12 How To Make Your Mustang Hook

How To Make Your Mustang Hook

Friday, December 12, 1997

Making Your Mustang Hook, Part 1
Tires and Drag Racing

Now-a-days, it’s not uncommon to see a street-driven 5.0 Mustang that has 400 and even 500 hp. With the wide availability of quality cylinder heads and 10 psi from an S-Trim Vortech, power is relatively easy to come by.

Once a person has spent the money to build an engine capable of these power numbers, one of the first things they do is take it to the drag strip for a quantifiable result, an ET slip. Unfortunately, many people are disappointed their first time out and come home with a 1/4 mile ET that is one full second slower than they thought it should be.

One of the most over-looked and taken for granted aspects of a good ET is traction. Consideration has to be given to tire choice, traction bars and other suspension tuning. This Water Box is part 1 in a 3 part series and will discuss tire choice. Traction Bars and Suspension mods will follow in the next few weeks.

Tires and Drag Racing
The most important modification you can make to give your Mustang optimum traction is investing in a pair of drag slicks. There is nothing like the feeling of letting out the clutch at 5000 rpm and feeling the car shudder and seeing the sky for a brief second. Too many people take tires for granted, or even worse, think they can get by with a street tire. For a person that will only visit the drag strip once a year, fine. But for someone who is looking for an optimized ET, slicks are a must.

Just about every brand of slick will work well. Plenty of serious racers all use a different brand of slick and do just as well as one another. We’ve tried all of the available slicks that fit the Mustang, Good Year, Firestone, Mickey Thompson, M & H and Hoosier. From our experience, no tire lasts as long, and hooks as consistently in different conditions as Mickey Thompson’s ET Drag. But you can’t go wrong with any of the other slicks we’ve listed.

Perhaps the most common MT size is a 26″ x 10″, which when mounted on a 15″ x 8″ wheel with a 5.5″ backspace fits a GT or LX very well and requires only minor hammering of the inner wheel well. At 26″ tall, the tire is nearly stock gatorback height. The 26″ x 10″ is a good tire and provides plenty of traction. But for optimum traction a better choice is the MT 28″ x 10.5″ slick. The tire is only slightly wider than the 10″ version, but the additional 2″ of height provide more leverage and a larger contact patch when the tire flattens during the initial launch. This alone provides more traction and better consistency. Unfortunately, this tire requires more hammering and minor trimming of the GT’s ground effects for a proper fit. Don’t be afraid of a little hammering, once the car has a tire on you’ll never know.

Slick Preparation
It has been traditional practice when mounting a drag slick to use racing inner-tubes and wheel screws. Wheels screws are drilled through the outer lip of the wheel and extend only a fraction of an inch into the tire, the purpose is to keep the slick from spinning on the rim during a hard launch.

While this is widely accepted, it’s not the best way to mount a slick on cars running slower than 8’s. For years, we too had used inner-tubes and wheel screws until a famous Super Stock chassis builder told us not to. So we tried a pair of slicks that were mounted tubeless and screw-less. Low and behold, the car’s 60 ft times decreased and the car was more stable on the big end.

There are several reasons for the improvement. Inner-tubes actually prevent the tire from distributing air pressure evenly and properly. When using an inner-tube, the bulk of the air pressure is placed on the center of the tire instead of evenly across the tread. Many racers use as little air pressure as possible in an effort to make the slick hook harder. When in fact, the average slick will hook its best without an inner-tube when air pressure is around 11 – 14 psi hot.

Too little air places most of its pressure on the outside edges of the slick, not fully utilizing the center. And too much air does the reverse. It’s much the same with radial tires, if they’re under-inflated the edges wear prematurely and over-inflation wears out the center of the tread. So once you’ve gotten rid of your inner-tubes, start increasing air pressure a pound at a time until the car looses traction and then back up a pound. Another way to check for proper tire inflation is to drive through a small amount of water and then onto dry pavement. Look at the water marks the slicks left. You’ll easily be able to see if the contact patch is even or if it is favoring the edges or center.

A slick with too little air pressure causes the car to sway and feel unstable at the end of the track. Running additional air pressure stabilizes the car on the big end of the drag strip and makes the ride feel much safer and stable.

