How to drag race your classic

Discussion in 'Classic Mustang Specific Tech' started by 10secgoal, Jul 22, 2005.

  1. Maybe this will become a sticky, maybe not. But it will be available for an easy search. Please do not ask what we think you should run for a setup. That is what PM's are for. I will not add everything tonight, but please add what you know, personally to be true and correct from experience, not what a buddy told you his cousin's friend did. I would like this to be a thread were you can come and find info on getting your classic to hook.
    There are a few things that are basic for drag racing. Tires: Don't go to the track without them. Don't be the guy at the track everyone is laughing at because you are complaining of a horrible track when you drop the clutch at 6k with 245 50 16 radials, and stock suspension. Suspension: Transfering weight is a key point. Planting the tires is great, especially when you have a ton of weight on them. Do not lower your car. A car will transfer weight much better if the CG (center of gravity) is higher, and if the car is level if not higher in the front. Do not slam the front and wonder why it doesn't transfer weight. Autocross cars are lowered to keep the CG down, for less body roll. We want body roll, in the form of front to back. To transfer the wieght you also want to loosen up the front. 90/10's, no sway bar, and since most of us run SB's, and no one makes a drag spring for us, 6 cylinder coils. And the all important roller perch. This one mod made it possible to hook at a horrible track, with 28 psi in the ET streets. It basically takes the shock out of its bind that is caused when the front end tries lift. The rear: You do not want the rear end to squat. As it is squatting, there is no wieght on the rear tires. Not until the rear is maxed out, and it stops squating, do the rear tires see any real wieght. This you see at the track pretty often in the form of a slight chirp or squeal, then a great hook. You basically want the car to pivot on the tires as the wieght comes back.Axle wrap: Alot of talk about this lately. When power is applied to the rear end, the pinion will try to climb the ring gear, causing the whole rear end to try to point to 12 o'clock. The leaf springs will "wrap up" and bow up in the middle, and down in the back. It will do this until the spring can't go any farther. then it will snap down, bow up in the back, and down in the front. Causing wheel hop, and often breaking parts when it stops and gets traction. A lift bar will help, but Caltracs are your best friend. They use rear end twisting to force the leaf down in the front, and lift the front end of the car. I will be back later
  2. can someone dig up the "how-to" on the roller perches and put it in here?
  3. Here's some more tips:

    - Move as much weight to the rear of the car as possible.

    - Lowering the air pressure in your rear tires helps create a larger "contact patch" in essence, making it seem like your tires are larger than they really are. There is a trade off however in rolling resistance. Find a happy medium.

    - Heat hurts horespower. Open your hood between runs.

    - Lighter is faster. Get rid of as much weight as you can. IE) Front sway bar.

    - Don't spin the tires, it only slows you down.
  4. and here is another key, drive it like you hate it :)
  5. the upper A-ARM shelby drop is not good for drag racing!
  6. These cars do not have full frames. Therefore they are not ridgid. Getting a good launch at the strip is critical for putting down a good time. If you are wasting energy (horsepower) by twisting the car instead of propelling it forward, then you are wasting precious time. In high powered cars it can lead to misfitting fenders and doors as well as floor pan stress cracks. Subframe connectors are an excellent add on that will tie the front and rear subframes together to have a more structurally sound platform. It made a huge difference in my car in the way it feels around town and at the strip. Mine are only bolted in too! I am going to weld them in place though to add more rigidity.
    In faster cars, 11.99 seconds and under, the need for a roll bar is needed at NHRA sanctioned strips. (11.49 IHRA) These will REALLY make the car stiff and strong. When 60 foot times start to get into the 1.6's and 1.5's, unibody cars do not take too well to these style take offs.
  7. Traction is a HUGE factor in drag racing. Having sticky tires is the best thing to help with traction at the strip: bottom line!
    But for those wanting to race their Classics, don't be afraid to go to the strip and try it out with street radials. Just drive around the water box. Spin the tires a little to get any rocks and dirt off of them and pull to the staging line. Launch as hard as the tires will let you. A little spin is fine because you know you are at the edge of traction. A lot of spin is just wasted ET.
  8. WOW i really hope this gets a sticky, so what rear springs and shocks are recomended?????
  9. 1) 6 cyl spring up front will be good
    2) I run the 3 way adjustable shocks from summit up front, they seem to do well
    3)ditch the sway bar when you're at the track. It really helps the front end to rise, that means more weight to the rear
    4)move the battery to the trunk
    5) I run stock replacement 4 leafs in back, with 1" aluminum lowering blocks and heavy duty shackles from mustangs unlimited (with poly bushings)
    6) not sure about rear shocks, I'm still running KYB's and the car seems to like them, I have some summit 3 ways but haven't put them on yet (and don't know if I will)
    7) I'm happy with my cal-tracs.

