BlackWS666

iTrader: (31)

My car has been running extremely consistent all year(11.1-11.2) and the end of the season is coming around and i REALLY wanted to get a 10.99 pass under my belt before this winters tear down. I have been running MT 28-10.5 slicks all season and have never had worse than a 1.55 60ft, with a best of 1.44. I decided to drop about 50 pounds of weight and switch to a MT 275/60 hopeing for a little more in the top end speed. Took it to the track a few weeks ago and blew the 275s off. I didnt adjust anything but the weight and the tires.

I was running QA1 shocks 0 front, 6 rear. And the tires were at 18psi cold with a 3-4 second roll out burnout with minimal, almost no smoke. The track was hooking well, and the weather was nice also. The weight changes were removal of pass seat and harness, door bars, formula hatch, door bars.

So what changes should i try for this weekends test and tune?

tomcowle

iTrader: (5)

foot braking? stage rpm? immediate breaking loose?

need more info or a video to begin guessing

ATVracr

iTrader: (5)

We run ours around 16psi
if it spins take air out, if it shakes add air

We never have good luck with a new set, seems they need 2-3 passes with good burnouts for them to work.

Phil99vette

iTrader: (11)

Slicks will tolerate too much RPM better than drag radials, back down the RPM. They need to dead hook. You need to find the max RPM you can leave without spinning them. I think we've got our leave down to 50rpms. If we add 50 it spins, if we take it out it will 1.2 to the 60'.

BlackWS666

iTrader: (31)

Im leaving at about 3000 on the footbrake. And yes the almost immediately broke loose. Car didnt get a chance for the frontend to come up.

Villain281H

iTrader: (5)

as mentioned, try lowering the rpm. radials are less forgiving than slicks, plus the sidewalls don't flex as much as slicks. Every car is different, but you may have to work at it a little. Try different pressures as well, but make sure each pressure you try is a legitimate pass (in the groove, minimal variables between runs, etc). If not, make 2 at each pressure before changing stuff.

My Nova going from 28 x 10.5 M/T stiff sidewall slicks at 15 psi to 275/60/15 M/T radials at 18 psi picks up about .05-.07 and 3/4 mph.

Derek
Derek

BlackWS666

iTrader: (31)

Alright I will play with the RPM at launch, what about suspension setup? Should it need to be changed, or is focusing on the PSI and RPM the only variables?

Pro Stock John

iTrader: (34)

Madman told me the start with the rear shocks on the stiff side. I had them at 7/7 and the fronts at 2/2, and then I took out 2 psi air in the rears, and put the fronts to 1/1 and went 1.35 on my 325's.

Phil99vette

iTrader: (11)

If you can't get it too hook I'd make some serious changes, take 300 out of the leave RPM, fronts full loose with full travel, get it to bite than start adding RPM, as the front starts to carry tighten it up. If you have an adjustable roll bar, get the car scaled.

BlackWS666

iTrader: (31)

Cars been scaled by Chuck @ Burkheart Chassis, and its been hooking perfect till i got these tires. Thanks for all the help guys, I will have my work cut out for me sat night @ US41.

1fast98

hmm, maybe i need to try slicks. i cant even come close to 3000 rpm launch on my 275/60s.

night ryder

iTrader: (20)

lower your tire pressure. i turned up my 2 step to 4k with 18psi and they spun like crazy. put it down to 16psi and they dead hook and lift the tires.


btw i have 275/40r17 so i dont have much of a side wall at all.

BlackWS666

iTrader: (31)

That will be the first thing i play with is pressure. Hopefully the weather holds out for sat. night.

tomcowle

iTrader: (5)

lower tire pressure and look at weight transfer (maybe the nose is too low?)

Stroked96Bowtie

iTrader: (22)

The tires will work, dont fret, and when they do you will have a new best 60ft. Happens everytime I see someone put these tires on.

I run 17psi in my 275/60s, my front QA1's are set at 6 if I remember right. Im assuming you have LCA brackets, etc. the full works on your suspension? I was one of the lucky ones, slapped DRs on and they hooked from the start...1.3x 60s.

viper,redZ

iTrader: (7)

I run my rear qa1 on 6 front suspension stock and 20 psi in the 275/60 1.55s on motor and best of 1.36 on the gas . I have a ptc 3600 its a little tight and stall to 2500 hooks everytime n/a . On the nitrous its a little more tricky . I hated my DRs until I started doing a real burnout and playing with psi do that and they will hook .

BlackWS666

iTrader: (31)

Im running a yank ss4000 stall. and my rear qa1's are always on 6. I have a solid 5 hours of test and tune saturday, hopefully i can make something work. How big of a burnout? The same as on a slick, Is that the trick?

night ryder

iTrader: (20)

i go from 1st to 2nd right away (th400), then sit at about 4 grand for about 2 seconds, then keep them going out of the box.

BlackWS666

iTrader: (31)

Thanks guys, im leaving know. I will post results once back.

BlackWS666

iTrader: (31)

She went 11.03 @ 120.68 with a 1.422 60ft. The tires were set at 17/16.5 psi, and was launching at 3000 off footbrake, and the burnout was exactly how i did my slicks. Definitely felt like she was grabbing better. So I cut .02 of the 60, and .07 off the quarter going to drag radials from slicks. MPH was exactly the same. Weather was near the same as the last time I went as well.