The Freeway Flyer Transmission: Is The Taller Gear Ratio Right For Your Ride?
What’s not to like about the Freeway Flyer transmission? At first glance the Freeway Flyer appears to be a bolt on solution to get more MPH out of your classic VW. While the desire to bolt a part into a car that will provide more top speed is the very essential core of hot rodding (regardless of what make & model you maybe into), like all products that offer an enthusiast increased performance: the entire system must be taken into account!
Building A Well Balanced System
Like most things in life, balance is the key to harmony. This credo applies to our old cars as well. If you are thinking about installing a Freeway Flyer transmission (aka FFT) the first item to consider is your motor. The fact is that not all VW motors will be produce enough horsepower to pull the taller 3.88 gear in the Freeway Flyer.
The Torque Multiplier
By definition a transmission functions as a torque multiplier. The lower the gear, the higher the torque multiplication. This why your car has a good scoot leaving the light in 1st gear and why it will bog if you let the clutch out in 2nd gear. The stock VW flat four needs all of the leverage provided by that low 1st gear to get that classic VW moving.
The Freeway Flyer’s higher potential MPH cruising comes at the cost of a lower gear ratio in the entire transmission gear range. This means that the 1st gear in your new Freeway Flyer will produce less leverage or torque multiplication than provided by the stock trans gearing.
Keeping Your Cool
Another fact that must be considered is that while the Freeway Flyer offers lower RPMs at the cruising speed, it will also reduce the RPMs of the cooling fan. While driving you may be tempted to cruise your motor at lower RPM than normal (because now you can) but soon you may find that your motor is stacking heat and running hot. Regardless of gear ratio or MPH, the fan needs to blow enough air through the baffles to cool your motor sufficiently. So, the FFT will deliver a higher MPH but you will still need to drive with a high enough RPM to keep the fan spinning in an efficient range to keep your motor at operating temperature. Adding an oil temp gauge would be wise if you don’t already run one.
There Is More To The Freeway Flyer Trans Than Just The 3:88 Gear Ratio
Please be aware that just because a transmission has a 3:88 ratio ring and pinion it doesn’t mean it is a Freeway Flyer. Beginning in 1967, the VW Bug, Ghia and T3 transmissions came with a 4:12 ratio ring and pinion with a .89 fourth gear. The .89 fourth gear provides an 11% overdrive. When VW started to offer the 3:88 ratio ring and pinion in 1973, the fourth gear was changed from the .89 to a .93.
The math shows that the 3:88 ratio is 6% lower of than the 4:12 ratio, but the .93 fourth gear is only over driven by 7%. Compared to the earlier model 4:12 ratio with the stock .89 fourth gear the overall final drive ratio between the these two transmissions are virtually the same!
Not All Freeway Flyers Are Created Equal
There are two widely accepted ways to build with a Freeway Flyer Trans:
- 4:12 ratio ring and pinion paired with a taller Bus .82 fourth gear
- 3:88 ratio ring and pinion paired with a .89 fourth gear
The 4:12/.82 Build:
The main difference between the two different FFT builds is found in the first through third gears. With the 4:12/.82 build the first through third gears feel the same as a stock VW trans, but fourth gear would be much lower a very noticeable drop in RPM from third into fourth. The 4:12/.82 build feels more like a traditional overdrive transmission.
The 3:88/.89 Build:
With the 3:88/.89 FFT build all four gears are effectively taller with a standard RPM drop when shifting from third to fourth. Many people prefer the 3:88/.89 build for performance applications as the ring gear is physically stronger than the 4.12 ring gear, due to the 3:88 having less teeth on the ring gear. The teeth on the 3:88 ring gear are also little bit bigger.
You Want Even More Overdrive…?
If you really what to lower the RPMs you can look into building a Double Freeway Flyer using a 3:88 ratio ring and pinion with a Bus .82 fourth gear for a final drive ratio of 3.18. If you need even more overdrive in your VW there is an aftermarket 3:44 ratio gear set available which could be perfect for those looking to make their mark racing in the salt flats!
The Freeway Flyer Transmission Is Right For You:
If you’re already the proud owner of a stoutly built 2332cc motor or a spunky boosted blow-thru application. If you’re motor is well built and producing around 80+ horsepower for Bug or Ghia (you’ll need 90+HP for a Bus) then you already have the power necessary to pull the Freeway Flyer’s taller 3.88 gear ratio without a problem.
The Freeway Flyer May Not Be Your Best Choice:
If you’re a stock motor enthusiast that is happily running the 1200cc, 1300cc, 1500cc and 1600cc engines, sorry but the Freeway Flyer trans is going to do your ride more harm than good. A stock 1600cc makes about 53HP and simply does not provide the grunt needed to make the tall gear ratio a practical solution. If you’re running a stock motor and have no plan to upgrade but still would like more MPH you may consider going with a taller rear tire. A taller rear tire will provide more rollout potentially increasing MPH over a shorter tire at the same RPM.
If You Must Have A Freeway Flyer:
If you happen to be one of those people who must have a FFT in your VW no matter what – we would ask you to consider this advise: build or buy a stout motor that will provide the power level needed first, before you install a Freeway Flyer. You will be dollars ahead and happier with your ride during the process. When you’re all ready and you have the power needed to pull the taller gears So. Cal. Imports will be here to get you hooked up! If you’re looking to build a suitable motor we can help you with that as well!
Choices Will Be Made!
Our choice would be to make you a happy customer rather than just sell you an expensive part that may or may not suit your application well. We just want you to be aware of the facts so that you can make an informed decision so that you can get the maximum amount of enjoyment out of your project, whether it’s a stock restoration, full blown race car or something in between!
Reference: Final Drive Gear Ratios
Stock VW Final Drive Gear Ratio:
3:88 with .93 fourth gear = 3.60 final drive ratio (7.2% OD)
4:12 with .89 fourth gear = 3.66 final drive ratio (11% OD)
Freeway Flyer Final Drive Gear Ratio:
3:88 with .89 fourth gear = 3.45 final drive ratio (11% OD)
4:12 with .82 fourth gear = 3.37 final drive ratio (18.2% OD)
Double Freeway Flyer Final Drive Gear Ratio:
3:88 with .82 fourth gear = 3.18 final drive ratio (18% OD)