Rear Wing Installation

Update 4/7/17

Some people were having problems with the bracket to frame attachment bolts breaking.  I wasn’t, but some were.  I think the real problem was that they were “upgrading” to a grade 8 bolt.  This is a high vibration application, and the bolt is in single shear.  IMO, this is not the place for a grade 8 bolt.  According to Carroll Smith, “There is no place on a race car for a grade 8 bolt.”   While I don’t agree with that statement 100%, as a general rule, I think that is true.

In any case, Exomotive sent me an upgrade kit for free.  Well, almost for free.   I paid a couple of bux for shipping.   The kit consisted of a drill bit (which was bent and I tossed), a good tap, and some upgraded fasteners.   The whole job took me about an hour.

During the original assembly, I upgraded to these allen bolts on the left.  Allen bolts are stronger than cap screws.   The new bolts are on the right.
Original assembly
Holes are bigger

 

 

 

Fasteners are Bigger

 

 

 

Final Assembly

This is the final assembly.  Certainly looks stronger?   We’ll see.  Now, if one of these breaks, I’m gonna be kinda unhappy.  😉

Does the car need a front wing?  Absolutely!   It needs a LOT of rear wing.  With out it, there almost no weight back there, and you just can’t get any traction.   Doesn’t seem to need anything in the front, though.   Not yet, anyway.

Original Installation

The car (apparently) needs a rear wing for down force.   I have been told by Exomotive and other racers that there is no need for a front wing.   There’s enough weight on the front, and enough down force from the hood that it only creates drag and doesn’t improve lap times.   We’ll see about that.

When I ordered the kit, I ordered the CoT wing mounts, both front and rear.   Not such a good idea.   The supply of CoT wings has pretty much dried up.   I have this dual plane wing that I’v had for a while, so I’ll use it for now.

Exomotive sells a really nice carbon fiber APR GTC-200 single plane wing that’s said to be very efficient.   But at $1,100, I’ll hold off on that for now.   At some point, I’ll probably break down and order one.  Hey it’s carbon fiber and looks cool!  It must make the car faster.  Especially if I put some stickers on it.  🙂

CoT wing mount
CoT wing mount

IMG_7756 (4)

AR Wing
AR Wing

So, this is the original installation.  The CoT wing mounts are slightly different than the APR mounts.  They put the wing up into the air a little more, and further back on the car.  And, ideally, that’s where you want the wing – up into clean air as much as possible.  It might even be a good idea to mount it directly to the rear roll bar.

Serpent Express TrailerWith the wing that high, it won’t fit in to my trailer!   That’s not going to work.   I could just take the wing off and on for trailer loading.  But that’s a PITA.  And sometimes bad weather will roll in quickly while I’m out on the track.  It’s a good idea to be able to come off the track and drive right on to the trailer.  I could just buy a new trailer.  But I already own this one, and I like it a lot.   Serpent Express Trailer

Shortened CoT Mounts
Shortened CoT Mounts

 

The first step is to shorten the CoT mounts.   Pretty easy.  A couple of minutes with a Sawz-All.   Then drill a couple of holes for the front mounts.   I drilled the top ones first.  Then decided I didn’t like that, and drilled the bottom ones.

 

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Then it’s a fairly simple matter of bolting the wing in place, with the proper struts.  I made the struts out of some 5/8″ alum rod and some 5/16″ rod ends.  I didn’t have any left hand rod ends, or a left handed tap.  So you have to unbolt it to make an adjustment.   Not a big deal really.   The struts only get adjusted once.  To fine tune the down force,  I’ll make adjustments to the top wing.

I haven’t tried it yet.  But this should easily fit in my trailer.

I set the main wing to 0.5* of down angle.   Ideally, it should be zero for good down force with minimal drag.   But the AOA will change as the car moves down the track,  and I don’t want to get any lift.  The upper wing is about in the middle of it’s range as a starting point.   I’ll use tire temps to adjust the angle.  That’s a good theory, isn’t it?  🙂