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Such thing as a dual-purpose E body? #3091285
11/02/22 09:16 PM
11/02/22 09:16 PM
Joined: Jul 2005
Posts: 673
California
BigDaddy440 Offline OP
mopar
BigDaddy440  Offline OP
mopar

Joined: Jul 2005
Posts: 673
California
My newest Mopar build-project, a 70 Cuda is heading to the body shop soon, and I'm considering all suspension options for this "clean-slate" build. I'd like some input.

Prior to paint, the car is being fitted with USCT weld-in sub frame connectors and front and rear weld-in torque boxes to help stiffen the car a bit.

I understand good handling and good drag strip qualities don't complement each other, especially with old cars...I get it.

I'm NOT looking to build a road race car, nor a dedicated drag car, but a street car that's handles better than it did stock and can still launch a decent street car 60ft time at the drag strip and run a respectably fast E.T.

I don't have any real E.T. / MPH goals for this car, but I'd like it to drive well on the street.


The Actual Question:

Given all the options out there: Hotchkis, Borgeson, Koni, RMS Suspension Systems, 4-link rear suspension, Cal Trac, Single / Split Monos, QA1 / Viking single and double adjustable shocks, and others...

Is it possible to build an aggressive looking street machine that rides and corners better than stock and can hold it's own at the drag strip? What combination of parts (listed or otherwise) would you use to achieve this goal and why?



Additional Information:

540ci all aluminum engine, 530 lbs, approx 700hp with a camshaft meant for street use. Automatic Transmission. Stall and Gearing to be decided after engine is dyno'd.


More or less the look I'm going for, minus the skinny's up front. (this is not my car)

[Linked Image]








Last edited by BigDaddy440; 11/02/22 09:18 PM.

1969 A12 Roadrunner
1970 Plymouth Cuda
1968 Dodge Dart
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091293
11/02/22 09:47 PM
11/02/22 09:47 PM
Joined: Mar 2003
Posts: 18,534
Fresno, CA
Jim_Lusk Offline
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Fresno, CA
I'd build based on the factory torsion bar/assymetrical leaf spring setup. Getting that to handle exceptionally well is pretty easy. Yes, handling suspension will affect 1/4 mile performance, not enough to take the fun out of it. You can experiment with removing the front sway bar links at the strip.

Re: Such thing as a dual-purpose E body? [Re: Jim_Lusk] #3091294
11/02/22 09:51 PM
11/02/22 09:51 PM
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Warren, MI
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Jerry Offline
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any car can be dual purpose as long as your willing to sacrifice the peak performance on both ends of the spectrum, you got a really big engine for road course use, long stroke creates a lot of windage problems. maybe too much torque for the corners as well. add the biggest widest stickiest tires you can afford. i see some guys putting in 315 series tires on both front and back of e bodies with mods.


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Re: Such thing as a dual-purpose E body? [Re: Jerry] #3091302
11/03/22 12:10 AM
11/03/22 12:10 AM
Joined: Feb 2010
Posts: 18,287
Granite Bay CA
Kern Dog Offline
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A Road Race car is going to be more fun on the street and still perform well on the drag strip compared to how a Drag Race car will perform on a road course.
Think of how the new Challenger and Chargers are. They are excellent street cars, fast at the quarter mile and great road course cars.

There are a number of aftermarket replacement front and rear suspension companies ready to take your money but in my opinion, the gains they may offer come with drawbacks and also have a high buy-in cost.
One big gain is oil pan clearance. Yipee! Another is header clearance. So what? Dougs and TTI make headers that fit around a stock chassis anyway. No gains there in my opinion.
The kits are shiny and have all new hardware so that seems nice.
Think about cars like the Mopar Action "Green Brick" 1969 Valiant. It retained torsion bars and leaf springs yet was a top contender in road course events.
You don't need Magnum Farce, RMS, Gerst, Hemi Denny or a Schwartz setup to ride well, handle well and hold together.
There have been instances of these aftermarket parts failing....broken welds car ruin more than the suspension.

Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091483
11/03/22 07:23 PM
11/03/22 07:23 PM
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Keep us posted what you end up doing I'll be curious to see how it turns out. My 71 is hopefully going to be a weekend 1/4 warrior street car, I figured good double adjustable shocks would help make the biggest improvement for versatility. I added a Hotchkiss front sway bar, tubular uppers, Hotchkiss strut bars, am trying to retain the stock rear sway bar, and a borgenson box. I'm not going for "good handling" but I do want it significantly better than it probably was stock if my RR is any indication of what 1970 felt like. The caltracs and mono leafs are as far towards the drag race side as I plan on going.


