Struts, shocks, lots of headaches...

[cali74]

So of course there are tons of suspension posts, and as an avid lurker I've looked through a ton of them, but I thought I'd post to get some feedback, responses to help the next guy (and myself) in the quest for a good suspension setup...

My situation isn't unique, but uncommon around here...

I've got a 74 that a 95 3.6 is going into.
All the suspension needs to be replaced - bushings, shocks, torsion bars, tie rods, ball joints...
Brakes aren't good and are 3" spaced(i rebuilt the front calipers and still wasn't happy with the old 2.7)

Also I'm staying with the narrow fenders and currently I have 6/7x16" fuchs

I would consider buying another set of wheels if needed, but would love to keep the ones I've got if I can for a while

My front struts are Boge and have the 3" spacing so I seems like none of the brake upgrades would work with them. Since I need new shocks too, lots of options come up as to what to do, along with varying prices.

I'd like to do the suspension just once to save the hassle and money of a second round. I will be driving the car as a daily driver but not a crazy amount of miles, or too much traffic - but it's not a track car. I'd like to do AutoX though and learn to whip the car around like it should be.

So far I've got rear monoballs and Wevo SPS that aren't installed yet, along with Tarrett adjustable sway bars and wevo rear sway mounts. The rest of the suspension parts have yet to be purchased.

So...the nitty gritty...

Will 930 brakes fit in my 6x16 front wheels with/without spacers? With spacers will the fenders be ok if I cut the lips (i forget the exact tire size I've got but they're potenza so3 205s in front)

Is there a way to do s/SC/Carrera brakes that would be trustworthy with the new motor (this would need 3.5" struts too though)?

Ball-Joints: De-cambered or not? Will I need the extra camber to fit the wheels with spacers? (or wider wheels for that matter)

Struts:
-I need new shocks and 3.5" spacing for calipers
1. get new bilsteins ~1000 including shocks --- then need to raise spindle to lower car? and revalve?
2. get rsr struts $? --- only used, or can buy new? new shocks also?
3. get adjustable struts/shocks from Smart Racing ~2000
4. get used 3.5 spaced struts from someone $? quality? lower spindle? new shocks + revalving?
5. Coil-overs? $? need to remove torsion bar setup below? -if so does it remove need for polybronze bushings also?


Torsion Bars - would want 22 probably
new torsion bars themselves $? (forgot, is avl on pelican)
polybronze bushings + low-friction mounts
do coil overs remove the need for these altogether?

monoballs? -should I do polygraphite strut top bushing instead of monoballs cause it's for street use?
-do coilovers have special needs here?

cross member- it's steel now
-going to install fuel pump up front -would aluminum cross member be better?
-coilover setup replace this? - what about fuel pump?
-is aluminum much lighter anyway? cost ??


rear suspension-
-need new shocks and torsion bars - i figure bilstein sports - revalve? and 30mm bars
-have wevo adjustable plates already + monoballs


Lots of questions, I really appreciate input on all this as I'm diving in deep with this project and don't want to sink after buying all the wrong stuff!

Thanks!

[DW SD]

Matt,
I'd recommend hunting for a deal which includes someone else's used Bilstein >'73 struts (3.5" spacing), the matching strut inserts and TBs upfront, and the corresponding rear TBs and shocks. May be hard to find, but would be a good way to reduce the cost and buy a known quantity.

My friend Mike in San Diego had an AL crossmember he wanted to sell, but you can track those down wihtout a problem.

In front, coil overs do not remove the need for polybronze bushings.

Another tip: any bilstein shocks can be used as cores to rebuilt and re-valved. You don't necessarily need new ones. You can also have Bilstein Struts raised to a specific height, so you don't need RSR front struts. Boge struts are not as suitable for raising since they are tapered in their design.

Why don't you go for a ride in my car and see if it is too stiff for what you want. That will give you some reference. Next AutoX you can ride in other's cars down at Qualcomm for more reference.

Seems like goal # 1 is decide how you are using the car, but also what you consider to be firm.

Finally, I think talking to Jae Lee at Mirage would be a great idea. He's the one that designed the custom valving for my car. I'm very happy with it. He can do anything from mild to wild and is very highly regarding here in San Diego for his suspension knowledge.

I wouldn't be surprised if he had some of the parts you need.
We can talk live for some more detail.

Doug

[Jack Olsen]

My two cents:

I don't know why you'd want 930 brakes if you're not tracking the car. SC or Carrera brakes will be plenty, and cost a fraction as much.

Decambered ball joints also don't make a lot of sense for street-only use. The same goes for RSR struts. You're not going to want wild amounts of negative camber for street driving.

Coil-overs make no sense at all for a narrow-body street-driven car. You'll restrict tire width in the front, especially, and it can be a headache in back, too.