And don’t worry about the slick spinning on the rim. If they’re properly mounted, it’s not a problem. We’ve paid close attention to slick travel, and on a high 9 second, 3450 lb Mustang, they only move about one inch every 20 passes, hardly anything to be concerned about.

D.O.T. Slicks, Sticky Street Tires and Drag Radials
There are a significant number of occasional racers that can’t bring themselves to buy a set of slicks but want something more than their Good Year radials provide. A number of companies have stepped up to the plate with offerings to meet this market. While a D.O.T. tire that works well at the drag strip sounds very appealing, they do not work as well as a true slick, regardless of what the advertising may claim. The only exception is Mickey Thompson’s ET Street series, which are nothing more than an ET Drag with some very small and narrow tread lines which all but disappear after a burnout or two. It’s amazing that they received D.O.T. approval, nevertheless, they work extremely well. M & H also offers a slick-like tire that has D.O.T. approval, they work fairly well but they’re not as good as the Street ET.

There are also a number of soft compound street tire offerings from Hoosier, MT, McCreary and BFGoodrich. All of these tires will provide better traction than a highway radial, but they still can’t match the performance of a good drag slick. There are some racers who have made impressive passes with these tires, but they’re the exception, not the rule. We even have a customer who runs 12.20’s on slicks and with exceptional driving, 12.60’s on his Michelin radials. But it’s important to remember that people with results like these are few and far between, so don’t be disappointed if you can’t duplicate them.

A common mistake we see at every drag strip we go to are racers doing burnouts in the water box with their treaded D.O.T. tires. Excessively heating a street radial can actual diminish its ability to provide traction. Many of the treaded “sticky” tires like the Hoosier Quick Time and MT Sportsman Pro will do a little better when hot. But the problem is that a treaded tire will carry water with it up to the starting line in between the treads no matter how furious the burnout. Even a small amount of water on the starting line will send the stickiest tires up in smoke. So if you’re racing with a set of treaded tires, try and avoid the water box. You’ll most likely hook better, and racers behind you will be much happier.

Slicks are a Wonderful Thing
Still, after knowing all the facts there are many people who are hesitant to buy a pair of slicks. The costs are relatively low, especially when compared to many of the other modifications people make. A used pair of 10-Hole LX wheels can be had for around $50, and 15×8 Weld Draglites are very affordable. A quality set of slicks will run you in the neighborhood of $300. So considering the cost, it’s a relatively inexpensive way to pick up 4 tenths, or as much as a second.

Time and time again we’ve seen cars with 300 hp run quicker times than cars with 400 hp, all because of traction. So if you’re planning to go drag racing, and want an optimum ET, be sure to go prepared and make sure you have a set of slicks. The bottom line is that you’ll never realize the full potential of your car with a radial or street oriented tire at the drag strip. Slicks are not that expensive and can often make a more substantial difference in ET than additional power.

Making Your Mustang Hook, Part 2
Traction Devices

Now-a-days, it’s not uncommon to see a street-driven 5.0 Mustang that has 400 and even 500 hp. With the wide availability of quality cylinder heads and 10 psi from an S-Trim Vortech, power is relatively easy to come by.

Once a person has spent the money to build an engine capable of these power numbers, one of the first things they do is take it to the drag strip for a quantifiable result, an ET slip. Unfortunately, many people are disappointed their first time out and come home with a 1/4 mile ET that is one full second slower than they thought it should be.

One of the most over-looked and taken for granted aspects of a good ET is traction. Consideration has to be given to tire choice, traction bars and other suspension tuning. This Water Box is part 2 in a 3 part series and will discuss traction bars. Part 1 – Tires and Drag Racing can be found in the Water Box Archives. Part 3 – Suspension Considerations is currently featured in the Water Box.

This installment of the “Making Your Mustang Hook” series focuses on traction devices. What follows is a brief overview of what they are, how they work and which ones we recommend.

What are Traction Bars?
The term “Traction Bar” is one that is still used (loosely) to describe a device that helps plant the rear tires during acceleration and increase available traction. They also go by many other names, Lift Bars, Trailing Arms, Solid Control Arms and many others. But they all strive to do the same thing – transfer as much of the car’s weight as possible to the rear axle during acceleration.

