I want to talk about the VW transmission advantages really quick. While it may seem that I am dropping a lot of money into the transmission your assumption is correct. This is money well spent as the transmission is a major component and integral catalyst to achieving top performance and efficiency goals.
I am justifying it because by using this O2A transmission I was able to gain superior engine/transmission placement mid engined in the rear of the car. I also will be able to save a good deal of money not having to custom fabricate an engine to bellhousing adapter like I would have had to do with the T5 transmission. The O2A gearbox is a direct bolt on for the 1.4L TDI 3 cylinder engine :-) This also can be considered an upgrade to the Polo gearbox cuz now we can use the 1.9L O2A clutch kit and get rid of the weak Polo 1.4L clutch. This allows us to now boost the engine without worry of clutch slippage or failure. The O2A gearbox is rated for a max torque capacity stock of around 260ft-lbs which is plenty for our purposes. We also now have taller gearing which gives us the ability to better take advantage of the diesels full torque range. Which will give us superior fuel economy compared to the stock Polo 1.4L TDI which achieves a healthy 62mpg freeway fuel economy rating. Even if I was not boosting the engine the stock AMF engine can easily be chipped to produce 115HP and 275Nm of torque or 202ft-lbs and in a car weighing 1,400lbs or less it will still be able to utilize the taller geared transmission with ease.
The other advantage is a person will be able to opt for the 1.9L TDI if they want greater raw power performance for serious track times. As the transmission is an O2A designed for the 1.9L TDI engines :-) Again they bolt right up no custom fabrication. Our rear bolt on subframe will include engine/trans mounts for both the 1.4L and 1.9L engines :-)
I was also able to eliminate the driveshaft which is one less moving part as well as the heavy Ford 8.8" differential and Lincoln Mark VIII axles, knuckles, hubs, and brake assembly. The estimated weight savings is around 100lbs which is pretty significant in and of itself. This also allows us to save big money being able to use the stock Passat/Jetta MK3 components such as axles, knuckles, hubs and brakes. All these parts total around $500 new.
We also save weight on the streamlined exhaust system. We will be going straight pipe which will only need minimal travel straight back which cuts out the Muffler, catalytic converter, and pipe length. Saving weight, money, complexity, and replacement costs down the road. This also gains us real estate under the car for an easier full under body tray design for increased aerodynamics!
Another overlooked advantage is part sourcing. Instead of having to go hunt for hard to find Lincoln Mark VIII parts we can now just go find everything we need out of a Passat/Jetta TDI which are rather easy to come by gaining time and efficiency. I am sure there are other advantages but this was just off the top of my head so I will add on as I have more time to really think more in depth on it.
Even at upwards of $3,000 this is not uncommon for a fully rebuilt transmission these days and all the advantages we gained were just huge for the overall kitcar design. I actually feel as though now I finally got it right and we can begin to really move forward with the assembly phase of the project.
GH
