Adding A bit of Aero to my Mk II Jetta

[Varn]

I decided to add a bit of aero to my VW Jetta Diesel. I have been able to get 55mpg all summer. The car does not lend itself to instrumentation that can measure fuel economy. No computer to tap into.

Here is what I was able to come up with.

The vehicle is almost always driven with the trunk full so getting into the trunk is important. I raised the trunk and used some cardboad boxes to shim the top piece of 8mm thick coroplast to the expected angle of 15 deg at the back of it.

The sides were made from 4 mm coroplast. I heated and folded the joining surfaces so that it would add strength and stability. The sides taper in. I under-lapped the two pieces that make each side and to add taper.


The other aero aids are the piece of unbacked formica shaped in front of the grill, a hood splitter and an extension on the stock under bumper spoiler.

Last year my goal was 50 mpg since I have seen 57 mpg twice in a row I am hoping for 58.

[Cd]

If you added a crease or hinge at the edge of the Kammback, it seems as if you could have it swing it up with the trunk. Of course this extention would need to be a piece of clear sheeting / plexi / lexan so you could see behind you .

Are you going to add wheel skirts and a belly pan ?

[Varn]

Hi CD
Yep it is a work in progress. Progress has been delayed by the lack of materials and time for designing . Your idea sounds good. I want to be able to see out back. If this small air foil works I might just make a true hatch back using some 3/4" square steel tubing, that won't happen sooner than next year.

I don't see any underbody work happening. The car is driven on both gravel and dirt roads. I have worked on front wheel skirts somewhat like arcosine's Hinged at the top and using bungies to hold them closed. My initial attempt was taped on without hinges or bungies, it failed when the tape gave up its stickem. The wheel flares just beg for some covers. With no instrumentation It takes a couple of tanks of fuel to see results. I refuse to go out on test drives and coast downs.

[Cd]

Actually you can use instrumentation on your car ( it's fuel injected ? ) :Official MPGuino preassembled now available

[Varn]

Hi CD
It is mechanically fuel injected. No spark or electronic timing.

Originally Posted by Cd

Actually you can use instrumentation on your car ( it's fuel injected ? ) :Official MPGuino preassembled now available

[dremd]

Cool stuff

[Varn]

Now if I could get 65 mpg like yours dremd. Of course your transmission costs more than my car.

Drove it to work as it was raining and both of us noticed that it was quieter than ever before.

Too bad the weather has turned cold and windy. Last time we were on the road we had lots of wind. Tonight we are going to be on the road and will have cold + wind. It is going to be hard to measure any improvement even if there is some.

[dremd]

My normal fills are in the 50-55 mpg range, I can easily stretch in to the 60's by slowing down, and have had a 78 mpg fill (very low speeds, lots of EOC no A/C etc).

Yeah, Transmission is pricey, main way I justify it is that it is still worth what I paid for it.

[Varn]

Very impressive dremd. It is amazing what the diesel engine will do. I assume that your 6 speed is more of an overdrive rather than close ratio type.

I drive mine at 55 mph max. No air conditioning and loaded to max vehicle weight. My next best mpg vehicle gets half the economy.

[dremd]

My 1st-5th are all basically the same as factory (a tad taller, but not much) and 6th is on top of that.
Your car is actually more impressive to me. Especially price/ mpg.