Follow my G3 Hemi Barracuda build on Youtube
https://www.youtube.com/watch?v=XSDAWczXoZw&list=PLTus_wQu8POADHEeJNJp2nr4NMHEyB9EK

2015 Tri-State Stock Super Stock Champion
2017 Monster Mopar Pro Winner
2018 Monster Mopar No Box Winner
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091507
11/03/22 09:17 PM
11/03/22 09:17 PM
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Oregon
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AndyF Offline
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I recommend being very careful about making major design changes to the vehicle. The more you mess with these cars the worse they become in terms of reliability and resale value. Very few shops have the ability to modify a car and maintain factory integrity. Most of the aftermarket stuff is designed to lower than OEM standards so the more aftermarket parts that you put on a car the more the reliability and reparability is reduced.

If it was my car I'd start with a tire size and stance that you like and then work from there. You'll most likely need an 18 inch wheel in order to find high performance tires. 18 inch wheels will give you enough room for 14 inch brakes which is what you'll need with that much power. You should be able to fit an 8 inch tire on the without any mods, if you want to go bigger than that then you need to start looking at making modifications. An 8 inch tire isn't going to handle the power that you are putting in the car so you'll need to figure out what you want to do. Once you start modifying the body and suspension for larger tires you get on a slippery slope and who knows where you end up.

The short answer is that what you want can't be done very well, especially on a budget. If you want to go down this path then set a budget limit and figure out what you can do within that budget. Trying to turn an E body into a Porsche or a C8 or even a Hellcat isn't cost effective. We learned this years ago with Tim's Valiant. By the time he was done it cost 2x of what a used Z06 would've cost and a Z06 would've been the better car. You'll run into the same problem with your car. You can spend $100K on it and a nice 911 Turbo will still out perform it on the street, road course and drag strip and have better resale value.

Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091620
11/04/22 12:24 PM
11/04/22 12:24 PM
Joined: Oct 2005
Posts: 157
Anchorage, Alaska
metallicareload Offline
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iagree
I suppose I’m trying to achieve the same multi role car also. It’s my summer daily driver, drag test & tune, auto-cross, and now I’ve done rallycross. It’s least proficient with 1/4 mile and auto cross, seems to be ok everything else.

I’m definitely biased towards staying within the stock “architecture.” I’ve got Firm Feel upper control arms, front and rear swaybars, 1.06” torsion bars, Dana 60 with CalTracs in back, subframe connectors and torque boxes. I think these all have been beneficial improvements combined with having the stock stuff rebuilt.

If I was able to do things over I would start with an overdrive trans and like at least a 4:10 gear. That alone I think would have benefits in all aspects. Other big thing is have a plan for wheels and tires. I didn’t. Light weight forged aluminum wheels with good tires specific to the task would be a huge improvement drive


440, 4-Speed, 3.54
1968, when Dinosaurs ruled the Earth
Re: Such thing as a dual-purpose E body? [Re: metallicareload] #3091694
11/04/22 06:57 PM
11/04/22 06:57 PM
Joined: Jan 2003
Posts: 27,213
So Cal
autoxcuda Offline
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Here's the Dick Guldstand Article on Handling Theory I posted on my 68 Cuda Autocrosser site 25 years ago. Archived on the Wayback Machine.

Handling Theory



---------------SOME HANDLING THEORY---------------



By now you have probably read enough "straight talk" articles about high-speed handling to be totally confused. Your condition stems from the fact that most such articles are written to sell rather than to inform. This section of the catalog will outline a few basic concepts which will help you make an enlightened choice about how to modify your car for superior handling. Some parts will get a bit theoretical, but the knowledge gained will be worth the effort, so bear with us.

Where to Start?
Where do we start this discussion of high-speed handling? I can tell you it doesn't start with G-forces, gum ball tires, spring rates or any other thing the enthusiast considers central to high performance.

It starts with Joe Average. You've met him. He’s the driver of that car acting as a moving chicane on your favorite back road. Joe is also the typical car buyer and the key to General Motor's plans for making big Profits. They want to sell a large volume of cars all based on the same basic design. To do this they must appeal to the large group of buyers in the middle of the market. Sport coupes like the Z-28 Camaro, Trans-Am Firebird and Corvette represent the most that GM is willing to do for the enthusiast. If GM can't sell hundreds of thousands of a particular part over the life of a model run, they are simply not interested. Their marketing plans rely on volume.

