How to Pick a Modern Suspension?

[cjperry81]

I am redoing my 66 and looking to upgrade the whole car. Planning on hot rodding my inline 200. I also am hoping to put a killer stance on the car with possibly 17s up front and 18s in the rear. With all the choices out there how do decide what suspension upgrades or systems to pick? Its currently stock. I want good handling but I dont plan on putting it through a road course anytime soon. So do I do a rack and pinion, remove the shock towers, mustang II front end? How do I pick and what are your recommendations? Id like to do discs up front for sure when I do all this work.

CP

 

[j69302]

You could do Open Trackers roller-ized suspension to improve it and keep the cost down.. In my opinion a rack and pinion is a must if you plan on driving it on curvy roads...or even in a straight line in some cases... I put the TCP rack on mine and it is hands down the best improvement I made to my car. There are less expensive racks as well, but I only have experience with the TCP rack - and if I ever get another mustang I will put it on that as well.. I also have tcp coil over conversion. It is over kill but did dramatically increase handling and ride quality.

Not sure how the racks fit with a 6 cyl.. You will most likely have to upgrade to the V8 steering linkages and spindles, and Im not sure if the rack will clear the 6cyl oil pans.

Theres also the borgenson integral powersteering box. which replaces the factory power steering with a hydraulic steering gear box.

The mustang 2 is not needed. By getting rid of the shock towers you compromise the strength of the front end. You also do a lot of cutting and welding to the frame. Unless you are putting a huge motor in there i would say dont do it. You can make a car handle better using upgraded stock style suspension.

People been racing this cars by modifying the stock suspension for years and years.. You get rid of the rubber parts and replace with roller bearings or rod ends and its a whole new world to drive in.

 

[2+2GT]

Tell you what. Before you spend a few thousand "upgrading" your suspension, spend a few hundred doing what's suggested here. Then, if you think it's still inadequate, you can start all that expensive chopping.

Arning/Shelby Suspension Drop

• "drop"
• 1" front bar
• GT springs front & rear
• Kayaba GR2 or Gas-A-Just shocks
• export brace
• Scarebird front discs
• 4-turn steering gearbox

Just this, probably under $1000, will totally change your cars' performance. Parts alone for the Mustang II suspension would run much more, and as stated, compromise the cars' strength.

 

[rbohm]

the biggest gains in handling and ride are going to come from updating the rear suspension. and you dont have to go too far to get a good combination. as 2+2 indicated, for the front suspension a good rebuild, lower the upper control are pivot point like shelby did, add the roller bearing spring perches, and a roller bearing lower control arm as well as adjustable strut rods, and since you are keeping the six use the stock 480lb/in V8 gt springs, and you are good to go for the front.

at the rear you may want to consider using a floating mount for the axle housing on the leaf springs, and use a torque arm to control spring wrap. that way you can use a slightly softer rear leaf for a better ride, but get the control of a stiffer leaf spring.

 

[NMEMJCM]

My car handles great, look at my garage for stance. I have everything 2+2 mentioned except I have the CPP front lower A-arm kit. This is a great kit and wont break the bank. It has a sub-frame the helps stiffen up the front of the car and it eliminates the strut rods. I noticed a HUGE improvement in the cars handling after this install. Here is the link

Disc Brake, Steering and Suspension Products for classic Chevy and Ford cars and trucks

This coupled with flex-a-form fiberglass leaf springs with a set of cal track traction bars will make for a killer setup.

 

[2+2GT]

Hard to beat the stance of this car:

 

[cjperry81]

First of all thanks guys for all of the imput. Its nice to have a good group to bouce ideas off of. Secondly "N" that is one bad 64.5 you have. I love the stance with a little bit of the rubber sitting up underneath the fender. Lastly I have a question since you guys clearly know your stuff. If i hot rod my inline 6 just to keep things interesting will I need to switch out my stock rear axel. Its stock currently but with hopes of high 200- low 300 horse power will I need to upgrade to an 8.8 or 9inch rearend? Or will I be safe with the stock rearend?

CP

 

[NMEMJCM]

I have seen V8 8" rear ends hold up all day with 300 hp, however with enough abuse, it wont last forever. Remember, if your peeling out, your not really straining the rear end. Its the hook up that will ruin your day. I personally will do extra work and pay more for piece of mind. An 8.8 will definitely hold up to your numbers, a 9" wont even break a sweat at 300 hp (unless you drive the car like a tard). I personally would swap out the 4 lug differential for a V8 5 lug 8". You can find them relatively cheap when compared to a 9" (a 9" is overkill i think for your application, and it takes more power to turn). If you do a disc brake swap, convert over to 5 lug rotors so your wheel pattern is the same all around the car. Don't get the 620 coils, as I fear they might be to stiff with that in-line 6 in there. Don't be afraid to cut a 1/4 coil at a time on the front springs to get the car to sit where you want it. Don't cut 1/2 coil at a time like I did.... unless you like going up driveways reeeeaaal sloooowwwwww like me because your front end is low.

