Need advice on: Aftermarket Brakes, Suspension, K-Member and Sub-Frame!

[SovereignZuul]

Prepare for question bombardment.

I don't know where to begin with this due to a total lack of experience with suspension and own no books on the subject.

I want to build my Charger as a street/race car.  99% of my driving will be street.  I should say, I've never driven a B-Body.  Biggest performance car I drove was my '79 Camaro, which was a dream, no body roll at all, never driven another car like it actually.  Whoever owned it before me I know had done a lot of suspension work.  So my frame of experience with RWD performance isn't that vast.  My Dart drives like a boat, same with my old Fury.  They are/were definitely not performance cars.

There are some pretty looking aftermarket parts that may enhance a B-Body's handling but I really don't know how.  I can identify the difference in appearances, just not the performance differences.  Along with the questions I welcome any product recommendations for these items or more.

What is the benefit of a tubular k-member with rack and pinion steering and coil over suspension?
http://www.magnumforce.com/magnumstore/shop/item.aspx?itemid=136
What makes this rack and pinion steering different than the old gear box steering?  Are they really different?  Which one is better?

What about the coil over suspension, what makes it different?  Pros or cons? 

Same for the rear.  Are coil overs better than the leaf springs/shocks?  What is the difference here?

Are bolt on sub-frame connectors worth the trouble or should I get some that weld in?  I'll be welding all the sheetmetal anyway next year so that wouldn't be a problem.

I read that the bolt in sub-frame makes torque boxes obsolete, any reason why?

Is it worth investing in these expensive suspension parts or staying with the classic set-up?  Is the difference really that significant?


I'm really looking for any nice big kits that include most of what I'll need for 4 wheel power disk, best suspension I can get.
Was looking to buy a kit like this perhaps.  A nice total package would help a newbie like me.
http://www.hotchkis.net/1970-mopar-bbody-tvs-system.html


I want to build the car right for me the first time rather than go back and do upgrades or major changes.


Thank you in advance for any direction and help!

[myk]

Whenever a car build starts in the dream phase, the most important question of all is this: what is your budget? 

The road I've chosen for my Charger is the classic setup with bolt ons; or as you pointed out, the Hotchkis TVS system.  I've only installed the shocks, subframe connectors and the sway bars, but already the difference is like night and day versus the stock suspension.  Best part of all is that these parts can be installed in your driveway with little more than hand tools and time.  I will recommend that you weld in your SFC's; anything bolted in will flex and move at the bolt locations before they ever combat chassis flex. 

People will argue the pro's and con's of coil over suspensions, aftermarket subframes and the like, but ultimately I think it's a matter of preference and budget. 

Finally, I wouldn't expect your big, beautiful, heavy B-body to compete with the fond handling memories you enjoyed with your Camaro/F-body; the Camaro is generally seen as a better suspension platform due to the more advanced suspension design as well as the lighter weight.  I think it's possible to make your Charger handle in a way that would make the original designers of the Charger suspension blush, but a large car like this one will have its limits.  Regardless, you'll still have a blast-that I can guarantee...

[HPP]

What is the benefit of a tubular k-member with rack and pinion steering and coil over suspension?
http://www.magnumforce.com/magnumstore/shop/item.aspx?itemid=136

Upside of tubular components is they typically weigh less than the stock pieces they replace and they may also be stronger. The caveat to this is their design may allow them to flex more and their construction and material selection may compromise their structural integrity at the expense of weight. Also, depending on their design, they may or may not distribute loads properly through the uni-body. Some Magnumforce systems loads all the suspension into the shock towers. That is not a good thing without additional reinforcement in the engine bay. QA1s tubular K frame is actually stronger than the stock system and provides some additional room, but weighs nearly the same as the stock K frame. R&P and coil overs I'll address below.

What makes this rack and pinion steering different than the old gear box steering?  Are they really different?  Which one is better?

