Great advice from Mike Kelcy - Team Camaro Tech
Brakes, Suspension & Steering Conversion questions, Steering & Handling

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post #1 of 9 (permalink) Old Mar 25th, 20, 06:35 PM Thread Starter
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Beth
 
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Great advice from Mike Kelcy

Hello,

Mike Kelcy is not a friend of mine. He doesn't like my politics, but this is a car forum, right ?

I think his suspension advice on 1st gen Camaros should be a Sticky.

I saved this post a while back. The moderators can decide if it's worthy; I believe it is :
-------------------------

Kelcy’s Suspension Advice

I'd do a LOT of reading, figure out what your budget is and how you want to spend it. You should improve braking, steering response and handling. Modern tires are a very important part of what you want to do - as they affect braking, handling and steering.

Disk brakes on the front end only are likely perfectly okay for street use. There are lots of kits out there; but be aware that larger brakes will inevitably mean larger wheels - so plan on wheels and brakes at the same time. I'd consider starting with brakes, wheels and tires.

You can get used C5 wheels (17" x 8.5" front and 18" x 9.5" rear) for $400 or so all day long. Two pairs of bolt-on spacers (front and rear) will cost about $250-$300 (I use 2" in the rear and 1.875" in front, but you should check your own car). That's about the most "budget" way of getting good modern tires on the car.

The IROC box is also a good budget choice and might be something you want to do fairly early on.

For the front end suspension you have two issues - correcting the poor camber gain and improving the responsiveness of the stock front suspension.

No tubular arm will correct the camber curve - that can only be done by changing the distance between the upper and lower control arm pickup points relative to the spindle length - i.e., move the pickup points closer together - the Guldstrand mod - or increase the effective length of the spindle - either by getting a longer spindle or by using a tall ball joint. The Guldstrand mod is cheap - some of your time and labor - but not quite as good as the tall balljoint/tall spindle option.

Increasing the responsiveness of the front suspension means replacing the upper and lower control arm bushings with bushings with less "stiction." While poly bushings are better than rubber, the Delrin/Del-alum bushings available from Global West and DSE are even better. Most of the better after market control arms also use Delrin/Del-alum type bushings.

So, for camber correction/responsiveness, in order of how much you will spend, you can

(1) do the Guldstrand mod and get Delrin/Del-alum bushings for your stock upper and lower control arms,
(2) do the Guldstrand mod and get aftermarket control arms with Delrin/Del-alum bushings,
(3) get tall upper balljoints and aftermarket control arms with Delrin/Del-alum bushings, or
(4) get tall spindles (but not with a 2" drop built in) and either stock or aftermarket control arms with Delrin/Del-alum bushings.

With any of these you would also use the front end lowering springs (or AFCO adjustable springs mounts and their 9.5" springs) and good shocks (Bilstein/Koni) of your choice. If you go tubular arms, I'd suggest you look at the adjustable upper arms and lower arms and tall ball joints from SC&C. Remember, only one camber correction method - Guldstrand mod OR tall ball joint OR tall spindle.

You'll want to make sure your steering linkage is all good, and replace worn parts, and you'll want a good front sway bar - I like the 1.125" hollow Hotchkis sway bar.

For the rear on a budget, stick with leaf springs. Hotchkis, Global West, DSE and others all have steel springs that work well. I'm partial to composite springs from Flex-A-Form because they allow a higher spring rate with a better ride quality than steel springs. Again I'd go with shocks from Bilstein/Koni. I'd skip a rear sway bar until you know you need it.

Subframe connectors are an extremely worthwhile add on, but recognize that to really work, they should be welded in and you should have solid body bushings.

But most of all, IMHO, it's important to read and understand what you're doing and why, rather than looking for a pre-packaged kit that's a manufacturer's idea what you should have on your car or someone's suggestions (like mine) on a message board
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post #2 of 9 (permalink) Old Mar 26th, 20, 10:48 AM
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Re: Great advice from Mike Kelcy

So, why do you say to use lowering springs over drop spindles? I've been concerned that shorter springs would can issues with suspension geometry.
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post #3 of 9 (permalink) Old Mar 26th, 20, 11:10 AM
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Re: Great advice from Mike Kelcy

Quote:
Originally Posted by Bruce1968 View Post
So, why do you say to use lowering springs over drop spindles? I've been concerned that shorter springs would can issues with suspension geometry.
So, did a little reading on Pozziracing and he says lower spindles actually help the geometry, if I am reading correctly. I was half right. I will change the geometry but in a good way.
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post #4 of 9 (permalink) Old Mar 26th, 20, 11:13 AM
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Re: Great advice from Mike Kelcy

Quote:
Originally Posted by Bruce1968 View Post
So, why do you say to use lowering springs over drop spindles? I've been concerned that shorter springs would can issues with suspension geometry.
Good info here.
first gen suspension geometry

Al

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post #5 of 9 (permalink) Old Mar 26th, 20, 11:36 PM
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Re: Great advice from Mike Kelcy

Starting point at best. As new stuff comes out and there's always new information.

That said, don't believe the marketing hype - mostly not true. No control arms (without more) will fix the camber curve no matter what anyone says now or ever.

David Pozzi is the master.

