Corvette aluminum Knuckle + 73 B-body LCA
#2150101
09/08/16 12:52 AM
09/08/16 12:52 AM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
I'm setting up my Swinger for autox focusing on weight distribution and unsprung weight. So to that end, I already have a Pentastar 3.6L & T5 to go in and I'm looking to mount a Rack & pinion forward of the front axle. I was brainstorming about front suspension setups that allow a forward facing steering arm and decent ackermann. So I was wondering if anyone considered using Corvette C4 aluminum knuckles(#13 w/ hub and bearing) and mating it to a 73up B-body LCA? I located a sample of each to prototype. aside,,Anyone use Performance Trends Roll Center Calculator? and have an Abody file?
Last edited by myduster360; 09/08/16 02:41 AM.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2150106
09/08/16 01:06 AM
09/08/16 01:06 AM
|
Joined: Dec 2003
Posts: 22,696 Bitopia
jcc
If you can't dazzle em with diamonds..
|
If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
|
Seems like a lot of effort/research/risk for not a lot of return. Reasoning being, AutoX's are normally on rather smooth surfaces, correct?, and unsprung weight is mostly about bumps, not weight transfer while cornering. Pure weight reduction, is found elsewhere a lot cheaper and easier. Now if Road Race is the goal, everything I have read indicates the OEM Vette bearings don't cut it. It you want sizzle and uniqueness, I'd head to rear with a IRS setup.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: OzHemi]
#2150147
09/08/16 02:15 AM
09/08/16 02:15 AM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
What is the lower control arm even from ? F body or something like that ? No they're off a B body,,,,just not a 72 and older. Seems like a lot of effort/research/risk for not a lot of return. Reasoning being, AutoX's are normally on rather smooth surfaces, correct?, and unsprung weight is mostly about bumps, not weight transfer while cornering. Pure weight reduction, is found elsewhere a lot cheaper and easier. Now if Road Race is the goal, everything I have read indicates the OEM Vette bearings don't cut it. It you want sizzle and uniqueness, I'd head to rear with a IRS setup. So your option for " a lot cheaper and easier" solution to a forward facing steering arm that does not result in negative ackermann and retains the t-bars,,,,is what exactly?? I'm honestly open to any options really Aluminum is just a side benefit not at all the reason to swap. Mounting the 3.6L would be a bit easier with the steering gear and drag link out of the way. Since its a good 10" shorter than a small block, it leaves a lot of room up front for a rack.
Last edited by myduster360; 09/08/16 02:56 AM.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2150544
09/08/16 07:08 PM
09/08/16 07:08 PM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
I was planning on running it in CAM-T, which looks pretty open. The 3.6l Pentastar will shave a good 200-225lb off the nose of the car and moves the CG back a bit. The plan was to get the suspension parts modeled and see how the geometry shakes out. It may wind up horrible. I have the C4 Knuckles already in Solidworks, so I just need to get the B-body LCA modeled up and figure out the suspension points. I was hoping to get a jump start on the chassis side if someone had some info on that.
Last edited by myduster360; 09/08/16 07:10 PM.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2150568
09/08/16 07:43 PM
09/08/16 07:43 PM
|
Joined: Nov 2004
Posts: 25,050 Texas
GoodysGotaCuda
5.7L Hemi, 6spd
|
5.7L Hemi, 6spd
Joined: Nov 2004
Posts: 25,050
Texas
|
Having designed a pull-rod suspension from scratch, I'd certainly like to give warning and have very well defined (accurate) XYZ coordinates when evaluating that suspension. Roll center height, roll center slope, roll center migration, bump steer, camber change heave/roll, kingpin inclination, scrub, ackermann/steering angle, etc are all big players.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: GoodysGotaCuda]
#2150635
09/08/16 09:18 PM
09/08/16 09:18 PM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
Seriously?!? You have data for an Abody? If so that would be sweet.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2150689
09/08/16 10:46 PM
09/08/16 10:46 PM
|
Joined: Dec 2003
Posts: 22,696 Bitopia
jcc
If you can't dazzle em with diamonds..
