66 BB coupe handling improvements

[Dan Pepper]

I have a '66 BB AC coupe that I love to drive - but I'm sure it can handle better. It seems a big spongy - especially in the rear - and can be really jarring on rough pavement. It's solid enough, with no squeaks or rattles. The car just doesn't feel tight over rough surfaces or in corners. Is this inherent in C2's?

It's a 50k original mile car, but judges have suggested I should have the rear spring re-arched. Should I do this or just purchase a new spring? The bushings/rubber looks good, but I'm not sure if it is elastic as it should be.

What can I do in my garage to improve the handling and ride and still keep it NCRS spec?

[Joe C.]

Re: 66 BB coupe handling improvements

Dan:

The biggest improvement would be achieved with a set of modern radial tires, but at a large points penalty. With that said, I suggest a set of Delco "Reactec" shocks, which you can paint "shock absorber grey" after removing the labels. A good bet is that all your rubber bushings, if still original, should be replaced, as they are probably dry and cracked. A reproduction rear spring will be very detectable because the corner cuts on the main leaf are at a different angle than the 45 degree originals. Also, the turn-ups at the ends of the leaves are also different. If the ride height at the rear is too low, and you feel you MUST correct it, then I would have the spring re-arched by a reputable shop. The spring was originally shot peened to relieve residual stresses caused by the arching process. I do not know if anyone can do this for you.
Hope this helps.

Joe

[Joe C.]

Re: 66 BB coupe handling improvements

Dan:

The biggest improvement would be achieved with a set of modern radial tires, but at a large points penalty. With that said, I suggest a set of Delco "Reactec" shocks, which you can paint "shock absorber grey" after removing the labels. A good bet is that all your rubber bushings, if still original, should be replaced, as they are probably dry and cracked. A reproduction rear spring will be very detectable because the corner cuts on the main leaf are at a different angle than the 45 degree originals. Also, the turn-ups at the ends of the leaves are also different. If the ride height at the rear is too low, and you feel you MUST correct it, then I would have the spring re-arched by a reputable shop. The spring was originally shot peened to relieve residual stresses caused by the arching process. I do not know if anyone can do this for you.
Hope this helps.

Joe

[Jim T.]

Re: 66 BB coupe handling improvements

If you love to drive your 66 more than you like to have it judged you could install a Vette Brakes fiberglass rear spring. If you could take a ride in another owners car with just the rear spring change to fiberglass you could evaluate if you like it or not. The rear spring is really pretty easy to change back to the original if you want to have it judged.

[Jim T.]

Re: 66 BB coupe handling improvements

If you love to drive your 66 more than you like to have it judged you could install a Vette Brakes fiberglass rear spring. If you could take a ride in another owners car with just the rear spring change to fiberglass you could evaluate if you like it or not. The rear spring is really pretty easy to change back to the original if you want to have it judged.

[Steve D.]

Re: 66 BB coupe handling improvements

I recently saw several "performance improvement" packages advertised (for '63 - '67)in one of the catalogs. Among other things, front and rear sway bars were included. I have a '63, and there is no rear sway bar. Were these an addition after '63 ? Can a rear bar be added?

[Steve D.]

Re: 66 BB coupe handling improvements

I recently saw several "performance improvement" packages advertised (for '63 - '67)in one of the catalogs. Among other things, front and rear sway bars were included. I have a '63, and there is no rear sway bar. Were these an addition after '63 ? Can a rear bar be added?

[Jack H.]

Comments....

First, no matter what you do, it's important to keep in mind you're dealing with a 'state of the art' suspension that's FOURTY years old. Sometimes we're shocked & disappointed when we actually experience automotive history at work; comparing yesteryear to the modern technology we're used to....

Second, before you run off and spend $$$ and time, why not get involved with your local NCRS Chapter and seek out someone who has an equivalent car that's been restored/preserved properly and politely ask if you can go for a drive to actually experience what 'correct' and/or 'improved' feels like?

Third, suspension components (shocks, springs, tie rods, ball joints, Etc.) all wear out insidiously slowly. The degradation in performance comes on so slowly that it's bearly perceptible over time. I've had some customers who bit the bullet to have their suspension restored and were literally SHOCKED by the handling difference! One customer took his restored Corvette home from the shop, stopped about 8-blocks from the shop, returned and said, "Is that what Zora intended? WOW! I've owned the car for 12-years and had no idea it could or should handle like that."

