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Old 10-10-2018, 03:06 PM   #1
ACII
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bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hy all..

this summer i was able to put a few hundred miles on my truck.

Unfortunately i am quite unhappy with the handling respectively with the driving characteristic.

THe truck is bouncing very hard , even with the installed air ride ( front / rear).

In Corners the truck is pushing over the front axle…..

Last week i was at a Football Stadion ….at the parking area the Ground was partly asphalted and partly filled with pepple Stones …

finally there were a lot of pepple Stones on the ashpaletd parts as well.

so after the Football game i left the parking area .. and it was really horrible because the truck was pushing over the front axle like hell ...because of the pepple Stones.. it was like driving on ice (almost :-) )


My Chevy 51 pickup has a Camaro subframe installed. The wheels were aligned by professional shop.

We have installed the subframe like that..

--> Original pickup - frame had have been widened , the Camaro subframe inserted directly into the frame..

Details pls see at the attached pics…

I guess with this Setup the geometry is off..


I hope some of you can give me a Feedback, what the reason could be for the miserable handling


i hope my Explanation is more or less understandable ...i am from Germany and my english is limited :-)

Hope to hear from you soon

Thanks a lot
Achim
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Old 10-11-2018, 06:37 AM   #2
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Couple of things I can think of from doing camaro sub frames in street rods in the 80's.
I assume it is all braced and welded. No bad flex in the frame.
Is the frame good and square and the suspension in the frame square?
What did you use for shocks?
What did you use for steering? Stock or a rack? If you modified the steering did you test it for ackerman angles and bump steer?
Did you put a front sway bar on it?
What alignment specs did it end up with?
Lastly post some more pictures of the truck and the over all setup.
Jimmy
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Old 10-11-2018, 02:29 PM   #3
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hy Jimmy;

see the answers below…..

Couple of things I can think of from doing camaro sub frames in street rods in the 80's.

I assume it is all braced and welded. No bad flex in the frame.
A: everthying is welded , i dont think that there is any bad flex..

Is the frame good and square and the suspension in the frame square?
A: visual the frame Looks to be in a good shape…, i Need to double check if the Frame is square…

what do u mean with the Suspension is square ????


What did you use for shocks?

A: I have no idea, it´s no Name - brand , latest at the Weekend i will take some pics of the front setup

What did you use for steering? Stock or a rack? If you modified the steering
did you test it for ackerman angles and bump steer?

A: everything is stock

Did you put a front sway bar on it?

A: it does have the original Sway bar

What alignment specs did it end up with?

A: i will scan the paper of the results of the shop which has done the alignment

Lastly post some more pictures of the truck and the over all setup.

A: More pics are coming soon :-)

At the front i have installed slam air - bags…. i drive the car with around 60 - 65 psi (front and rear)

I am also thinking About to remove the front air - bags and to try original coil springs and original Shocks

CU
Achim
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Old 10-17-2018, 01:12 PM   #4
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hy

so during the Weekend i was able to make some more pics of my front Suspension set up..

So pls let me know what do you think About ??

I have installed on the front some Slam specialities ….Maybe thats also a Kind of Problem of my harsh riding ???

i am also thinking About changing my front Shocks to adjustable once..

Because beside my harsh ride ….. the truck has a Kind of bouncing effect…

Some more Details ...see attached pics.
Also pls have a look at the bushings….. i have installed some new once , but not sure if the bushings are sitting properly ????

I hope you understand what i mean :-)

CU soon

Achim
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Old 10-18-2018, 07:00 AM   #5
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

From the little I can see in the pictures and your answers here are my thoughts. Rear bag pressure seems really high for the weight. It my be your bag placement but that could be a partial cause of a stiff ride. What air pressure was in the bags when the alignment was done? That the only place the alignment will be good. For what ever reason the front looks to have a lot of camber gain in the pictures. That will have an effect on the way it drives at different air pressures. What I was asking about the suspension being square is about the wheel base being the same on both sides and that they are square with each other. I have fixed a few drag cars over the years that were built out of square and they drove really bad. A well built and aligned chassis is easy to push on a flat surface. Post some pictures of the rear suspension and the thing on the ground at ride height.
Jimmy
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Old 11-11-2018, 08:15 AM   #6
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

hy

the alignment was done at around 60 psi front / back.