 

[rbohm]

First of all thanks guys for all of the imput. Its nice to have a good group to bouce ideas off of. Secondly "N" that is one bad 64.5 you have. I love the stance with a little bit of the rubber sitting up underneath the fender. Lastly I have a question since you guys clearly know your stuff. If i hot rod my inline 6 just to keep things interesting will I need to switch out my stock rear axel. Its stock currently but with hopes of high 200- low 300 horse power will I need to upgrade to an 8.8 or 9inch rearend? Or will I be safe with the stock rearend?

CP

the stock rear end will do fine until the power level gets above 250-275hp. at that point the stock rear end becomes suspect. however to get to that power level you are going to have to turbo the motor. if you want to keep your stock four bolt wheels, then look for a maverick from 70-72 that is powered by the 250 as they have the 8" rear end.

one more thing, if you are going to keep the six, DO NOT install a rear sway bar as that will cause large amounts of oversteer.

 

[PoppyMod]

First of all thanks guys for all of the imput. Its nice to have a good group to bouce ideas off of. Secondly "N" that is one bad 64.5 you have. I love the stance with a little bit of the rubber sitting up underneath the fender. Lastly I have a question since you guys clearly know your stuff. If i hot rod my inline 6 just to keep things interesting will I need to switch out my stock rear axel. Its stock currently but with hopes of high 200- low 300 horse power will I need to upgrade to an 8.8 or 9inch rearend? Or will I be safe with the stock rearend?

CP

Bud,

The only changes to that 8" rear, would be, new bearings, seals etc. and a "posi" type locking rear and lower gear set, in so inclined.
These 8" carriers will stand up to 400 FT.lbs of RWTQ. So many folks put money into a 9" setup when not necessary. Don't be another.

 

[MustangB]

one more thing, if you are going to keep the six, DO NOT install a rear sway bar as that will cause large amounts of oversteer.

I have a question. In my minds eye, as I imagine a car moving through a turn without a rear sway bar, I see that rear-end wanting to come around into an oversteer situation.

I am trying to picture how less weight on the front end, combined with a sway bar out back, would contribute to oversteer.

I am not trying to be an a-hole here. I am merely seeking knowledge. Could you give me a quick rundown on how the dynamics change in this instance? I don't want a long response, nor do I want to hi-jack this thread.

 

[2+2GT]

Well, you have a choice, oversteer or understeer. Oversteer means, essentially, that the rear end will fishtail out while the front wheels will still steer, which means you can still maintain some degree of control at the limit. Understeer means the front wheels will skid first, meaning your first clue that you have passed the limit is the car begins to plow straight ahead. Could be a problem on a curve. A thick rear sway bar, or more weight in the rear, will cause the rear of the car to become the dominant axle.

 

[Smitten65]

Did I miss something or does cjperry81 have a 66 stock I6? If so, that would mean has 4 bolt type axles, front and rear, unless changed by the PO. Front disk are out there for the 4 bolt but I would think if he really does hit 300 HP, the the 7.5 rear axle of the six will be a problem. That would mean he might as well get an 8" 5 bolt and switch all the front to V8 suspension pieces, because he might not be able to 17 or 18 rims in 4 bolt very easily.

 

[2+2GT]

I wasn't worried about that, because 300 hp from a 200 I6 is exotic and expensive. Low-mid 200's is about the limit for naturally-aspirated.

 

[DukeGnarley]

If it were me, i would switch the rear end out for an 8" and swap the front spindles out for v8 ones to get the 5 lug. the early 4 lug pattern is NOT the same as the newer 4 lug stuff, so finding cool 4 lug wheels may be a problem. the added strength benefits are a bonus, but probably not needed. 8" rears can be found pretty cheap, and it opens up your options for disc brake swaps.

Oversteer/Understeer is primarily controlled by the roll rate of the front and rear suspension. Whichever end has a higher roll rate will be the first to let go. By adding a rear sway bar, you will be adding to the rear roll rate which may put you into roll oversteer instead of understeer. Generally it is preferable to have a slightly higher front roll rate, which gives you roll understeer. You CAN use a rear sway bar if you also increase the front roll stiffness.

