After much searching and reading I’m still undecided on which direction I want to go. Now before I get my rear end handed to me (pun intended) for not including enough info, I’m looking for handling over drag racing. I have a tunnel mounted pro TA, tubular LCAs and PHB, LCA relocation brackets that I might not use, and it’s all on a 94 Bird M6 car.

I see that most prefer Strano/Koni, Strano/Bilstein or BMR/Bilstein. I don’t want to lower at all if possible. Maybe 3/4” max. I’m running 305/35ZR18 in rear and I had to ditch my bumpstops. I’m looking at QA1 double adjustable coilovers that include a plate to weld up in spring/shock tower for support. I know most coilover guys run Vikings but I’m leaning coilover for adjustable ride height more than anything. Looking for advise or feedback on street behavior with this setup.

Sway bar- same thing. Looking for street and handling not a fat drag bar. I know the Hotchkis is probably the best option but I don’t really want to spend $500+ on a sway bar. What I’m wondering is, would a 22mm solid be good or too stiff?

 

Well if you are looking for handling over drag, a long torque arm would have been more suited (don’t worry though it’s not going to hurt you and I also have a tunnel mount). All the rod end stuff is a step in the right direction. I had a set of Eibach, and hated them and moved up to the Strano/Bilstein, and just over a year ago went with the UMI/AFCO coilover setup and love it. I also recommend going with the Strano sway bar setup. I have had good experience with them. I am running 315/30ZR18 on all 4 and still have my bumpstops and would advise against removing them.

 

The short one puts the instant center higher, right? That will give the rear more anti-squat and this what you want for a small course, but not what you want on track with long fast sweeping turns.

 

Thanks for the input.

I went with the short tunnel mount (Spohn Pro unit) only because it seemed to be stronger. I’m planning on twin Precision’s and I figured, go big on TA.

How did you run a 315 and keep the bump stop? I didn’t see a way to keep em even with the 305. I rolled my fenders and it’s close with them cut off. Maybe it’s my wheels. I might try to fabricate some on there once I get the new rear axle and different wheels. I’ll check them coilovers out. Appreciate the feedback.

 

I’m not planning on any autoX, just want good handling combined with some power for street use. I might hit the strip just to see what it runs but not planning on making it a track only car. I’m seeing all these posts about the watts link and I like the idea but I’ll just run the PHB for the time being. I need to make the PHB support rod too. Working on subframe connectors this weekend and tying them into frame and tunnel mount.

 

I think it has to do with the UMI/Afco coilovers. I was looking at mine on the lift last weekend and the factory 17" don't go low enough to hit the bump stops even if the were up against the inner fender, so 18" wheel will just clear even more.

 

You definitely need to search a little more. QA1s and Vikings are non-gas charged twin tube drag shocks, not something you want for a street car and really not something you want for handling, ride or feel. Poor, floaty handling and overly stiff ride, worst of both worlds.
You want a shock that is at least gas charged at minimum. If you are worried about being lower you can keep your stock springs and use Koni Sports and have fantastic handling, ride quality and feel. Pair that with strano 35mm front, 22mm rear swaybars and the car will be very well balanced and flat in corners.
If you want coilovers you can run the UMI/Strano custom Afco's that are monotube and gas charged which will be ideal for handling and feel. There is also ridetech and Penske.


You need to get proper fitting wheels and put your bumpstops back on. Im running 315/40/17s and didn't have to touch my bumpstops at all and didn't have to roll my fenders (but did anyway for extra clearance).

 

Thanks JD AMG. That’s the kind of feedback I’m looking for. I did see a lot of people say that they kept their stock springs. I definitely don’t want the floaty and overly stiff ride. That’s exactly what I’m after, flat and planted in the corner. So I’ll go with the factory springs and Koni shocks. It’s easier to go up if needed then spending unnecessary money now. I was kinda thinking the 22mm is about the biggest I want to go on the rear sway bar. I’ll look at the Strano kit but I’ve been eyeballing the Spohn kit. I’ll see how they compare. Thanks again.

