New best, but still spinning with drag radials

[TexasBlownV8]

Made 8 runs today, mostly around 13.0, with a couple in the high 12s, with a best of 12.88 @ 106 mph, on a 2.00 60' (which was my best, by the way). I run M/T 275/40-17 ET Streets on stock 17x8" rims, at different pressures. Historically, my best times are with 18-19psi, but a little (and I mean just a little) better traction with lower psis, down to 14.

I do a decent burnout, but at the line, always just spin the tires at launch, at least a little; and sometimes most of the ay through 1st or when getting into 2nd. Not nearly as bad as street tires, of course, but still not getting good power to the ground at launch, with all 60' times in the 2.0's and 2.1s. If I can just hook and not spin, I know I can knock at least a couple tenths off the 60'.

My V6 is an automatic, and I rev it up to 1800-2000 rpms, then floor it when taking off...and that's when I spin the most...taking off from the line.

Next time out I'll have someone videotape it, which I want to see what the suspension is doing, too (adjusting the d-specs to different values didn't seem to make much difference either).

Fellow Stangers running slicks can launch at high rpms (manuals of course) and hook right up with no spin at the launch. So the track is decent, just not sticky enough for my DR's it seems.

FWIW, last year I was able to hook on the same DRs at the line very nicely, for 2 runs (with 19psi in the DRs), and then the spinning/slipping began again and my times dropped off. That was before the recent gear change, so now I'm getting more torque to the wheels at launch.

I think it's time for some full slicks with appropriate rims. Any recommendations or other suggestions (or questons)?

 

[Freaknazty]

wild guess here but are your tires still good enough to run ? i ran those same tires on my setup and got 1.5 out of them (with more power of course but still ) my best results were with them at around 14psi cold so 15-15.5 after burnout , i always gave them a good smokin not showoff type shit but a good spin

other than that you might need relocation brackets .....lca angles might be off from you being lowered ....

 

[don_w]

I also used to have good results with the 275/40-17s, even with 4.10s and the KB. I ran them at 17psi cold, and gave them a healthy burnout, especially the first run of the day. And freak said, they may be worn out or old, too. I never had a set for more than a few months.

You might also try the 275/50-17 M&H DRs. They will fit on the 17x8 wheel, and the extra 2" dia will help.

 

[TexasBlownV8]

Hm. Good to get the feedback and positive experiences from the same tires.

I do have relocation brackets, lcas, ucas, etc. Pinion angle is correct, no wheel hop, just lack of grip.

The tires have about 50 passes on them at the most, and have a lot of tread still on them. I bought them new last summer. They get driven to/from the track (at 32 psi) for 25 miles each way, so about 250 miles of highway driving on them.

I always let them cool off about half an hour when I get there, then lower the pressure, let them sit about another 15 mintes, and lower the pressure the rest of the way to around 18-19 to start with.

The do spin less when I get a decent burnout (5 seconds is what I shoot for at about 3-4K); I don't do those heavy-smoker kinds of burnouts, just enough to clean them off. [at one point today though, I wondered if I had actually gotten a good enough burnout.]

The track is also kind of hit-or-miss when it comes to prep and traction. But it does seem to do better earlier in the event for me (like the first few runs grip better than later ones).
There is another track that peeps tend to prefer, its farther away but much better. I really want to get out there and see what she'll do, too.

I do check tire pressure before each run, so I know what I'm running at (for note taking and such). [Oh, and they are rotating in the proper direction per their arrows!]

The 28" M&H tires might indeed be a good alternative, since they'll rotate less (larger diameter).

I will check the wear indicators this week to see where they are at, but like I said, thev're hardly been used.

I just might actually not be doing a good enough burnout. I am using the powerbraking approach with my automatic, and I could easily be holding down on the brake too much (have to hold it down to keep it from leaving the burnout area!). A line lock would take care of that...if not getting a good enough burnout is part of the answer, and it could be I think.
(That's where I needed someone to shoot video, too!!!).

As always, Thanks for the ideas...keep 'em coming!

 

[don_w]

The tires have about 50 passes on them at the most, and have a lot of tread still on them. I

The do spin less when I get a decent burnout (5 seconds is what I shoot for at about 3-4K); I don't do those heavy-smoker kinds of burnouts, just enough to clean them off.

Two thoughts on the above...

1. I usually could only get about 75 runs out of a pair of DRs... so 50 runs could be on the down side.

2. I usually do my burnouts at around 6K, in 2nd gear. That puts me at the ~50mph I want to be during the burnout.

 

[Freaknazty]

Two thoughts on the above...

1. I usually could only get about 75 runs out of a pair of DRs... so 50 runs could be on the down side.

2. I usually do my burnouts at around 6K, in 2nd gear. That puts me at the ~50mph I want to be during the burnout.

yep sounds like you might be running outa tire ......

and i do the same second gear but around 5k 3.90's

where i run its the same the first 2 runs are usually the best we go during tnt nights mainly thats why though...... i found the pro tnt nights are the best time to go the prep the shit outta the track ...... but i also blew a clutch , friend blew rear end , 2 more older stangs cooked trannys , and a vette blew a rear and that was all in 1 night ....so be carefull what you wish for lmao when they hook somethings gotta give somewhere

 

[TexasBlownV8]

Yeah, I realize an extreme hooking is a big strain, and I do have a liiiiiiiiiittttttle concern with that on the tranny side, but not on the rear end.