Last, beauty is in the eye of the beholder. So, one man's opinion can be VERY different from your observations/expectations. As President Regan said, "Trust but verify...."

[Jack H.]

Comments....

First, no matter what you do, it's important to keep in mind you're dealing with a 'state of the art' suspension that's FOURTY years old. Sometimes we're shocked & disappointed when we actually experience automotive history at work; comparing yesteryear to the modern technology we're used to....

Second, before you run off and spend $$$ and time, why not get involved with your local NCRS Chapter and seek out someone who has an equivalent car that's been restored/preserved properly and politely ask if you can go for a drive to actually experience what 'correct' and/or 'improved' feels like?

Third, suspension components (shocks, springs, tie rods, ball joints, Etc.) all wear out insidiously slowly. The degradation in performance comes on so slowly that it's bearly perceptible over time. I've had some customers who bit the bullet to have their suspension restored and were literally SHOCKED by the handling difference! One customer took his restored Corvette home from the shop, stopped about 8-blocks from the shop, returned and said, "Is that what Zora intended? WOW! I've owned the car for 12-years and had no idea it could or should handle like that."

Last, beauty is in the eye of the beholder. So, one man's opinion can be VERY different from your observations/expectations. As President Regan said, "Trust but verify...."

[Duke W.]

Re: 66 BB coupe handling improvements

The key to good handling is good tires and fresh tires usually reduce ride harshness because worn or hardened old tires loose their high frequency damping characteristics. Also, it's always been my experience that when tires go "off" from either heat cycling or age hardening, the car will tend more to oversteer at the limit. What tires do you have and how old are they?

C2s are prone to oversteer at the limit because their roll stiffness distribution was set up for miminal understeer. This can be mitigated by replacing the front anti-roll bar link bushings with urethane. (The OEM type rubber pillow block bushings are okay.) The OEM rubber anti-roll bar link bushings compress with body roll and reduce the effectiveness of the front anti-roll bar, which transfers roll stiffness to the rear, and this can get the car into oversteer. Urethane front anti-roll bar link bushings mitigate this response.

As the rear spring link bushings compress and harden the rear becomes very harsh. They should be replaced ever five years. I'd also recommend replacing the rear anti-roll bar link bushings with OEM parts.

This $20 worth of parts and a couple of hours labor can make a big difference.

Shock absorbers are a key to ride and handling yet users know virtually nothing about them. Adjustable shocks are best because they allow you to tune the suspension response to your specific desires - do you want the best ride possible or razor sharp response and high speed stability? You don't have a choice with a with a fixed rate shock. Someone who has no idea what you want or may not know anything about Corvettes chooses for you.

I keep suggesting Spax shocks that have eleven way adjustable rebound damping on the car without removing the shock, but I don't think anybody's listening.

To develop a good handling and riding car you start with the best tires for your needs, and you sometimes need to choose between handing and ride quality. Then get a set of adjustable shocks and find the alignment setting that work best. Next tune the roll stiffness to get the dynamic response you want. The last thing to do is change springs and this should almost never be necessary. Beyond this, occassional refreshing of the rear spring link cushions should keep your Corvette handling and riding very well for a forty year old design.

Duke

[Duke W.]

Re: 66 BB coupe handling improvements

The key to good handling is good tires and fresh tires usually reduce ride harshness because worn or hardened old tires loose their high frequency damping characteristics. Also, it's always been my experience that when tires go "off" from either heat cycling or age hardening, the car will tend more to oversteer at the limit. What tires do you have and how old are they?

C2s are prone to oversteer at the limit because their roll stiffness distribution was set up for miminal understeer. This can be mitigated by replacing the front anti-roll bar link bushings with urethane. (The OEM type rubber pillow block bushings are okay.) The OEM rubber anti-roll bar link bushings compress with body roll and reduce the effectiveness of the front anti-roll bar, which transfers roll stiffness to the rear, and this can get the car into oversteer. Urethane front anti-roll bar link bushings mitigate this response.

As the rear spring link bushings compress and harden the rear becomes very harsh. They should be replaced ever five years. I'd also recommend replacing the rear anti-roll bar link bushings with OEM parts.

This $20 worth of parts and a couple of hours labor can make a big difference.

