Drag racing suspension mods..suggestions?

[biomedtechguy]

I am posting this here because I believe that you pro touring guys should have lots of suspension info. My 70 Roadrunner (440 6bbl, 4 speed, Dana 60) has a lot of wheelspin in drag racing applications. On my wish list is traction improvement and front suspension replacement. I am considering a leaf spring relocation kit and some aluminum Rally wheels all around, with the rears in a size maximizing tire width inside of the stock fenders (although I would consider tubbing if I HAVE to). Rear leaf spring relocation and Cal Tracks, etc. or should I just go 4 link? On the front, I want rack and pinion power steering (it is stock manual now) and other improvements like adjustability, but I also will have to have good travel and setup to allow for weight transfer to the rear on launch, along with the other improvements in ride, driveability, and handling that may come along with it. I primarily use the car for car shows which I DRIVE to, street cruising, and occasional track days. Thanks for your suggestions!

 

[Cranky]

What size are your rear tires and what is the stance of the car. Do you have access to scales? Is the rear end high? Lowering the rear can and usually does help traction but sounds like you are wanting your cake and eat it too. It's difficult to set up a car for drag racing and make it handle well too. Basically, it's a compromise. Moving the springs in will allow larger rear tires but generally will not help the car handle in corners but using stiffer springs will help. What kind of tires are on it now? With today's tires, you can get pretty decent traction but it also depends on how fast your car is. Mini tubs will allow a fairly large tire to fit in. I had 12.5W's on a 68 roadrunner years ago that had mini tubs in it but also had ladder bars. They actually measure just a tad over 13" of tread width and were a tight fit.....

 

[HYRDGOON]

Same questions as Cranky. Can also tell you Cal Tracs alone made a huge difference in wheelspin in my car

 

[biomedtechguy]

Thanks guys. I believe that any updating done right with modern components will improve handling. Let me be more specific: I want to add suspension parameter adjustment flexibility that will overall improve over stock, FOCUSING on drag race acceleration and performance. In other words, I would expect an OVERALL improvement in driveability and ride with a HUGE significant improvement in traction and drag racing suspension adjustability. If I chose, for instance, an AlterKation Transformer front end, would that accomplish that? would there be a better choice for what I want to achieve? What, if anything, would I gain/lose going 4 link over leaf spring relocation and Cal Tracks? Also, I want the widest rear tires under the fenderwells in the REAR, not so concerned about the front, and I would prefer not to tub, but I am not opposed to it. Thanks a lot!

 

[HT413]

I have a 4 link and mini tub setup and IMHO, you'd have to cut up the car significantly to get that all in there (plus unless you do it yourself, I'd think it would be a pretty costly job). You never mentioned your et goal, but there are plenty of poeple getting deep into the 10's with super stock springs and stock front suspensions on 9" wide tires in factory wheelhouses. My car when done will be a 11/12 second street car, so my setup is way overkill. I just like the look and feel of the big tires out back, to be honest.

 

[Hemirunner]

Put caltrac bars and their split mono leafs on the rear. You can use their drag shocks as well or go to double adjustables if you're really serious. A 275/60/15 on a set of lightweight aluminum 15x8 wheels in the rear will help. As for the front, you can do it with the stock front suspension. I run an alterktion in a drag application but the stock suspension will do just as well. You just need to ditch the sway bars and make sure evything pivots easily. Double adjustable shocks are mandatory on front in my opinion. Drag and pro touring suspensions are polar opposites in my experience.

 

[Budnicks]

Budget, your fab skills, welding skills & your suspension tuning skills,
may also all play a big part here too...

There's allot of stuff out there too,
QA1 {I use allot of their stuff now} Rielly Motorsports, Magnum Force Racing,
PST, Ride Tech, Competition Engineering & even Alston or Chassis Works
or other co.'s too have decent engineered suspension pieces, for front & rear
some more or less bolt in, some need more fabrication & welding,
some are lighter or stronger than others or better engineered/design too etc...

If you want to go really fast, stay safe & have allot of suspension adjustability
4-Link & coil overs, racing slicks, but you need to modify the car more too...
If you going to go racing "for real, actually get the best out of the car", this is the best overall choice IMO,
but for a street/strip car, maybe not so much & it's allot more work...
I've been 6.90 @ 190+ with them...

Shocks styles & sway bars sizes, will dictate allot of the street manners & handling...

Ladder-bars are good too, easier maybe to fit & install, less adjustment than the 4-Link thou...
Been in the mid 7's with ladders & coil-overs

Just don't skimp on heim/rod ends on either of the above,
they are under allot of stress & forces, not a place to be cheap...

Super Stock springs work really well too, with the spring relocation or bigger tire or not...
Just not much adjustability thou...
Generally pretty good for up-to about hi-9's IMO, doesn't mean you can't go faster thou...

CalTrac's work very well for what they are, std length axle, no tub/wheel well mods
{except rolling under the lip} to clear 315/60/15 MT Drag Radials
I've been 8.58 @ 156 on the stock RR springs
{also with spring rollers in the rear to free up some spring travel}

Shock & tire choices will be a real deciding factor...

