Gears for turbo car with 5sp

evilcw311 · Dec 8, 2014

Trying to decide if I want to go with 3:73's or a little lower. I've heard some people say that with a turbo that they didn't like the 3:73's, felt like it was wrapping up too quick.

Others I've heard say they loved their 3:73's with a turbo.

What gear are most of you turbo guys running that have 5sp's?!?!

Car is not for drag. Mainly street toy, autox, and such. Will see some highway use and even some trips.

Let the debate begin!!! Lol

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Sinned83 · Dec 8, 2014

I'd say 3.55's.

slow90coupe · Dec 8, 2014

3:27 or 3:55.

96blak54 · Dec 8, 2014

2:73 - 3:27

evilcw311 · Dec 8, 2014

Thinking 3:55. I'll be doing a t56 swap next winter so a lil steep won't be as bad.

2:73 is lower then what my factory is I do believe.

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slow90coupe · Dec 8, 2014

2:73 will be an absolute dog and will take a century to spool up

ebaccm26 · Dec 8, 2014

Depends on what the rest of your setup is like. My car has 3.08's and it spools very quickly. It is hard to keep the car out of boost as is and with 3.73's I can tell you it would be far less enjoyable to drive on the street, I'd consider changing it up a little but certainly not as high as 3.73's. Maybe a 3.27 or at most a 3.55.

g36 monkey · Dec 8, 2014

Depending on the setup, I would say 3.55.

96blak54 · Dec 8, 2014

2:73 dog? Tell that to the guys running 8's

evilcw311 · Dec 8, 2014

96blak54 said:
2:73 dog? Tell that to the guys running 8's

I'm not gonna argue that, but wow!! Seems like a really flat gear to run that fast. Who's doin that and what kind of crazy power are they putting out!?!? I'm just curious to see what they are doing to accomplish that.

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96blak54 · Dec 9, 2014

Turbos work off heat. The more heat, the more power. What better way to produce heat, but with a tall gear. The lag from a 2:73 eases the launch while the engine is "heating up" so to speak, then the turbo spools up from the engine struggle....typicall turbo. All this really has to do with setup. Poor set or the right setup can be a balancing ball only to fall either side. Im no turbo expert by any means, but have witnessed plenty of turbo guys spending $100 or more for 2:73 stock gears. Most people trash such a gear.

kb1982 · Dec 9, 2014

3.55 would be my guess. Turbo's love load, but too lil gear and you will bog it down. Hell, running 8's, you have alot of trap speed and need the airplane gears. The more horsepower, the less gear you need to compensate for.

BOOOSTD · Dec 9, 2014

kb1982 said:
3.55 would be my guess. Turbo's love load, but too lil gear and you will bog it down. Hell, running 8's, you have alot of trap speed and need the airplane gears. The more horsepower, the less gear you need to compensate for.

^ agreed.....I'm running turbo with 373's on street and its fine and she spools pretty quick. The 373 was already in when I was NA so I left the gear alone to try out. That said, if I was choosing a gear at my power level I would go 355.

D3VST8R96GT · Dec 9, 2014

slow90coupe said:
2:73 will be an absolute dog and will take a century to spool up

It would spool quickly (compared to a 373)... the load on the drive train would worry me on a stockish car.

Like they said turbos love load

D3VST8R96GT · Dec 9, 2014

3.08s or 3.27/3.31s

I sell you a set of 3.08s for 20$ Lol

Addermk2 · Dec 12, 2014

You need to know what size tire you'll run, what horsepower you're targeting, how much the car will weight, and what your shift RPM is.

For me, I'm going to be 3300lbs, looking for 700hp, want to run 28" tires, and trap no higher than 6300rpm.

My ideal gear is 3.73

With 700whp and a 3300 lb car, I should be capable of trapping around 138mph. The 28" tire, 6300 rpm limit and the transmissions 1:1 drive gear, coupled with 3.73s should put me around 141mph (not accounting for tire stand up).

So my possible speed is below my limited speed (just not by much). If I make more than 700hp, I should go to a numerically smaller gear (3.55)

evilcw311 · Dec 12, 2014

I'm running a 295/40/18

700 for now, more later

Not worried about 1/4 mile really

Close to stock weight

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lutter94 · Dec 12, 2014

I have some 3.27's sitting in a box (removed when I swapped 3.73's in). Pm me if you want them.

Addermk2 · Dec 12, 2014

evilcw311 said:
I'm running a 295/40/18

700 for now, more later

Not worried about 1/4 mile really

Close to stock weight

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You might as well just keep whatever gear is in the car now.

JGcoupe · Feb 27, 2015

As mentioned, the tire size is a contributing factor when gear searching.

I currently have 3.90's and 26" tires but I plan on stepping up to a 28" (someday). Going to a taller tire will lower (numerically) the gear ratio. Look it up for 4x4's and you can get a visual on how tire height affects gear ratios & RPM's.

http://www.4lo.com/calc/geartable.php