Fitting a front lip spoiler

7 10 2010

I’ve been after a front OEM-style lip spoiler for the Roadster for a while.  I think they improve the look of the front of the car, and they’re also meant to add a bit of front-end stability at speed.

The original OEM Mazda spoilers are horrifically expensive, so I’ve been on the lookout on the Bay for a cheaper alternative.

I found a new fibreglass one last week, being sold by a guy a couple of miles away.  It came primed, ready for paint for £50.

I decided I wanted it matt black.  I’ve painted a few plastic parts before and by far the best product I’ve used is this stuff:

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It’s almost magic – coverage is great, it gives a really even finish with no drips, and is very quick to use.  Half an hour in the garden and it was painted up and looking like it’d come out of a Mazda factory – the matt Plastikote gives a real OEM finish.  Don’t put it on too thickly as it may crack as the spoiler flexes.  Wipe the spoiler down with panel wipe, and give it a fairly light coat, concentrating on the inside of the brake vent ducts.  Give it ten minutes to go tacky and repeat.  A couple of passes like this and it’ll look perfect.  Hang up to dry overnight.

Fitting

The fibreglass spoilers aren’t as flexible as the Mazda originals, so whilst they will bend a little, you have to be careful fitting them.

I used the Mazdamender Method.

You’ll need a couple of blocks, two clamps, some stainless steel 6mm bolts, nuts and washers, and a couple of short stainless self-tappers.

First, locate the metal rods behind the front bumper on each side.  These bolt on to the edge of the front bumper to hold it in place.  There’s a single 10mm nut on each one on the underside, with the top nut being a captive one welded to the rod.  I sprayed liberally with Plusgas and gently snapped the heads off both with a socket.  Argh.  These nuts are exposed to a lot of road dirt and on mine the nut, bolt and captive socket had all rusted into a solid mass.

I unbolted the other end of the rod and removed it from the car, and using a Dremel and several diamond cutting wheels remove the captive nut completely.  After a bit of an argument with a pair of pliers, I was left with a metal rod with a bolt hole in the end.  Out with the plastikote again to cover the bare metal, and then bolt back onto car.  You might be lucky and get the original bolt out, but if not this method allows you to refit it with a stainless nut and bolt instead.

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The picture above shows the lip spoiler when finally fitted – do not screw in the self-tapper on each end of the spoiler just yet!

I offered up the spoiler under the bumper, raised up on a couple of blocks of wood.  On each end, about six inches in from the edge, you’ll see a mounting flange that allows you to bolt each side to the metal rod – line this up with the rod and the existing hole in the bumper, and bolt it in very loosely.  Do the same on the other side.

Now the spoiler is very roughly in place, I took a couple of spring clamps and used them to hold the lip spoiler in the correct place.  Ensure that the edges of the lip spoiler where they curve up fit correctly as these will look conspicuous if they aren’t aligned.

With a copy part in fibreglass, you’ll probably have to squeeze and move it around a little to get the best fit.

Once done, get under the front of the car and using a 6mm drill make the mounting holes in the original bumper by drilling through the new spoiler’s mount points.  Pass a stainless bolt through each one, put a washer on the rear and very loosely bolt it up.  Repeat around the front of the car.

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When you’ve got all bolts in place, you can start gently tightening them up – I found that there was a bit of an art to this to get them all lined up correctly.  Be careful not to flex the fibreglass too much, and use the two bolts attached to the metal rod as your initial reference point.  Tighten these up gradually, checking the alignment as you go, and then tighten the inboard screws in sequence.

When these are in and the spoiler is mounted to the bumper correctly, there are a couple of tabs on the brake vent ducts that need to be screwed into the existing undertray.  I used short stainless self-tappers to attach these as below.

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Finally, take a couple of stainless self-tappers and screw in the edges of each side to the car bumper.  I found a small pilot hole helped me get this flush (see second picture above).

Job done.  Sit back and admire.

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Took me approximately 30 minutes to do this from start to finish and I’m really pleased with the result.

As well as looking better, it turns out that it does actually stabilise the car at speed – mine feels a lot less light on the front wheels at motorway speeds.

 

UPDATE:  well, it’s been nearly a week and already I’ve put a small crack in it.  Aaargh.  Nothing to do with my new coilovers and lower ride height, honest.