pro touring setup- HELP NEEDED!!

[DTM Racing]

I went with Reilly Motorsports AlterKtion front and and Streetlinx rear. Take a look at their setup and see if it'll work for you.

Riddler

Great setup for a show car or drag racing. Terrible for any motorsport where cornering is involved.

[sccacuda]

Take a look at QA1's K-frame as well.

[hogpowr]

thanks guys. anyone running leaf springs in the rear that can give me some spring rates they are using? Sounds like 200lbs springs for road racing is the ballpark. again my car is mostly all steel. (fiberglass hood and bumpers)

[hogpowr]

hotchkis recommends 160lb rear leafs. firm feel says 200lb leafs. anyone have a thought on the two?

[DTM Racing]

Hotchkis uses sway bars and shocks to control the car, Firm feel uses a softer shock and sway bar with a stiffer spring.

[OG_Racing]

I say what ever gets you wider tires on the front. I think the 215 vs 335 is no a close match. the rear tires prob push the fronts while your turning in. Just my guess. Sweet ride tho.

I agree 100%. I would run a minimum of a 275 up front. All your weight of the big block you're going to need a lot more tire to turn and stop it.

[High Plains Mopars]

Nothing like starting in the top rung of competition right out of the gate. Most of the optima events tend to be populated by some of the best PT style cars and some of the better drivers around. If you haven't turned a corner in anger on a road or autocross course previously, you are going to be at a significant disadvantage right out of the gate, even with a very well set up car.

All that aside, no, you don't need to go to a coil over conversion to have a good handling car. You can make a significant improvement with the stock stuff as a lot of the Mopar geometry is much better in OEM form than the same era Chevy and Ford stuff. The two biggest issues with the OEM Mopar system is bump steer and the lack of torsion bar selection. The Mopar torsion bar in your Challenger is only available in 1.0, 1.06, 1.12, 1.18, and a special order 1.24 rate. The physical size of the anchors means you can't get anything bigger than 124 in a t-bar. That limits your wheel rates to something between 175 to 425#. That is the equivalent of a 400-850# coil spring range in a Camaro. So the Mopar has 5 choices where the Camaro will have 10 choices in 50# increments to chose from to optimize the spring rate. As such, you need to spec out the t-bar first, then back into the proper leaf rate to balance the car against your selected sway bar choices. IE, with a large rear sway bar, you leaf spring choice could drop down to the 120# range.

There is a '69 Charger that has participated in some of these events on the stock set up and has done reasonably well. He does post on here, but I don't recall his user name. However, if you plan on winning these events, you may eventually have to go to a conversion suspension to be able to quickly dial in the required rates and to loose additional weight to help speed up your car.

First, I'd step up your front tire size. 215 isn't much better than a drag race tire. Then decide on a course of action for the suspension. As mentioned, Hotchkis tends to use softer spring rates with higher roll rates and shocks that are dialed in to support these rates in a complimentary fashion. Old school autocross approaches tended to use much higher spring rates and roll rates with more basic shocks. So, I'd say it all comes down to your shock budget. How much are you willing to spend here and you can decide on how to spring the car.

The Hotchkis package is a nice, dynamically tested package of parts that are proven to work well together without compromising street capability. If you want to chase a more track oriented set up, then you will want higher spring rates than the Hotchkis package recommends and that means you will need to step up to complimentary rate shocks This could mean some high end adjustables or some specially valved units built specifically for your application.

I believe the Hotchkis Challenger is using 1.06 t-bars and 160# leaf springs. By contrast, some autocross Mopars are using 1.24 t-bars and 200# leafs. Also, keep in mind that overall weight of the car will impact the effectiveness of these rates. Since Mopars are so limited in t-bar rates, weight loss in the only way to improve the effectiveness of these limited rates available.

So you can make the stock stuff very effective for somewhere between $3-6 grand, depending on shock selection. I'd venture a guess that this type of suspension will be able to handle the driving capability of 90+% of the drivers out there. Whether or not the $10-12k cost of a conversion suspension is worth it is really dependent upon your ability and your seriousness of the effort you want to put into competition. Obviously the optima series have very limited rule constraints about suspension set up, so you may be looking at entering a spending war to be in the top tier of competition with these guys. This spending could come through actual hardware upgrades or driving schools to improve the nut behind the wheel. How bad do you want to win?

[hogpowr]

thanks high plains. awesome input. I currently have a firmfeel 1.06 tortion bar and sway bar up front and have left back half pretty stock. that is going to change this winter. decisions, decisions. I know this...... the car is going on a serious diet this winter. have to see how much lighter fiberglass fenders are than steel. going to do bumpers and deck lid for sure. already have a glass hood. keep the input coming!

[benno505]

i believe a 275 will fit in the challenger front wheel well with the correct backspacing which i do not know.
with some slight rubbing.
bigger tyres, better brakes, lighten the car up.

magnumforce suspension also drastically reduces your overall weight also and gives really good clearance for everything

[hogpowr]

anyone have an idea on what backspacing is needed for 18 x 275 wheel/tire combo up front?

[J-440]

Jack your car up, take off the tire. Now get a plumb bob and take measurements and write them on the garage floor. Use a tape measure to get your spacing correct. Then take those dims to any tire/rim store and they'll hook you up. I did that and mine fit like a glove.

[High Plains Mopars]

I'd suggest you visit a few more mopar oriented sites to work into some possible combinations of that. I believe it will fall somewhere between 5.5 and 6, but the offset of that back space is equally important. Try protouringmopar.com, moparts.com, or cuda-challenger.com

[hogpowr]

thanks guys. ordered some hotchkis stuff for the front end. going to wait until winter to really get into the back half of the car. I hate having a perfectly good car tied up for the few nice months we have here in milwaukee. BTW. if anyone reading this is in milwaukee area. lets hook up. I don't know anyone in the area into old cars that drive hard, shift nicely turn and stop. (and actually use the cars for that purpose) most people around here that have old cars, couldn't imagine leaving in a cloud of smoke, stopping fast or turning their 40 year old car around much more than their driveway.