There's more than one way to skin that proverbial cat, different strokes for different folks, what works for me may not be ideal for others...

here's a little explanation from Chris Alston
http://www.cachassisworks.com/stories/techcac-003_web.pdf

Check out Calvert site {CalTracs}
http://www.calvertracing.com/index.php

Here's a decent write up & some tech advice etc., it's from 2005 but still relevant...
http://www.baselinesuspensions.com/info/Launching_A_Drag_Car.htm

I hope some of this helps & good luck what ever you decide,
IMO some are more suited for all out racing &
some are more suited for a little bit slower, street/strip cars too...

 

[biomedtechguy]

GREAT information! Thanks. 1/4 mile times in the 10s-11s from my perspective would be the fastest. I want to be able to drive my car to shows, up to 2 1/2 hours one way. Wanting to do a stroker in the future around 650hp and torque. Since I am already having rear traction problems, and I haven't yet put slicks or drag radials on it, I have a clean slate. I likely will go the relocated leaf spring Cal Tracks route for budget and performance reasons based on what you have shared. As far as the front end is concerned, I have replaced a number of worn stock components, but I am still not satisfied with it and as I get older, the stock manual steering isn't getting any easier to deal with. Thanks again!!

 

[Canyon707]

We shop at the same stores. Quality matters.

 

[Budnicks]

GREAT information! Thanks. 1/4 mile times in the 10s-11s from my perspective would be the fastest. I want to be able to drive my car to shows, up to 2 1/2 hours one way. Wanting to do a stroker in the future around 650hp and torque. Since I am already having rear traction problems, and I haven't yet put slicks or drag radials on it, I have a clean slate. I likely will go the relocated leaf spring Cal Tracks route for budget and performance reasons based on what you have shared. As far as the front end is concerned, I have replaced a number of worn stock components, but I am still not satisfied with it and as I get older, the stock manual steering isn't getting any easier to deal with. Thanks again!!

Some of the stuff you can get from Summit Racing {lowest price & free shipping}
or Mancini Racing
If your on a budget check out QA1, tubular k-member & tubular adj. upper control arms adj. or not,
even a tubular lower control arm, that has the sway bar mts. even, strut rods or dynamic adj. strut rods...
You can still use stock locations, stock style torsion bars &
stock style steering if need be too,
just more limited on oil pans {prefabbed mass produced headers too}
with stock type rear steer draglink etc.

Not cheap quality {$ wise} but still not as pricey as some of the others,
especially in full kit form....

With the QA1 you can buy a piece at a time if need be, bolt on...

I like the SPC upper control arms {I got from Mancini Racing}
they are double adjustable, even while still on the car, easy peasy...
maybe not as cheap thou $250 ea. IIRC

 

[383man]

I have a 4 link and mini tub setup and IMHO, you'd have to cut up the car significantly to get that all in there (plus unless you do it yourself, I'd think it would be a pretty costly job). You never mentioned your et goal, but there are plenty of poeple getting deep into the 10's with super stock springs and stock front suspensions on 9" wide tires in factory wheelhouses. My car when done will be a 11/12 second street car, so my setup is way overkill. I just like the look and feel of the big tires out back, to be honest.

He is right on as my car is like he says. My 63 Plymouth Sport Fury uses just Superstock springs in the back with the longer MP shocks. All the rest of the suspension is stock other then Comp 90/10 shocks up front. I have stock wheelwells as the complete body on my car is stock and the springs are in the stock location. I just use Hoosier radial slicks that are 30 x 9 and I run them on the street and strip. The car hooks fine on them as it has run 10.70's on the 9" wide tires. I built my 440/493 eng as a pump gas eng and it has the full exh system as I can drive it for hrs with no problems. I have driven it to Carlisle PA a few times which is about a 180 mile round trip.
The point is you dont have to tub your car to run 11's or 10's if you dont want to. The tires are very good in todays world and with a good suspension you can hook good on even 9" tires. Sure you can tub your car and run 12" wide tires under it if you like but our point is you dont have to tub your car to run 10's or 11's. I only use SS springs but you can run the Caltracs as many do and they seem to work very good. Good luck , Ron

 

[biomedtechguy]

Thanks so much guys!! Great info!! Thanks for the pictures also! The car is apparently in great shape body-wise (without media blasting it to see for sure). As far as tubbing goes, that decision also depends on how wide a rear tire I can get without tubbing, but a buddy of mine says a 315 will fit without tubbing.

 

[Hemirunner]

That's a 13" tire. Everything will have to be perfect to get it in there without tubbing and it's going to rub hard on the outer wheelhouse during compression. Leaf spring relocation is a must.

 

[biomedtechguy]

That's a 13" tire. Everything will have to be perfect to get it in there without tubbing and it's going to rub hard on the outer wheelhouse during compression. Leaf spring relocation is a must.

