First time at track with twin turbos

2012 GT auto stock gears, it is my daily
Mods/prep:
Hellion 62mm twin turbo on 5lbs boost - 561rwhp and 460rqtrq
Nitto nt555r 305 on 10in rim(will swap to 11in rim once my toyos are dead) - I will admit I did not drop enough tire pressure out of them, lowest was around 20.5 with warm tires
Koni yellows with front full stiff rear full soft
Ebaich springs, bmr rear ower and upper control arms with the relocals and brackets, bmr panhard
I was leaving off idle as I have never launched a turbo car/foot brake bumped in
Was 80 degrees today
Now to the numbers
Best of 11.574 @ 126.16mph
60ft 1.985
1/8 7.656 @ 98.74

Prior to turbos (tuner for turbos dyno'd prior to install to check everything was good and it was at like 350rwhp I think) at same track I ran a 12.19 at 115 best time and a 1.9xx 60ft iirc, but was also like 60 degrees. Other runs on 70+ degree days I ran 12.2-12.3 at 112-114 or so.

Overall kind of let down with the runs, I was hoping for a low 11. I will work on foot brake bumping in before my next visit but I am on the stock converter so cant rev it out all the way, hopefully this will at least give me a tenth or two. If anyone has any tips/pointers I would appreciate it, I will be going to my tuner soon to chat also

With a 126mph trap speed your car should be capable of high 10s. That should give you some encouragement.

If you plan on going to the track on a regular basis, I would suggest getting a bump box, and I just happen to have one for sale.

https://www.s197forum.com/threads/davis-technologies-bump-box-350.136229/

There is at least a half second in your 60' alone.

a better converter and some tires and you'll pick up a ton of ET

Time for a higher stall converter!

Any reason only 5 PSI?

Sorry for the no replies, usually it notifies me but did not for any of these and then I went on vacation so didn't use my phone much. I talked with the shop/tuner and he is against a trans brake and such due to the car being my daily and how rough it is on the car - he told me really the only thing he would suggest is a pure track tire. 5lbs of boost was the start just to get used to it and we have gone up to 7lbs for now with a boost a pump, the car will stay here most likely until I finish school in 2021 then once I am settled I plan to build her more.

I tried to foot brake and rev out the stock converter but the brakes do not hold the car at all =/ looks like I am doomed to be a high 1second 60ft or have to turn to roll racing

I agree with your tuner, keep current wheel/tire setup for regular driving and get a 15' or 17' wheel for the track with MT ET Street Radials. Stock stall speed will be a limiting factor but with a good tire and suspension setup, you should still be able to go lower on the my 60'. On my Tokico D-Specs, I run the fronts very soft and rears about half firm with passenger side rear shock a bit stiffer than driver's side.

Alright time to bring this thing back up. Long story short: fuel system, e85 and more power happened - my high boost setting is just under 10lbs of boost and Im at 700rwhp and 610rwtrq. Definitely ready/need a new wheel setup. I am going to go with either sve or the racestar 15x10 in the rear. Still on stock gears and converter. Now I plan to go with a 28" tall tire over the 28(smart move?). I am stuck between MT et street r, the et street pro radial and now perhaps the bracket tire they have. I am tempted to throw the biggest tire I can on, but I am wondering if the 275 pro radial should hold my power level (and save weight)? I currently don't race competitively but would maybe be into bracket racing in the future. I would use this set 90% for the strip, and maybe on the street if I have Mexico plans. I have seen countless threads but no one seems to mention their power level or are in the 400rwhp ranges. Which tires/sizes do you guys recommend? Once again, thanks for the help!

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I run an 18x10 Roush wheel with 305/45/18 MT ETS and they are 29" tall, gains you an inch. I'm at about 400hp and they hook well for me. 18 lbs of air on track.

28” at least. The 275 pros seem to hold a lot of power to the ground with proper suspension set up.

Your shock settings seem backwards to me. Front should be on the soft side and rear should be in the middle or on the firm side depending how the car reacts when you launch it. The rear/body of the car should not come down off the line. For drag radials, 20 psi is okay. They aren't like slicks. So that might be close for psi that you are running. I like MT drag radials if you plan to keep running a radial drag tire. There are people on this site that run 295 MT SS with 15x10 wheels. I would run a 15" wheel. I ran the 275s which are 28" tall on my car, but my car isn't very fast. The more sidewall you have, the better. But if you throw converter at it, maybe you will have to run a more aggressive tire. IDK. As mentioned above, the 60 ft is the issue. Are the Eibach springs a lowering spring? A drag spring? My experience is that front end travel is mostly determined by the type of spring you are running, and how much stored energy the spring has. You can adjust the shock, but if the travel isn't there, then it's not going to matter much???

