Why higher gearing?

[Jeffy_2010]

So I'm kind of at a loss why just about everyone anymore says you need higher gearing for running FI, when did this become a rule? I mean for years there have been old school guys running procharged muscle cars with 3.73's, 3.90's, and even some 4.10's. Why the change all of a sudden saying that we need 3.31's or 3.55's? Can someone like beefcake or whipple enlighten me about this please?

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[DrDing.Muscle]

I think it has to do with the already high gearing of the MT-82 trans.
3.66
2.43
1.69
1.32
1.00
0.65

With that first gear being 3.66 for a FI car making some power that makes for a very radical and fast first and second gear and traction is also more of an issue. With a NA car the gearing helps get the car out of the hole but with FI I do not believe that much gearing is necessary plus you lose top end speed and with a FI car trap speeds are going to be much higher.

 

[LethalPerformance]

I think it has to do with the already high gearing of the MT-82 trans.
3.66
2.43
1.69
1.32
1.00
0.65

With that first gear being 3.66 for a FI car making some power that makes for a very radical and fast first and second gear and traction is also more of an issue. With a NA car the gearing helps get the car out of the hole but with FI I do not believe that much gearing is necessary plus you lose top end speed and with a FI car trap speeds are going to be much higher.

Excellent explanation. Also having to shift to 5th at the top end of the track can be avoided with a better gear. We ended up putting in 3.31's for this very reason.

 

[Strokerswild]

FYI:

"Low" gearing = high numerically

"High" or "tall" gearing = low numerically

Carry on....

 

[Glenn G]

A high horse power car will have trouble putting power down with shorter gearing, that and it will reach redline in that gear very quickly requiring more up shifts which hurt time.
A 700 hp that car constantly blows the tires off in first,second and third gears and has to shift 5 times to finish the quarter will be much slower than a 600 hp car than can consistently launch well, hold the gears longer in it's powerband and shift only 3 times in the quarter

 

[Jeffy_2010]

I mean I understand that the lower gearing will be more snappy/torquey how ever we want to describe it lol, but how much of a difference is their between the 3.73 and 3.31? Would 3.55's be a happy medium? I plan on installing a whipple down the road, guess I could always just try the stock pp gearing and see how manageable it is

 

[Grimace427]

The difference between 3.73 and 3.55 isn't enough to really notice especially for FI. I'd go with 3.31 gears personally. 3.55 would be a happy medium for an N/A car IMO.

 

[Glenn G]

I've never had a supercharged car, but alot of turbos so YEMV but once I started getting into serious boost in my cars, there was not a one that would not have felt better with some talerl gears, the shorter gearing became a huge liability on some of them, Would go from building boost to lighting the tires up and pitching the car sideways in a moment.

 

[jasonstang]

For one is strength. For two getting power down easier.
When you have very close ratio especially on a FI engine you are not hitting the boost long enough.

 

[Jeffy_2010]

Fair enough reasons, what ring and pinion set would I need to buy from frpp? Due to me having the torsen?

 

[beefcake]

the trans, especially the auto, has a 4.17 first gear......

when you look at some of the older trans with gears in the mid 2,s you needed alot more gear.

now, with that said, our very first pass with our 2011 car, with the vortech, went 10.8's, with a 4.10 gear, and no converter. it does take some work with that much gear to get the trans cal right, but it can work well, if done right

 

[LethalPerformance]

Fair enough reasons, what ring and pinion set would I need to buy from frpp? Due to me having the torsen?

Are you running a manual or auto? What power level are you aiming for and will you be drag racing the car or is it just for the street?

Thanks, Jared

 

[beefcake]

Fair enough reasons, what ring and pinion set would I need to buy from frpp? Due to me having the torsen?

if it was me, i would go for a circle d 3c before changing out the gear.

the car will still drive great on the street, but the converter will not only be stronger and hold the power better, it will allow the 60's to drop quite a bit.

 

[Inigo]

shifting into 5th sucks. I wonder how difficult a swap would be from 3.73 to 3.31

 

[LethalPerformance]

shifting into 5th sucks. I wonder how difficult a swap would be from 3.73 to 3.31

It's not that difficult if you have the proper tools and a lift. We had ours installed by Power By the Hour performance in just a few hours. You'll need the gears, gear install kit and the Whipple flare tool in order to properly calibrate the body control module.

Give us a call if there's anything we can help you with.

Thanks,
Jared

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