Tire Spin and Control

[MikeStang 247]

Have a few questions with regards to tire spin and ways to control it.

 

I am still getting accustomed to the way my car runs and drives but I am no novice when it comes to being on the track and have plenty of exp with high speed driving, however I almost got myself into a jam this past weekend while playing around with a friend at CTC.

 

We decided to do a bit of spirited driving at about 2 am on a vacant road from about a 55 mph roll and when I put it to the floor and let the transmission downshift on its own the ass end broke loose so fast and violently that by the time I reacted I had begun moving from the right lane to the left as a result of the back end going to the right and my correction.... Thank goodness my carb had a hesitation and my friend was the one calling the start and got a jump on me haha.

Anyhow I made the steering correction in time and maintained control and I have since not gotten down on the car hard enough to have that happen again.

 

I have tried hard launches and when the motor gets to a certain area in the RPM range it spins and the back end goes to the right fast.

 

With my past cars when I would get tire spin under hard acceleration, the vehicle would always track straight and not have the rear end kick out to one side or the other, but with my newly completed 69 this is not the case.

 

I am aware that if your clutches are getting weak in the rear end that the vehicle will pull to one side or the other when you have tire spin, but my rear end was rebuilt correctly by Me and is pretty much just broken in, so I don't thing its weak clutches.

The tires are 20" Nitto 555s and have pretty good tread still... I will be going to 17" tires and wheels when I can afford it however.

My battery is in the trunk on the passanger side, and I have welded in sub frame connectors.

The suspension consists of 4.5 leaf Reverse Eye springs and KYB Shocks all the way around as well as full roller front suspension and 620 drop coils with adjustable strut rods.

Transmission is a 4R70W with 3.25 gears out back which will probably get swapped for some 3.73s

 

So what are my options here?

I was thinking maybe add some lift bars to see if that would do any good.

I just feel like I cant really use the power that's on demand safely and that sucks.... I always thought there was no such thing as too much power but if you cant use what you have what good is it haha.

[MikeStang 247]

Oh forgot to mention its a 4 Pinion Factory Ford Posi Unit

[1969Fstback 58]

You obviously have too much horsepower. Lucky for you I have a solution that will cost you zero dollars. Pull your motor and swap me for my anemic mostly stock 302. Problem solved, very very little spinning.

 

You're welcome.

[FrozenMonkey 12]

Don't mash the pedal and put it in the gear you are going to gun it in manually. Ease into it. If you are still blowing the tires off the car then start tossing money into it. 3.73 gears are just going to make your problem worse. Time for a 4 link coil over setup maybe. :P

[MikeStang 247]

Lol yall cracked me up.

Problem is when going 55 mph or less and you stomp it the trans down shifts on its own and breaks Em loose lol.

So tough to keep it in gear lol

[barnett468 418]

this is hilarious, horrible prob t have, lol.

 

besides simply removing 2 spark plug wires to cure the prob, do you have traction bars?

 

do you have staggered shocks?

 

if no traction bars the first thing i would do is install some cal tracs.

 

a locker might also help.

 

i also don't think the kyb's are doing you any favor, if they are the gray ones, throw them in the trash for sure and look at the orange adjustable koni's.

 

also, it you have plain NT555 tires, you need NT555R or NT05R.

 

http://www.nittotire.com/race-tires/nt555r-dot-compliant-competition-drag-radial-tire/

 

 

just what is your setup if ya want to fess up?

 

do ya got some kind of supercharger on it?

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Edited October 15, 2014 by barnett468

[MikeStang 247]

The KYB's are the white ones and I have run them on several different cars in the past and had no issues, my friend even had them on his 69 with no problems.

But the KONI's are next on my list

 

The Nitto's are 555R think they are a 255/35/20 or something...They are pretty sticky... just driving for 5 min and pulling into my driveway through small pebbles produces a nice rock shower in the wheel wells.

 

Dont think a Locker will do much good as both my tires are turning when I mash it now lol and the rear is freshly built.

 

I dont have any traction Aids at all, but will be looking for a set of Caltracks today.

I have 4.5 leaf reverse eye springs and hoping they will settle a little more than they have as I know they should be lower. I also need to cut my front springs.

 

Drove it to work today and found out the float was sticking down on the carb giving me some grief so I raised it up a touch and fixed that and now the 1-2 shift at 1/4 throttle with the snappy shift breaks the tires loose .... Its almost not fun to drive at this point it just feels sloppy....

 

The motor is just a 408 making 550 hp and 500 plus torque at around the 4.5k mark which is i think some of the problem LOL. RPM and shifts coincide when the motor is making close to peak Torque and not helping things any.

 

No staggered shocks either.

 

Was going to take it to test and tune tonight but not sure I wanna do that until I get this problem solved...Altho it may act different on sticky track.

[Rip Rock 13]

I personally would back down to a 17" and put on some mt et street 2. From what I was told and seen first hand the 555R don't actually hook that good. One one car I'm using Toyo 888's. They seem to hook good for around 650wrhp, but the torque kicks on a bit later. I have several buddies with et street2 tires that are around 600-700wheel and the torque is about the same. I'm in the same boat with my tires. Next year i will be running those. I'm right around 700/650ft wheel. I'm running a 4 link on my car so it is a bit easier for me to dial it in.

[MikeStang 247]

Yep I am dumping these 20s as soon as I possibly can... I think a BFG would work better then these things LOL.

Wish I could afford a 4 link, or knew how to build one lol.

[rwcstang 201]

yeah bring back to 17 or 18, I have BFG Sportcomp 2s and they are awesome tires!