[cali74]

Awesome, thanks for the feedback!

Doug - is that a trick question asking why I don't go for a ride in your car? Definately :-)

Jack - coil-overs-->no: check! (I had only asked because of the rising costs of doing all the other modifications like new struts/shocks/raising spindles/bushings)

As far as SC/Carrera brakes - can I only find a used set and rebuild, or would they be available refreshed from the usual places (VCI, et al.)?

[DW SD]

You should be able to find rebuilt brakes or rebuild them yourself. Carrera brakes are hardly more than SC ones, so look for those. There is more heat sink with Carrera rotors. The calipers are wider, but the rest is very similar or the same.

Doug

[randywebb]

I'd just get the whole F/R suspension off a Carrera - you get the brakes incl. calipers & rotors both, the struts, balljoints, Al F Xmember and the nice Al rear bananas. That is essentially what I did in mostly bits and pieces over a few years. Just do it one swell foop and be done w/it...

[ted]

cali74 interesting you mentioned your goals for now are to AX only.
Unfortunately the parking lot at Qualcomm stadium where the SD AX events are held may be destroyed soon after the 2006 AX season.
Either the Chargers will move or rebuild, either way the parking lot is lost.
See this thread for more on the threat of losing our local AX venue.
So building a hot AX car may be short lived in San Diego.
Unless you can accept a drive to California Speedway 2 hours north for AX events.

That said you might consider either leaving your car close to stock for a Lexus like ride or take the plunge and go the route Doug did on his silver RSR. Doug's set up is very good in parking lots and great at the dedicated race tracks. His set up is optimized when using R Compund tires. Sometimes the rougher parking lot AX tracks like a little softer set up than Doug's. Softer provides more compliance with the uneven and rough parking lot surface. The Q parking lot is rough and bumpy.

I'd say take a ride with Doug and if his set up is acceptable then consider a similar Mirage re-valved shock set up. Mirage’s shock re-valving specifications are based on unique factors such as spring rates, chassis weight, sway bar size, tire compound and driver as well.

As for brakes I'd try some more aggressive pads before you change anything, again check with Mirage.

You did not mention which type of differential is in your car?
An open differential in a narrow body 3.6 could provide unexpected thrills.
Some differential info follows.

Torque-biasing differentials or TBD provide lock-up on acceleration only. The amount of lock-up (5-80%) increases as the amount of torque increases. On deceleration, lock-up is negligible, making the TBD the ideal diff for the slower speed turns of autocross. (In the same slower-speed turns, an 80% LSD would most certainly cause understeer.) A torque-biasing differential performs like an open diff whenever one of the two drive wheels lifts off the ground or even trys to come off the ground. Lock-up and traction are lost until both drive wheels are again planted firmly on the ground.

Limited-slip differentials or LSD provide lock-up on both acceleration and deceleration. The amount of lock-up on acceleration and deceleration can be adjusted by selection of the internal plate sequence. This setting is normally referred to as a percentage. Lock-up on deceleration allows aggressive entry into a turn and late braking, reasons why most Time trailers prefer LSDs, rather than TBDs.

(a) Street / autocross - Torque-biasing
(b) Street / track - Torque-biasing if light-duty track use, with stock suspension. 40% limited-slip if car has stiff suspension or power upgrades.
(c) Track only - 80% limited-slip differential.

With your street biased 3.6 I'd prefer a 40% LSD over the TBD.

Call Jae at Mirage before you do anything. He has set up several competitive narrow body big HP vintage racers. He can guide you from street to full race set ups and save you money.
Mirage 1 858 581 1101

[cali74]

Thanks for the info! It will depend on when the car is ready to be put together and what parts I have whether I rebuild the tranny before driving the car or not. The current one is the stock 915 - which I think is open differential and mag case.

I'll definately talk to Jae at Mirage - though I like to read up on the board before calling places of business to get advice as I don't want to waste their time until it's necessary :-)

As far as sticky pads on the brake setup I have - that's a good idea, and I was thinking about doing that - except that I would need to put together the front suspension with the current struts and buy new shocks for these struts, then test the brakes - then redo it all as soon as I decide it's not enough. I'd like to err on the side of stronger braking to begin with (even if that's only sc brakes) as then I'll have the 3.5" struts and can upgrade easier later if the car does see track time.

With Qualcomm going out the door it looks like I might just get a taste of AX before having to drive to the tracks to get the fun time in. This was one reason I wanted the 3.6 - a reliable powerplant so I could drive long distances and still drive the track if needed (that and being able to start it all the time without worrying that it might die). Eventually I'll probably just hook up a trailer to the 911 and tow my motorcycle to the track - saturday could be car track time, sunday on the bike (assuming there are the proper events of course)!