Whats your rear susp/ tire setup for track?

[trashmechlv]

I was trying to get an idea of what people are running for a rear suspension setup and what tires? The reason I ask is because I took my GN to track last night here in Vegas. First of all it was record heat and still about 105 degrees at 9pm start. I could not hook up car at all with horrible 2.50 60fts. The only reason I even tried to run with the excessive heat was its the last test n tune here until end of summer and I recently bought my car and did some work on it.
My rear suspension is all stock and rear bushings visually look ok. Front susp looks like it has a fairly recent rebuild. Im running 275/60/15 Nittos on stock rims. I started at 24psi in tires and gradually dropped pressure eventually ending at 17psi with traction getting worse. I did burnouts until I saw smoke. I left the line from 10lbs boost down to idle and just roasted tires, had to pedal car a few times. Also felt tires spinning about 1/2 track with car squirrely.
Looking for some setup ideas that work well with low 60ft times. My car is stock eng internals, Precision TE44, 3 inch downpipe, stainless headers, stock IC, Precision 65lb injectors and 100 octane chip from TT. running 21lbs boost. Stock 8.5 posi rear. PTC 10" 2800-3000 non lockup stall. I just installed PTC stall after having a sorry 12" non stock converter in car. Went from building no boost and leaving like a turd to instant boost and shredding tires. Ive owned many cars and have made lots of passes on the track in the past but haven't had a car making this much power coming on so hard with the turbo. I felt like a rookie out there. Runs were similar with 2.50 60ft and 13.90s at 101mph. I believe this car has 12s in it with a good 1.60 or 1.70 60ft time. Maybe just need slicks or better drag radials? Thanks for input. It was fun running down Mustangs with 2 second head starts with the back of my car skating around.

[Scoobum]

28x9 slicks
70/30 shocks up front-50/50 rears
ATR rear sway bar
1.6 foot brake launches
 

[trashmechlv]

Thanks, what boost do you launch at?

[Scoobum]

I come off the footbrake at 2800 RPM.

[motorhead]

315/35R17 Nitto NT05R Drag Radials
Auto-X/Road race type suspension
1.7 60'
11.9 @ 112mph
Timeslip is at the end of the video:

1191at112mph

[Charlief1]

I'm gonna start a little differently than most would. Have you had the car up on a lift so you can check all the bushings? If not I'd do that before you even consider doing any suspension mods. This may be related to the tires and heat or it could be suspension related.with the temps you're seeing out in Vegas right now I would expect the track surface to be well over 120 so it would be a bit slippery.


Since the tracks out there are going to be closed due to heat soon I'd say do some reading up on good set ups and once you get one scale the car to see where the weights sit. You'll be surprised where the weight is sitting.

[Tim Hensley]

                                                      Part # or Keyword
I run this it fixed my 60 ft

[Tim Hensley]

well that did not work
I added a Hellwig Pro touring #55809 fixed my 60
I have UMI rear bars the new bushings  was nice  +for the ride but was no help in the 60ft

[Steve Wood]

As Charlie mentioned, the track was way too hot to make it easy to get traction.  I suspect there were a lot of others out there complaining because they were not hooking.  Also, you are running Nitto's and they are a great drag radial for the street but they are not so good at the track if for no other reason than they use a much harder rubber compound and they just don't hook as well as M/T, M&H, or Hoosiers.  I run the same Nittos as you on both of my cars and they do pretty good on moderate days on the street but when the temps hit a hundred, they spin instead of bite.  It does not help any that you are running them on the stock wheels which are a bit narrow and make them a little squirrelier as the tire pressure comes down.  Nittos are great street tires, last much longer, and are not absolute suicide if you ever see rain.

I suggest you find a set of 8" wheels with 4.5" back spacing and add a pair of of the above mentioned dr's to them.  Note that some of the above brands specifically say NO street driving on them.

As Tim mentioned, the Hellwig bar works very well to equalize traction between the two rear tires.  It is light weight compared to the solid 1 1/8" bars that so many of us run, and geometrically is similar to the much more expensive H&R bar which works better than the factory style mount.  It is nearly impossible to launch a car with more power than stock without a good rear bar.