We need to look at how Joe drives and what he expects from a car. Then we can compare his style with that of "The Enthusiast Driver." Once we understand these differences, we can look at how they affect the overall design of the car. The
best way to examine these differences is by watching our two drivers negotiate a typical turn.



A Typical Turn
Let's assume a 180 deg. medium-speed corner with a radius of approximately 230 feet. This turn will have a total distance along its circumference of 722 feet. If you are having a hard time visualizing it, think of a 180 deg. freeway on-ramp with a recommended speed of 25 m.p.h. Assume also that Joe and Enthusiastic are driving base-model coupes which weigh about 3500 pounds. Cornering in a normal manner, Joe will round the turn at 30 m.p.h. His subjective reaction to the cornering experience will be that the car handles just fine. Enthusiastic will corner at 45 m.p.h. He feels that the car leans to much and is not precise.

Why do Joe and Enthusiastic have such different reactions to driving the same car around the same turn? The simple answers are that Enthusiastic is going faster than Joe or that the base-model coupe is designed for Joe’s driving style rather than Enthusiast’s. While these answers are valid, they don't help us decide how to obtain superior handling. We’re looking for a more fundamental understanding. To get it, we have to discuss some basic physics and the nature of human response to time-distance relationships.

page 4



A Typical 180 deg Turn

1webDguld2.gif
[Linked Image]



It's Only Natural
The basic physics we need to examine is the concept of energy. Of particular interest is
kinetic energy, the so-called energy of motion which is present in all moving objects. The amount of kinetic energy in any particular moving object is determined by both the weight and velocity of the object. It is important to realize how weight and velocity influence the amount of energy. This relationship is expressed by the formula:



Energy = 1/2 Weight x Velocity^2



This tells us the amount of kinetic energy increases in direct proportion to added weight
and in geometric proportion with added velocity. Thus if the weight doubles the kinetic energy also doubles, but if the velocity doubles the energy will be four times greater.

Let's get down to earth by seeing how much energy is involved as our two drivers round the typical turn as above. When Joe Average rounds the corner at 30 m.p.h., he is cornering at about 0.279 g. The amount of energy involved is about 142,785 newton-meters. Enthusiast Driver goes around the turn at 45 m.p.h., or about 0.628 g,
which is not that slow for a base-model car. The amount of energy involved as Enthusiast corners is about 321,183 newton-meters. Notice that while Enthusiast is going 50 percent faster than Joe (45 vs. 30 m.p.h.) the amount of kinetic energy involved has increased by 125 percent (321,183 vs. 142,785 newton-meters).

You're thinking this is all very interesting but wondering how it relates to improving your car. Well, it means that the amount of energy involved with your car during cornering is the basic physical design criteria used in the construction of all suspension components. Think of the suspension components as devices to resist, store and control energy. The spring is a good example. We always hear people talking about spring rates. What does "spring rated" really mean? When we say that a spring has a rate of 250 pounds per inch, it means the spring can store 250 inch/pounds of energy for each inch of compression.

Why don't we use our example again? If we assume that as Joe goes round the turn his
outside springs are compressed one inch; then as Enthusiastic Driver corners, the outside
springs will be compressed an additional 1.25 inches. How does this extra compression affect the driver's subjective reaction to handling? At this point we get to the second important concept: the nature of human response to time-distance relationship.



It's Just Human
Back at our typical turn, we can watch more closely-as our two drivers negotiate the corner. Recall that Joe Average went around the turn at 30 m.p.h., or to put it another way, at 4 feet per second. Assume that as Joe enters the turn, the car takes 2 seconds to roll over, compress the outside springs and come to a steady-state cornering attitude. Likewise, at the exit of the turn, Joe’s car takes about 2 seconds to unroll and get comfortably straight again. Watching Joe go through our 722 foot long turn, we see that it takes him 88 feet to transition into the turn, that he has 546 feet of steady-state cornering and another 88 feet of transition back onto the straight. Joe spends a total of 16.4 seconds in the turn.

Page 5



Of these, 4 seconds (24%) are spent in difficult transitional cornering maneuvers, and 12.4 seconds (76%) are spent in relatively easy steady-state cornering. This is why Joe feels that the car handles fine. At 30 m.p.h., he spends relatively little time doing the difficult tasks of getting on and off the proper line and has a good deal of time in the middle of the turn to make corrections.

