Autocross Suspension Options

[97CobraLSC]

So I drive a 97 Mark VIII. It's been spring swapped with AAS parts. I originally planned to make it a nice car, but it has it's fair share of cosmetic issues, so it's going to be my autocross car.

With that being said, I have realized that it's near impossible to find higher spring rates springs and good dampers.

The Cobra Bilsteins are impossible to find for the rear. Koni Yellows are still made, so I might go with that.

I'm out of options for the front. I saw the thread on TCCOA where a stock shock body was cut apart and had a Bilstein racing shock mounted inside. I would like to avoid that if I can, but I'm not above doing that if it's my only option.

Next question is springs. I want something with a higher spring rate. These AAS springs are soft. That's nice for normal driving, but not what I need.

It looks like the Tbird LX Sport and Eibach springs have about the highest rates. What about the Vogtlands? Outside of that, are there any other options?

Thanks!

 

[chris2523]

cobra bilsteins are impossible to find? i just googled it. they are everywhere... including ebay.
http://www.americanmuscle.com/bilstein-hdirs-shock-9904.html

start reading tccoa/sccoa. we have the same suspension as the Tbirds and Cougars and way more people autocross those than Lincolns.

the vogtland drop springs are progressive. i hear good things. stiffest of several listed here.

http://forums.tccoa.com/showthread.php?t=133651

 

[97CobraLSC]

cobra bilsteins are impossible to find? i just googled it. they are everywhere... including ebay.
http://www.americanmuscle.com/bilstein-hdirs-shock-9904.html

start reading tccoa/sccoa. we have the same suspension as the Tbirds and Cougars and way more people autocross those than Lincolns.

the vogtland drop springs are progressive. i hear good things. stiffest of several listed here.

http://forums.tccoa.com/showthread.php?t=133651

Chris,

I guess I wasn't looking for the right thing in regards to the Bilsteins. Thanks for the heads up.

I've read a TON on TCCOA and SCCOA and just wanted to see if anyone here had more insight.

 

[lobird91]

You don't want progressive rate springs for racing so avoid the Eibachs and Vogtlands. I would look for the Tokicos or Suspension Techniques as they are linear. Hold off on sway bars until you run it a few times to determine where you need to adjust, too many people just throw on big bars and think the car handles better. Bars are tuning aid and should be matched accordingly. Brace the heck out of it and run stiff bushings everywhere you can. These cars really can handle to be as big as they are.

-Alan

 

[markup97]

I am still running air, and will be putting the 1.375" front and the 1.25" rear bar is BECAUSE the air suspension is soft. Using a heavier bar on a softer spring will help keep your overall ride quality nice while firming up/negating the body roll associated with softer springs (in this case, bags).

Alan is partially correct on his bar assessment. We used bar diameter to fine-tune the car for oversteer/understeer by running various diameter bars front and rear. Softer sprung/dampened cars required beefier bars to get a neutral feel than cars with higher spring/dampening rates. he is absolutely correct on stiffening the chassis and installing less compliant bushings. Front k-braces, subframe connectors, front and rear IRS braces, and a rear strut tower brace are absolutes to get these heavy, wallowy pigs to stiffen up. Jury is still out on front strut tower brace, but I can't see where it would hurt to invest in having one made (3-point preferred).

 

[lobird91]

You can use them to tighten up the handling with bags, but what effect have you created on chassis dynamics. You have to establish a baseline and determine where your suspension needs help. These cars tend to understeer already so a larger front bar is only going to make that worse then you end up chasing the rear bar stiffness trying find neutral.

-Alan

 

[97CobraLSC]

You don't want progressive rate springs for racing so avoid the Eibachs and Vogtlands. I would look for the Tokicos or Suspension Techniques as they are linear. Hold off on sway bars until you run it a few times to determine where you need to adjust, too many people just throw on big bars and think the car handles better. Bars are tuning aid and should be matched accordingly. Brace the heck out of it and run stiff bushings everywhere you can. These cars really can handle to be as big as they are.

-Alan

I actually found a set of Tokicos (shocks and springs) so maybe I'll start with that and go from there. When I bought this car, it already had a bigger rear anti-sway bar. I hope it doesn't cause too many issues right off the bat.

I am still running air, and will be putting the 1.375" front and the 1.25" rear bar is BECAUSE the air suspension is soft. Using a heavier bar on a softer spring will help keep your overall ride quality nice while firming up/negating the body roll associated with softer springs (in this case, bags).