How They Work
To greatly oversimplify things, during a launch or when under load, the rear axle attempts to rotate upward. If left unchecked, the rear axle will rotate upward to the limits of the flexibility of the stock suspension and then snap back downward in a spring-like effect. This action creates the very undesirable effect known as wheel-hop. It is also the action that causes a suspension to “unload” and loose traction after it initially hooked.

Traction bars take this mechanical energy created by the rear axle rotation and using leverage, lift the front of the car and apply weight to the rear suspension. By limiting the amount of distance the axle can rotate and providing a solid stopping point, wheel-hop is also eliminated (with good tires and quality track surface).

But one important thing to remember is that in order for any rear suspension traction improver to work, the tires must provide enough bite for the rear axle to rotate and apply leverage to the rear. A tire that is spinning does not provide the necessary bite for traction aids to work as they were intended. Even a serious 4-Link type drag race rear suspension will not be effective when used with the Mustang’s stock 225 gatorback radials. Many people are disappointed after spending the money on a set of traction bars and labor to install them only to find they are no better off than before – the car still cannot hook.

Pinion Angle
Some manufacturers have produced products that promise big potential traction increases by altering the Mustang’s rear pinion angle. The pinion angle can be changed several degrees by using adjustable upper control arms and/or adjustable lower control arms (traction bars).

We spent several exhaustive track sessions experimenting with dozens of different pinion angles on a mid 9 second Mustang (equipped with adjustable upper and lower control arms) and found no improvement over the stock pinion angle geometry. Many of the settings actually hurt the car’s 60 ft. times and subsequent performance.

In our experience, the most important thing to consider when setting pinion angle is to ensure that when under load, the driveshaft will be as in-line with the pinion as possible. This usually requires an initial setting of negative 2° to negative 4° so that the pinion aims slightly at the ground. This setting is usually achieved with stock length upper and lower control arm settings. 90% of the traction bars we install are Mega-bites (we’ll get into why in a little bit) and even the “seniors” which are fully adjustable end up with a proper pinion angle 9 out of 10 times right out of the box with HP’s initial factory setting. To make certain your geometry is correct it’s necessary to use a pinion angle gauge, something we do with every traction bar install.

Which Ones Should I Use?
So now you’re asking, “Which ones should I buy?” Let us start this off by saying that there are over 25 commercially available traction bars and just about every one we’ve ever seen does a decent job. The most important thing is that they eliminate the weakness and flexing that is inherent in the factory upper and lower control arms. This is actually more important than corrected geometry. The stock Mustang 4-link rear suspension is actually quite good and capable of impressive 60 ft times with nothing more than adequate rigidity. We have one customer who has gone 10.04 @134.92, with a 1.37 60 ft. with just polyurethane bushings in an otherwise 100% stock rear suspension. The control arms aren’t even boxed.

So, with that being said . . . We exclusively use HP Motorsports Mega-bite rear control arms for several reasons. They’re extremely high quality, affordable, have some nice features and work well. HP claims improvements in 60 ft times over many other competitor’s traction bars. We recommend them for several reasons, but not because we’ve seen them provide better traction than others. We have had just as good 60 ft times with Southside bars, various tubular control arms and even the old Lakewood slapper bars (one of the first traction bars ever conceived which still work quite well).

But the Mega-bites do offer some serious advantages over others. They feature quality polyurethane bushings as opposed to the solid mount used by Southside and others. These bushings eliminate the severe torque box damage that is so common when using a solid mount. The bushings also transmit much less NVH into the passenger compartment.

The Mega-bites alter the geometry of the rear end, which changes the anti-squat and anti-dive percentages providing increased downforce on the tires. By this, traction under acceleration and braking is improved. And they come complete with spring spacers so the rear ride height of the car is easily adjusted.

There are also other types of rear suspension systems, like those offered by Griggs racing. Griggs developed several road race oriented components that also do a very good job in a drag racing environment. We’ve installed them many times with excellent results. But for the average drag racer, they’re kind of pricey. And when equipped with a set of slicks, we haven’t seen any 60 ft improvements over Mega-bites. Griggs claims advantages over others when using street tires but we have yet to test this theory.