R&P systems are much less weight than an recirculating ball steering box. Their precision also tends to make them provide more positive road feel. However, applied to classic cars, R&P systems tend to perform best in front steer systems because of the force load put into them. Simply bolting one on in place of a stock box can lead to less than stellar results with increased bump steer and reduced turning radius. So yes, there will be a pronounced difference in feel compared to stock. Which is better, well, most new cars now days use R&Ps, but heavier trucks tend to still use recirculating ball. Unless you are completely swapping out the suspension system to best utilize the R&P capability, I'd stick with the proven reliability of the stock set up. A Firm Feel box will get rid of the over-assisted stock steering box.

What about the coil over suspension, what makes it different?  Pros or cons?  Same for the rear.  Are coil overs better than the leaf springs/shocks?  What is the difference here?

Again, lighter weigh but also more compact packaging for more room under the car, the ability to specifically design components to provide only one or two functions instead of multiple jobs, and the choice of infinitely more spring rates to balance the car. Coil overs allow you to quickly swap spring rates with only removing a couple of bolts and reset the ride height anywhere you wish. Also an associated benefit is that a coil over system, front or rear, typically requires an entirely alternate suspension design which means it can also utilize improved geometry to provide an over all better range of motion and adjustability. If you are a racer who needs to quickly adjust things, coil overs are a necessity. If you are a street driver who likes to set it and forget it and never pushes the capability of the system, coil overs are an expensive way to look good.

Are bolt on sub-frame connectors worth the trouble or should I get some that weld in?  I'll be welding all the sheetmetal anyway next year so that wouldn't be a problem.

IMO, bolt in is better than nothing at all, but weld in provides a more sound foundation. Welding up seams in the sheet metal provides nearly identical returns.

I read that the bolt in sub-frame makes torque boxes obsolete, any reason why?

They provide slightly different functions, so they aren't totally obsoleting torque boxes. Torque boxes tie the sub frames into the rocker panels and floor plane. This provides additional torsional/twisting resistance. Sub Frame connectors were developed out of the drag racing world to provide beaming or bending resistance, but by virtue of tying things together, they also provide some measure of torsion resistance also. If you get connectors that bolt/weld to the floor, this is another measure of support they can provide to increase torsional capability. IMO, reduction of flex in the unibody is the first step in making a suspension system perform well.

Is it worth investing in these expensive suspension parts or staying with the classic set-up?  Is the difference really that significant?

IMO, the stock system can be upgraded to be capable of performance beyond the ability of 90% of the drivers and their intended usage, so IMO, no, very few need a coil over system. For that matter, who needs a 572 Hemi, so want seems to be an equally weighted choice or the motivating factor. That's not good or bad, just preference.

I'm really looking for any nice big kits that include most of what I'll need for 4 wheel power disk, best suspension I can get.
Was looking to buy a kit like this perhaps.  A nice total package would help a newbie like me.
http://www.hotchkis.net/1970-mopar-bbody-tvs-system.html

Again, IMO, you don't need 4wheel discs since the vast majority of braking is done with the front of the system. However, brake choices will be driven by wheel choices as 15" wheels limit available sizes and 18" wheels means you can put so much brake in them, you will have under utilized capability. If you decide to use your car in high speed road events that require repeated high speed stops, then the 4 wheel discs would make more sense.

I agree a whole system may be the best approach for you. The Hotchkis TVS is an excellent set of components that can be added in pieces, if desired, to slowly upgrade the car, or added all at once. Firm Feel also has a large selection of parts and a conversation with them can give you a catalog of part to pursue. Also, PST offers several different kits from basic component rebuilds to stepped up stock components and big brake options. These companies will also offer spring rates that complement the cars performance.

[SovereignZuul]

My budget, up to 20k a year at the moment, which I know (and have experienced) is totally subject to change at any given moment.  10-15k is more reasonable without pushing my limits and destroying any spending cash for trips/vacation/etc.  If I really had to I can sell my investments but I don't want to.

