Quote:
Originally Posted by cliffyballs
I traded with my brother-in-law for this car, when i got it it already had high/cold air intake and performance exhaust. It also has aftermarket wheels on it which will be coming off soon.
I have attached a picture of kinda what im thinking.
I am thinking of having the "butt" of the boat tail rounded is there any aero gain to that?
Also i am in the process of getting one of those scan gauge things for testing my MPGs
Side note Someone suggested getting an air splitter for the front of the car you negate a belly pan...anyone ever heard of this?
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You are well on the way already.
I agree about the present wheel/tire combo. They are nice, but are not really what you want for an aero package. I am guessing that you are looking into some narrower low rolling resistance tires with either moon caps or something similar and rear wheel fairings.
You might give some thought to lowering the car. VW showed a concept car. They cleaned up the front end and lowered the car either an inch or inch and a half...nothing radical which meant the car should have kept a good ride in the real world. I don't recall whether there was a belly pan on the show car or not. It was a part of their planned Bluemotion (diesel) attempts to field a 70 MPG vehicle.
You might want to establish some baseline speed/RPM charts at the speeds you expect to travel at and then do some digging around to see what alternative gear sets or transmissions there may be to get the cruise RPMs down. That is one of the good things about VWs, there have been a lot of parts over the years. Lowering cruise RPMs is one of the ways that the manufacturers have been getting their EPA highway figures up. It also makes the cars quieter which is not all bad. I think there are also some pulleys to spin the alternator slower, but you have to be careful not to overdo it if you are using the AC in hot weather or driving at night a lot.
You might also give some thought to the influence of exhaust gases on the airflow.
You might take a look at the drawings of the
Formula XL1 Concept for a little inspiration about the aero treatment of the rear wheel areas. It is an outgrowth of the
original 1 Liter project.
Wiki
You might want to first think about the materials you intend to use to fabricate the boat tail with as they may have a practical impact on what shape you can easily build.