Taijutsu

As a long time troll I find it interesting how much time/money we spend on engine performance. It seems to be our main focus.

Then there are those who have spent the time/money to get the best from their suspension. Doing some testing w/stopwatch and temp gun and tires seem to be good start.

Some of us have gone so far as to switch out sway bars looking for the best handling.

I remember a post where some members have gotten serious about adding heim joints in their suspension where ever possible. I can see where that would take out some slack/slop in our suspension.

I'm sure testing and swapping parts looking for the best combo has to pay dividends. I am curious what adding the heim joints will do other than the ability to lube them for less friction? Am I missing something?

Is this the very last thing to do when looking for the last bit of performance? Does it change the ride quality for better or worse.
I'm determined to get my 74 up and running. Then I will of course want to improve a few things, while I'm in there!

TIA

R

PainfullySlow

Like you I have a keen interest in improving the handling of my car.

The simple fact is that as a general rule, Americans are all about straight line speed so engine mods come first. Additionally it is a lot easier to modify an engine than it is to diagnose and tune suspension and geometry. For me, straight line speeds don't thrill me.

I realize this is going to **** off a lot of people here but it is my opinion that it takes far more skill to navigate a road course than it does to mash a gas pedal at the drag strip. In order to handle that road course, your car must have dialed in suspension.

I will not track my car so I am limited in the amount of speed that I can generate so engine mods are for the occasional quick shot of power and for a really lovely exhaust note, however I really dislike slowing down for turns so my plan is to start with a VBP suspension kit, some 18" wheels and rubber and then start dialing it in from there.

As to the heim joint question, I am intrigued and will be following as I would like to know the answer to this as well.

jb78L-82

I posted this on my 78 L-82 4 speed in September...

I have a 78 L-82 4 speed car with the gymkhana sport suspension (67,000 miles) that I have owned for 34 years and I have tinkered with the suspension one part at a time over all those years to achieve the perfect balance of superb handling, steering response and a firm but not harsh ride. Not knowing if you have a base suspension (most likely since most did not have the sport suspension from the factory) or the sport suspension, below is what you need for truly sportscar handling with a great ride for your 78:

Front:

550 lbs front coil springs/1 inch lower than stock-$100
1 1/8 inch solid front sway bar (OEM Bar size)-$200
poly upper and lower control arm bushings-$50
Bilstein HD shocks-$150
Front Spreader Bar-$100
Custom blueprinted/rebuilt OEM steering box- GTR 1999-Gary Ramadei-$300

Rear:

360 monospring-$300
Bilstein Sport shocks-$150
OEM Style Rear Sway bar (not the aftermarket type bars. I highly discourage NON OEM/GM style rear sway bars)-7/16 or 9/16 or 3/4 inch (I have this one replacing the stock 7/16 inch bar)-$200
Competition adjustable strut rods with heim joint ends-$200

Total Cost $1750

This suspension will get you a FAR SUPERIOR suspension than what came on the car when it was new, X3 if the car had a base suspension from the factory. You will need to add 17/18 inch rims and tires (ZR rated only W/Y sub rating) later to maximize the superior suspension setup. I have ultra high performance summer only tires Front-255/45/17 ZR and rears 255/50/17 ZR's.

This car not only rides great, has tons of steering response, but can handle like a modern sportscar!^^^^^^^^^^^^^^^

As for the heim joint adjustable struts...makes the rear end feel more planted since there is much less camber changing under a load and has little to no detrimental effect on the ride quality.....................One of the best value upgrades you can make to the suspension....front spreader bar would be #1

ignatz

I would disagree with your first sentence. There are plenty of handling related discussions on this forum.

I would heartily agree with 'jb78L-82's mod's. They are pretty close to mine and really made it a whole new car. To what he said, I would add aggressive alignment spec's, low profile sticky tires as he points out, replacement of every single flexible rubber joint with at least poly or better, the best brakes you can afford, and these things pictured which will pin down your differential. I could swear I once saw a video at the back of the car showing an alarming amount of movement otherwise, but can't find it now

Taijutsu

I'm not going to count the posts, but I think we start w/engine mods for more power. Then we work on the chassis to keep things under control.
The smart guys do some real testing. Most of us go w/seat of the pants.
I'm sure there is all kinds of flex in our cars!
JMHO

ignatz

Just to be clear then, you are not looking for handling advice, you are just offering an opinion?

Taijutsu

I'm looking for handling advice.
You seem to want to argue about what comes first and most often. If that is important to you start a poll on your own thread.

Go start a flame war someplace else.
Alan has been helpful.
What constructive info do you have to the topic?
The topic is NOT what comes first to a new vette owner.
That was my own personal opinion.

Regardless of what is more important to someone.
I'm interested in improving the handling of my car.

R

ignatz

I took the time to read the posts. I read jbl's and decided to add something that I thought would be useful. Since he answered the question about the Heim joints I thought a little more about back end movement and decide to mention the crossmember support. I searched my photos to find a picture of the crossmember. I also wondered if I could find the video showing differential movement so I spent a little time searching for that.