I have attached some pics of the rear Suspension.

Also the result of the alignment , i hope u can read it cuz it is in german.
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Old 11-11-2018, 08:19 AM   #7
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

i will send some more pics with the truck on the Ground....

But that will take some days, because i come to my Garage just every second Weekend.
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Old 11-11-2018, 08:24 AM   #8
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

better pic of the alignment results :-)
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Old 11-11-2018, 03:04 PM   #9
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Don't know if this is making contact or not but it looks like it could easily hit or bind when cycling
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Old 11-11-2018, 04:16 PM   #10
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

well spotted :-)

but thats a bit misleading on the pic , respectively the rear axle was pumped up to the maximum at time the pic has been shot ... so that means at ride hight there is plenty of space..

In general i dont think that the rear axle is a problem... even with around 60 psi it feels ok at the rear during hitting a pothole

CU
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Old 11-14-2018, 08:13 AM   #11
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Here's a couple of things I see. The lower arms with the bags that far forward need to be trussed. They will bend. The forward location and the high bag pressure will kill the ride quality. I would put shock waves on it if it were mine. What bag pressure was it aligned at and do you drive it at the same pressure? Have you tested the front shocks at ride height to see how much travel you have in both directions. They look like they may be to long. Have you looked at the bag length at ride height both front and rear? If they are on the short side of the recommended install height that can hurt the ride. Now on the alignment it has just 2 degrees of caster and 3 would be better. Now it looks like it has more camber in it than the spec of 1 degree and they were able to get it close on both sides but not able to get it down to 1 degree. This makes me think the clip may be up a little high. The tires are showing both under inflation wear and what looks like camber wear. I would put a new set on it and get it back on the alignment rack. Heres where you need an alignment guy that knows a bit about performance or race cars. Have him put it on the rack and do a camber gain test on the truck. Do 2" lower than ride height, 1", ride height and plus 1" and plus 2". This will tell you what the camber gain is through the travel that you use for most driving. During this test you will also get the bump steer numbers. With this information you can work out whats up with the front end. Here is a page on the first gen Camaro that has a good bit of information on tuning the front.
Jimmy
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Old 11-14-2018, 08:20 AM   #12
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Heres the link. http://www.pozziracing.com/first_gen...sion_geome.htm
Jimmy
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Old 11-14-2018, 05:30 PM   #13
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hello Jimmy

and thx for ur time and great feedback..

The car was aligned with around 4 bar (58 psi)...and i do drive it at that pressure.
Unfortunately i cannot drive with much less pressure...because the truck is sitting in general very low and i almost scratch the ground with for example around 54 psi...
So that means the bags starting to lift the truck mainly at around 52 -54 psi

During the upcoming weekend i will take some pics of the truck on the ground at riding height..

I think it is quite important that u see how the bag and shocks located respectively sitting at ride height.

Currently i am not really sure what you mean with the "forward location" ?????

What do you guess would be a normal air pressure for a nice / good ride quality for that kind of truck with a light aluminum LS1 engine.. ???

In my opinion the subframe is not installed at the right position. The truck is sitting generally too low.
As a countermeasure i am going to buy some bigger wheels.. currently i have installed 16 inch wheels....the plan is go for 20.

Furhtermore i am thinking about to buy some turntables and caster /camebr gauges to start playing with the alignment by myself..

What do you think about that..is it worth the money ????

Also i am thinking about to install some adjustable upper a arms ... can u recommend that stuff ??
TO be honest that kind of a arms dont look trusworthy...

Regarding the shocks ... i already drove the car without shocks at all..the riding quality was still the same..