Thanks for the "size translation" lol. Leaf spring relocation kit is in the plan. I would not want the fender to be contacted by the tire under any circumstances. THanks for the info!

 

[HYRDGOON]

Yes there's a few guys with 315's stuffed into the wells but I'm willing to bet they're all street driven cars none of them are launching hard.

I know where you're coming from with the front suspension and for the cost of all the little things adding up instead of playing around just bite the bullet and get the magnum force or the AlterKtion. I would prefer the Magnum force of the 2.

As far as the back end goes are you happy with your ride quality now? If you just want to go to the track and have a car capable of hooking up occasionally I would start on the cheap and work your way up. Cal tracs and split monos as Hemirunner said you can firm up the spring at the track and instead of focusing on one do it all wheel why not get a pair of steelies with some slicks to throw in the trunk when you're headed to a track day. Then run whatever you want normally?

My 522 made 660 peak torque at the crank N/A and my springs were super soft so I had bad wheel hop. As a temp fix while I decided what to do (new springs, 4 link) I added Cal Tracs and you wouldn't believe the difference especially on a shitty set of springs.


There's a Pro-touring tire size thread here and a how wide can i fit in the 66-70 Mopars section that I've been all over because I'm trying to determine how big of a tire I can fit as well but with a different goal in mind. I just want style and to fill the well as I'm (hopefully) changing me wheels this year.

http://www.forbbodiesonly.com/moparforum/showthread.php?99928-Pro-touring-tire-size

http://www.forbbodiesonly.com/moparforum/showthread.php?98201-Rear-tires-and-wheels

- - - Updated - - -

Budnicks, I wish I'd known about those SPC double adjustable UCA's I just spent double that on a set of Magnum Force double adjustables

I wasn't sure who sold tubular LCA's either so thanks for that heads up!

 

[Cranky]

Thanks so much guys!! Great info!! Thanks for the pictures also! The car is apparently in great shape body-wise (without media blasting it to see for sure). As far as tubbing goes, that decision also depends on how wide a rear tire I can get without tubbing, but a buddy of mine says a 315 will fit without tubbing.

That's a 13" tire. Everything will have to be perfect to get it in there without tubbing and it's going to rub hard on the outer wheelhouse during compression. Leaf spring relocation is a must.

Isn't a 70 roadrunner fender well pretty much the same as a 68? I mentioned earlier that I had 12.5W's (13.25" of thread) and my car was mini tubbed with ladder bars and they were snug in there. I don't see it happening with a 315 unless they are short and the rear is lifted some and if you do that, you're not going to see the much advantage if any that a wide tire offers. Throw some scales under your car at normal ride height then jack up the back 2" and look at the difference it makes. Even just a few lbs can make an adverse effect on traction especially when you're on the edge to begin with. Yeah, you can throw some weight in the back to help counter act it but why do that? Weight out past the rear wheels hurts handling too plus it slows pitch rotation on the launch which is something you don't need if your traction is already at a minimum.

 

[Hemirunner]

Yeah the 68-70s are all the same. Like I said, it's gonna hit the outer tub on the launch and anytime you hit a bump. I've been 9.90 at 140 at 4250lbs in a 70RR on 275 drag radials. I'm planning on a 315 on my new car, but it's mini tubbed and I'm planning on as near as 2000HP as I can get.

 

[biomedtechguy]

Thanks. I was repeating what someone said re: the 315s. NO, I am not going to jack up the rear to make them fit. So I will see what will fit, and decide from there. Fat tires on the back are for grip and appearance. Thanks again!

 

[daytona kid]

Not sure about this guy's tire size. I've used this vid several times before for similar discussions but it's a perfect example of the traction you can get with not so wide tires. I'm guessing they are 315x60 M/T street/drag radials, which is 30in dia x 11.9in tread width and 12.9 section width, and I believe will fit snugly in a 70rr well. Minor trimming and/or tweaking of the well lip may be needed. I'm pretty sure his car is not mini-tubbed and leaf relocated from looking at the rear in the vid. If you want your car to sit lower in the rear you may need to do a "de-hump" mod. I'm planning on 315s for my 68 charger. Several of us here have done the de-hump which helps keep a tall tire from rubbing up in the outer well. I also installed off-set leaf hangers. They give 3/4in more room to each side to the leaf, which is where the tire will hit before the inner well. Unless you're just wanting the "super wide tire look" I don't believe mini-tubbing and leaf relocating (which are both a good bit of work) are really necessary to get all the traction you should need while strip racing. I've had 3-70RRs with N50x15s which were 27.5 dia x 12.65 section width. They sat fairly low with no rubbing after very little well lip tweaking. Also note the guy says he is running a stock front end. Just saying you don't have to do a lot of unnecessary work and/or go broke to go fast! jmho.

https://www.youtube.com/watch?v=bkGD3JITfb0

 

[65hemi]

That's my buddies' Satellite (since sold). 295/65-15 MT drag radials, no tubs, leaf springs w/CalTracs, stock front end, all steel except hood. Ran low 9s