(Project) Boat tail-4 Door Sedan VW Mk2 (1990 Jetta GL)

[JethroBodine]

Thanks TC. Dang.

Wait... I just saw some spray latex house paint today at the discount auto/tool store, right next to the Tite-Bond glue. I love one stop shopping.

[JethroBodine]

There was a light mist on the way to work. When I got out I saw some condensation tracks on the tail. And here they are;



Left side, at an angle.



Right side looking forward.



Straight forward.

I like these tracks better than the twin spirals I used to get on the trunk lid(even though the two cyclones were kinda' cool in a light snow).

I also made a template overlay, and all I can say is...Oops.



In my haste to have the car runnable, I seem to have deviated a bit in my measurements. This will have to be addressed in the spring( probably) as I don't have nearly the free time available between now and snow fly.

[MetroMPG]

Originally Posted by JethroBodine

Whew! Do NOT put a tail on your car unless you like talking to people.

That's so true!

When I was making the prototype tail on the Firefly, I had people stopping their cars at the end of the driveway and getting out to ask me about it.

I saw a driver stop mid-turn in an intersection to look at it.

[itjstagame]

Wow very nice! Can't wait to see the results on the run.

When you get this tested to really see what you have, I have another addition I've always thought of and thought I would throw a mock up out there.

Its horribly ugly and just a suggestion, but I have always wonder about air deflectors and recombinors (not a word) around the lower section of the exposed wheel. I would think ABA or tuft testing would show some benefit, I'm not sure how bad the air is off the wheel, but this would be a triangle or rounded shape to try to match the air off the wheel and smooth it into the tail.

I figure it should be about the same purpose as the humps on the back of old open roadster race cars, like this porsche has:

Anyway just a thought for future discussion.

[Weather Spotter]

As another boat tail driver I agree to your lots of comments form others. I get it all the time.

your project is looking good, any plans for a window for rear view?

[JethroBodine]

Weather Spotter- You are definitely one of my influences for starting this project. I really enjoyed reading( and re-reading) your build project. I was going to do a rear window, but, I cut out the rear seat support and tried lying down in the vacant rear seat/trunk area and found it more than long enough for me. I'm now leaning toward using a license plate camera instead. This would allow both a quicker and easier way to seal the passenger compartment for the winter. I have LOTS of experience driving vehicles without a rear window, so I don't really notice the loss.

MetroMPG- Obviously, also a great influence for me and this build, I almost used cardboard( I have an inexhaustible supply) sealed with resin as my media, but on the 3rd or 4th read of your thread you mentioned bubbling, I assume like 3wheelers water based problems. Thought I'd try this route. Time will tell.

itjstagame- I've got a ways to go before I get to the tire strakes, but you do bring up a good point. I'm thinking along the lines of aerohead's t-100. Might not be feasible around here as I drive on dirt roads to get home.

[MetroMPG]

Yeah - I can heartily recommend NOT using cardboard for permanent mods!

(And the prize for most obvious statement of the day goes to...)

Unless perfectly encased in resin (which must never, ever crack), by design it will thirstily lap up water and eventually turn itself into a bloated mess.

[Weather Spotter]

If you add the rear window you can remove the side mirror. on my car that was worth 1.6 MPG. Even with a window you can still lay down back there. I have done it in mine. You might want to add a wooden frame and mount a cheep set of blinds or a curtain

It looks like you will need to redo the angle of the top anyway so that would be a good time to do it.

Do you ever get over to Michigan? I would be interested in comparing our tails

Is there anything you want more pictures of or user data on my car?

[JethroBodine]

I'm not sure, but with the template overlay it looks like there might not be a good location for a window. I will be keeping an open mind until I actually get to that stage.

How's yours holding up? Any new developments? Any observations?

A few testing updates on mine, so far;

on my calibrated test hill, I have been coasting from 45 mph to a +5mph over what I was getting before the tail( as an example, if I had accelerated to 76 previously, I would have gotten 81, and of course that would be an average),

P&G now works better than DWL+EOC for my commute to work. Every time I tried P&G over the summer, I used .03 to .05 gallons more going to work. After the tail, I'm now getting about .02 gallons better out of P&G.
20.45 mile trip,
summer record of .20 gallons(102.25 mpg),
recently( before tail) around .29 gallons(70.52 mpg),
after tail DWL/EOC at .23 gallons(88.91 mpg),
and after tail P&G .21 gallons(97.38 mpg).

[Weather Spotter]

As for a window, right in the middle of the back looks like a good spot for a small one.

Mine is holding up good. One guy rear ended me but his hood crumpled, I had to do some touch up fiberglass but no big deal. My seal on the top leaks a bit of water during heavy rains but that is not a beg deal. it puddles then evaporated.

My best idea is about 5-7 MPG gain. I know my coating distance has gone way up. I regular coast .75 to .9 of a mile to a stop. with a tail wind I go a mile.

I get lots of comments on it and lots of looks but I like it.