I can already tell with those explanations just doing an enhancement of the stock system should be plenty for my needs.  Not doing any professional racing so those "super" systems now seem unnecessary for me.  I just want a fast street car out of this thing that I can fully enjoy on curves and straight lines.  I will still put it on a track every once in awhile for fun.  I just did my first official drag racing last weekend on a track.

I can say, all the V8 Chrysler cars I've driven have the least enjoyable steering I've ever experienced.  In my Fury and Dart I get no feedback from the road and it feels like the car is floating.  You can spin the wheel with your pinky!  Not fun imo.  I'll look into those companies, anything to improve that Mopar steering.  I'll do some research now that you guys pointed me in the right direction.

Thanks for your wisdom in this matter, I really appreciate your words!

[SovereignZuul]

Double post, sorry.

I'm guessing something like this may work best for me?

http://store.uscartool.com/b-body-chassis-stiffening-kit.html

I've already got some fiberglass fenders on the way soon and eventually a fiberglass hood as well.  I'm guessing I lose some support with the fiber glass parts. Would the radiator and fender braces be needed to provide more support in light of having glass fenders and hood?  If not I can save some money and time by not including them.

[Mike DC]

          
The floating no-feedback steering has as much to do with the suspension geometry/alignment as the steering hardware itself.   The front end was designed for manual steering with zero caster.  Modern cars designed for power steering usually have several degrees designed in from the factory, and that makes them naturally return to rolling straight ahead when you let go of the wheel.  You fix this issue on an old Mopar with aftermarket UCAs to move the upper balljoint backwards a little.


I find that in general you should not trust what GM/Ford guys tell you about fixing a Mopar suspension.  Most of them don't understand it very well and their prognosis for fixing anything is to tear it all out & replace with a GM/Ford/aftermarket layout.  (Will their suggestions cure the specific problem you complained about?  Sometimes, yes.  But you also might be able to cure a stalling problem on a 426 Hemi by swapping in a fuel-injected Toyota engine.  That doesn't make it the wisest way to fix things overall.)

[krigel]

I just finished installing the Hotchkis TVS as well as the Fox Shocks, torsion bars, and fast ratio pitman/idler arm, the Firm Feel Stage 3 box, and an after market disc brake kit for the front...here's what I would do differently....The TVS stuff makes the car handle a ton better....but I'm not a fan of having to shim the upper control arms so much to get them to fit right. I would use Firm Feel tubulars if I had to do it over again, as they fit more like a stock arm. Other than that though, the TVS is great. Bang for the buck, it's about as good as it gets.

For front brakes, use stock components from an A body, but get a good dual diaphragm booster. I didn't go this route in the beginning, and it has cost way more to back track and only use half of the aftermarket set up (I couldn't bring myself to put a Chevy style booster in my Charger). A good set of stock style front discs and rear drums are more than enough if you aren't pushing 600 horsepower. Add in a proportioning valve, and you'll be good.

I've got 18 inch rims on mine too, and it is so much fun to cruise in. Once you get it into corners, it handles great for a big car, but it's not going to handle like a Porsche. What it is, is a really confident handling muscle car that you can plow into corners.

[SovereignZuul]

I'll keep that info in mind.  I remember it being a bit nerve racking driving my Fury on the highway due to that floating feeling. 

I'll look for Mopar style equipment indeed.  I don't recall even seeing a booster in my Charger, the master cylinder is right on the firewall directly.  Lack of a booster means manual brakes right?
You can kind-of see the master cylinder in this pic:  http://i.imgur.com/SvTf8fs.jpg

I'll probably be putting 15" wheels on the car.  My personal taste isn't into low profile tires and "big rims" even if my daily driver has them (factory).



Just quoting my fiberglass/reinforcement question from 70 Charger forum.

I've got some new fiberglass front fenders for my 1970 Charger on the way and I want to know what I may have to do to prepare the car special to mount them.

I've never had or worked with fiberglass parts before.