The track prep is indeed hit-or-miss out there, always has been. But sometimes, just sometimes, they get it really good and right, at least for awhile.

I dont mind a little it of slip/spin at the line, and in fact, when the DR's were new, that's what they were doing, but only at the line. Of course that was with less power, too.
But once off the line, I don't want any slipping..and sounds like maybe they're reaching their end of the road because of that.

A couple other things I realized after thnking about this more, are:

1. I removed quite a bit of weight from the back of the car, probably about like 50 lbs from what I normally run (no heavy mufflers, much less gas in the tank like 1/4 and less full where normally I'm about 3/4 full, and no spare tire), so the back end was lighter than what I'd usually run.

2. I don't think I'm getting a good consistent burnout. There are times I know that I don't get good enough, and those times I usually do spin more. But one time on a late run with 15psi I got a really good burnout, and new it; it still spun through the first 40' or so, but got off the line much better. So I would have to admint I think part of the problem is not enough burnout and that's something I have to correct.

Regardless, time for me to get a line-lock; I'll want one anyway for the next set of tires so i can burn them out properly, too.

Thanks guys...it's always good to share useful information

 

[TexasBlownV8]

Just a little update, today I hit the track again and had some nice results:

The TIRE SPIN ISSUES ARE NOW GONE!

Since the last time out, changes were:
- installation and use of a line lock
- removal of front sway bar
- installation of rear sway bar
- FINDING THE PROPER SETTINGS FOR MY D-Specs
Besides all these, I actually INCREASED my rear tire pressures, running them 25 psi all day, and got better 1/4 speeds.

Was always able to do a good burnout with the line lock, and depending on the rear settings on the dspecs, would get no to a little spin.
I did a little ahead of time 'street testing' this past week and with 30psi in the DRs on the street, and setting both front and rear dspecs to 7.5 and 7 turns respectively, did a few 'launches' and had no spinning whatsoever on the street! So i was hopeful.

Then at the track, I narrowed down the rear dspec settings to just where some rear spin would start to occur: and that was 5 turns out from full hard. So running rears at 5.5 turns or more, no spin whatsoever.

I only got a couple runs in and was working on a couple tune issues before trying hard launches, but I do know the setup will grip now. And besides the grip at the line, I also no longer have the issue of it breaking loose after leaving the line. Complete traction all the way through 1st and 2nd now (until a brief tire-chirp in the 2nd-3rd shift).

Before these adjustments and when creating this thread back in January, I was running 1/4 times of 13.0's-13.2's with 60' of 2.0-2.1 and 105's top speed.
With the changes mentioned above, today I consistently ran 12.8's with 60''s of 1.95-1.99 and 106's.

Now to refine some things and get a little more seat time, and get those 60' times lower.

Thanks to all the help, everyone!

 

[FnSweet06]

Good to hear!

Where'd you go, Midnight Madness at SanAntonio Raceway?

 

[TexasBlownV8]

No, TAD (Temple), daytime; much closer for me. Local club (AAS), about a dozen of us went.
But I will make SAR this year, too, at least once

 

[stkjock]

congrats on getting the car better dialed in

are you leaving off the foot brake?? and I dont see a stall in your sig are you still using the stock stall converter? I'm not an auto guy, however IMHO, you would benefit from getting a higher stall to let you leave harder.

 

[Vapour Trails]

Your front d-spec setting is what I use (7), but I go much stiffer on the rear (0-2) My thinking on the rear setting is you want the shocks to oppose compression of the rear springs. If the springs aren't compressing as much during the violent weight transfer to the rear of the car, then the tire sidewall will compress more, which should result in better traction.

When I still had an entirely stock suspension my best 60 was 1.89. The next time out with lowering springs and d-specs, set as mentioned above, I put down a 1.74 time.

 

[TexasBlownV8]

Your front d-spec setting is what I use (7), but I go much stiffer on the rear (0-2) My thinking on the rear setting is you want the shocks to oppose compression of the rear springs. If the springs aren't compressing as much during the violent weight transfer to the rear of the car, then the tire sidewall will compress more, which should result in better traction.

When I still had an entirely stock suspension my best 60 was 1.89. The next time out with lowering springs and d-specs, set as mentioned above, I put down a 1.74 time.

I tried harder rear settings my first time out after putting them on, from 1-3 turns on the rears. Nothing would stick at the line. Of course I had the front swaybar on at the time.

This last time the hardest rear I tried was 4.5 from full hard, and that was the worst loss-of-traction run the whole day.

I still plan on tweaking settings on getting proper weight transfer and suspension travel. I also realize a lot of you are running stiffer settings on the rears, and it works well for your setup. Maybe it's the extra weight I have up front with the FMIC and supercharger, or maybe because I'm a fairly big guy (225 lbs), but getting proper traction is absolutely necessary!
And this is just one setup combination that allows me to run and get traction at the line. It may not be the optimal setting yet, so I'll keep trying things.


Regarding the stall converter, I'm still running the stock one. I am seriously considering upgrading to a higher one this year, so I can launch much harder. Of course without traction, that didn't matter...but now I can start to consider it again.