Alan is partially correct on his bar assessment. We used bar diameter to fine-tune the car for oversteer/understeer by running various diameter bars front and rear. Softer sprung/dampened cars required beefier bars to get a neutral feel than cars with higher spring/dampening rates. he is absolutely correct on stiffening the chassis and installing less compliant bushings. Front k-braces, subframe connectors, front and rear IRS braces, and a rear strut tower brace are absolutes to get these heavy, wallowy pigs to stiffen up. Jury is still out on front strut tower brace, but I can't see where it would hurt to invest in having one made (3-point preferred).

SFCs were #1 on my list of chassis modifications and my class allows it, so it's high priority. I already have poly / UHMW bushings in the rear, so it should be set. I have thermo-plastic in the front and that should help a fair bit.

You can use them to tighten up the handling with bags, but what effect have you created on chassis dynamics. You have to establish a baseline and determine where your suspension needs help. These cars tend to understeer already so a larger front bar is only going to make that worse then you end up chasing the rear bar stiffness trying find neutral.

-Alan

I guess it's a good thing it has a larger RSB already if they tend to understeer. My last experience with autocross was a FWD, so understeer was a killer. I appreciate the advice. I'll see if I can order the Tokicos.

 

[markup97]

Alan,
Weight distribution and corner weights led me to my bar choice, as it lent a more theoretically balanced tune to the suspension. Now, this was not taking into account for bag stiffness and absorber dampening rates. I understand about the understeer/oversteer of chassis dynamics, as well as just how much of a pain these front bars are to change. Going with a theoretical ideal/thick front bar diameter first and having different bars for the rear will allow me the ability to tune for oversteer/understeer and future mods. If the rear bar is too stiff, I can swap back to stock or use a T-Bird/Cougar rear bar to fine-tune it. Once more front weight is added or weight is moved around in the car, I can again tune the bar for better control of body roll. By then, I may also have gone with a tuneable damper and can fine-tune it from there. Since stronger/stiffer bags aren't offered for these cars, tuning by bar is almost your only option unless, like the O.P of the topic, you convert to springs.

97CobraLSC,
SFCs and front/rear subframe braces are your best first mod for these cars. Just like their Fox-based forebearers, they are sloppy and as rigid as a wet noodle. If you are to auto-X or Solo, chassis bracing is 100% a must. Glad to hear you are going this route! Also, if your class allows, swap to a better brake set-up, as stopping 3850lbs repeatedly on stock brakes becomes a lesson in butt-pucker factor scaling!

 

[97CobraLSC]

Alan,
Weight distribution and corner weights led me to my bar choice, as it lent a more theoretically balanced tune to the suspension. Now, this was not taking into account for bag stiffness and absorber dampening rates. I understand about the understeer/oversteer of chassis dynamics, as well as just how much of a pain these front bars are to change. Going with a theoretical ideal/thick front bar diameter first and having different bars for the rear will allow me the ability to tune for oversteer/understeer and future mods. If the rear bar is too stiff, I can swap back to stock or use a T-Bird/Cougar rear bar to fine-tune it. Once more front weight is added or weight is moved around in the car, I can again tune the bar for better control of body roll. By then, I may also have gone with a tuneable damper and can fine-tune it from there. Since stronger/stiffer bags aren't offered for these cars, tuning by bar is almost your only option unless, like the O.P of the topic, you convert to springs.

97CobraLSC,
SFCs and front/rear subframe braces are your best first mod for these cars. Just like their Fox-based forebearers, they are sloppy and as rigid as a wet noodle. If you are to auto-X or Solo, chassis bracing is 100% a must. Glad to hear you are going this route! Also, if your class allows, swap to a better brake set-up, as stopping 3850lbs repeatedly on stock brakes becomes a lesson in butt-pucker factor scaling!

Are there SFCs that are prebuilt for this? I'd do weld in. I imagine the Fox-body ones are too short and I can't find info if the guy is still making them for the Tbirds.

As for brakes, I currently have Cobra brakes front and rear. I need to upgrade the pads, but all in due time. I hope that I can get the weight down, but I need to find seat tracks or make some.

 

[lobird91]

Are there SFCs that are prebuilt for this? I'd do weld in. I imagine the Fox-body ones are too short and I can't find info if the guy is still making them for the Tbirds.

As for brakes, I currently have Cobra brakes front and rear. I need to upgrade the pads, but all in due time. I hope that I can get the weight down, but I need to find seat tracks or make some.

Unfortunatly you are pretty much stuck with bolt in SFCs if you still want to be able to get the fuel tank out. Contact SATURN5 he has a jig and can build you a set.