|
If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,696
Bitopia
|
What is the lower control arm even from ? F body or something like that ? No they're off a B body,,,,just not a 72 and older. Seems like a lot of effort/research/risk for not a lot of return. Reasoning being, AutoX's are normally on rather smooth surfaces, correct?, and unsprung weight is mostly about bumps, not weight transfer while cornering. Pure weight reduction, is found elsewhere a lot cheaper and easier. Now if Road Race is the goal, everything I have read indicates the OEM Vette bearings don't cut it. It you want sizzle and uniqueness, I'd head to rear with a IRS setup. So your option for " a lot cheaper and easier" solution to a forward facing steering arm that does not result in negative ackermann and retains the t-bars,,,,is what exactly?? I'm honestly open to any options really Aluminum is just a side benefit not at all the reason to swap. Mounting the 3.6L would be a bit easier with the steering gear and drag link out of the way. Since its a good 10" shorter than a small block, it leaves a lot of room up front for a rack. Sorry, I thought you said you were focusing on Unsprung weight and F/R weight balance.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: TC@HP2]
#2222808
12/29/16 03:08 PM
12/29/16 03:08 PM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
I was thinking a longer upper arm would have been mandatory but after measuring and modeling the A-Body LCA and seeing that it's so similar in length to the 73 B-Body, it's not so cut and dry. I recently picked up a copy of Auto-Ware FRONT SUSPENSION GEOMETRY PRO. Once I have the stock A-body suspension points entered, it should more easily show changes in RC and Camber curve that different length control arms make.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2223698
12/30/16 11:29 PM
12/30/16 11:29 PM
|
Joined: Nov 2003
Posts: 3,577 Long Island, NY USA
BergmanAutoCraft
master
|
master
Joined: Nov 2003
Posts: 3,577
Long Island, NY USA
|
I was thinking a longer upper arm would have been mandatory but after measuring and modeling the A-Body LCA and seeing that it's so similar in length to the 73 B-Body, it's not so cut and dry. I recently picked up a copy of Auto-Ware FRONT SUSPENSION GEOMETRY PRO. Once I have the stock A-body suspension points entered, it should more easily show changes in RC and Camber curve that different length control arms make. Very cool post. I'd love to see any numbers yoy generate. Don't let the naysayers stop you. If nothing else you will learn quite a bit.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: AndyF]
#2225010
01/01/17 07:09 PM
01/01/17 07:09 PM
|
Joined: Jan 2003
Posts: 27,466 So Cal
autoxcuda
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 27,466
So Cal
|
The C body knuckle is probably a better choice (old kit car setup) or use a stock car type knuckle.
But sometimes it is better to learn these things yourself so by all means build it, test it and try it. There are stock car circle track modular aluminum uprights, spindles, and steering arms out there. IIRC, Sweet or Coleman. And there are lots of brake setups for those that are usually less expensive than the one made for a specific production car.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: AndyF]
#2226007
01/03/17 12:08 AM
01/03/17 12:08 AM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
The C body knuckle is probably a better choice (old kit car setup) or use a stock car type knuckle.
But sometimes it is better to learn these things yourself so by all means build it, test it and try it. To accommodate the rack and pinion, the C-body would need a custom forward facing steering arm that provides enough ackermann without putting the tie rod end through the brake rotor. Ball joint to Ball joint, 88-93 C4 knuckle is about 1" taller than the tallest C-body. Kit Car specs says the SAI is 9 degrees. The C4 knuckle I have here is measuring its KPI at ~17 degrees, which seems awfully high. The Googles claims the 88-up C4 KPI is vague but claim to be in 13-15 degree range. A side benefit is that the C4's front bearing's 47 tooth tone wheel will provide a convenient wheel speed input so the ABS module can output mph to the PCM for throttle and speedometer.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: myduster360]
#2226029
01/03/17 12:34 AM
01/03/17 12:34 AM
|
Joined: May 2008
Posts: 1,131 Thigh-Gap Junction
@#$%&*!
New user name, Same old jerk!
|
New user name, Same old jerk!
Joined: May 2008
Posts: 1,131
Thigh-Gap Junction
|
I'm setting up my Swinger for autox focusing on weight distribution and unsprung weight. So to that end, I already have a Pentastar 3.6L & T5 to go in and I'm looking to mount a Rack & pinion forward of the front axle. I was brainstorming about front suspension setups that allow a forward facing steering arm and decent ackermann. So I was wondering if anyone considered using Corvette C4 aluminum knuckles(#13 w/ hub and bearing) and mating it to a 73up B-body LCA? I located a sample of each to prototype. aside,,Anyone use Performance Trends Roll Center Calculator? and have an Abody file? Do it! I assembled a certain '65 Coronet with the late LCA's and it gets you a TON of room between the frame and control arms (something A-bodies dearly need). Biggest hassle is custom made strut rods. A-body LCA's are indeed a little longer than the B-bodies for some reason. We used the late B,F,M,J spindles and steering arms with stock rear-steer setup. Keep in mind that the A-bodies mount the shocks much farther outward than the B-bodies. This will reduce shock effectiveness (going to B arms) and probably require removing the frame extension for the bump stop. I've wondered about those C4 knuckles in the past since my silly brother has at least 2 of those cars and they're easy to see with the nose tilted.
Last edited by @#$%&*!; 01/03/17 12:38 AM.
|
|
|
Re: Corvette aluminum Knuckle + 73 B-body LCA
[Re: @#$%&*!]
#2226059
01/03/17 12:57 AM
01/03/17 12:57 AM
|
Joined: Jan 2003
Posts: 350 central IL
myduster360
OP
enthusiast
|
OP
enthusiast
Joined: Jan 2003
Posts: 350
central IL
|
I saw the different shock location. I figured if the math works out on the C4 knuckle and B-Body LCA, i'd fab a shock mount as close to the knuckle as I could get it. Something like this Firm Feel example.
Last edited by myduster360; 01/09/17 10:08 PM.
1972 Swinger 3.6L Pentastar Diablo CMR tuner
|
|
|
|
|