no traction

[runx68SWB]

whats going on everyone.... i ran a 15.2 at 89 mph at the track this weekend with very bad traction problems.... i plan to lower the back end about 4 inches this week as well as add a set of kyb gas a just shocks.... the way she sits now is above stock height (36 inches from ground to the top of rear wheel well.... too high).... i feel that hurt me a great deal.... any help as far as suspension ideas would be greatly appreciated.... if this thing hooks up it should run very well.... may just have to put sand bags in the bed LOL

[jmanz69]

What kind of tires you have on there? If you got some small street tires you will get no traction. Need to have some width to them. Lowering the rear should help with the weight transfer quite a bit. Also, going with a softer shock will help. you need to get the weight to shift back easily. I would recomend against putting in sandbags. Don't want to add more weight, that will just slow you down.


Good luck, and go fast.


jamnz69

[383 Stroker]

what were your 60' times?

[Wasted Income]

Sandbags are not a good idea. You will definitely get more traction, but you are also adding mass that needs to be accelerated. The benefits do not outweigh the costs. I'm sure you were just kidding though.

Plus, any IHRA or NHRA dragstrip would not allow loose items to be in the bed while racing.

Good luck!

[runx68SWB]

im running an auburn pro differential with 4.10 gears in the rear with 315-60-15 bfg drag radials.... what i thought was sure to stick.... my suspension is certainly lacking being that it is stock and has been running the same shocks that i put under her 7 years ago.... im surely not in need of more power.... just have to get what power i do have to hook up.... i know there has to be at least a half second loss in the suspension.... buddies said my tires were smoking half way down the track

[runx68SWB]

yeah.... i was only kidding about the sand bags.... ive stripped quite a bit of weight off that darn thing.... sure as heck arent going to put it back on there LOL my 60' time was 2.364.... not real good

[383 Stroker]

That 60' is pretty bad. The best 60' I have got is a 1.84, most of the time mine are in the high 1.80's low 1.90's. Check out this site for NHRA altitude correction factors. http://www.prestage.com/carmath/NHRA...on_Factors.asp

[Longhorn Man]

If you have that much rubber under there, sounds to me like you need to tune your tires for drag racing, (find the proper psi) and learn how to launch it.
every stop light is a chance to launch it. Try to make it leap out of the hole without spinning the tire(s) The best way to do it is to brake torque it a little so you get a tiny bit of spin, then as the nose starts to sink just a little, you apply throttle.
Radials are a b!tch to drag on. Try that, it feels odd, but it will help it.

[Wasted Income]

For the best holeshot, you'll want to load the torque converter up (the powerbrake, brake torque, etc), so that the powertrain is pushing against the brakes. On the last yellow, let off of the brakes. Don't worry about redlighting. Not many vehicles short of a prostocker will react that fast. The key is to get a roll going before you apply more grunt. It lets you get some movement before you give 'er the berries. If you "shock" the tires by stomping it off of the line, the tires will break loose and you will run crappy times. Remember, even a little bit of wheelspin is bad. There is less friction when the tires are in the kinetic state (spinning) versus the static state (rolling).

[runx68SWB]

thanks for the info fellas.... i was wrapping her up to about 2300 and launching there.... that seemed about all it would hold before the tires were going to spin.... may need a little more stall speed as well.... those are some exceptional 60' times 383 stroker.... obviously you arent having a traction problem.... they say these bfg drag radials work best when they are bald or near bald so i think ill put a few miles on them and lower this thing.... all i can do is run it again and see what happens.... what a guy will do for a few tenths of a second LOL i was running 18 psi in those tires by the way

[Wasted Income]

If you're having problems with smoking the tires half way down the track, one thing you definitely don't need is more stall. If you aren't already, you're gonna be launching right in your powerband.....good if you have the traction to handle it........baaaaaad if you don't. I'm still pullin for you to leave "gently" and roll into the throttle. I'll bet you pick up a couple of tenths.

Keep us posted, eh?