Enthusiast Driver experiences quite a different situation. He is going of 45 m.p.h. or 66 feet per second. Remember that basic physics indicates that there is 125% more energy involved because Enthusiast is cornering 50% faster. Remember also that the greater energy causes the outside springs to compress an additional 11/4 inches. Assuming a "linear" suspension response time, it will take Enthusiast 4.5 seconds of transition at each end of the turn. He spends 297 feet of transition during turn entry (66 feet per second x 4.5 seconds), has only 128 feet steady-state cornering 297 feet of transition at the exit. This is why Enthusiast thinks the car is unresponsive. He is in the turn for a total of 10.9 seconds. Of these, he spends 9 seconds (82%) of the time in difficult transitional cornering and 1.9 seconds (18%) in relatively easy steady-state cornering.

The technical name for this phenomenon is yaw response. The yaw response characteristic of a car is the single most important of that group of traits we call "handling" The parameters for determining an ideal yaw response characteristic
are derived from study of the human nervous system. The yaw response must be designed to make the driver feel comfortable at the speed he wished to go. It cannot be too slow or too fast. It must be slow enough so the driver can react to steering inputs; yet, it must be fast enough so that corrections can be completed before an off-road excursion occurs. The "base-model coupe" has been designed by GM with an ideal yaw
response for Joe Average, who normally corners at about 0.300 g. If a driver wants to corner at some higher speed, then the suspension must be modified to provide an ideal yaw response at the higher speed. In other words, we must keep the yaw time, when expressed as a percentage of total cornering time, constant. To keep Enthusiast Driver comfortable going around our typical turn at 45 m.p.h., we must modify the suspension so about 18% of total cornering time is spent in transitional cornering. This is what is meant by keeping yaw time constant.



The Indicators Game
At this point we should scrutinize the primary indicator of cornering performance- namely cornering force as expressed in g's. At the present time, we all tend to focus on how many g's a car can generate. We normally equate high g-forces with good handling. Does this equation really hold-up? Sometimes it does and sometimes it doesn't. We have all read comparison road tests where the car with the highest cornering force was also the slowest through a slalom course. This happens because g-forces are measured on a skid pad which tests only steady-state cornering. The skid pad tells nothing about yaw response characteristics during transitional cornering. Yet, it is these characteristics which are the most important factor contributing to superior handling.



The Skid-Pad

1webDguld3.gif
[Linked Image]


100 ft. radius

Does this look like your favorite back road?

Page 6



Whether high cornering forces translate to superior handling or not depends on the honesty of the suspension designer. If he designs a complete system which takes into account both transient and steady-state cornering, then yes, high cornering forces will mean superior handling. However, if he uses tricks just to yield high cornering force numbers and does not do his homework on the remaining suspension components, then no, superior handling will not result. Remember, skid pad results are indicators; the real test of good handling is how your car performs over your favorite back road, in transition as well as "steady-state."

How can we judge the honesty of the designer's work? A good place to start is by examining how General Motors upgrades a base-model coupe into either a Z-28 Camaro or Trans-Am Firebird.



A Lesson from GM
It is a myth General Motors cannot design good cars. Their engineers and technical staff are among the best in the world. If you have any doubts just look at GM's impressive competition record. It includes numerous successes doing both officially sponsored corporate projects as well as countless backdoor efforts. You may re-member their NASCAR efforts of the 50's, the Grand Sport Corvette, and the racing Camaros of the late 60's. From our point of view, the only problem is that these superior technical capabilities are generally just used to produce designs for the average buyer rather than the true enthusiast.

When these talented engineers redesign the base coupe into a Z-28 or Trans Am, they treat the whole car as an interrelated system that . They make detail changes to a wide range of suspension components. The Z-28 or Trans Am differ from the base coupe in the hardness of rubber suspension bushings, the rate of both front and rear springs, the diameter of sway bars, the ratio and feel of the steering gear, the width of the wheels, and the size and compound of the tires. It takes the combined effect of all these changes to maintain a balanced car which (1) exhibits



Speed Time Comparison

1webDguld4.gif
[Linked Image]

Steady-State

--------------MPH -G-force-Total -Steady state-Transition
time time time
Joe Average 30 mph. 279 16.4 sec 12.4 sec 4 sec
(76%) (24%)
Hero Driver 45 mph. 628 10.9 sec 1.9 sec 9 sec
(18%) (82%)





cornering forces in the 0.800 range and (2) has good yaw response characteristics. Notice that they change several of the major system components and not just a single item such as a front or rear sway bar. The total system approach produces a car with an integrated, balanced feel derived from all the parts working in harmony.

