Everybody wants to know about what gears to run with turbo's and i think it's time we gather input from people that have these setups. In example: 8psi with 3.50 gears, 10psi with 3.73 gears, so on and so forth.
I have a few friends with turbo's in 2v mustangs, who really tear up the highways on stock gearing and never think about getting a quicker gear ratio, but just adding more PSI. I've also seen the same stock turbo setups from people online and here on this forum. My only problem with these resources are that they've never had any quicker of a gear ratio with these setups.
With that in mind, i would prefer to get input from people that have had two different gear ratios and can tell us about the difference/changes they noticed. But since this general argument/inquiry is based upon the use of quick gear ratios with turbo setups, anyone running good numbers on the track or have input from driving on the street; your input will be much appreciated as well!
So lets break down some facts:
Your motor will max out RPM quicker applying gas out of gear and/or with less resistance (complimenting mods).
Most Turbo kit companies claim peak Boost/Power/Torque curve (done spooling) at around 3,300 RPM.
Rear axle gears simply quicken the turn rate of the rear wheels, reducing resistance on the motor.
My understanding of spooling/building PSI (making the most use out of your turbo):
If the rear gears make it easier for the motor to power through its RPM range (less resistance), it should benefit a turbo setup as well; the turbo will be spooled sooner as its reached maximum boost thus putting out maximum torque and horsepower sooner. I also understand that with quicker axle gears you run out of transmission gear, and top out sooner, making you shift into a fresh gear. Correct me if i'm wrong or just plain stupid, but when i had 4.10's i shifted from 6,200RPM from every gear into a new gear starting at around 3,500RPM. I also understand that even though your RPM is spewing out alot of exhaust at 3,000RPM, this doesn't mean the turbo has spooled (filled) itself up quite yet, otherwise known as turbo lag. But still; a turbo will spool faster with 3,000RPM+ running through it than any lower RPM.
Now, here is my theory:
The quick gears will help the motor get through the low RPM's quicker, and achieve its full potential sooner, as well as eliminate ALOT of the feeling that comes with turbo lag (slow acceleration while the turbo trying to fill itself up), thusly creating a great acceleration curve.
My final thoughts are:
An identical motor/mustang with a 6speed(supplying another gear to prevent topping out too soon in 5th) and quick gears, always at its max PSI/Power/Torque curve will be faster than a car taking a second or two longer to build up to its peak with a 5 speed and slower gears.
Then again i have no personal turbo experience which could just leave me being very, very wrong.
I have a few friends with turbo's in 2v mustangs, who really tear up the highways on stock gearing and never think about getting a quicker gear ratio, but just adding more PSI. I've also seen the same stock turbo setups from people online and here on this forum. My only problem with these resources are that they've never had any quicker of a gear ratio with these setups.
With that in mind, i would prefer to get input from people that have had two different gear ratios and can tell us about the difference/changes they noticed. But since this general argument/inquiry is based upon the use of quick gear ratios with turbo setups, anyone running good numbers on the track or have input from driving on the street; your input will be much appreciated as well!
So lets break down some facts:
Your motor will max out RPM quicker applying gas out of gear and/or with less resistance (complimenting mods).
Most Turbo kit companies claim peak Boost/Power/Torque curve (done spooling) at around 3,300 RPM.
Rear axle gears simply quicken the turn rate of the rear wheels, reducing resistance on the motor.
My understanding of spooling/building PSI (making the most use out of your turbo):
If the rear gears make it easier for the motor to power through its RPM range (less resistance), it should benefit a turbo setup as well; the turbo will be spooled sooner as its reached maximum boost thus putting out maximum torque and horsepower sooner. I also understand that with quicker axle gears you run out of transmission gear, and top out sooner, making you shift into a fresh gear. Correct me if i'm wrong or just plain stupid, but when i had 4.10's i shifted from 6,200RPM from every gear into a new gear starting at around 3,500RPM. I also understand that even though your RPM is spewing out alot of exhaust at 3,000RPM, this doesn't mean the turbo has spooled (filled) itself up quite yet, otherwise known as turbo lag. But still; a turbo will spool faster with 3,000RPM+ running through it than any lower RPM.
Now, here is my theory:
The quick gears will help the motor get through the low RPM's quicker, and achieve its full potential sooner, as well as eliminate ALOT of the feeling that comes with turbo lag (slow acceleration while the turbo trying to fill itself up), thusly creating a great acceleration curve.
My final thoughts are:
An identical motor/mustang with a 6speed(supplying another gear to prevent topping out too soon in 5th) and quick gears, always at its max PSI/Power/Torque curve will be faster than a car taking a second or two longer to build up to its peak with a 5 speed and slower gears.
Then again i have no personal turbo experience which could just leave me being very, very wrong.
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