[runx68SWB]

uh oh.... think it ate my post.... thanks for the responses fellas.... tire psi was 18 and launch rpm was approximately 2300.... that was about all she wanted to hold.... id like to get the 60' time a tad bit closer to 2.0.... your 60' times are exceptional 383 stroker.... that thing has to scream out of the hole.... ive got the drop coil springs and the shocks ordered.... i think these drag radials are TOO new.... need to burn a bit more rubber off of them... i hear they work best bald.... ill give her another go in a couple of weeks.... ill be happy with a half second improvement.... thanks again

[Randy70C-10]

Where's your battery? You can get some weight transfer by moving your battery and gas tank under the bed.

[383 Stroker]

What kind of burnout did you do?

[bigjimzlll]

sounds like atleast a half tracker....lol...

[mikep]

Ive had pretty good luck running way low air pressure with radial TA's. In my last street strip type car I ran 295/50-15 TA's and with a 3800 lb car and traction bars I ran 12.57 at 109 mph power braking at 2400 rpm on a 3000 stall converter. Tire pressure was no less than 10 lbs. I Drove around like that for a few days before I remembered to reinflate. I even talked a few guys at the track into dropping their pressure from 20 to 10 and they all picked up a solid second.

[Wasted Income]

The problem with lowering the pressure alot with RADIALS is that they tend to "cup" in the middle of the tread. It looks like you're getting a lot more of a contact patch, but the tire could actually be lifting off of the track in the middle of the tread. Bias ply on the other hand does not have this problem.

[runx68SWB]

i didnt want to drop the air pressure much lower than the 18 i ran because i have to hit the highway for 2 miles or so between my house and the track.... next time ill take something to inflate my tires.... im going to surely try the rollout technique.... burnout was solid.... got plenty of smoke.... seemed to have warmed the tires up well

[mikep]

Originally posted by 67 LS1 SWB
The problem with lowering the pressure alot with RADIALS is that they tend to "cup" in the middle of the tread. It looks like you're getting a lot more of a contact patch, but the tire could actually be lifting off of the track in the middle of the tread. Bias ply on the other hand does not have this problem.

Patch or no patch I picked up nearly a full second and so did 3 other guys with traction problems who were racing the same day and I did that every time I went out after that with great results . With no other change I saw one guy with severe traction problems in a torquey 383 68 camaro go from 14.5 seconds to 13.2 seconds. He couldnt have been happier at the end of the day. I mean it. He was the happiest man I have ever seen. It was funny .

[Low69CST]

I think if you lower the back of your truck atleast, that it will help your times, weight will transfer better. You could also get some 90/10 shocks and turn them upside and put them on the back. Also, a rear swaybar can help stop the axle torque from giving one tire more traction than the other.

How'd you get that big rubber under your truck? I'd like to get tires that wide under mine, except on dubbs instead of 15's

[Low69CST]

About the tire cupping, what I read was to do a burnout and look at the rubber on the asphault. If the rubber is heavy in the middle, then take air out, if its heavy on the sides, add air.

Keep doing this until the rubber is even all the way across.

[runx68SWB]

the tires fit just fine as it sits.... couple of inches above stock but its going to be real tight once i lower it.... the problem i have is that my rearend is 3/4 inch longer on the passenger side.... off center unfortunately.... it would work perfectly i believe if the rearend wasnt off like it is.... the passenger side clearance should be fine but i am going to try and use a wheel spacer on the right side.... no more than a 1/4 inch.... i should have room.... its going to be very close.... could only have a half inch between the inside well and the tire.... i hope it works other wise ill have to go with a little smaller tire

[Low69CST]

Why don't you get an adjustable panhard bar kit?

[Longhorn Man]

Originally posted by Low69CST
About the tire cupping, what I read was to do a burnout and look at the rubber on the asphault. If the rubber is heavy in the middle, then take air out, if its heavy on the sides, add air.

Keep doing this until the rubber is even all the way across.

This is 100% true, BFG and good year said the same thing on a report I did in high school.
You can also check the tire tread temp across the foot print of the tire, if the sides are cool, deflate more, and if the center is cool, inflate.
I don't think wheel spacers are legal on NHRA tracks (most traks go by there rules).

[Wasted Income]

I'm not saying that it won't help, what I'm saying is that it is possible to deflate too much and that is a detriment to performance.