In addition when I do my welding body work next spring I'll be putting in subframe braces and torque boxes.

Big starting question is, how fragile are the fenders mounted to a stock body?  Do they need special braces to prevent stress or cracking on the fenders?  Do the Charger's fenders just hang or are they part of an area that flexes and can be damaged where the stock steel is tough enough?

Currently my Charger's bumper is removed (bought it that way) so I'm not sure what it mounts to yet.  Do the fenders do any kind of front end support to be aware of that needs mounting modification so it won't hang on the fiberglass?

I was looking to perhaps buy this kit:  http://store.uscartool.com/b-body-chassis-stiffening-kit.html

That includes the subframe parts I want, plus fender and front core support.  Are the fender and core supports worth doing or will they be a negative addition in regards to the fiberglass fenders?

I'll also be investing in a fiberglass hood when ready.  My hood is completely rotted out in the front and needs replacement anyway.

Thanks for any replies!

[myk]

Hmmm.....not sure I understand.  If you're going for optimal handling in car like this, 15" wheels aren't the ideal choice.  Big rims with thin tires is as much for handling as it is for style...

[SovereignZuul]

Is it really that big a deal for the handling to have big style wheels and slim tires?  Part of this is my ignorance, I apologize, still learning here.

Most of my desire for specific wheels/tires is style.  Anyway wheels/tires are way off for me, I've got a lot more to do to my car first.
I want the American Racing 200-S wheels, I think those come in 17" at the largest diameter, so this is still possible.

This is my daily driver, so you can see I'm used to driving on these wheels:  http://i.imgur.com/XcfkFjd.jpg
I put about 40 miles a day at least on those tires and wheels.  The tires are brand new yoko sport a/s, less than 2,000 miles on them.

Every time I hit a pothole, bump, road construction, or anything that's not flat nice road it feels painful for the car.  The highway construction I've been dealing with everyday is hell on those tires/wheels.  I've got to come to a full stop where the old road meets the cut/grooved construction area or else WHAM!  The wheels wear out quick developing small leaks and minor bends.  I just had them repaired a few months ago.  Maybe this is just me?  I don't know, I just don't like these style wheels.

[HPP]

myk, I don't think he is looking for ultimate handling so much as significantly improved handling. You can improve things a lot and still use 15" wheels and tires. It won't be the best, but it will still be worlds better than stock.

To MikeDC's point, the alignment is also part of the package to consider that will contribute to the feel as well as all the hard parts. If you put all brand new parts in it and then put the original alignment specs on it, you've negated the full benefit of the upgrades. The original specs were developed for skinny, bias ply tires. Modern radials can tolerate a much more aggressive alignment and still wear decent, plus provide improvement in of the feedback and feel of the system.

[SovereignZuul]

myk, I don't think he is looking for ultimate handling so much as significantly improved handling.

Pretty much.  Just wanted to:
#1 Learn.
#2 Figure out what options will be best for my build.

I've been reading, browsing, and trying to pick up a lot of knowledge by asking the people I know and at least am learning quite a bit.

[Mike DC]

                                                                          
Well, here's my list of suggestions:


--  Add bracing/stiffening to the unibody & K-frame.  The specific areas to fix are well known so do a search of past threads.

--  Make sure it has reasonably fresh ball joints & bushings everywhere.  Rubber bushings are fine as long as they aren't old enough to be in college.

--  If the car still has front drums then get rid of them for some kind of discs.

--  Give it aftermarket F/R swaybars & shocks.  None if this stuff needs to be super-maxed-out Hi-po gear, just get something decent that was designed in the 1990s-2000s.

--  Swap the steering gearbox for a rebuilt/tightened unit from Firm Feel or Steer & Gear.

--  Replace the UCAs for aftermarket units with the ball joint moved back.    

--  New/stiffer front torsion bars & rear leafs wouldn't hurt, but don't go overboard with stiffening the corner springs.  Replacing them is only really important if your car is still wearing its original 40yo stuff.
 