The other thing to notice is that all of the revised parts are stiffer than the normal part. The springs are stiffer, the sway bars are stiffer and the rubber bushings are harder (which is another way of saying stiffer). As we discussed above, they must be stiffer to deal with the increased energy generated by higher cornering speeds.

Page 7


No Free Lunch
We need to understand one final point. Every given set of suspension components has a limited working range. As suspension components are modified for higher cornering speeds, the working range becomes narrower. Thus, the base-model coupe rides well at slow speeds, corners satisfactorily up to about 0.450 g and is uncomfortable at 0.650 g (145%). The Z-28 or Trans Am has a firm ride, corners well to 0.720 g and becomes difficult to control at O.70 g (107%). A good combination street/slalom car has a very firm ride, corners well to 0.875 g and feels "edgy" at 0.900 g (103%). The typical race car has no ride comfort, corners well at 1.200 g, and leaves the road at 1.210 g (101%). Notice that as cars are tuned to handle well at higher g-forces, low speed ride comfort is sacrificed.

Under current technology, the twin goals of pillow-soft low-speed ride and superior yaw responses at high cornering forces cannot be accommodated in the same car. The truth is that tuning the suspension to work well at higher cornering speeds always trades off some low-speed ride comfort. We must each individually decide
how much low-speed ride comfort should be sacrificed for added high-speed cornering capability. As a wise man once said, "There is no free lunch"

So there it is, the real "straight talk" about high- speed handling. You won’t remember all the details but you should remember the following three points. First, superior high-speed handling is more than just high cornering power. It must include a balance of both high cornering power and correct yaw response characteristics. Second, a car with superior high-speed handling is produced only by the systematic modification of a wide range of suspension components. Just bolting on a sway bar or some other part won't get the job done. Finally, as cornering speeds get higher, the suspension system must get stiffer in order to handle the increased energy levels.

Author-
Dick Guldstrand



page 8


--------------HOW TO PREPARE YOUR CAR--------------
Over the years, we have found two basic steps common to all successful car preparation.

The first step in preparing your car is to determine the condition of basic suspension
components (ball joints, idler arms, etc.) The successful operation of any high- performance part is dependent on sound basic suspension components. A car with as little as 20,000 hard miles on it may need some or all of its basic components replaced before high- performance parts can work to full efficiency. Guldstrand Engineering offers a full line of heavy-duty basic suspension components which are designed to provide the foundation necessary for any high-performance or race car.

The second step in preparing your car is to decide what function you want your car to serve. This is the single most important decision that you will make and your satisfaction depends on it. Experience has taught us that there are three general functional categories:

GRAND TOURING-This category represents best all around design for high-performance street use. Parts installed on a Grand Touring car must be selected with equal concern for handling and ride quality. Owners of factory sports coupes, such as the Z-28 or Trans Am, who desire additional performance without sacrificing ride quality should use Grand Touring parts. These high quality parts will provide the fine tuning which factory cost cutting measures do not allow.

SLALOM-This category is for cars used in auto cross and slalom competition. Slalom parts are designed with greater concern for handling than for ride quality. Owners of factory sports coupes who engage in auto cross competition will find that these parts greatly improve handling and response at the expense of some ride comfort.
Slalom parts are engineered to withstand the higher energy levels generated by high cornering forces. They will help you find the fast line between the cones.

RACING-The racing category is designed for
its cars used solely in sanctioned road-racing events. Racing parts make no pretense at providing any of the comforts normally expected in a road car. They consist of proven products which have been used on winning national and professional race cars since 1967. If you are a racer looking for those few extra tenths of second needed to keep ahead of the competition, these parts offer maximum performance.

It is our experience that GRAND TOURING parts give the best general street performance results. They provide what most of our customers feel is a good balance between ride comfort and handling. The SLALOM and RACING parts have been proven on slalom courses and race tracks around the world. They represent our latest developments in high-performance parts for these specific uses. SLALOM and RACING parts should generally be used only by those engaged in these specific activities.

