Trying to improve consistent 60 ft times with nose heavy 71 convertable

The car in the video below wieghs 4250 with me in it

http://www.youtube.com/watch?v=hURJ7cGE37w&feature=channel

I'm still chasing a decent 60 ft. time this one at Firebird in April was a 1.505 the best its done. In better air it ran 10.12 140 with 1.53 60 ft. I think I need a taller, softer front spring to get the weight transfered as I have to roll on the throttle to keep from spinning at the initial launch. As pictured it has 750# road race front springs and I'm going try some 260# Moroso Trick springs I had lying around if I can get them in the car.

We took some additional video at the Irwindale 1/8th mile last week and I could only manage a 1.60 as the track was a bit down on traction due to a lot of street tire cars. I get no front end rise unless the tires bite forst which I think is bascially backwards.

The rear suspension is Slide-a-links with Cal-Trac monoleafs and QA1 DA's. I get reasonable separation at launch but the side wall of the tire does not show any wrinkle (325/50/15 Hoosier Drag Radials). We took a little Flip video camera mounted under the car and could see the urethane bumper in the slide-a-link compres by about a half an inch so I have just made some solid bars to replace the sliding link to see if I harness some of that rotational energy to better plant the rear tire. But I think the problem is the fornt suspension not the back.

In front I'm running TCP strut rods and lower control arms which effective have rod ends instead of rubber bushings, and my own modified upper arms with poly urethane springs mounts which move with virtually no bind and Qa1 DA's also. I have seven inches of front travel measured at the spindle which according to Calvert should be enough, but the stiff springs I have had on it for the road course track day stuff have almost no stored energy for a drag strip launch so I don't get that kind of almost wheels up launch you see on a lot of early Mustangs. The front half of the car weighs 1170 D-side and 1080 P-side in the front with me in it. Yeah I'm fat too.

As mentioned I'll try the Moroso springs but I'm looking for a better recomendation or real world experience as I have not heard good things about them. Thanks in advance.

Havent run the moroso deals but have used six cylinder stock type springs on a falcon, stock control arms. Had to actually shim the top of the springs about an inch to get off the bumper's and that was with an iron head cleveland. worked well. You may not be able to go that light but certainly a lot less than the 750 you have now will help out.

dkp

I didnt hear it knocking the tires off in the video, what converter and rear gear?

CDMBill wrote:I get no front end rise unless the tires bite forst which I think is bascially backwards.

Actually it's the other way around........

You can't have nose lift and/or weight transfer without first having a given amount of initial traction.......no initial traction = no nose lift/front-to-rear weight transfer. If it was possible for weight transfer to happen first before traction happened (or inital rear suspension separation causing increased traction), then the nose would lift no matter how good/bad the starting line was.


A lighter front spring compressed more will definitely store/release more energy than a heavier spring. And that can be a good thing if that's really what the car needs. Only way to tell for sure is to try a lighter spring and see what happens. I will say that if you can find a lighter factory spring I would go that rout first (if possible) before buying a Moroso spring because they don't always work "perfectly" in every combo. Some times they act stiffer than the stock springs they replace, sometimes they take forever to settle & take a final ride height set.

You know a 1.5 60 ft is still pretty good considering that it's at 4200+ lbs.

Thanks guys. To Richter69 its a stock geared Lentech AOD 2.46/1.46/1.00 with a 9" Edge converter that stalls a bit over 4000 RPM.

Where I am trying to get to is a footbrake launch from 1500-1800 rpm where I can simply mash the gas instead of rolling down the throttle. The video is the best its done with a very fast roll down, but still a roll down not just mash the gas. When I do that it blows the tires off immediatly and I have to pedal it to get it moving.

Has anyone dealt with a particular business that really knows early mu Mustang/Torino front end setups for drag launches?

Does anyone know of a calculator for figuring installed spring height? I'd like to buy one more set of springs rather than trial and error a bunch of them as track time is precious around here.

I know the free and installed height of the exisitng 750# springs as well as another set of 620# which just rest on the upper bump stops about 1.5" lower static height. These are both the same wire size (.720) and free height (13") but the 750's have four active coils and the 620's have six yet they compress more. I have much to learn about coil springs.

Have you tried any different convertors? Sometimes something alot looser could help. Not sure if its an option if its a multi purpouse car???? Same thing with a programable ignition, to pull some timing and kill a little torque.

I had a much tighter 2800 stall 10" in the car which was intended for N20, which is on the car but not being used, as I'd like to solve for N/A traction and consistency first. It was the opposite situation, I could run 20 lbs. in the drag radials and it would just drive out with the throttle mashed and pick up when it got on the cam. 1.55 best 60 ft.

I did make a small cam change from a 112 to to 109 lobe sep with more agressive ramps (HT 440 and RT) along with the converter over the winter along with an increase in compression form 10.6:1 to 11:1 still on pump gas. The MPH went up from a best of 132 to a best of 140 so the changes did make more power at a slightly lower peak rpm no doubt due to the tightened lobe sep. Best ET went from 10.49 to 10.12, but I know I'm leaving ET on the table with the inability to leave at full throttle. All of the changes were intended to try and get the heap into the very high nines on motor through the full exhaust as driven to the track with the skinnies up front. My own stupid rules based on what we do at HRM's Drag Week.

Pulling timing is the last option but I think there is more in the chassis without another converter change.

I would try this question over at Yellowbullet on the stock suspension section. A guy on there named Moneymaker Racing seems to know his shit about older Fords.

Or call Calvert racing.

Fred Brown makes that variable stall control which is supposed to be good for 1000 rpm increase/decrease...you may want to try that?

Good ideas, I'm going to talk to Alex at Moneymaker re spring choice before I finalize that but I have found some good information by way of Jay Brown regarding spring calculators from the book, How To Make your Car Handle. The Moroso tech line said the car is too heavy for either of the two springs they stock that are the correct 5.5 diameter for a Mustang and suggested Landrum.

I've arrived at an OEM spring from a 73 Torino, Moog #8224 which is 17.81 free height, 10.5" installed and a rate of 357 lbs/in.

This should be an improvment over the Grab-a-track spring in it now which is 13" free height, 10.5 installed and 750 in/lbs. They are back ordered, of course.

You mentioned that you do some road course stuff. You wouldn't happen to be running a front sway bar, would you?

maverick wrote:You mentioned that you do some road course stuff. You wouldn't happen to be running a front sway bar, would you?

if you are take it off.

I've been running the car recently with the front anti-roll bar disconnected at both ends and secured with zip ties. I know it adds weight in the wrong place but I haven't removed it as I like to be able to switch back and forth quickly. I'd guess it weighs around 15 lbs.

I will be trying the new springs and roller spring perches next to see if I can get the weight transfer, hook and 60 ft. I'm looking for without removing it completly. If I need that extra .01 off it goes.

CDMBill wrote:Does anyone know of a calculator for figuring installed spring height? I'd like to buy one more set of springs rather than trial and error a bunch of them as track time is precious around here.

I know the free and installed height of the exisitng 750# springs as well as another set of 620# which just rest on the upper bump stops about 1.5" lower static height. These are both the same wire size (.720) and free height (13") but the 750's have four active coils and the 620's have six yet they compress more. I have much to learn about coil springs.

a coil spring is just a torsion bar wound in a cicle . more coils with same dia . just a longer bar . to figure install pressure free lenght minius instaled ht . times spring rate . same deal as a valve spring