NashvilleCat - thanks for the call out.

Mike - '68 Camaro - aftermarket or modern pretty much everything.


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post #6 of 9 (permalink) Old Mar 27th, 20, 10:22 PM
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Re: Great advice from Mike Kelcy

Mike, excellent post!
& Thanks for the compliment!

When choosing control arms, consider the cost and work involved in removing your old bushings and pressing in new Delrin bushings, plus the tubular arms come powder coated. You must buy tubular upper A arms because they provide the extra positive caster you need. You can only get 3 degrees positive caster with stock parts, with the Guldstrand mod, barely 5 or so if you are lucky. The Guldstrand mod only moves the A arm rearward 1/4" or so and that means you will have to use a big stack of shims on the rear A arm stud to get enough caster. Some lower arms have the lower ball joint moved forward in addition to the upper moved rearward this gains caster without moving the wheel rearward like the upper only method does. The spindle is near the lower ball joint so moving the top ball joint does not move the rear back much but tire clearance to the rear inner splash panel is a tight spot.

I did a suspension analyzer run with both the Guldstrand mod and a .5" tall upper ball joint. I did not see any adverse effects on roll center movement (like going below ground) and the camber gain was higher, so I didn't see any down side to doing it other than it further increases bump steer to the point where you need to modify the steering linkage. A .5" tall upper ball joint with .5" tall outer tie rod end is as much as I would use without bumpsteering the car. I would also remove the springs & cycle the suspension in bump to insure the upper ball joint is not binding. It should be OK but close enough you should check it out.

I'd look at the Ride Tech Street Grip rear Fiberglass springs. They have some "extras" that the Ride Tech people asked for and may be better than other options. I like the idea of the lower unsprung weight and the glass springs dampen road shocks for a better ride.

I can say in the case of Ride Tech or Hotchkis they have worked a lot to come up with a complete package that works, and you need to know a lot to think of substituting other parts. You can get a better ride if you substitute a softer spring for example but if your ride height is pretty low, the car will be hitting the bump stops all the time and that will not be a good ride. If you trim the bump stops, the car will probably hit the pavement. The shocks can make a huge difference in ride quality. You could do a 380 to 450 front spring and good shocks with a ride height that allows decent suspension travel and be OK with a better ride than a 600 lb front coil the tuners use. If you try and autocross or go all out, the front will dive too much and rise too much on acceleration and the car will not be optimum but with adjustable shocks they can make up for the lack of spring rate.
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post #7 of 9 (permalink) Old Mar 28th, 20, 06:24 AM
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Re: Great advice from Mike Kelcy

All, I can say this is all great information, but me without a college degree I am having a bit of a hard road understanding it.

So I have two 69 verts, heavier and with a different balance than coupes. I want to keep them as stock looking as possible, but will replace things if they are hidden or look stock.

327 car has stock front end, decent gas shocks, but with 6320 springs and 1" solid sway bar, rear is re-arched factory monos with poly end bushings, but rubber isolators. I also have solid subframe bushings. stock 14x7 rims with 215-70/R14 BFGs.



I am using the 327 car as a test bench for car #2 an SS350.

So I did my best to get a good alignment to improve the handling (using Dave Pozzi's settings, pretty sure I got a good amount of positive caster). But what I am experiencing might be helped by this information here, so I want to get a real world scenario and fix.

So I am little confused about bumpsteer, understeer & oversteer.

The issue I have is when coming hard into a curve:

1) if I just gradually ease into curve, the car goes in fine, but at the "apex", inside edge will rise up and the car will dart to inside of curve and I have to back off the steering input to stay on track. Car sawing back and forth if I don't keep a tight line on it.

So I use method 2) when entering the curve, I will put more steering input in to raise the inside edge of car at beginning of curve ('pre-loading it'), then back off steering a bit, so I can keep the rest of the curve centered without decreasing steering input.

So what issue do I have?

And can it be corrected by the taller ball joints? If so, which one, just the upper, or both? Can I keep the stock A-arms and rubber bushings? Front end is already pretty low to the ground, so I need to keep some space between subframe and a-arms.



Thanks for any advice!

Kevin


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Last edited by KevinW; Mar 28th, 20 at 06:37 AM.
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post #8 of 9 (permalink) Old Mar 28th, 20, 10:39 PM
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Re: Great advice from Mike Kelcy

You have oversteer. Do you have a rear sway bar? Quick fix is to soften the rear by attaching the end links to the end of the bar if you have any adjustment holes. Or disconnect one end link which will disable the rear bar and try that.

What size is the front bar? Solid or hollow? what manufacturer?

Pick a flat sweeping turn, enter at a fast speed but where you don't have to brake or accelerate through the middle of the turn. Turn in to the apex and note if you have to add more steering turn to keep the car on the correct line, or if you have to countersteer turning away from the apex. It can help to put a white stripe of tape on the top center of the steering wheel rim.
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post #9 of 9 (permalink) Old Yesterday, 06:02 AM
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Re: Great advice from Mike Kelcy

oversteer! thx

Solid 1" Addco bar, no rear sway bar, just factory 10 bolt with mono leaf springs

Can this be helped without adding a rear sway bar?

Might be a while before the car comes out of winter hibernation.

Kevin


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