Have someone video you off the line so that you can see what the car is doing, I have a measly 330 whp (if that since it's at 5K DA) /4.10 gears/3K converter, but with a stock (soft) shock I get no traction around town, and if I floor it, the back end drops way down and the tires brake loose. When I was racing my car I ran Strange single adjustable, set on 6 (11 being the firmest) for the rear. World of difference.

jam07GT said:

Your shock settings seem backwards to me. Front should be on the soft side and rear should be in the middle or on the firm side depending how the car reacts when you launch it. The rear/body of the car should not come down off the line. For drag radials, 20 psi is okay. They aren't like slicks. So that might be close for psi that you are running. I like MT drag radials if you plan to keep running a radial drag tire. There are people on this site that run 295 MT SS with 15x10 wheels. I would run a 15" wheel. I ran the 275s which are 28" tall on my car, but my car isn't very fast. The more sidewall you have, the better. But if you throw converter at it, maybe you will have to run a more aggressive tire. IDK. As mentioned above, the 60 ft is the issue. Are the Eibach springs a lowering spring? A drag spring? My experience is that front end travel is mostly determined by the type of spring you are running, and how much stored energy the spring has. You can adjust the shock, but if the travel isn't there, then it's not going to matter much???

Have someone video you off the line so that you can see what the car is doing, I have a measly 330 whp (if that since it's at 5K DA) /4.10 gears/3K converter, but with a stock (soft) shock I get no traction around town, and if I floor it, the back end drops way down and the tires brake loose. When I was racing my car I ran Strange single adjustable, set on 6 (11 being the firmest) for the rear. World of difference.

Click to expand...

I definitely will have someone film me, that is a great idea. As far as my suspension the springs are just lowering springs. I know it isn't ideal for drag racing not having a dedicated drag suspension and I am leaving a lot of potential untapped. I didn't go with drag springs and the drag struts/shocks because I only visit the track on occasion and like to take off/on ramps at speed and also wanted the car to be able to handle higher speed maneuvers if need be (I always try to have openings when playing around but I'm not perfect and have had to weave when accepted Mexico highway races in less than ideal circumstances). I was afraid if I did a full drag suspension then the car wouldn't handle or respond well. Plus I did my suspension work when power was stock and never imagined throwing turbos on the car/needing a drag setup.
My understanding for the strut/shock settings was if its soft in the rear and stiffer in front was the weight would transfer to the softer rear easier. I never thought about my actual springs not being able to allow the proper transfer though like you brought up.
I'm becoming more aware I may be wanting the car to perform better on a strip vs my current setup which would be better suited for autoX or such which I never have done and probably wont. I appreciate the help!

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For the rear shocks it's all about Newton's law that for every action there is an equal and opposite reaction. If the body of the car is coming down, then the tires are coming up. If the body of the car remains neutral or even comes up slightly, that means the tires are being pressed into the ground. Running a really sticky tire can make up for a mediocre suspension setup to a degree, but I would bet that you need to stiffen the rear shocks up. Auto cross and drag race are just totally different. They require very different setups to work really well. I am not familiar with Koni yellows, but I would try setting the rears right in the middle for starters, then stiffen them a click at a time if the body is still coming down off the line. There is SO much left in your 60 ft time.

Just make one change at a time and then make several runs to be consistent and see what the effect was before changing something else. I think I usually ran 22 PSI with my MT SS Drs, but, again, nowhere near the power you have. Probably between 18-22 would work best. You want the most tire PSI you can get and hook up with. But if you are running the slicks, then you would go lower than that.

While a converter and tires would help your ET for sure. If you were going to do autoX then I'd be very careful about a higher stall converter. While it's true you can drive a 3K or 4K converter around no problem, they are soft below whenever they flash and probably wouldn't work very well for autoX.

Others who have more experience with fast mustangs can comment, but looking at videos and stuff, it seems like the mustangs don't need as much weight transfer. Of course, if you are going to go super fast, I am sure they do. My Chevelle had 7.5" of front end travel. Light springs. The headers about dragged on the ground. But it allowed for a lot of weight transfer which is what those cars need. I measure the front end separation on my GT with and without the front sway bar. It made no difference. If anything, for your setup I would just put the stock springs back in. With 28" tires, the car will look awesome.

As someone mentioned above, sometimes the right passenger spring needs a little more stiffness. We used to use an air bag on that side "back in the day." Now drag springs sometimes come with a slightly stiffer spring on that side, or I guess you can just adjust that shock to be a little stiffer. I ran my rears on both at 6/11, but, again, I had nowhere near the power you have.

Also, if you are going to really run this car hard with slicks, I would look into a. axle girdle/differential cover like the FRPP one an also the CHE rear end brace. I have both and they are super easy to install. The rear axle brace is nice. You won't have to weld up the tubes or any of that. I assume you already have a driveline loop and one piece driveshaft?

Also, take a look at where you have your lower control arms mounted in the BMR brackets. With your car lowered, I wonder if you'd want to use the second hole from the bottom or even the bottom hole??? I know everyone always says that you should have the lower control arm parallel, but I never see anyone running it that way on a street type drag car. The further back the instant center, the more "anti-squat" you get, but it hits harder too.

Here is an article on the basics:
https://www.dragzine.com/tech-stori...spension-adjusting-instant-center-anti-squat/

https://www.cheperformance.com/products/che9l

Hey, keep working at it and you will get there. The fun of this sport, to me, is figuring all of this out.