Old Geezer

iTrader: (3)

12psi too low. [Our M/T tests w/ that tire, in 15" size, indicated 15-16psi was the best.]
The vid shows:
1. The tire takes a hit, but bounces. Shocks not able to control the axle. [KYB's are not what I would use.] Low psi also contributes to the "basketball" effect.
2. Can hear down track shift, it sounds as tho the tires loose grip. U have any data logs? Look at the rpm trace.

nocooler

iTrader: (5)

There is a video of what Chuck is talking about here:


26x11.50 ET Streets in that video. The shock couldn't control the hit, so I moved the control arms up and it started hooking.

mgood613

iTrader: (1)

Thanks for the info guys, I have a feeling some DA rear shocks are in order, then maybe a control arm adjustment.

This was the first time I was able to get video and still pics of the launch. I tried posting the pics but they keep failing to load.

I did notice I started to get a little wheel hop when I went down to 12 psi, these are 26-10.5-16 et streets.

ssvert99

iTrader: (26)

The KYB shocks are not helping matters for sure. If you are looking for optimum performance you will need to get a good shock on the rear to help with tire control. We have a sweet deal on the Viking rear shock to match the fronts you have and that will get you going in the right direction so we can get you setup for correct weight transfer and tire control.

Give us a call!

NW Iowa WS6

iTrader: (9)

Exactly, every car and track is different, my car moving the torque arm steeper netted me a harder hit and kept the front up longer, I also have a odd brand tranny crossmember (RAC off ebay) built like a brick **** house but I think all its hole settings are lower than BMR UMI etc. In the bottom hole on mine the rear end is tipped down so much my shocks won't even bolt in because they are rubbing the axle tubes

mgood613

iTrader: (1)

Pics of the launch.

ssvert99

iTrader: (26)

...and killing the sidewall, lots of wheel speed.

Better shocks for tire control, maybe a bit more pressure(determined by weight transfer and shock setting), and maybe a bit less launch rpm.

Forcefed86

iTrader: (4)

I agree with the low pressure theory. Pressure looks too low for as hard as your hitting the tire. If you drop play back speed to .25 on youtube you can see the rear bouncing back up really well. Either don't hit the tire as hard, or run more pressure and/or taller tire.

RENE'S RAGE

iTrader: (96)

I'd put a 15" rim with a 28" tire.
A lot more sidewall than you have now.
And skinnys too....

mgood613

iTrader: (1)

Thanks again, I'm learning a lot!

I didn't realize you could slow down a youtube video. I watched it and was amazed.

I actually what to try more psi, then control arm adjustment, then 28".

I might put skinny's up front if I can find a used set, or I have some 215/16 wheels and tires I might put on at 45psi.

flintwrench69

iTrader: (11)

That front tire looks huge compared to the rear. 12 psi sounds too low for that tire/wheel combo. Seems like you should be leaving at 5k & getting decent traction but short sidewall & lapeers track surface doesn't help. I wouldn't be buying any shocks, that tire combo could use some help. I would bog a decent amount leaving at anything below 5500 & I got stock Bilsteins.

mgood613

iTrader: (1)

So I ended up getting the ssra kit on and a set of 15x10 racestars with 275 50 15 MT et street radials on them. I then bought a set of 15x5 racestar fronts and went to the track.
I was just going after mph this trip, I knew the radial tire wouldn't help any at the track.
I was 11.72 at 121 with 1.8-1.9 60's
I'm looking at rear tires right now and was wondering what people's thoughts are on Hoosier 27x11.5x15 QTP bias pli.
I am getting on the limiter just goin through the trap 6500.
I don't want to go too big (28)? Any thoughts?
I still drive this on the streets so I would like to stay away from a slick for now.
and I did end up getting da rear Vikings. Lol just haven't put them on yet.
Thanks

mgood613

iTrader: (1)

Or do I try a 26x11.5x15 QTP and the growth on the big end will be enough to take some gear out?
I have tried mt et streets 26x10.5x16 and they dropped me around 200 rpm through the traps, just didn't let me leave over 4000 rpm at the line.

ssvert99

iTrader: (26)

Most of the acceleration(et) is had in the first 300 feet. You need to concentrate on the 330 times and the rest will follow. I would strongly suggest to run a 28" tire on a 15" wheel, but if you aren't in a position to do that then the 27" QTP will be the best option for what you have mentioned.

mgood613

iTrader: (1)

Thanks for the reply

mgood613

iTrader: (1)

Well, I went back to the track today.

Changes,

1.85 Slp rockers, SSRA

Rear control arms brought up a hole. Now at 2 degrees, was 5.

D/A Viking rear shocks C/4 R/14

15x5 racestar fronts with 165/85r15
15x10 racestar with Hoosier 27x11.5x15 17psi

Launching at 4200-4300 rpm controlled spin

1.78-79 60fts
11.5-11.6 1/4 ET's
121mph


Last time to the track the fronts liked R/2 C/14 so I kept it there, I changed it up a bit but got slower. I still would like to get low 1.6 60 ft's at this track, it's not know for good traction but I feel I could do better.

With going from 26 to 27in tires will that cause me to lose mph? I ask this because I changed out the rockers and went to a taller tire and gained a little on the mph but thought it would be higher.

Any thoughts with the new changes/info?

I also got around to weighing the car 3580lbs with me in it. I'm 225lbs.
Thanks, Mike

mgood613

iTrader: (1)

The only video I have is a buddy taking it down the track, I am a shaking mess.

I know the video sucks but it's all I got.

mgood613

iTrader: (1)

I'm starting to get my rear suspension and tires dialed in. I still need a bunch more passes in but it's a start.

They had a car at the track hit the guardrail today and closed down test n tune for a while.

Ran a 11.38 at 121mph with 1.64 60ft
couple 11.4 with 1.65-67 60 ft's.

Thanks for all the help guys, now


https://www.youtube.com/watch?v=XyJS...ature=youtu.be
https://www.youtube.com/watch?v=6foT...ature=youtu.be

Bitemark46

Is your right rear shock a single adjustable? Looks as if the rear pass side is squatting. And you have some separation on the drivers side.

Have you plotted your suspension yet?

If I had to guess you may have a high AS which could be the cause the drivers side separation. Try and that down if you can.

-Mark

mgood613

iTrader: (1)

The rear shocks are Viking D/A, I have them both set at C14 R6. I had it reversed like the instruction suggested for settings but I couldn't get it to hook at all. I read a thread on her that suggested these settings and they dropped my 60 from 1.78 to 1.63 and allowed me to leave at 5500 instead on 4000 rpm. I have my front torque arm in the middle settings and my lower control arms are a 2* uphill from axle to body.

What would your suggestions be? And how to go about it?