So Hook Up and Go
So there it is. An oversimplified explanation of how and why traction bars work and which ones we recommend. But, there’s always a catch. As we mentioned earlier in the article, unless you’re using a stickier tire than what came with your car, traction bars won’t make any real difference. They need at least a little traction before they can begin to fully function as they were intended. We’ve seen impressive traction from Mega-bites and fairly large BFG Drag Radials, but for optimal traction there is no replacement for a good set of slicks. The bottom line is that you can spend as much money as you want on the rear suspension, but if you’re trying to find traction with lots of power and the usual radials, you won’t.

There are also many other factors and suspension considerations that can help a car hook, or hurt an otherwise capable suspension set-up. In Part 3, we’ll address weight relocation, improved weight transfer and other topics.

Making Your Mustang Hook, Part III
Suspension Considerations

Now-a-days, it’s not uncommon to see a street-driven 5.0 Mustang that has 400 and even 500 hp. With the availability of quality cylinder heads and 10 psi from an S-Trim Vortech, power is relatively easy to come by.

Once a person has spent the money to build an engine capable of these power numbers, one of the first things they do is take it to the drag strip for a quantifiable result, an ET slip. Unfortunately, many people are disappointed their first time out and come home with a 1/4 mile ET that is one full second slower than they thought it should be.

One of the most over-looked and taken for granted aspects of a good ET is traction. Consideration has to be given to tire choice, traction bars and other suspension tuning. This Water Box is part 3 in a 3 part series and will discuss suspension considerations. Part I – Tires and Drag Racing and Part II – Traction Devices can be found in the Water Box Archives.

This installment of the “Making Your Mustang Hook” series focuses on suspension considerations. By considerations, we mean all the things we haven’t yet addressed that can make a substantial difference.

Polyurethane Bushings
Many people already know that the soft factory control arm bushings are not conducive to efficient suspension travel. In other words the soft rubber factory bushings flex a lot during launch or cornering and allow the suspension to move further than it should, harming handling and traction. By installing a quality set of polyurethane bushings in the 8 pivot points of the rear control arms handling and traction are greatly improved. Polyurethane is much more dense than the factory rubber bushings and therefore much stiffer. They increase traction by preventing the factory suspension from traveling too far. The only down side is that they are also better at transferring noise and vibration into the cockpit. With polyurethane bushings you’ll also experience a rougher ride. But it’s worth it.

All good aftermarket traction devices come standard with polyurethane bushings. But don’t feel the need to run out and buy a set of traction bars just yet. The stock rear lower and upper control arms on a Fox chassis work extremely well with just the additional stiffness offered by polyurethane bushings. We have had very good results with polyurethane bushings and just a few other chassis mods. One of our customers, Mario Crocenzi has run as quick as 10.04 with nothing more in the rear suspension than polyurethane bushings in the factory control arms and an air-bag.

Polyurethane bushings installed in the front control arms can also provide a substantial improvement, especially for road racers. But to put it bluntly, they suck on a street car. Every little bump and vibration is transferred and seemingly amplified in the cockpit and steering wheel. So if you have a track only car or don’t mind major sacrifices in ride comfort, polyurethane bushings in the front control arms are an asset. But if you drive your car everyday on the street we wouldn’t recommend it.

Chassis Stiffening
Providing your rear suspension with a rigid chassis is important and aids in effective weight transfer to the rear wheels and eliminating chassis roll. Chassis roll is the natural tendency of the body to “twist” during hard acceleration.

Subframe connectors make a very substantial improvement in rigidity and are fairly inexpensive. They should be your first step in providing your rear suspension with a solid chassis. Don’t waste money on any bolt-in subframe connector. Bolts simply don’t provide a strong enough mounting point. For a subframe connector to provide optimal strength in MUST be welded-in. It’s also important that they be beefy enough to prevent flexing. Many of the available subframe connector kits available are too flimsy to provide quality stiffening. Use a heavy-duty weld-in connector like the ones we offer.

We’ve seen many cars that hooked hard without subframe connectors. And several of them are easily distinguished by the tell-tale wrinkles in the rear fenders and cracking A-Pillars around the front windshield. A uni-body suspension flexes more than most people realize.

