Sweetstang84

Hey all. Sorry, its been a while since I've posted. Been pretty busy with mods on the 'stang. I apologizes if this thread exists, but I had trouble finding it when I searched the existing threads. I'm very excited and happy with all the performance mods I've added. Honestly she feels pretty uninhibited and she definitely puts me back in my seat a bit at full throttle. This made me stoked to go to the track and lay some times down. This was my first time, making me quite the novice at the strip. I was pretty disappointed to only have laid down a 14.27 at 98.98mph at best. The temp was well over 100 out with humidity, so maybe I can blame it partly on heat soak, and partly on my inexperience. But maybe my expectations are too high..? I am running an automatic as well. Relevant Mods list:

-BBK CAI
-73mm Throttle body
-BAMA 93 race tune
-Rear seat delete
-Aluminum DS
-Staggered tire set up, 285 in the back on NT555 Nitto summer performance tires.
-BMR pan-hard bar

If there are any pointers out there, they would be much appreciated. As I said, maybe I am having some unreal expectations, but I figured with that kind of mod layout I should easily be running under 14's, maybe 13.7/13.6. Thank you community!

laserred38

What gears do you have and what was the DA that day?

With your mods, depending on gears, you should be mid to low 13s.

Sweetstang84

laserred38, Thank you for the reply. Sorry I forgot to list the gear layout. I am running on stock gearing ratio. I agree with the mid 13s range, but again, maybe its just my inexperience at the track. I also am unsure of how much heat soaking is an actual problem, or myth? Or maybe my car just isn't running that fast.

Joeywhat

OK.... Stock what? Two different ratios offered from the factory for V6. For the 2.73 ratio I'd say that's about right.

Sweetstang84

Well I am a bit embarrassed to admit my ignorance, but I have no idea. Thought I knew my car pretty well. I was not offered any optioned when I purchased the vehicle. I have an absolutely bare bone stock v6. I did not get any package/options when I got my 2014. So I would defer to your judgment. So the gears alone are tankIng my 1/4 mile? The transmission is probably the topic I know the least amount when it comes to modding.

JimC

Yes, you have the 2.73 rear end. Good for MPG, but really slow coming out at the light. Your 60' is probably pretty long due to the gears.

laserred38

Yep with the 2.73s you're pretty much right where you should be. Next mod should be some 3.55s with the auto. Those will make a big difference in waking the car up.

I ran a 12.7 at 117mph in 100* heat, using A/C in between runs and absolutely zero burnout or weight reduction on a loaded Premium GT with Glass Roof. With a harder launch or some slicks, my mph should put me in the low 12s if not high 11s. I was selling the wheels and tires to a buddy that was at the track with me though, so I wasn't going to beat on them. Besides, doing a burnout on street tires is pretty much a waste anyways. Oh yeah I didn't touch the air pressures either. Literally run what I brung and came in 2nd in the street class (bracket racing), my first time having the car out at the strip lol

Sweetstang84

Wow, ok lots of good advice. I wish someone would have made me aware of this before all the mods. I mean, honestly the car seems pretty 'awake' and fast to me right now compared to stock and some of the weight reduction. I also realize that you need to be able to put that power down and the transmission obviously plays a huge role in that (not just engine power output and tires). So I really want to take full advantage of all of these great mods I put into the car; I feel like I will change the direction of the thread a little. The 3.55 are my best bet? I have seen that there are a ton of different options; so what do the gearing ratios mean and what would be best for my application? I still have a hard time believing that this is whats holding me back, wow, but I believe the experience of the mustang forum

5.M0NSTER

2.73s are deffinitely holding you back. 2.73 means that the driveshaft makes 2.73 revolutions for 1 revolution of the back wheels. This is known as the final drive ratio. Its used in combination with transmission gears to adjust the balance between lower high speed RPM (good for fuel economy), and better acceleration (higher engine RPM at same speed).