Page 9


--------A FEW WORDS ABOUT UNDER STEER---------

It is widely believed that installing heavy front springs in an automobile will increase under steer. While this is true for race cars which have a minimum of body roll, it's not true of most factory springs in your grand touring car will eliminate body roll and prevent the front tires from rolling under. The added traction gained by keeping the tires from rolling under more than offsets the added load created by the heavy front springs. Thus, your front end will stick better.

If you have an under steer problem with your grand touring or slalom car, there are numerous remedies to cure it. The following are the first four remedies you should try.

Remember to make only one change at a time so you can evaluate the improvement.

1) Increase the front tire pressures relative to the rear.
2) Realign the front end to increase negative camber and positive caster (see alignment
specs below).
3) Install heavy front springs to limit body roll and prevent front tire roll under.
4) Install a rear sway bar, increase its size, or install stiffer rear springs.



CAMARO/FIREBIRD ALIGNMENT SPECIFICATIONS

YEAR USE CAMBER (deg.) CASTOR (deg.) TOE-IN

1967-1969 RACING 1 ½ to 2 neg. 3 to 4 1/8 pos. 1/8" out to 1/8" IN
SLALOM 1 to 1 ½ neg. 1 ½ to 2 ½ pos. 0" to 1/8" IN
TOURING ¼ to ½ neg. 3 to 4 pos. 0" to 1/8" IN

1970-1981 RACING 1 to 1 ½ neg. 3 ½ to 4 pos. 0" to 1/8" IN
SLALOM ½ to 1 neg. 2 ½ to 3 ½ pos. 0" to 1/8" IN
TOURING ¼ to ½ neg. 3 to 4 pos. 0" to 1/8" IN

1982-Present RACING 1 to 1 ½ neg. 4 to 5 ½ pos. 0 " to 1/16 " I N
SLALOM ¼ to ½ neg. 3 ¼ to 3 ¾ pos. 0 " to 1/16 " I N
TOURING 0 to ¼ neg. 3 to 4 ¼ pos. 0 " to 1/16 " I N



NOTE: These settings represent a place to start. Optimum setting for each track or driving techniques must be determined by testing.

Last edited by autoxcuda; 11/04/22 06:59 PM.
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091702
11/04/22 07:16 PM
11/04/22 07:16 PM
Joined: Jan 2003
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Pikes Peak Country
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TC@HP2 Offline
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Everybody has made some good points so far. I'll give you my input on this because I have done a very relevant experiment right along these lines.

Way back in the 90s, I built a 425 horse small block for drag racing. High compression, long duration cam, single plane intake, big carb, the usual. Mated it to a built automatic with high stall converter and a 4:56 spool out back. Dropped it in the car I had that was most complete at the moment. This was a basic street car I picked up at an auction. Nothing fancy, but basic and solid. Completely stock suspension all the way around. Stock t-bars, sway bars, leaf springs, around 3500#. I did put lightweight wheels and slicks on it. Car would run 12.7 to 13.0 at around 105. Ran it for a summer while I was working on two other cars I had.

2nd car that was further along was a pro-street style '67 Plymouth. Big t-bars, big sway bars, flat leaf springs, non-adjustable gas shocks, fat 17" Goodyear Gatorbacks (remember those), and subframe connectors. Weighed around 3200#. Transplanted the engine, trans, spool and drag wheels/tires directly into this car. Car ran 13.2 @ 102 like a freaking clock, pass, after pass, after pass. Occasionally it would dip to 13.4 based on the DA but it was deadly consistent. Ran this for a summer.

3rd car finally was completed to a point it could be used year 3. Dedicated drag car with six cylinder torsion bars, modified SS leafs, three way adjustable drag shocks with 90/10 front and 50/50 rear, no sway bars, dedicated drag style fuel system, subframe connectors, roll bar, weight around 3000# Moved the entire driveline combo into this car. In this chassis, the combo ran 12.0 to 12.7 at 108. Set up was very DA sensitive and after having a car that ran like a clock, it took constant adjustment to get it to work consistently.

So, there are three examples if differing stock style configurations utilizing the same exact same powertrain and the resulting impact on drag strip performance. Never took any of them to an autocross or road course. Two of them did drive on the street. The '67 was an absolute kick to drive on the street - solid, cornered flat, firm without being rough. The other was okay, but nothing impressive. It was stock. The drag car, just driving around the strip to the scales, tech, return road, wallowed like a drunken pig. I'd never want to drive something like that on the street. Could any of these been better, faster, quicker with link or coil over suspensions, sure. It just wasn't where I wanted to go with these cars so I'd ask you, what defines " hold its own" at the drag strip? My 13.2 e.t. small block put many a larger displacement and faster car on the trailer.

