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Discussion Starter #1
It looks like it will take a better part of my budget to install the turbo kit and get it tuned. I won't have anything left to invest in a gear swap right off the bat.

What exactly will be the side effects of running such a steep gear with a turbo setup? Will it still make boost and be fun to drive? I bought the car with 4.10's otherwise I'd never put such a gear in the car.

If anyone reading this has a 3.27 geared rear end and is looking into getting 4.10's I'd consider swapping (94/95 rear of course!).
 

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I went from 3.73s to 3.27s and it felt like I gained 50rw (when I was 5spd)

Turbos love load

You'll prolly spin a ton with those 4.10s and the car will feel kinda slow, when you swap gears be ready to change your pants
 

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Discussion Starter #3
I'm sure I can find someone who will trade me. All the guts are brand new so it'll make it that much better. Thanks for the reply.
 

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4Jenna same deal switching from 3.55's to 3.27's with a TKO?Wont that effect down low RPM power?
 

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i went from 373s to 331s and it felt like a new car

i have few different tunes in the car and the 550 tune tune wiht 331s felt like the old 650 tune with 373s
 

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When swapping to the higher gears you will be able to load the turbo in the lower gears and will also have better traction. With the lower rear gear, your going to outrun the turbo in the lower gears but its going to pull like a freight train in 3rd and 4th, when going to a 3.27 you will lose a bit of pull in the higher gears but you will be able to use your lower gears better, but overall the higher gears work better when its all said and done.

When i got my turbo setup going i wa running around with 3.90s, the car would go good in 1st and 2nd but as soon as the turbo finally spooled good, it blew tires off, 3rd and 4th hooked and pulled awesome and spooled good. This was a 8 psi. I tested the 12 psi spring and with the low gears it would fry tires all the way through 3rd gear, car actually felt slower due to such tirespin. i eventually swapped to 3.27s and the car is much smoother and loads the turbo good like it should. The car does feel doggy out of boost and is much more dependent on the boost for sure. But it all works out ok. Im currently running 6 psi now since i blew my trans and am putting around with 4 cyl t5s.

Dont worry, the car will still be a blast to drive even with the 4.10s, depending on your power level. you might not need to get 3.27s, if your going to run less than 10 psi and stay that way 3.55s might be a better choice. if running more boost and power the 3.27s is probably going to be better.
 

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I'm in the same situation as the thread starter, but I have 3.73s and a T56. I'm looking to run 10-11PSI, low 500s in HP/TQ. With all that being said, and my first gear being 2.66, what advise would you give me? Also, I drive a 2V modular, which notoriously has horrible low end power. Thanks all...
 

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Just drive it and see how it feels and how you like it.

Tuning shouldnt be an issue. On the dyno your going to be in the higher gears doing the pulls. Spool up will probably be as fast as its going to get as the dyno really loads a car hard.

The issue is you need to make sure your fuel enrichenment and spark timing is going to be appropriated for the load. Only thing a gear swap is going to do is make it easier/ quicker to get to that load. A gear swap isnt going to magically need to be retuned IMO, just realize with a gear swap your going to be getting those higher loads/boost in the lower gears more easily so you just have to be ready for it and make sure your tune is. Dont tune your fuel curve to your 1st and 2nd gear. Cause if you swap to higher gears your load will be higher faster and you will need to be richer if your hitting boost. Tune your AFRs and timing to 4th gear, even with low gears i doubt you can "outrun" the turbo then, even more so on the dyno where your under even more load.

Stock mustang ECUs are load based for fueling and spark anways so it doesnt really even matter RPM is irrelevant.
 

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Discussion Starter #12
Nah. Hell, 2 taller tires would probably cost half of the gear swap anyway. And they'll make the car look hideous!
 

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im in the same boat as you man. im awaiting for warmer weather to have the 3.27 installed. track times with the 4.10 in video: only getting 114 mph i should be around 120mph with 3.27 installed


fast forward to 30sec.

 

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Discussion Starter #15
im in the same boat as you man. im awaiting for warmer weather to have the 3.27 installed. track times with the 4.10 in video: only getting 114 mph i should be around 120mph with 3.27 installed


fast forward to 30sec.

2004 Mustang gt turbo track day - YouTube
Back from the dead.

Just wondering if you ever swapped your gears and if there was any gain in your ET's from it.
 

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This is from another post that I answered about rear end gearing.
In my case with a very low weight car 3.55 rear gears with a TKO600 my car could not make over 3-4 pounds of boost in first gear and 7 pounds in second gear, the car was not lugging the motor enough. The turbo lag was just too much until 3rd gear. My car has GREAT traction due to the weight being over the rear end and the traction aids that I have put on my 2,270 pound car. Everyone told me to put a taller gear in the rear so I gave it a try, the difference was like night and day. I put 3.08's in the rear end and now I am making 8 pounds of boost in first gear and 10-11 in second , 3rd gear up I make what is set on my boost controller. That an improvement 50-80 HP in my fist two gears alone. My car is great with traction so some cars may not be able to take advantage of that much extra HP. I think traction, transmission and cars weight will be the deciding factors but tall gears work well with turbo's. If I added even taller gears I think I would pick up more but with 3.08's in the rear and 150+ mph in 4th gear I will stay where I am at.
 
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