84-'87's the scrub radius is 47 mm with the P185/80R/13 tires and is probably several mm's more with the later 14" Hi-Tech and 15" lace wheels. On the '88's, the scrub radius with the stock 15" lace wheels is only 40 mm's as shown above. That's a 15% reduction in scrub radius so it surely would be felt. It's also the most likely reason why GM left the steering damper off of the '88's.
The reason a larger scrub radius gives more kickback is because the tire pivots on the ground not about the center of the tire contact patch, but rather around the point on the ground drawn between the ball joints. When you hit a bump though, the force acts through the center of the tire contact patch, so the further the center of the patch is from the actual pivot point, the longer the lever arm trying to wrench the wheel around the pivot point.
To improve the kick back in earlier cars, the trick is to find wheels with a greater offset than stock. That's part of the way GM reduced the kickback on the '88's. Higher offset wheels move the center of the tire contact patch further inboard, closer to the ball joint line reducing the scrub radius. But everything is a compromise. Higher offset wheels will tuck under the fender further and most people want a wider looking stance, not a narrower one. By playing with wider rims and offsets though, you can achieve a reduced scrub radius and still maintain the sidewall at the outside edge.
(Edit for clarity)[This message has been edited by Bloozberry (edited 06-02-2014).]
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olejoedad
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JUN 02, 06:48 PM
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Wish I could give you another ' + ', blooze!
Nice post!
Edit to add....
Just checked, somehow I had never rated you......???
Oversight corrected.[This message has been edited by olejoedad (edited 06-02-2014).]
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