Drag racing experience - 15 or 17 inch rear wheels?

[MrBhp]

Those tires appear to be hooking well.

 

[Red-Candy-Metallic]

Those tires appear to be hooking well.

I am very happy with them. Both the 275/60R15s on the 2012 GT (manual transmission) and the 285/40R18s on the 2014 Mustang GT (automatic transmission) are hooking quite well. In each case I am doing a minimum burnout, just enough to clean off the tires. On the rare occasion (mostly when I am in New England) when the temperature is on the low side, I might sit on them a little longer, but nothing real smokey. As an aside, now having used them both, I prefer the Forgestar wheels to the Racestar wheels do to the fact that you can use the same conical lug nuts as the factory wheels. Both sets of wheels have performed well so far and both sets are light, but the shank style log nuts are somewhat annoying because the required washers can bind up when you removing them.

 

[429244]

So when are you are going to stop test and tune and start racing?
Shank style lug nuts are a pain but when you start getting into 1.5 60' times on a 4000 pound car, they start to matter.

 

[Red-Candy-Metallic]

So when are you are going to stop test and tune and start racing?
Shank style lug nuts are a pain but when you start getting into 1.5 60' times on a 4000 pound car, they start to matter.

I have been giving that some thought and I may try some bracket or index events if that opportunity arises. I know Bradenton does have some regular bracket competition, perhaps once a month, and some of the guys there asking me the same question. I know that bracket racing is more complicated than it looks and consistency is a key factor, but also that choosing the right dial-in and monitoring your opponent as you make your way down the track can make the difference. I shouldn't say that I know, but rather, so I have heard. I think the guy who wins the Sportsman class at Bradenton most often is running a 15 second Fox body.

I figured there was a reason why the shank style was in use, so I would assume there is some type of strength advantage?

 

[429244]

I figured there was a reason why the shank style was in use, so I would assume there is some type of strength advantage?

Yes. The shank style lug nut spreads the load over the more of the wheel stud.

 

[JEWC_Motorsports]

A lot of tracks follow NHRA rules which state you need a open ended shank lug for a certain ET. I dont remember what the ET is.

 

[86GT351]

I thought DR's and stock manual tran's were not a good combo from the shock?

It can work. It takes time to perfect the launch point.

 

[Midlife Crises]

I don’t know that there is a “Shank Style” lug nut requirement for a certain class or ET but I do know there is a thread engagement requirement for lug nuts in general. Basically, the nut must engage the threads of the stud equal to the diameter of the stud. If you are running shank style nuts only the threads above the shank count. The threads in the shank part of the nut offer nothing to actually hold the wheel in place. If your lugs are being inspected they should be looking to see how much engagement you have in the hex part of the nut. The open ended nut let’s the inspector see and measure this.

 

[MrBhp]

I don't know how it is now. The rear lug nut was based on the tire, not the et. Full slicks had to have open nuts with a protrusion of bolt equal to the bolt diameter. The front lug nut was based on trap speed with the same protrusion requirement as the rear.

 

[Midlife Crises]

It’s pretty simple really. The rule is the same for all vehicles. If you have 1/2” studs the nut must engage at least 1/2” of the threads. 5/8 studs, the nuts must engage at least 5/8” of the threads. No protrusion is required but the rule does say the lugs should be open. Getting all the way into the hex part of a shank nut is why I had to install 3” studs in the rear axles. In the NHRA rule book there is a picture of a proper fit shank nut that makes it very clear.

 

[JEWC_Motorsports]

Do you have a new rule book? Last one i have is 2019.

 

[Midlife Crises]

Do you have a new rule book? Last one i have is 2019.

Just a quick Google search for NHRA lug nut rules 2023 will turn up the current information. I just download the book each season to see what may have changed.

 

[Red-Candy-Metallic]

I made it back to Bradenton Motorsports Park on the 4th. This was my first outing with the Steeda CAI and Steeda 93 octane custom/email tune. The car's new low ET is about .16 better than the preloaded SCT 93 octane tune with the stock airbox (DA corrected 12.46 @ 111.30 MPH). The DA during this latest outing ranged from +228 ft to about -350 ft and the temperature ranged from 58 to 52 degrees. The three timeslips on the left show the best three ETs and the timeslip on the right shows the car's highest trap speed to date. The first run remains essentially the same after DA correction, but the others would be higher (DA corrected) due to the negative DA at that point in the night. This was the first outing that the car ran 90 MPH and under 8 seconds in the 1/8 mile as well. Of course, I am not making any claims regarding the new CAI and tune, I am just trying to report the results as objectively as I can. If my DA assumptions are suspect, I apologize for that.