    Overall, the cars rides pretty good. With the sway bar attached it still handles decent. Ride height is about 1.5" lower than stock, and it sits level.
  10. Ok, here is some more info. I am learning as I go. It is possible to have weight transfer too fast. After moving back out to Ca, I find the "track" sucks to no end. And I am having to learn more, and try harder for traction. Especially now with just, a little more power. I found that I may be letting the front end coming up too fast, too easily. Giving the rear tires no wieght on them until the front suspension is maxed out.
    Here is something I actually saw a while back. I never payed too much attention to it as I had NO traction problems. This write up here has ALOT of good info about weight transfer, why, why not, and shocks.
    After reading the info on the shocks ( A MUST READ )I figured it was well worth it to try it out. Since I changed from 4.11's to 3.25's the front just wasn't coming up as fast, and not transfering wight to the back tires nearly fast enough. So I took out my 90/10's(Carreras come up VERY easy. I could actually easliy lift the front of my car 9in by lifting the fender), and traded with 12sec67. I put in his summit adjustables, and set it to its firmest setting and gave it a shot. I did previously pull a 1.62 with this set up about 3 weeks ago. But was VERY inconsistant. I re-set my traction bars, and got the car to go straight. I was making a B line for the wall right out of the hole. Now I could relax and pay attention to what was going on. I only managed to pull a 1.67, but I pulled a 1.68,1.69 and a few low 1.7's. The car is much easier to control now that the front end comes back down without the 90/10's. The car still isn't hooking, but has gotten better. I am debating right now softening the fronts, or limiting the front end with straps and putting the 90/10's back in. Will come back with updates if the track lets me back in.
  11. Turn off the air conditioner!:rlaugh:
    Lose weight(aluminum heads, radiator, sound deadening, rear seat, sway bar, spare tire, jack, keg, etc...)

  12. I used Rancho 9000's on the rear which CalTracs recommended. They worked good and the best part was they are easy to adjust between rounds unlike the 3 way adjustables from Summit.
  13. do you know what part number the rancho's are?

  14. The part number is: RAN-RS99159 from Summit Racing $90 each. One word of caution.......these shocks are not for a daily driver because the travel is really limited. I used them all last year and did not bottom them out but I had my CalTracks adjusted to 1.5 turns (preload) each side and the shocks on #3 setting. Lets just say you could not push the back end of my car down easily.:nice:
  15. At what point is a full rear drag set up needed? Would the stock design with some cal tracks, better leaf springs, and drag shocks w. slicks be able to handle 400 or so hp?
  16. sure. The stock style suspension is fine. You need subframes, and preferably a 9" with 31 spline axles. Leaf springs, cal-tracs, etc. are used on some cars running in the 8's in the 1/4, which is probably around 800+ hp. I'm always confused when I see a backhalfed 4 link car running 11's at the strip, I guess they got jipped on the engine, lol.
  17. Well the plan for my car is to be able to run high 11's or low 12's on all motor. (Possibly a 331 putting out around 410 hp). I want to get the suspension right, and get the most out of it before I worry about boosting HP numbers to make the car faster. There's nothing worse then having a 500 hp motor, but getting beat by 300 hp car that has a better set up.
    Right now im thinking the following:
    caltracs, 90/10 shocks, 6 cylinder springs up front, and new leafs in the rear. The car will be getting a roll cage for safty and to strengthen the body, and roller perches.
    Are fiberglass leafsprings better for drag racing?
  18. Running the 6 cylinder springs in the front and removing the sway bar should just about take care of the front end.

    You really need to talk to John Calvert before making any firm plans. He is a master at setting up Mustangs--have you visited his site? The Calvert team are well versed in what works. When you deal with them, you are getting some of the best advice out there for bolt-on applications.

    The Caltracs are proven and work best with his system which includes mono leaf springs and the appropriate shocks. The parts are all available from Calvert. There is no marketing hype there, just stuff that works as intended.

    Here is one of many Stangs found on the Calvert site that is tearing it up with Caltracs:


    I really don't think the Mustang above is traction limited, no matter how huch HP he is putting to the pavement.