'14 GT Automatic - drag racing results from a few simple mods

[rcm90]

I don't mind so much losing some around town, but wonder if went with a less aggressive convertor then yours I can keep the hwy just lose in the city if that is possible?

Does the convertor do anything on the car while it is in motion or is it just from a stand still?

On the highway the stock and aftermarket converter should be commanded lockup with zero slip. This is why mpg will not be altered. The drivability/mpg around town depends on the trans tune in the car. The tune could command the converter stay unlocked until 50mph regardless on load, resulting in a large drop of mpg. Where my car is commanded to lock in 2nd with a pretty high load percent. So over 20mph the converter is locked through the 2-3, 3-4, 4-5 and 5-6 shifts resulting in better mpg around town due to the lower rpm and it feels more like a stick car than a stalled automatic unless I give over half throttle.

I've had the car both ways and with the converter locked down low while being on e85 im only down 1-2mpg vs it being unlocked and on regular gas.

 

[Five Oh Brian]

You know, in retrospect, it was probably the 4.10 gears that hurt my highway mileage more than the converter.

I live in a very hilly area, so my converter is quite loose going up hills when in drive, which hurts my mileage in town more than someone in Kansas, for example. If I shift into "S", then I can pick a gear and get the converter to lock up going up hills, though, to help with mileage and keep heat down (from slippage). I suppose I could have the tuning adjusted. I was more concerned with tuning the converter for WOT at the dragstrip, though. Ah, the fine details of tuning an automatic!

 

[rcm90]

You know, in retrospect, it was probably the 4.10 gears that hurt my highway mileage more than the converter.

I live in a very hilly area, so my converter is quite loose going up hills when in drive, which hurts my mileage in town more than someone in Kansas, for example. If I shift into "S", then I can pick a gear and get the converter to lock up going up hills, though, to help with mileage and keep heat down (from slippage). I suppose I could have the tuning adjusted. I was more concerned with tuning the converter for WOT at the dragstrip, though. Ah, the fine details of tuning an automatic!

That will play a large difference. Where I live it ranges from flat high desert to mountains with a 4200' base elevation to about 10,500'

I didn't like driving the car in the mountains with the converter unlocked because it would hang at like 3500rpm going 45-50mph up a steep grade. Now with the converter locked and e85 it chugs at 1300rpm up a 5,500' climb over about 15-16miles.

 

[skaarlaj]

Only thing I have been on the fence on is the convertor. I know in quarter mile it helps a lot but I drive my car a lot on the highway, I know it still locks up, but just don't know how much it will take from the MPG as I enjoy getting 24/26 MPG at 75 MPH. My wife and I go on at least 1 if not 2 trips a year in the mustang of 2K miles round trip each.

I'd bet that a tune that was meant specifically for your needs would put your mileage nearly exactly the same as a stock converter car, as when any locking converter is "locked" the trans input should be moving at the same speed as the flex-plate taking the whole "Fluid couple" and "slippage" out of the equation just like a manual trans car. Just tuning the "when" and "how long" the converter is locked through tuning. Or maybe a separate tune specifically when you're at the strip?

 

[Five Oh Brian]

Finally made my first passes of the season yesterday (Pacific Raceways near Seattle). I was hoping for a new personal best based on the addition of a new, very minor, modification. DA was in the 0-500' range with temps around 65 degrees. However, mother nature thought a very strong headwind would be a perfect way to welcome me back to the track.

Last year's best pass was an 11.57, and yesterday I ran an 11.58, a pair of 11.59's, an 11.60, 11.61, a pair of 11.63's, a pair of 11.64's, 11.65, 11.66, and 11.67. All were at 116 mph +/- a couple tenths of a mph. My 1/8 miles were all 7.40's averaging 93 mph. Sixty foots were consistently in the 1.60-1.64 range on M&H Racemasters @ 23 PSI.

I believe the strong headwinds cost me nearly a tenth and a couple of MPH in the 1/4 mile, so my verdict on my latest mod will have to wait til my next track day (next Wednesday, weather permitting).

Links to a couple decent pics of my car launching yesterday >>> click here and click here. This guy takes very good pics and I've bought quite a few from him over the past few seasons. Can't wait for these to show up in my mailbox!

 

[wbt]

No offense but you really need to upgrade your tuner and remove some gear out of the car to achieve better times.

 

[Five Oh Brian]

No offense but you really need to upgrade your tuner and remove some gear out of the car to achieve better times.

No offense taken. My car is a true daily driver and I need the back seat, so I don't want to put a roll bar in the car. That means no need to go 11.49 or quicker for me (our local tracks are very strict with the NHRA rules). I'm plenty happy running 11.50's with the car.

Also, as a daily driver, how the car feels on the street is just as important to me as how it runs on the track. I love how 4.10's feel on the street, so I'd never put taller gears back in the car - even if it made the car marginally quicker at the track.

Thank you for the feedback, Warren. I know that you really know these cars inside & out.

 

[wbt]

No offense taken. My car is a true daily driver and I need the back seat, so I don't want to put a roll bar in the car. That means no need to go 11.49 or quicker for me (our local tracks are very strict with the NHRA rules). I'm plenty happy running 11.50's with the car.