In response then to that reply, where you said "I'm not going to count the posts, but I think we start w/engine mods for more power. Then we work on the chassis to keep things under control.", well that kind of sounded like an opinion, so I inquired as to whether that was the case, and then got Is that your best? I will leave you work out whatever it is you are looking for.

69427

Chill, dude. Ignatz is an intelligent contributor here. Ya might learn a bit more here if you have a better attitude.

jb78L-82

Yep, I agree. Ignatz and many others are what make this forum what it is...a great resource for facts, opinions, suggestions, discussions...take what you want from the posts and decide what you want to do...otherwise move on...unfortunately, lately I have noticed a trend towards trying to squash poster's opinion more often...too bad...

Bikespace

Subscribing. Hopefully we can get some more great tips for low-cost, big return upgrades before this thread gets locked for overabundance of snark. jb78L-82 and ignatz posted some good ones.

Here are some followup questions to keep this constructive:

What are good sources for the stock-style rear swaybars, and would using heim joints at the ends benefit you (you'd likely have to make them yourself)?

Does swapping to an electric fan give you better options for a front spreader bar?

jb78L-82

I bought my spreader bar from Speedirect.com but MidAmerica has them also. This spreader bar fits C3 SBC with the stock mechanical fan which is what my car has as well:

http://www.mamotorworks.com/Corvette...block-642193-1

I use this 3/4 inch OEM rear GM style sway bar with my stock 1 1/8 OEM front bar:

http://www.mamotorworks.com/Corvette...le-34-602628-1

I use the stock GM rear sway bar endlinks on this bar^^^^

I would not use heim joints on the rear sway bar but would here which I also have:

http://www.mamotorworks.com/Corvette...d-kit-602910-1

Bikespace

Thanks for that! The price of the sway bar end link (yoke) as a new reproduction make me want to improvise something ($110 on eBay right now). But if they work, they work, and they cost what they cost.

Herbie53

Does adding a spreader bar change the alignment?

Taijutsu

I'm still waiting for George & Skunk Works to chime in.
Attacking the first line of my post is not the best way to start any discussion.
I'm still open to good advice from those that know!

cagotzmann

Assuming all suspension parts are in perfect working order as OEM factory parts you won't notice the difference on the street.

Spring rates / shocks will give you a feeling of harsh or smooth on the roads. From factory smooth to VB&P harshness (550) & 360 rear springs. Depends what you what from your car.

Now what I call harshness depends on the quality of the roads. We here in Canada get a lot of rough pot hole roads every spring, the VB&P kit is very harsh compared to the factory rubber / softer springs on these roads. But at the track which is new and nice and smooth the harshness goes away and at time seems soft in hard corners.

Do you want it to handle track days ?


Then you need to upgrade rubber to poly, stiffen all the springs, add thicker sway bars, proper alignment , tight steering parts and most importantly get much better tires.

The tires are the biggest change that you will notice.

If you will only drive on the street with 15" tires factory spec parts are just fine. If you have a flexing old tired frame a spreader bar can help.

I have the complete VB&P Street & Slalom kit with SPC upper arms, poly everywhere, spreader bar.

To give you an idea of handling changes.

1. VB&P Kit with 255 15" T/A Tires (1:41 laptimes)
2. add michelin 245 18" super sport tires (1:36 laptimes)
3. added 275 18" Nitto NT01 tires (1:32.8 laptimes)

The tire is the contact point between the car and the road.

Taijutsu

I would like my car to be able to do a track day safely.
What is your next mod?

R

cagotzmann

If you want to handle track days safely then start with your brakes. The factory calipers seals (rebuilds, new etc ) Don't take the heat very well.
Mine where all replaced in ~ 2011-2015 (factory calipers) switch to wilwood in 2015.

my stack of failed / leaky calipers from track days.






Replacing the steering system with a Flaming River r&p, the factory power steering leaks to often under hard use, hoses fail etc. Flaming River cradle is also very heavy to further stiffen the front end.

With Nitto NT01 tires the steering is taking a beating.

Then I would like to replace the front suspension with dual adjustable coil overs for more adjustments, which will then push the problem to the rear suspension.

But I like making 1 change at a time so I can measure the value of the change and the effect on lap times.

Taijutsu

I like it that you have lap times to back up changes and mods. There is a comfort factor that a street car should have. Twitchy and unstable are not confidence building.

I considered the VB&P set up, but I'm sold on coilovers on all 4 wheels.
Then comes who has light wheels for unsprung weight?
What track do you run?

mrvette

I have posted my list of handling mods to the car over the 22 years I have owned it.....in many threads.....

I did '92 vette wheels in '95 yet....2.5" VBP adapters....kept same centerline....cut the ebrake cable mount and moved it....
changed to rack steering in winter 01-02.....

cross support a year or so later....

360 spring in rear, and the ride was a HUGE improvement over the stock steel '72 spring....
Billy Stein shocks on all 4 corners....sports....

255/50/17 in front 275/50/17 in back....

it corners nice....but I don't race it....