Since you will be bracket racing when you do take it to the drags, the consistency of the handling suspension on the drag strip can be a big bonus to predicting e.t.s and going rounds. The high power engine will be a bear on an autocross, but it can be managed with a soft right foot. On a road course it will certainly require some good braking to haul it down from speed it will be capable of.

Re: Such thing as a dual-purpose E body? [Re: TC@HP2] #3091764
11/05/22 03:08 AM
11/05/22 03:08 AM
Joined: Jul 2005
Posts: 673
California
BigDaddy440 Offline OP
mopar
BigDaddy440  Offline OP
mopar

Joined: Jul 2005
Posts: 673
California

Thank you to all who responded, it's truly appreciated. I do want the car to sit lower and more aggressive than stock, and I do plan to run a staggered wheel size with quality disc brakes on all four corners. The biggest recommendation take-away here was = to keep and work with the factory style suspension. If I go that route, I think I have a pretty good idea of what I'd run up front, but could use some advice on a high quality front shock, preferably adjustable, that works well with 1.03" torsion bars. I believe I've read AndyF recommend an adjustable Koni shock in a previous thread. Also, any thoughts on the factory lower control arms? Any value in a QA1 lowers or are the stock units the way to go?

Out back, I do want to run a wider tire than a stock set up would allow. Running a custom width rear, or B body width rear is planned, and unless I were to go with one of the 4-link systems, I'll likely relocate the leafs inward a bit to make room for more tire. I have no plans on modifying the inner wheel structure. I don't need to go that wide nor do I like that look. I believe there's a few leaf spring relocation kits out there. If anyone would care to provide any information on their E body rear suspension sets up, and how they work on the street vs drag racing, that would be great. I'm concerned about wheel hop if I run a rear leaf that's too stiff.

Once again, I'm really taking this all-in and considering the advice that's being offered. Thank you.


1969 A12 Roadrunner
1970 Plymouth Cuda
1968 Dodge Dart
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3091811
11/05/22 10:09 AM
11/05/22 10:09 AM
Joined: Jan 2003
Posts: 5,322
Pikes Peak Country
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TC@HP2 Offline
master
TC@HP2  Offline
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Joined: Jan 2003
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Pikes Peak Country
My current E body runs 26x10x15 in front and 26x12x15 rear with a 1" relocation kit. Leafs are zero arch oval track versions with a sway var. Front is turned down an equivalent amount with big T and S bars. No street or track time on this set up yet.

I've also test fit a 295/65x15 drag radial in this set up. This was the same tire I used on the drag race set ups. Super grippy. It fit in the well okay but was pretty tall compared to the 26" set up.

The 1" relocation kit allows you to move the springs in parallel and will allow as much tire as possible within the stock wells. If you move the leafs in 3", then you would need to modify the well to utilize the additional space. The stock well should accommodate a 305mm tire with careful backspace selection on the rim. There is a user here that has a 315 square set up in his Cuda, so you can put a lot of tire under an E body without sheet-metal changes.

There are numerous quality shocks out there in preset range, a limited adjustment range, single, or double adjustable. IMO, unless you are a meticulous record keeper or are familiar with playing with shock dampening, I'd recommend against double adjustable for a casual user. It is very easy to go down the wrong path when you have 64 separate adjustments on four corners and you are trying to remember what you had each one set to.

Wheel hop is a problem with leafs that are too soft, not too heavy. The leaf is overpowered and twists up until it reaches a non-elastic point where it snaps back. This can be addressed with more leafs, more half leafs, snubber, or another traction device. Cal-tracs and split leafs may work well in this situation without going with higher rates but may not articulate as well. I have no experience with Cal-tracs. The trick to doing this to avoid spring wrap is that you then will need to balance the spring rate of the leafs against the front t-bar rates. A heavy leaf pack to avoid axle wrap may require more than a 1.03 t-bar to remain neutral handling. It definitely would not need a rear sway bar. Handling is al about the balance of rates front to rear. This is why Hotchkis and others have actually softened the leaf rates on their systems while only moderately stepping up the front rates. A good drag set up may need to be the opposite so you will need to compromise a bit on both or have some ability to adjust in either direction based on what your doing on any particular day. At 700 some horsepower, you will always have the ability to annihilate the tires. No triple duty suspension system will ever allow you to just dump that much power into it.

