. Drag Radials

[robert campbell]

Joe/David,
Or anyone who wishes to weigh in. I am searching for more traction for the GNS this winter. Bought the Lentech AOD re-programed valve body and it works great!! 3,000 RPM stall. 3.70 four pinion trac lock. 31 spline Superior axels. Purpose built 302 with 12 pounds of boost at 6,000 rpm.

This winter it gets the Maier racing sub frame connectors. 90/10 front shocks and rear racing shocks. Now the question.

In your opinion, what is the best radial drag slick? I am looking at a 275/50/15 radial drag slick. I went conservative and put on a 235/60/15 BF Goodrich drag radial on an 8 inch Crager rim with all the offset back. They are overmatched at this point to hold the car. There are multiple brands out there with this size tire. All are around 26 inches in diameter which is where I want to stay. So this is a brand specific question. Want to hit the track and see what she will do.

Thoughts? By the way, what air pressure do you guys run? If you use a tire like this.

Rob

 

[joedls]

Joe/David,
Or anyone who wishes to weigh in. I am searching for more traction for the GNS this winter. Bought the Lentech AOD re-programed valve body and it works great!! 3,000 RPM stall. 3.70 four pinion trac lock. 31 spline Superior axels. Purpose built 302 with 12 pounds of boost at 6,000 rpm.

This winter it gets the Maier racing sub frame connectors. 90/10 front shocks and rear racing shocks. Now the question.

In your opinion, what is the best radial drag slick? I am looking at a 275/50/15 radial drag slick. I went conservative and put on a 235/60/15 BF Goodrich drag radial on an 8 inch Crager rim with all the offset back. They are overmatched at this point to hold the car. There are multiple brands out there with this size tire. All are around 26 inches in diameter which is where I want to stay. So this is a brand specific question. Want to hit the track and see what she will do.

Thoughts? By the way, what air pressure do you guys run? If you use a tire like this.

Rob

Do you want this tire for the street or the drag strip?

 

[robert campbell]

Street mostly and no tubes please. By the way, the old 750 Demon you had was an exact fit. This engine may be a block splitter if I abuse it like David. More boost, more water methanol. 38 total on the timing and right up against the first stage nozzel!!

Rob

 

[joedls]

Then I'd probably go with Mickey Thompson Street Radials. I'd start off at 18 lbs with your car at the track. Then adjust up or down from there depending on whether it spins or bogs. The thing about drag radials is they're less forgiving than slicks or bias ply "cheater slicks". You have to find the sweet spot with drag radials (suspension, tire pressure, launch rpm). With a slick or a tire like the Mickey Thompson ET Street bias ply, you can spin the tire a little and it will still hook. If you spin a drag radial, it's harder to recover and hook.

The other thing about the MT drag radial is you're not gonna get much mileage out of them, especially with your lead foot. Probably 5K-7K miles.

One last thing. They suck in the rain.

 

[robert campbell]

Joe,
My 235 60R 15 BF Goodrich Drag Radials react exactly as you say. Once they go up in smoke (or lack of traction and no smoke) there is no recovery. The are also nearly wore out as my foot is heavy!! This car is not a canyon carver so the rain is not a big deal and for the most part it does not see rain. They have a 8 inch tread contact where the 275 50R 15 will have 10 inches. And keep me in the 26 diameter range.

Have not been on the track since the late 80’s. Val’s Fastback had a dual quad 428 jet motor with some caming and headers. 4 speed car with 9 inch and 3.90’s. I had an old set of Halibrand wheels (the real deal and I wish I had them) with some 11 inch M&H slicks, around 30 inches tall. They were a bit hard and the car front heavy. We did not record 60 foot times, but it did not hook well. Best time was 11.98 and the tire diameter gear ration were way to tall. Basically 3 full gears and hit the lights at around 4,500.

You and David have so much more recent experience in this area!!!

Rob

 

[di81977]

I raced 3 seasons in my HCS with Nitto NT555R drag radials and was not pleased with their performance. I'd also recommend 16-18psi as a starting point. Also, once you go through the waterbox. I like to count to 3 after they start to spin and I see smoke.

I will be interested to see how the AOD with the valve body does. My 68 convertible had an AOD and I HATED it for racing. Could not hold second, but it was stock.

Now that both my Mustangs are sold, I have gotten into road racing with my Mazdaspeed 3. That is a blast, but so much harder on your car than drag racing.

 

[di81977]

Here is me racing Mr. Teets 428 CJ. Don't ask Bob about tires. He was racing on Polyglass.

 

[robert campbell]

Very confident in the AOD now. Shifts just like a C4 or C6. Was looking at the Nitto's.

Bob's car with Polyglass and that heavy front load must have launched like my old big block combination. Only worse. Bet he was coming on like gang busters at the end!!!

Those vidieo's of David's car launching were impressive. I have never used an auto on the track yet. What was your launch procedure? Did you have a line lock?

Rob

 

[robert campbell]

Di,
What engine, tranny, rear end combo was in your HCS? To beat Bob's car it must have been healthy!!! What size were the Nitto's?

Rob

 

[di81977]

A line lock would be great, I did not have one. I would pump the brakes before staging. At the light I would then keep one foot on the brake and rev the engine into the torque curve (2,500-3,000 RPM) - as high as you can go without spinning the wheels at the light and spinning them off the light. This is something that you will want to play around with to find the optimal launch RPM.

Fortunately I did have a B&M shifter and a tach with shift light, allows you to just bang the shifter up for each gear without any worries about missing a shift when the light goes on. You will also want to play with your shift RPM's to find out which give you the best times.

Another tip - leave when you see the last set up yellow/amber lights go on. Any later any you will have terrible reaction time.

The HCS was pretty mild, ran in the mid to high 12's at sea level. 351W stroked to 393with Aluminum heads, Edelbrock intake, 650 CFM holley DB, Hooker headers and Mallory ignition. 3:73 gears with Auburn limited slip and a C4 with 2800 stall.

Long story, but I was running 245-50-16. I had an extra set of wheels and they were 16". Allowed me to change them at the strip and not have to drive on them.

 

[robert campbell]

Di,
Thanks for the info!! Me and an automatic launch are new. Your set up is very similar. Light info is very helpful. Back in the day when I ran it was not quite as sophisticated!!

Rob

 

[gt/csj4]

Here is me racing Mr. Teets 428 CJ. Don't ask Bob about tires. He was racing on Polyglass.

He also autocross' in poly-glas. Lol man, what a ride that is. :cheesy:

 

[joedls]

I raced 3 seasons in my HCS with Nitto NT555R drag radials and was not pleased with their performance.

I have to agree. These tires are OK for the street and will last a lot longer than MT ET Street Radials but I had no success with them. However, I have heard a lot of good things about the Nitto NT05R drag radial.

 

[gt/csj4]

I have to agree. These tires are OK for the street and will last a lot longer than MT ET Street Radials but I had no success with them. However, I have heard a lot of good things about the Nitto NT05R drag radial.

I can attest to these, I ran these on a 94' GT I once had awhile ago, and they were a perfect culmination of compound, grip, and are very forgiving under heavy launches. But of course, with every drag radial, they are useless in even damp roads