My car has 3.73s, that's what the GT TPs came with. Other GTs came with 3.31 or 3.55s

I think 3.31 may be a good option too. V6 Performance Package came with 3.31s

Take a look here to see the difference final drive ratio makes in terms of top speed/engine RPM in each gear. May not be totally curate for a V6, but gives you a good idea.

https://themustangsource.com/forums/...dsheet-483731/

Sweetstang84

Ty 5.Monster! This definitley clarifies things a bit. I will follow up.

Sweetstang84

So talking about this now, out of curiosity, what kind of gains would I expect to see. Sounds like with all the power mods on the car now, DS ect... This will be night and day? Also, If I buy the part, is this an expensive install for a shop to do? I have done a lot to my car on my own, but the transmission is a different beast entirely for me. IDK if I am ready to tackle that, I would feel much more comfortable with a ford dealer doing it.

Joeywhat

The final gears are in the differential, not the transmission. I would expect most shops to be around $500 including parts.

The difference will be noticeable.

FYI - there's nothing special about dealer mechanics. Most don't know a whole lot. I wouldn't have my rear end job done at any of my local service centers (even the one I go to for ALL warranty related stuff). Maybe if I could get the one guy who really knows what he's doing.

See if you can find a rear end shop. There are some that specialize in differentials. A transmission shop can also likely do a good job.

Sweetstang84

Awesome, sounds good. Again sorry for more ignorance. Looked at some pics and just saw those gear were in the differential. The difference being noticeable seems like and understatement according to what laserred38 mentioned. If he figured mid 13's and I was running a 14.5 on one of my runs, that's shaving almost a full second off. Just speculation? I guess this should have been the first mod I did, not the last..?

Sweetstang84

Perusing around the nets though, I have seen some V6 auto owners have run a 14.2 1/4 on 2.73 bone stock??

laserred38

That sounds about right too, but there's so many variables to consider. The autos have different ratios in the transmission, so 3.55s on an auto is like 3.73s on a manual. Personally I wouldn't do 3.73s on an auto 2011+ S197, but that's my thought. I actually use my car on the freeway a lot and with the 3.73s (manual) that I have now, I hardly ever get above 20mpg on the freeway.

Joeywhat

3.31 is a good compromise. Unless you're racing for money I don't see the need to go any higher for a V6. I can still get 30mpg all highway, and it's plenty fast enough to get into the 13s.

SpectreH

Agreed. The '11 and later auto won't work well with 3.55's and above. The stock 3.15's work well in my GT, and 3.31's would probably be safe too. There was another thread here where some guy was going to install 4.11's, even though everyone told him not to and explained why. While he was nice about it, he basically told everyone they were wrong and he was right. Well, I haven't seen him post any results after the swap, leading me to believe that perhaps we were all right after all.

Joeywhat

People forget that our gearboxes are geared a LOT shorter than previous Mustangs. A 3.73 is likely very similar to a 4.11 in terms of final drive ratios between our cars and pre 2010.

killaz05

I know many who run 4.10s in the automatics since the transmission does all of the shifting. It is way too much for a manual. 3.55 gears will definitely be noticeable to you. I upgraded from 2.73 to 3.73 gears in my manual and it was a huge difference. One of the best mods you can do.

Now to the 1/4 miles times. I have 305s in the rear and 3.73 gears, tune, CAI, etc. I was in the mid 14s mostly due to my inexperience. It is so hard not to spin the rear tires when I launch. Traction control just shuts me down hard if I were to use it, which I tried since I was spinning so much. So I have to practice more at the strip but it isn't very close and I rarely go. The car is a monster on the streets so I know the speed is there.

In this review (http://www.caranddriver.com/reviews/...take-road-test), they had a STOCK manual gearbox mustang do the 1/4 miles in 14-flat. This is what tells me that the problem is with me and not the car. One day maybe I'll get some suspension mods to help put the power down. I usually launch at 2k rpm but full throttle after dumping the clutch just spins the tires (305/35/20 Mickey Thompson Steet Comps). If anyone has some tips to share with us novice drag racers, feel free

FromZto5

^ yeah you guys should be well into the 13's easy.... don't you think?