2014 Mustang GT - Brembo Package
60,000 miles
Steeda CAI and 93 octane tune
Stock 6R80 automatic
Stock 3.15 limited slip rear axle
Ford Performance rear LCAs
Legato axle backs (on the car when I bought it, may replace with GT500s)
Forgestar 18"x10" wheels and 285/40R18 Mickey Thompson ET Street S/S tires
(combination is 24 lbs lighter than stock and is approximately the stock diameter)

Not a lab environment, but to summarize my experience with this car (Actual times / DA corrected times / DA):
As bought, stock except for Legato axle backs - [email protected] / [email protected] / 2500 ft
FP LCAs, wheels and drag radials - [email protected] / [email protected] / 1700 ft
SCT preloaded 93 octane tune - [email protected] / [email protected] / 15 ft
Steeda CAI and Steeda 93 octane tune - [email protected] MPH / [email protected] MPH / 228 feet

DA Calculator - Density Altitude Calculator - DragTimes.com

 

[Red-Candy-Metallic]

February 1, 2024 - Bradenton Motorsports Park, Florida - Throwdown Thursday (AKA Test & Tune)
2014 Mustang GT, 6R80 Automatic, Brembo Package, Steeda CAI and 93 Octane Tune (1oz octane booster/gal)
285/40R18 Mickey Thompson ET Street S/S tires on Forgestar 18"x10" D5 Drag wheels
(passenger seat, rear seat, and strut brace removed, 1/4 tank fuel, front tires 45 psi, rear tires 18 psi)
DA ranged from approximately +254 to -165

 

[MrBhp]

Nice!

 

[Red-Candy-Metallic]

Nice!

Thanks! The car has responded well to the limited mods and the air was great that night. While I can't be certain that the weight reduction (100 lbs?) made that big a difference, it certainly seems to have contributed to the low ETs and higher trap speeds. Given my original hope to run high 12s, I am pretty excited to be running in the low 12s now.

 

[429244]

So when are you are going to stop test and tune and start racing?

The car seems to be doing its job. If you could improve your reaction time (or keep your RT close to the first pass), I bet you would do well. I am guessing you are shallow staging?

 

[Red-Candy-Metallic]

The car seems to be doing its job. If you could improve your reaction time (or keep your RT close to the first pass), I bet you would do well. I am guessing you are shallow staging?

The car has exceeded my expectations, so it's definitely holding up its end. I agree, I certainly need to focus more on the tree once I'm stagged. I am shallow stagging in an attempt to get the lowest ET possible at this point, and I bet you know that from experience. I was planning to do some bracket racing in January, but they pushed that event off to March and have not schedule any bracket events between now and then. I think the track is focusing on more lucrative events, but I am not complaining if that keeps the track open. The staff at Bradenton Motorsports Park does a tremendous job on the track, even for test & tune events, and I am thankful for that.

 

[Red-Candy-Metallic]

The car seems to be doing its job. If you could improve your reaction time (or keep your RT close to the first pass), I bet you would do well. I am guessing you are shallow staging?

This past weekend, March 16 - 17, Bradenton Motorsports Park in Florida hosted two NHRA bracket racing events. Each day was considered a separate event. I competed in the Sportsman class, which included ETs from 11.0 to 20.0. I was fortunate to have some coaching from an experienced racer who I have gotten to know from Test & Tune events. He also competes in a mostly stock 2014 Mustang GT. Although I was certainly intimidated, given my "first timer" status, his detailed explanations of the registration process and the general flow of the day went a long way to reduce my anxiety. Each day's event started with about 25-30 cars in the Sportsman class. At around 9:00 am we had our time trial runs, followed by the first round just before 12:00 pm. First round losers had the option of a "buy-back" to continue racing (eligible to win cash, but not receive points). I know this is already a long post, so I will follow-up with each day's slips and I description of how my runs went.

 

[Red-Candy-Metallic]

March 16, 2024. Car # 1113 (Time trial, first round, buy-back round)
Although the car has run as quick as 12.17@115 MPH with some minor weight reduction and great weather conditions, I chose to run it with the full interior and a full tank of fuel. The DA was also on the high side for most of the day, so the car was running in the 12.5x range. I made my time trial run, lost first round, lost buy-back round. The DA was 1304, 2053, and 2393, respectively. I have been keeping a spreadsheet of past runs, but I expected the car to slow down more than it did, so I missed the dial-in for the first round and the buy-back round. Although I had 5/10 runs with RTs in the .0xx range on the preceding Sunday, my RTs were certainly novice level at best, and I fouled out (gratuitously) in the buy-back round. Lots of "humble pie". Time of day is actually an hour later than the slips show, since the change to DST is not reflected in their system.