Alan,
Weight distribution and corner weights led me to my bar choice, as it lent a more theoretically balanced tune to the suspension. Now, this was not taking into account for bag stiffness and absorber dampening rates. I understand about the understeer/oversteer of chassis dynamics, as well as just how much of a pain these front bars are to change. Going with a theoretical ideal/thick front bar diameter first and having different bars for the rear will allow me the ability to tune for oversteer/understeer and future mods. If the rear bar is too stiff, I can swap back to stock or use a T-Bird/Cougar rear bar to fine-tune it. Once more front weight is added or weight is moved around in the car, I can again tune the bar for better control of body roll. By then, I may also have gone with a tuneable damper and can fine-tune it from there. Since stronger/stiffer bags aren't offered for these cars, tuning by bar is almost your only option unless, like the O.P of the topic, you convert to springs.

I understand your theory and the reason you have chosen that direction. Ideally in a "race" car we would tune with spring rates first and bars after, but given limited options for both springs and bags for these cars we are more or less "stuck" with what is out there. I have also ran the Addco 1 3/8 front bar on my Thunderbird with both Eibach and Tokico springs and with multiple rear bars (89 SC, 1 1/4, 1 3/8) and never could get the setup neutral, I feel the bar is just too big to cope with the understeer than is built into the available spring rates for this chassis, but that is just my experience and my opinion YMMV.

-Alan

 

[Lvnmarks]

Here is what I have from SATURN5 (Bob)...

Standing at what would be the rear....



There are a few other designs as well (all home made) but there was a company at one point making front tubular k members too

 

[97CobraLSC]

Here is what I have from SATURN5 (Bob)...

Standing at what would be the rear....

There are a few other designs as well (all home made) but there was a company at one point making front tubular k members too

I think Bob lives pretty close to me. I would love to have all of that. I imagine it wasn't cheap for him to make those, however.

 

[markup97]

Alan,
This is exactly why I like sharing information and opinions, it helps to get different points of view and experience levels to draw conclusions from. Being that there really isn't a lot of performance options out there for the air ride systems, it leaves us with precious little to work with. Converting to springs (and/or coil-over set-ups) opens a LOT of doors to tuning and working with spring/dampener/bar rates. Being I am staying with bags, I have pretty limited options (and since mine will not be an all-out race car I have a bit more flexibility when it comes to bars).

O.P,
Your choice of Cobra brakes is precisely the upgrade I had in mind, and again I am glad to see you already at that point. Sadly, the Fox stuff will NOT work as the fuel tank and rear floor pan brace is right in the way for straight-through SFCs. That, and the Lincoln is spaced a bit wider than the Fox. Being up under my car today got me thinking of how I will be constructing my braces and how I can integrate some of what is already there. Surprisingly, for a northern car mine has ZERO rust in it.

I wish I could be of more help as I feel I have learned more than I can contribute. My advice is based on years of playing with the Fox chassis and some of it may well not apply here.

 

[97CobraLSC]

I need to find a spring manufacturer that can make 550 lb/in and 700 lb/in springs that fit the Thunderbird shocks or at least are the same dimensions. I checked TCCOA but it doesn't seem like what I'm doing is common whatsoever.

 

[lobird91]

No, building these cars as full racers is not very common place. Most people are looking to compromise a smaller increase in performance for a better ride. As far as off the shelf springs are concerned the Suspension Techniques are the stiffest mass produced springs at 432/631.

 

[97CobraLSC]

No, building these cars as full racers is not very common place. Most people are looking to compromise a smaller increase in performance for a better ride. As far as off the shelf springs are concerned the Suspension Techniques are the stiffest mass produced springs at 432/631.

Those are linear? I haven't been able to find a set or how to buy them.

I see them listed on the TCCOA Suspension article, but it seems that they aren't made anymore. Seems to me they are like most things with this car; they just aren't made anymore.

 

[lobird91]

Correct they are discontinued, you will most likely have to find them used unless someone has some in backstock somewhere PN is 60225. If you google them lots of places list them for sale, but they are all drop ship type places so they probably don't even know they are discontinued. Couldn't hurt to call a few and ask though....they still listed them in the 2012 application guide so some could be floating around out there.

 

[97CobraLSC]

Correct they are discontinued, you will most likely have to find them used unless someone has some in backstock somewhere PN is 60225. If you google them lots of places list them for sale, but they are all drop ship type places so they probably don't even know they are discontinued. Couldn't hurt to call a few and ask though....they still listed them in the 2012 application guide so some could be floating around out there.

I'll have to give that a try. I am going to be getting some Koni's with Vogtlands already mounted. I'll see how those do and then try to find the ST springs.