Next, you have to be certain that the bushings are good as mentioned above.  If for no other reason to be sure the car launches the same way each time and does not try to change lanes on you.  Be sure the front control arm bushings are good (particularly the upper passenger side at the rear under the down pipe)-and ball joints for sure.  A car that goes crooked on launch will probably try to do the same when you lift at 120.

Having boxed lower rear arms can help as well. 

Be sure your limited slip rear end is actually working properly!  Find some clean pavement, load the converter, and do a strip type launch.  Get out and look at the stripes.  They should be pretty much equal in length as an indication the rear is working.  Then look at each stripe for eveness of "blackness" across the laid down patch of rubber.  If the stripe is blacker in the middle than on the edges, you have too much air in the tire.  If the stripe is blacker on the outside than the inside, you don't have enough.   Play with the air pressure until you get the most consistent stripe.

You should not need air bags on the average car.

With regard to shocks, I think stock shocks on a car that is a daily driver is the way to go.  You never know when you may have to swerve hard to miss an air plane landing on the stripe or such.  If you can find one of the tubular front sway bars, put it on the car.  Never hurts to lose a little weight up front.

I don't know what your converter is actually stalling at, but, I have found about 2700 rpm and around 5-6# of boost is a pretty good beginning launch point for a TE44 until you prove that your tires will stick under the given track conditions at a higher boost.

Sometimes, things are so bad that you may have to use the chip to detune the car a bit in order to keep from spinning up in second gear.  Those are the days that you might be better off at home in front of the AC and TV.

[motorhead]

Can't argue with that.

[trashmechlv]

Thank you for all the input everyone. Steve, I have read most of your info on your website dealing with these cars and it is very helpful. I also think a lot of it was the crazy temps, track temp was probably super hot baking in 117 all day. I will look into a better rear sway bar and give closer inspection to the bushings. I can box my lower arms myself if that helps. I am kicking myself for trying to save a few bucks by buying the Nittos since they cost less and would last longer.    Do the MT drag radials hook that much better than Nittos? Searching on the forums I have seen people cutting good 60fts on Nittos. I would just buy slicks but have a 22 mile drive to and from track mostly all highway and don't have a car trailer. I may not have anybody go to track with me that could bring my slicks for me. The car is not a daily driver so I shouldn't have been so worried about tire wear. At least I have all summer to sort it out, not going to attempt running again until well into Sept or Oct when temps drop.
Mike
 

[Steve Wood]

M/T's will consistently hook better at the strip under a wider variety of conditions.  They are much softer and therefore, more sticky.  Most drag radials do not like a hard burnout...just enough to warm the surface.  Most of the tire companies have some comments as to how they think they work the best on their sites.

They don't handle as well in street driving.  I like the Nittos, but, then, I don't go to the track anymore. 

I have not been impressed by slicks on these cars unless one is a lot faster than 99% of us.

I need to rewrite the suspension part of the page and get more inline with my current thoughts.

[SuperSix]

* SuperSix stands by to update...

[motorhead]

M/T's will consistently hook better at the strip under a wider variety of conditions.  They are much softer and therefore, more sticky.  Most drag radials do not like a hard burnout...just enough to warm the surface.  Most of the tire companies have some comments as to how they think they work the best on their sites.

They don't handle as well in street driving.  I like the Nittos, but, then, I don't go to the track anymore. 

I have not been impressed by slicks on these cars unless one is a lot faster than 99% of us.

I need to rewrite the suspension part of the page and get more inline with my current thoughts.

I will argue that my NT05Rs handle pretty well for a drag radial.  Being low profile helps.  My M&H DragMasters = wobble city by comparison.

[trashmechlv]

So is their a big difference in all the available aftermarket rear sway bars? I see a wide range of pricing. Is a 1" rear bar good or should it be larger? Saw a Spohn 1" bar for $174. Hellwig bar around $200ish.  Sounds like this would be a good investment since my car has stock rear bar on it.