Shock absorbers are a key to ride and handling yet users know virtually nothing about them. Adjustable shocks are best because they allow you to tune the suspension response to your specific desires - do you want the best ride possible or razor sharp response and high speed stability? You don't have a choice with a with a fixed rate shock. Someone who has no idea what you want or may not know anything about Corvettes chooses for you.

I keep suggesting Spax shocks that have eleven way adjustable rebound damping on the car without removing the shock, but I don't think anybody's listening.

To develop a good handling and riding car you start with the best tires for your needs, and you sometimes need to choose between handing and ride quality. Then get a set of adjustable shocks and find the alignment setting that work best. Next tune the roll stiffness to get the dynamic response you want. The last thing to do is change springs and this should almost never be necessary. Beyond this, occassional refreshing of the rear spring link cushions should keep your Corvette handling and riding very well for a forty year old design.

Duke

[Duke W.]

Re: 66 BB coupe handling improvements

First you have to thoroughly understand what "performance improvement" means to you. To some it is ride. To others it may be mid range handling or limit handling.

As Jack said below the design is 40 years old and you won't be able to get the ride and handling of a C6. You can make improvements to both, but not necessarily simultaneously.

Rule number one: TIRES ARE EIGHTY PERCENT OF THE RIDE HANDLING EQUATION, so once you decide what you want as an end result, pick the best available tires for your needs.

Rule number two: Get educated on shocks - what the do and don't do, and select and adjustable shock if you want the most tuning options.

Rule number three: Buy a book like "How to Make Your Car Handle" by Fred Puhn so you can get a basic background in suspension geometry, alignment, springs, shocks and anti-roll bars.

Once you understand how different components affect the ride and handling and understand what you can reasonably change and what's cast in concrete you can do some "system engineering" (based on your overall end objective) and select a set of components and settings that you think will give you what you want and then go from there.

In general, Corvettes have a reasonably good setup for handling, but it can be improved with alignment and judicious bar changes. I have never bought an off the shelf "suspension kit". Rather I do my own "tuning" by making single changes, then evaluating whether it gets me closer to my overall objective. I've spent as much as five years tuning a car to get what I want. I didn't spend a lot of money, but it did take some time. That's what hobbies are about.

Duke

[Duke W.]

Re: 66 BB coupe handling improvements

First you have to thoroughly understand what "performance improvement" means to you. To some it is ride. To others it may be mid range handling or limit handling.

As Jack said below the design is 40 years old and you won't be able to get the ride and handling of a C6. You can make improvements to both, but not necessarily simultaneously.

Rule number one: TIRES ARE EIGHTY PERCENT OF THE RIDE HANDLING EQUATION, so once you decide what you want as an end result, pick the best available tires for your needs.

Rule number two: Get educated on shocks - what the do and don't do, and select and adjustable shock if you want the most tuning options.

Rule number three: Buy a book like "How to Make Your Car Handle" by Fred Puhn so you can get a basic background in suspension geometry, alignment, springs, shocks and anti-roll bars.

Once you understand how different components affect the ride and handling and understand what you can reasonably change and what's cast in concrete you can do some "system engineering" (based on your overall end objective) and select a set of components and settings that you think will give you what you want and then go from there.

In general, Corvettes have a reasonably good setup for handling, but it can be improved with alignment and judicious bar changes. I have never bought an off the shelf "suspension kit". Rather I do my own "tuning" by making single changes, then evaluating whether it gets me closer to my overall objective. I've spent as much as five years tuning a car to get what I want. I didn't spend a lot of money, but it did take some time. That's what hobbies are about.

Duke

[Dan Pepper]

Re: 66 BB coupe handling improvements

Thanks for the great advice. I'll go ahead and replace the rubber with OEM parts, and try a new pair of shocks.

As for tires, I have brand new set of performance white stripe radials on the car (installed afer the left rear Firestone radial separated on Hwy 26 while cruising to the Northwest Regional meet last summer - scary!). Also have had a set of bias ply repro goldlines on the car as well, so I do appreciate the difference tires make in handling!

[Dan Pepper]

Re: 66 BB coupe handling improvements

Thanks for the great advice. I'll go ahead and replace the rubber with OEM parts, and try a new pair of shocks.

As for tires, I have brand new set of performance white stripe radials on the car (installed afer the left rear Firestone radial separated on Hwy 26 while cruising to the Northwest Regional meet last summer - scary!). Also have had a set of bias ply repro goldlines on the car as well, so I do appreciate the difference tires make in handling!