Can I get schooled on 1/4 mile? Tire - Suspension Technique

[Monera3v]

Hello everyone,

This year I would really like to get my car into shape for 1/4 mile runs ( And maybe some course runs )

Car is a
2005 Mustang GT with a M90 blower making 400hp 400 tq, 5 speed

I am trying to get the car to grip a lot better and lower my nasty 2.1 60'

Setup wize I am running
Tires:
255/40/18 BFG kdw in the front
295/35/18 bfg drag radial in the rear

The results are

SPin spin spin spin city!


Suspension wise as follow;

Ford racing K spring (1.5" drop)
UPR HD hem join lower control arm w/ BMR relocation bracket
BMR HD upper control arm *poly bushing* with BMR upgraded bracket
BMR Pan bar
RTR Sway bar
Tokico hp shocks

Will be swapping out to 3.73 unless someone advise other wise?
Rebuilding the rear end and tlock


If i should change anything please advise.


I don't want to switch up to a Big n Small wheel / tire setup.

What tire should I look into getting for the rear? Even if it means buying new wheels I am fine with that.

Any info would be much appreciated!

Best so far I have done is 13.1 ~ 109mph
With 3.55 and full stock weight

14680739_685244909604_2796137697956951435_n.jpg

[Laffs]

Seat time. Play with launch rpm and technique see what works best. Also try doing a longer or shorter burnout, drag radials don't need to be smoked in to oblivion but you need to put some heat in them. Big diameter drag radials and a stick with a lowered suspension isn't ideal for great 60ft times. Not wanting to go with slicks on bigs and littles limits you so perhaps a 15-16 inch wheel and drag radial.

Gear ratio, you are going to get more spin from a higher ratio so you will have to practice more once you go in. Pick which ever ratio will get you close to trapping close to the top of 4th gear is what I was always told.

Suspension wise if you really want it to drop the 60s ditch the lowering springs and the stock replacement struts for something that will let the car transfer more.

Aside from that put the car on a diet for the track, pull the spare tire, stereo, rear and passenger seats before the track day. A basic rule of thumb is that every 100lbs you pull off the car will net you 1/10 in the quarter.

[Slick_89_Hatch]

I would check instant center or at least play with the different locations for mounting on the relocation brackets.
Play with your burnouts and tire pressure also. I found things worked well for me around 18psi with my 235/55R15 MT ET Streets.
Next would be change rear tires and rims IMO. Nick has good success with his 17" ET Streets. I'd see what his set up is as well.

[Monera3v]

I am hoping that
Rebuilding the rear end + the TLock will give me some tracking
I also think my shocks were blown, hoping those factors are to blame for some spinning.
I am looking at some BMR drag springs? Would it make a difference?

So I was told not to mix bias with street tires?
What kind of tire do I need to look at to continue running my street rubber upfront?

[Slick_89_Hatch]

I really think the MT ET Streets are the way to go, especially since you can drive to the track with them. If the shocks are indeed blown and tloc is not functioning then those are huge factors as well. I wouldn't worry about drag springs until your other issues are sorted out.

And to my knowledge (which isn't alot on this) mixing bias and radial are a receipe for wobble.

[TC86GT]

First off don't fear the gear. To me going from a 3.55 to a 3.73 wouldn't be worth the effort. Step up to a 4.10, especially on a bigger/heavier '05 GT.

Tires, 15" set-up with a sticky slick or DOT type of slick. Bias ply will be your best bet, even if it spins the recovery will be quicker and still push you forward. If you had an automatic, I'd probably suggest a radial but typically the radials and manuals are a tough animal to tame.

Mixing bias ply and radials, yes you may get some "wishy washy" feeling at speed but it's far from an uncontrollable thing. Just keep it pointed forward and run it out the top end. I've done it both ways, bias ply in the rear, radial up front and bias ply in the front and radial in the rear. Never felt unsafe or out of control.

Sure you could swap out the suspension for a better drag oriented set-up but you can't have it both ways. Stiffer for cornering and straight line grip...one or the other or a happy medium for both. If you are satisfied the way the car is now, just gear it up, and throw on some sticky tires. 109mph is good for mid 12's easily, but the 2.0 60' is killing you. Get that into the 1.6's on a sticky tire and you'll be looking at a half second decrease on ET just leaving harder.

My current '86 GT is lowered, stiffer springs and shocks/struts and when it was a 5 speed/4.10 combo, I had 16" radials up front and 15x8 wheels with a 26x8.5 slick out back. It'd go mid/high 1.6 60' times on motor running high 12's and on the bottle it left with a 1.52 best 60' dropping into the 11's.. Definitely not a drag suspension under it, but with enough power and enough traction...it'll go.

[WidowrRacing]

I would recommend starting with a slick mounted on a 15' rim and then you can actually get a decent baseline and mod your car from there. Your car will only get faster with traction not being an issue.

I'm so done with the low profile drag radials.....don't get me wrong they're great for the street but not the track....just not enough side profile for a consistent hard launch.

[Monera3v]

Can anyone recommend a tire I should go with?

[TC86GT]

Full slick, MT or Hoosier 26x10 on an 8-10" rim.

DOT slick, Hoosier Quick Time Pro or MT ET Street bias ply in 26x11.50.

Plenty of tire that will take you well beyond your current level. Toss them and a jack in the trunk and swap them at the track.

Don't forget to put on a driveshaft loop if you don't have one already.

The '05+ cars are 31 spline axles/diff so they will take some power in stock form.

[WidowrRacing]

I think the 35 series profile is the problem for track use with your current DR's

You would have much better results with a 275/60/15 DR or a full slick in 15'.

Latemodel resto offer SVE drag rims and tires in 15x10 for your car with an optional skinny if you want it....these are cheaper than others unless you can find a good deal used.

Mickey Thompson or Hoosier seem to be two of the most common tire choices.