73 z28 front suspension

[jst8a5.0]

Ok, my eyes are burning from looking at the subframe thread. Is there any bolt on A arms/spindles that improve geometry for a 73 Z28? I am looking for a better ride and handling without going the full subframe route. I can't seem to find info on how aftermarket a arms/spindles help performance other than not flexing like the stockers. I am just basically looking to "modernize" the handling while having the option to use 17"+ wheels and big brakes and have a noticeably better handling. Can someone help point out some good options, maybe Tyler B and someone from Kore? Thanks a bunch!

[ProdigyCustoms]

With a 2nd gen your already in decent shape. Uppers arms like Speedtech will give increased caster. Tall spindles will give better camber gain. A quick box like a ATS of DSE 600 will quicken the steering, combined with some tie rod sleeves to eliminate some steering deflection. A good hollow sway bar like Hotchkis would be nice. Anything beyond that is pure bling.

[lil427z]

call kyle at dse. dont cut your shelf short.
rick k

[jst8a5.0]

Thanks Prodigy and lil427, I'm not sure what you mean by cut myself short. Was that a response to Prodigy or possibly a refence to an entire subframe from DSE? I was reading about Brett Anderson's 2nd gen and Savitske got him some A body steering arms (spindles?) and SPC arms. He says he is no professional and that he beats on it. It's hard for me to envision how it rides and handles by that description. I don't need to build a track car, but rather one that rides and handles like a 4th gen and will surprise the owner when he pushes it past where it would have previously given way. Thanks again guys!

[thedude327]

If you do a DSE video search on youtube, there are some vids. of DSE's second gen. going through it's paces. It recently won the autocross at Pigeon forge, TN. too. Not an endorsement, just something to watch how the car handles. Oh and this is their second gen test car.

Paul

[Marcus SC&C]

Okay first a few basics. Upper A arms simply connect 3 suspension pickup points,they don`t define them. The location of the pivot bushings and upper ball joint pivot ball do that. As a result upper A arms cannot make any meaningful change in geometry per se. They can only change static alignment which may result in a performance improvement. That would also be true using any other method to achieve those same specs. What the arms CAN do is allow you a wider range of static alignment adjustment. In some cases they NEED to be changed to accomodate real geometry changes that then cause the stock A arms to be a poor fit.

The 2nd Gen has a pretty decent front end in it to start with. Not great but decent. Camber gain is neutral to mmild. Roll center is roughly ground level and could stand to go up a bit to shorten the front RC/CG moment arm. Bumpsteer is pretty good especially by the standards of the day. They respond well to more postitve camber and properly designed aftermarket upper A arms or even SPC lower A arms will help with that. With very aggressive negative camber settings they can turn in impressive track performances at the expense of a very short tire life. That said GM engineers knew even in 1970 that the cars could benefit from more camber gain and recomended doing mods to achieve that in the road race section of the 1970 Chevy High Performance manual. Unfortunately the mods are quite a bit more complicated than the G Mod on 1st Gens because the 2nd Gen`s UCA perches are so much shorter. We`ve refined the geometry they achieved with those mods by moving the outter pickup point with tall ball joints and combining it with SPC adj. upper A arms to get a complimentary performance alignment. The improved geometry basically lets you enjoy the performance of full race settings while running street friendly settings with great tire life. We have a number of clients autocrossing,open and close course road racing 2nd Gens with this package who have seen a big jump in performance and how well they place. Some of our clients are even running our tall ball joints with Global West,DSE or Hotchkis arms they already had.
For a totally plug and play fit I recomend the SPC arms with the HD bushings. The greasable bushing cross shafts are a bit shorter and may require a little bit of massaging on the A arms perches for a perfect fit. We`re working with SPC to tweak them a bit for a 100% bolt on fit.
There`s no such thing as a "tall spindle" for a 2nd Gen. All 2nd Gen spindles are "tall" (using the hot rodder vernacular for any spindles taller than 1st Gen/A body or G body spindles). We do have several clients running them with AFX aluminum spindles. The tall version is about the same height as your stock ones but you can run them with our tall ball joints to achieve more the more aggressive geometry discussed above. So why run them if they`re not taller? Big weight savings, easy bolt on modern 13"+ brakes, 1" drop, huge C5 wheel bearings,about a 30% reduction in lateral roll center migration etc. They need to be run with `65-`72 A body steering arms and outter tie rod ends. For that reason we don`t consider it an official StreetComp package, although we do sell them. The Chevelle arms are shorter and give a quicker steering ratio and more aggressive ackerman for improved low/medium speed turn in. It`s particularly noticable in autocross conditions where turn in is razor sharp. It really makes the car feel lighter and more nimble. Mark SC&C

[jst8a5.0]

Uhhh, yeah. I don't know that reading that only once is gonna work for me I am def gonna have to go back over that a few times. I understand for the most part what you said. I understood about the A arms not changing geometry just making it more adjustable. I also understood about the longer upper ball joints helping the camber gain. I am not sure about the turn in and all the rest unless that means that the dimension from the centerline of the 2 ball joints to the centerline of the outer tie rod was shorter meaning better or quicker turn in, in which case I don't think that would be relevant or necessary for this build.

The car will never see autocross or any other racing. It just needs to surpass with ease the failure point of the original setup. It's sort of like when someone gets a musclecar after not having one since they were a teenager and they hit the gas and spin the tires and get a little sideways. In all actuality it's probably a mid 14 second car but it doesnt matter in their eyes. It's just that I want this project to actually be more than the customer will ever need without going into the full subframe and me having to learn every facet of suspension technology. I REALLY appreciate the well thought out and very informative response. Like I said, I will be going over that again!

[David Pozzi]

Tubular upper arms for more caster.
Stiffer springs to keep the car off the bump stops and to lower it, 600'ish front/ 175 rear. Usually the car winds up as low as it was before due to the old sagging springs.
Stiffer anti-roll bars to help it corner with only slight lean.
shocks tuned to match the springs
Wide tires and wheels proper high perf tires really help the car stick.
Bigger brakes a plus
Delrin A arm bushings are great, helps reduce deflection, I don't like poly bushings.
Fast ratio stiff feel steering box.
Solid subframe mounts
"G braces", subframe to firewall braces, that stiffen the chassis.
Subframe connectors, weld in preferred.

Taller upper balljoints are a plus, but stock will work for street duty. I don't see any downside to the tall UBJ except cost.
David

[jst8a5.0]

Another concern I have is the horrible inside tire sweeping motion that most cars of that era had. I have a 74 pontiac ventura that kills the insides of the tires with an "in spec" alignment. I really don't want to get the customer into some nice 18"s and have the rest of the tread perfect and eat the inside of the front tires. Under "factory spec" alignment, would the car drag the insides of the tires under cornering or would they be like a new Mercedes where they lean into the curve?

[David Pozzi]

A 74 Ventura sub is like a first-gen Camaro and rear steer. The second gen has less Ackerman steering correction plus less bumpsteer. We have run our 73 Camaro a lot and don't have any tire wear issues other than autocrossing puts a little extra wear on the outer shoulders of the front tires.
David