This won't build a track star.  It just builds a decent item that handles/rides well enough that you won't be thinking about it.  A little better than you'd expect from most cars, and A LOT better than a 40yo car should handle.

[myk]

Ok, I get it.  I just figured that if we're talking about hotchkis packages, aftermarket coil over setups and the like, and a possible budget of $20K a year, I figured we were building something just short of a track car. 

If we're keeping the stock wheel and tire size I'm guessing the coil over setups and all the other trick parts is overkill.  A poly-based bushing rebuild and maybe larger torsion bars, an aftermarket steering box, front discs and good shocks should do the trick...

[fy469rtse]

Big vote of yes for the US car tool kit ,
Look at bracing or plating to bottom arms , not a fan of coil overs , introduces stresses elsewhere that the body's on these cars were not designed for , that floating feeling in your fury is soft or light duty torsion bars , get .96 or larger bars , will improve that soft feel,
Add rear sway bar , heavy duty front sway bar ,
Get a proper rebuild done on the steering box , solid adjuster sleeves between tie rods ends ,
Those upper arms , get the ones with bushes, stay away from helm joint types, not for the street, race only and short life , start with these mods , won't break the bank, will leave money for other stuff
While your repairing rust and putting in the us car tool stuff  , add the hemi torque box's to sub frame,
And some of the younger guys on here are wrong about the small wall tyres large diameter rims , if that was so they would use them in the world of motor racing , look at tyres used in NASCAR , or any proper racing
Your not going to get it to handle like an evo , it's a muscle car , but all the above will improve it with out you spending all your money on this , good luck with it
Post and photos as you go, but most of all search on here for what all of us have done including me ,
And I know the above improves handling ride and performance from experience 

[fy469rtse]

Get the correct dual diafram booster that will fit straight on , hemi style is the one
These are made brand new these days , look up pirate jacks I think
It's a remake of heavy duty factory piece , brand new
But look on the threads here , keep reading on threads on here , and most of all do what suits you, it's your car , best advice I can give you, keep reading and be informed, that way you will know what you want and what's needed to achieve it,
Some good mods on here and don't have to cost the earth

[Mike DC]

And some of the younger guys on here are wrong about the small wall tyres large diameter rims , if that was so they would use them in the world of motor racing , look at tyres used in NASCAR , or any proper racing

Racing wheel/tire combos are heavily controlled by rules.  

20" rims and 30-series tires is usually going too far.  But still, keeping the sidewalls on the slim side for handling does help.  

I recall a study once that the best handling (on some sports car or another) was had by using 17x8" rims and about 45-series tires.  Neither smaller nor bigger rim diameters did as well.  



It also helps handling to have the tread width on the narrow side compared to the rim width.  Whereas the muscle car hobby seems to hate the looks of this.  We applaud cars running 10" wide treads on 8" wide rims.  

[SovereignZuul]

I figured we were building something just short of a track car.

Maybe some day.  Aim high, hit somewhere in the middle?  Either way I didn't know before I asked so it was an exercise in learning at least.

Indygenerallee on here offered me the sub-frame connectors (US Tool ones) he had lying around via PM for a good price so I've ordered those from him.  The rest of the parts I've just ordered from US Tool's website right now.

Right now it seems a combination of Hotchkis and Firm Feel stuff does seem the best route.  Going to continue my research, it's great having some advice to point me in the direction I need, thanks again.

I am one of the younger guys, but I never connected with the modern look of big rims/thin tires.  If I'm going to break the bank on anything it will be my motor.

Wow, those pirate jack kits are nice looking, and easily affordable! 
http://www.piratejack.net/index.php?page=shop.product_details&flypage=yagendoo_flypage_1.tpl&product_id=25&category_id=8&option=com_virtuemart&Itemid=6

[71charger_fan]

I've been running the CAP (now QA1) k-member for years. Here's the car currently in for paint.