Higher spring rates will also increase the roll rate.

I used to have a 6 cly in a '66 coupe with a v-8 suspension. It had 1" drop 620 coils, a 1-1/8" front sway bar, 4.5 mid eye leafs and a rear sway bar (7/8 or 1" i think). I didn't have any problems.

 

[2+2GT]

There are quite a few aluminum wheels that will fit the 64-70 4-bolt cars. I can think of at least four different wheels I've seen right off the bat.

Here's a few more:

http://www.summitracing.com/search/.../Wheel-Bolt-Pattern/4-x-4-1-2-in/?Ns=Rank|Asc

 

[Hack]

What the others have said about under/oversteer is right. Remember that your rear leaf springs are quite stiff in roll. Basically you already have pretty good rear roll stiffness without even having a rear sway bar.

I recommend you decide what you want in the front and complete that part of the car. Then drive the car to determine whether you want a rear sway bar or not. If the car pushes (understeers) excessively, you can use a rear sway bar to reduce that effect.

 

[zookeeper]

While everyone has their own opinion on handling, I for one think the rear sway bar is essential to getting ANY car to corner well. The stock 4-leaf springs and new replacement 4-leaf springs are very limp and offer no real roll control at all. I have 5 leafs on mine and wish they were a touch stiffer for frisky driving. When setting up a suspension, I believe that letting each component do it's own job is the only way to go. For example, spring rate should be just stiff enough to keep the suspension from bottoming out, not for roll control. Sway bars should control body roll, but need to be properly sized. Mine is a 3/4 adjustable and is set on full stiff. As for oversteer, it hasn't even been an issue. My fastback with 15's on it will out-corner my '88 GT with 17's and sticky tires on it and that's saying something. Personally I think the "sway bars equal oversteer" thing is a myth. Any car can be made to oversteer if you're rough with the wheel, brakes or throttle, the suspension needs to be tuned to the driving. I currently have 5 cars in my household, a 2004 F250, a '97 Suburban, '88 GT, '69 Corvette and my fastback and all but one came from the factory with a rear sway bar. Think that's an accident? I was once told by someone here that "our early Mustangs weren't designed to use a rear sway bar". Bullstuff. They weren't designed for radial tires, either, but who here is using bias plys? Until someone shows me in person or with lap times on a track how on earth their Mustang could possibly get worse with a rear swaybar, I'll have to assume that I'm doing it right. After all I've driven my car with and without a rear bar I can can say with all certainty it's much better with.

 

[rbohm]

I have a question. In my minds eye, as I imagine a car moving through a turn without a rear sway bar, I see that rear-end wanting to come around into an oversteer situation.

I am trying to picture how less weight on the front end, combined with a sway bar out back, would contribute to oversteer.

I am not trying to be an a-hole here. I am merely seeking knowledge. Could you give me a quick rundown on how the dynamics change in this instance? I don't want a long response, nor do I want to hi-jack this thread.

its all about balance between front and rear roll stiffness. for example using a 1" or 1 1/8" front bar with a 3/4" rear bar in a V8 car will give you good balance between front and rear roll stiffness. on a six cylinder car though, you create an imbalance due to the lighter weight of the six up front. a 1" front bar without a rear bar does just fine in a six cylinder car.

I wasn't worried about that, because 300 hp from a 200 I6 is exotic and expensive. Low-mid 200's is about the limit for naturally-aspirated.

actually for a naturally aspirated street motor, high 100's to low 200's is about the limit, with high 200's to low 300's for a turboed street motor.

 

[12sec67]

Mustang 2 is junk for handling!

I did a customers 1966 mustang SIX with the same suspesnion as the v8. The reason was he wanted to do a v8 swap later but only had the money to do one or the other at this point.

REAR:
swapped to 8 inch in the rear with 5 leafs and a 3/4 rear sway bar and 11 3/4 wilwoods in the rear.

FRONT: v8 suspension with shelby drop and 620 springs and 1" sway bar. also did v8 manual steering and went to wilwood front 11.75 disc brakes.

wheels: some black thrust type 17x 8" wheels and 235/45/17's all the way around on a red car. man it did look mean when we were done with it.

the engine was a stock SIX with a T5 transmission.

The car was so fun to drive! it felt pretty fast with the 5 speed and it did great as far as handling and stopped great . Car was light with tight firm suspension and very little body roll in the tight turns. it did so well being so light in the front I cant imagine it with a quick ratio rack and pinion.


I wish i had a picture for you...man that was a fun car to drive!