A roll bar or roll cage also provides a great deal of chassis stiffening along with driver protection. Again, weld-in is much stronger than a bolt-in roll bar, though when done properly, a bolt-in roll bar is NHRA legal in unibody cars like the Fox chassis. Relatively few street cars actually need more than subframe connectors and even fewer drivers are willing to make the sacrifice.

Weight Reduction
Any weight that you can remove from your car will help it run quicker. And any weight that you can either take off the front end or transfer to the rear will make the car’s front end unload more quickly thus transferring weight to the rear end.

These are a few very effective ways of removing a lot of weight off the front end:

  1. Fiberglass hood

  2. Tubular cradle

  3. Tubular control arms

  4. Coil-over conversion

  5. Remove front sway bar

  6. Relocate battery to rear of car

  7. Light weight front wheels and tires

  8. Remove front bumper and 5 mph shocks (track only cars)

  9. Lightweight Front Runners

Weight Transfer, Front Suspension
Physically removing weight from the car or relocating it to the rear is important. But is is also very important to have a front suspension that reacts quickly upon launch and applies leverage to the rear suspension for added traction.

Removing the factory front sway bar is one quick, easy and completely free way to help your car hook harder. The factory front sway bar is intended to keep the suspension tight while cornering and eliminate body roll. The problem in drag racing is that it prevents the front end from easily rising into the air during a launch. By removing it, the front suspension can more easily raise during acceleration/launch and apply leverage to the rear tires. Not to mention you’re shedding over 15 pounds of weight.

The front sway bar is not the only consideration when making your front suspension more efficient for drag racing. The front struts are also very important. The factory struts are designed for a comfortable ride and balanced handling. But in drag racing it’s important to get the front end up in the air. A quality pair of Drag Struts like those from Koni or Lakewood are designed to extend much easier and then compress gradually for a more controlled wheelie/launch. It’s not uncommon to see the front end of many hard hooking cars with cheap front struts bouncing as they leave the line making the car more difficult to drive. A good drag strut will help eliminate this problem.

Koni drag struts are adjustable and can be made firmer when driving on the street. They are an excellent choice and are just as at home on the drag strip as they are on the highway when adjusted properly. Lakewood drag struts are a more economical choice but do not offer the adjustability or engineering of Konis. The Lakewood 70/30 struts are perfectly acceptable on the street and also work very well at the track. Lakewood 90/10 struts are tolerable on the street for limited use and are preferable over the 70/30s at the track.

The Mustang has coil springs at all 4 corners. And as with most other factory components the stock springs are designed to provide a comfortable ride and acceptable handling. But with a drag suspension, it’s important for the front end to unload quickly and smoothly and the rear suspension to resist severe squatting which can result in a springing (unloading) that kills traction.

There are several quality drag race oriented spring kits on the market. By far the nicest for the front end is offered by Griggs. It is actually a coil over conversion kit. The Coil over feature is much more compact and lightweight than the factory set-up and provides a wide range of spring choices and ride height tuning options.

Eibach also offers a high quality drag race spring kit. The front springs are designed to help the front suspension raise up quickly and transfer weight to the rear. The rear springs feature unique and different spring rates for the left and right.

RV air bags are also an effective means of increasing rear suspension effectiveness. A bag placed inside the right rear coil spring keeps the suspension from squatting down too far and then unloading. They’re economical, very tunable through different air pressures and can be very effective if your rear suspension squats too much during launch. An air bag in each rear coil spring offers the ultimate in tune-ability.

We discussed front struts but haven’t yet mentioned the importance of rear shocks. Many cars do just fine with the factory rear shocks. But with higher power levels and an efficient suspension they may not provide enough stiffness. Lakewood makes an affordable 50/50 rear drag shock that works very well in making the rear suspension firmer. And they’re tolerable on the street for all but the pickiest drivers.

This 3 part series has given the average drag racer many of the basic ideas and necessary mods behind making a Mustang pull sub 1.40 60 ft times. But the most important thing to remember is that without a quality set of slicks or very sticky tires, all the other money spent on suspension mods will do little more than help your high horsepower Mustang peel out in a straight line.

How to make your Mustang hook…check out this 3 part reading advice.