100_1843.jpg295Chall0005.jpg
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3092101
11/06/22 06:12 PM
11/06/22 06:12 PM
Joined: Dec 2021
Posts: 810
Loudoun County, VA
Brad_Haak Offline
super stock
Brad_Haak  Offline
super stock

Joined: Dec 2021
Posts: 810
Loudoun County, VA
I'm ASSuming your idea of dual purpose isn't limited to: Purpose 1 - drive to drag strip & back; Purpose 2 - run down drag strip

Only semi-joking here, since the experience w/ my Challenger is the suspension setup that worked best for overall handling on the street wasn't a good choice for getting down the strip on street-legal rubber.

I decided years ago that on-track performance was the priority, with the ability to drive to & from the track the second priority (constraint). I can pull 1.45 60-ft on a 275/60R15 DOT drag radial, but Holy Mother of G*d, do NOT ask this car to go around a corner quickly! shock + laugh2


2021 Challenger 6.4L Scat Pack 1320 (2022)
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
wheels, tires, air filter: 1.714, 11.833 at 115.80 (DA 310 ft)

1973 Challenger 452 ci street/strip (2008)
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
Re: Such thing as a dual-purpose E body? [Re: BigDaddy440] #3108239
01/03/23 05:45 PM
01/03/23 05:45 PM
Joined: Nov 2015
Posts: 4
LA
racerjoe Offline
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racerjoe  Offline
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Joined: Nov 2015
Posts: 4
LA
I'll keep this simple. I doubt you will be on the autocross or drag strip every weekend and the car will see more miles on the street, right? Build it to handle well since it will be a nicer car to drive on the street. Having a good autocrossing car will be a by product of that. A car setup just for drag racing won't be fun to do any real street driving with. Don't be afraid to use large t-bars, like something around 1.12, just get some good shocks to control them. Sounds like you have the HP to run a decent number. I'm not sure what "hold it's own means" because that can be a vastly different number based on who you ask. A 700HP engine in drag prepped car should run low 9s easy. I don't see any reason why you couldn't run 10s with it in street trim.

I've run the Grand Champion event at Moparty for the last 2 years. We autocross, drag race, and speed stop. I used to drag race a lot. My car is set up for autocross/street now. While drag racing is fun, the autocross is much more fun and I'd rather have it perform better doing that. Not to mention street driving is a blast. It's fun to cruise down the interstate keeping up with modern cars and taking exits at high speeds.

Re: Such thing as a dual-purpose E body? [Re: racerjoe] #3109002
01/05/23 02:22 PM
01/05/23 02:22 PM
Joined: Jan 2010
Posts: 1,387
NW Chicago suburban area
Mopar Mitch Offline
pro stock
Mopar Mitch  Offline
pro stock

Joined: Jan 2010
Posts: 1,387
NW Chicago suburban area
One way to offset the ride -- between drag and autocross, etc -- is to use double-adjustable shock absorbers. BUT... you have to learn how to set your settings with them... practice, practice, practice... multiple lessons and different results.

Also, learn different settings of tire PSI (front vs rear) for each type of event -- drag and autocross.


If you further dare, try and make different front wheel alignments... keep all the results in a log book.


I also run the Holley MOPARTY Grand Championship event... lots of daytime autocrossing, then some evening drag racing... an overall blast of fun!

Last edited by Mopar Mitch; 01/05/23 02:26 PM.

Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: Such thing as a dual-purpose E body? [Re: Mopar Mitch] #3109403
01/06/23 01:17 PM
01/06/23 01:17 PM
Joined: Feb 2022
Posts: 533
Nor here, Nor there
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Dart 500 Online content
mopar
Dart 500  Online Content
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Joined: Feb 2022
Posts: 533
Nor here, Nor there
As others have said, I'd build it to be a great handling street car before even thinking about drag racing, IMO that can even be band-aided if you're looking for a great ET after the fact.

Re: Such thing as a dual-purpose E body? [Re: Dart 500] #3109456
01/06/23 03:47 PM
01/06/23 03:47 PM
Joined: Nov 2015
Posts: 4
LA
racerjoe Offline
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racerjoe  Offline
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Posts: 4
LA
Nitrous doesn't car what suspension you have. It will go faster!







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