Hope to hear from you soon again :-)
Thanks a lot in advance

CU
Achim
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Old 11-15-2018, 07:53 AM   #14
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

On your rear suspension the bags are halfway between the housing and the front end of the bar. That is a forward location. If you know the rear weight and the distance from the pivot to the bag and from the pivot to the housing you can calculate the load on the bag and the bar. The best place load wise for a bag or a spring is directly over the housing. That in most cases is not practical so we place them just in front or just behind the housing. Here is a page where you can see the math and enter numbers and it will show you the loads.
https://www.engineeringtoolbox.com/levers-d_1304.html
When it comes to alignment I have used plates and the Longacre gauge to do the drag cars I have had and it worked just fine for that. Sold all that when I got out of racing and I now use a local shop that has really good understanding of modified and performance suspensions and can do all the checks for camber gain, bump steer and ackerman checks I want and give me really good numbers on what I have and work with me to get it where I want it.
There are lots of ways to improve the front end from taller ball joints, moving the upper ar mount to longer a arms. The first thing you need is the information on where your at and where it needs to be then you can make a plan. Google second gen Camaro handling and do some reading. That one under yous is front steer so it is second gen.
Before went to 20" wheels I would put taller tires on it. They do 2 things for you. Raise the truck and ad a softer side wall that can greatly improve the ride.
Jimmy
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Old 11-15-2018, 03:18 PM   #15
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hy Jimmy,

ok just to get sure about ur second last post...with that statement u just meant the rear suspension ???

"Here's a couple of things I see. The lower arms with the bags that far forward need to be trussed. They will bend. The forward location and the high bag pressure will kill the ride quality. I would put shock waves on it if it were mine."

if yes... to be honest i dont think that the rear suspension makes any trouble.
The hursh riding comes pretty sure from the front axle.

Thats a very good idea ..to mount some bigger tires ....especially its not a problem at all to find some cheap used once.

also i will buy some tools to setup the alignment in my garage , at least to have a first glue where i am

So at the weekend i will shot some more pics and no i will have some more readings in the internet :-)

CU and big thx again
AChim
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Old 11-16-2018, 08:14 AM   #16
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Harsh ride come from everywhere. Here is a easy test to see how stiff things are. Stand on the bumper and bounce it up and down. You should get a few inches of movement. Used to do this all the time to show folks how bad there shocks were. If the car stopped moving quick the shocks were good it it cycled 6 or 7 times they were dead. One thing that shows the back is going to be harsh is the high bag pressure. My 65 with the bags right in front of the axle fully assembled with a wood floor in the bed needed right about 30 psi to get it to ride height. Once you do the math on your rear suspension you will see just how stiff a spring rate that bag is to hold up the rear. About twice as stiff as what it would be if it was close to the axle.
Good ride is made up of tire side wall, spring rates, shocks, alignment, suspension design and a good seat. I have worked hard to get my 66 to handle well and also ride good. Went through 2 sets of wheels 3 sets of tires, two or three sets of springs, 3 sets of shocks and a few trips to the alignment rack to get where I have it. Shocks and tires for mine made the most improvement. Getting a shock that was valved for the truck verses the ones that just happened to fit was huge. Then I found that tirerack.com has ride quality ratings on the tires they sell and that helped get a feel for the side wall stiffness when choosing new tires.
Jimmy
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Old 11-16-2018, 11:28 AM   #17
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

So, 2nd gen Camaros are pretty good. Looks like the alignment is for a straight axle. I would set to something like Caster = +5.5 to +6 degrees, Camber = -.5 to -.75 degrees, and slight toe in, like 1/8". As to the rough bouncy ride, tuning the air pressue maybe 80 psi front and 40 - 50 psi rear, then it's good shocks. BUT, if you are going to put a bed floor in it (150 - 200 lbs) that will help too.
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Old 11-17-2018, 09:38 AM   #18
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Re: bad handling / driving characteristic after Camaro subframe ! What is wrong ?

Hy

unfortunately i will not come to my Garage this weekened to make some new pics and measurements :-(

I Need to wait til next Weekend

so anyway the next steps will be ..

- to replace exisiting tires with bigger onces
- adapting caster to the mentioned + 5 / +6 degree

i will Keep you updated

i have currently one further Question...

Do you recommend to buy some adjustable Shocks e.g. QA1 ?


thx
Achim
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