Also, as a daily driver, how the car feels on the street is just as important to me as how it runs on the track. I love how 4.10's feel on the street, so I'd never put taller gears back in the car - even if it made the car marginally quicker at the track.

Thank you for the feedback, Warren. I know that you really know these cars inside & out.

Understood. I believe there is more on the table if/when you want to make changes.

 

[skaarlaj]

So did you ever swap out the two piece drive-line for another 1 piece, I remember way back in this thread you bent the new 1 piece and ended up reinstalling the stocker? I just have a hard time being "OK" spending that kind of money for a new drive-line when my stocker isn't giving me any grief as of yet. Also, do you ever plan on going with some long-tube headers?

 

[Five Oh Brian]

Understood. I believe there is more on the table if/when you want to make changes.

I guarantee that when I'm ready to go faster I'll be hitting you up for advice. Thanks for all that you contribute to these forums!

 

[Five Oh Brian]

So did you ever swap out the two piece drive-line for another 1 piece, I remember way back in this thread you bent the new 1 piece and ended up reinstalling the stocker? I just have a hard time being "OK" spending that kind of money for a new drive-line when my stocker isn't giving me any grief as of yet. Also, do you ever plan on going with some long-tube headers?

I pulled the 1-pc driveshaft and sent it to Shaftmasters to rebalance. Turns out it was never bent at all and it was a poorly installed pinion bearing from my 4.10 gear install that caused the vibration, so a new set of 4.10's went in and the 1-pc went back in, too. No problems since then. The 1-pc only netted me a .050 second improvement in ET in the 1/4 mile, on average, but it is supposedly safer at high speed than the factory 2-pc. Plus, I only have to run one d/s safety loop, so that savings offset the cost of the 1-pc a bit.

I keep looking at long tubes, but I'd have to pay someone to install them and that makes the total cost too high for the gains IMO. I've been considering a lightweight K-member up front to save weight, though, and putting headers in at the same time might be more economical since the engine has to be lifted for both jobs.

 

[Five Oh Brian]

I forgot to mention that almost every pass, my reaction times are in the .0XX's, so coupled with the super consistent passes (all within a tenth of a second), I think my car would be a great bracket racer. Just wish I had the time to run the bracket series! 25-30 years ago I used to win some occasional money & trophies at our local track drag racing, but that was before a busy career, a mortgage, and raising kids!

 

[Riptide]

Brian your local race tracks insist on cages for coyote cars in the 10s? That sucks.

 

[wbt]

Brian your local race tracks insist on cages for coyote cars in the 10s? That sucks.

Why? NHRA and IHRA rules state if you run quicker than a 11.50 then you need at least a 5pt. roll bar down to 10.00. Aftermarket axles, trans blanket, harness, helmet and jacket are other requirements. There are safety rules for a reason.

If you don't want to abide then don't participate. Our local tracks are no different and they are cracking down at the NE track's too.

When you are a track owner, have to pay insurance to operate and be liable if you don't adhere to the rules and risk lawsuit then you will enforce. Plain and simple.

You as a car owner should also be concerned with safety for not only yourself but the person next you in the other lane.

 

[Riptide]

It sucks because I don't want any of that in a street car. Not looking to debate it. I've read about eleventy billion debate threads on the subject already.

 

[Five Oh Brian]

It sucks because I don't want any of that in a street car.

I hear ya. That's why I'm done modding now that I'm within a tenth of a second of needing a rollbar. At some point, I might opt for the rollbar if I choose to mod the car some more, but for now I'm enjoying my car at its current performance level.

 

[skaarlaj]

With the amount of power some of these new vehicles come from the factory with, You'd think they'd be a bit more linient with some of the stuff. Imagine buying a newer Viper and maybe buying a good set of slicks or drag radials, and needing a damn roll-bar to continue racing......Weak

 

[Five Oh Brian]

With the amount of power some of these new vehicles come from the factory with, You'd think they'd be a bit more linient with some of the stuff. Imagine buying a newer Viper and maybe buying a good set of slicks or drag radials, and needing a damn roll-bar to continue racing......Weak

NHRA rules allow 2008 and newer cars to run below 11.50 w/o a rollbar if the car is 100% factory stock. For example, there is a local guy (Derek) with a grey Challenger Hellcat that has run as low as 11.12 in the 1/4 mile and our local tracks allow him to run since the car is factory stock on street tires. Most of the time he spins his way to 12 or 13 second runs, though, as street tires just aren't enough for 707 hp, so I've beat him every time I've run against him (gotta represent!!!).

 

[skaarlaj]

Good job man, I love seeing people with a million hp lose to a decently set up car. I've seen alot of 500+hp cars show up at the eighth mile track that I go to on factory or street tires and get absolutely owned by a much inferior vehicle who happened to remember to show up with drag radials, or slicks.

 

[CoreGT]

I keep looking at long tubes, but I'd have to pay someone to install them and that makes the total cost too high for the gains IMO. I've been considering a lightweight K-member up front to save weight, though, and putting headers in at the same time might be more economical since the engine has to be lifted for both jobs.

Headers really isn't bad. Get the harbor freight engine support bar, drop the k member, and you have all the access in the world. Hell, maybe I'll do it for some extra coin lol.