I have an 18” rear wheel, I believe they are repopped Corvette 18/17 wheels. I got them with the car. If I hadn’t already bought new tires I would go with something else because the brake upgrade won’t work with the 17’s. But the tires are very close to the inner tub and I’m not sure if they would have worked with the bumpstops. I would have tried to keep them but it wasn’t an option for me because the previous owner already cut them off completely. I’m a firm believer in a bumpstop, it’s there for a reason but it just surprised me that guys are fitting a 315 on with their stops. I don’t know why the guy removed them then. I’ll grab a pic of the inside when I get home from work. I really think these wheels have a lot to do with my clearance issue.

 

Those wheels are probably +56 or +58 offset. 315s need a +43 to +45 in the rear. So the previous owner just made them fit with a hammer and cut the bumps

 

Yep, most likely. That makes sense.

 

Here’s my inside tire clearance.

 

For street shocks, I'd generally say Koni < UMI single adjustable < Penske DAs < Penske TAs both in performance and price. When I converted from the Koni DA's (rebuilt only 2 years ago & supposedly they have the same rebound valving as the SA's but they add compression adjustment also) to the Penske DA's, the custom valving was night and day better than the Koni DA's.

For a relatively low budget, I'd also say Koni SA's all around.

Springs, from memory I think on the upper perch it remains at stock ride height, or on the bottom perch it lowers it 3/4"? If you go with aftermarket, something like 500-650lb front rate and rear rate matched to your rear roll center height (probably 150-200 for stock, or up 200-300 if lowered significantly). Rear roll center gets adjusted by using aftermarket parts to lower the panhard bar or by using a watts link which has a similar mechanism.

Front bar solid 35mm if you like a quicker reaction on quick maneuvers such as a slalom and don't care about the extra 10lb of weight but a more jarring response to one-wheel bumps, or front hollow 35mm if you like the wheels a little more independently compliant over bumps. Rear bar I'd say around 22mm solid if stock rear roll center, or up to 24mm solid if rear roll center has been lowered a lot.

For a non-drag application the LCA's should be just slightly higher at the axle than at the chassis... 5-8* angled down seems to be a recommended value with the car at the expected ride height. If that's close to what you can achieve without the lowering LCA brackets, I'd leave them off. If you choose to use them, I'd definitely weld them on.

The above should give you a fairly neutral vehicle where you can perform a bit of throttle oversteer when necessary to help aim the car.

For the rear wheels, that's not much clearance. I'm currently running a +50 offset ZR1 replica with a 1/4" spacer, which puts my effective offset right around 43-44mm. My new unmounted wheels are ~44mm offset. For street tires, that ~44mm offset might be enough if you don't use a lot of lateral grip.

If you do end up rubbing, a combination of correct effective offset, big hammer, tubular LCA's (which you already have), ride height adjustment (which isn't easy on stock rear suspension), more spring rate (but too much is bad), fender rolling and more round (less square) edge of the tire (where the sidewall meets the contact patch) will work. You won't necessarily need all of them, but those are the common adjustments depending upon where it's rubbing.

 

Thank you for taking the time to share all that info with me. I was right there with spring rates, leaning toward 170-190 on the rears and figured 575-600 on the front. I will be pulling a lot of the weight off the front of the car and putting a cage in it.

 

Yes, needs spacers or hammering. Do not run it like that. Articulation and suspension compsession will make one or both side rub.

Abkut 45mm offset is what you need or hammer it. Your choice

 

Typical spring ratio range for stock rear roll center height is 3:1 to 4:1 depending upon driver taste & bar rate. For lowered RRC, 2:1 to 2.6:1.

Higher rear spring rate will reduce rear lift during braking and reduce squat during acceleration. The higher rate rear springs may be harsher over bumps, dips & rises, but it will have less float. I'd go with the 600 fronts and either 150 or 200 in the rear depending upon your preferences.

 

Placed order today. Got Moog replacement springs and went with Koni Sports in car adajustables. Didn’t get subframe connectors on this weekend, I’m wire wheeling the floor where it’ll be covered by the SFC and slapped on some POR15 to keep things from going south on me. Now just need to get my sway bar coming. Appreciate all the help and good info here guys.

 

Just an fyi, many people have found that moog stock replacement springs end up making the car sit much higher than factory. I have seen it happen many time and not just on f-bodies.

 

Just like the above post says, careful with the mood replacement springs, it seems more often than not the car ends up sitting way higher with those. There is nothing wrong with your stock, used springs, they don't wear like rubber bushings or shocks do.