improving aerodynamics with OEM parts

[mkviken]

think i might go for the under tray, exhaust shield and axle guard.


cheers for the part numbers Geoff

[malaroo978]

Hi guys, hoping for some help again! (Sorry!)

I just wanted to collate all the part no.'s that I need so I can contact TPS without sounding like an idiot and know what I need for installation etc.

I'm after getting the engine undertray, 1a + 1b, 2a + 2b and 4 definitely. Possibly no.3 pending inspection of my exhaust system!

What I've got so far:

Engine undertray
1K0 825 237 P  - x 1

1K0 825 951 – x 3 (bolts)

Rear covers from A3 or TT
1K0 511 539 E – x 1

1K0 511 540 C – x 1

8E0 825 267 – x 4 (what do I need to install these)

Rear axle cover as fitted to bluemotion
1K0 501 713 D – x 1

1K0 501 682 - x 1

What other parts do I need? I think I've listed the undertray, no.4 and the rear covers are 2a and 2b I think? I'm getting confused with part numbers and brackets/bolts/rivets needed!

What tools do I need to install? I.e. what type of rivet gun (assume they are pop rivets?) and I'm hoping I don't need to drill anything... Sorry if I've missed the information, it would be good to have it all in one place! Cheers guys

[bacillus]

Hi guys, hoping for some help again! (Sorry!)

I just wanted to collate all the part no.'s that I need so I can contact TPS without sounding like an idiot and know what I need for installation etc.

I'm after getting the engine undertray, 1a + 1b, 2a + 2b and 4 definitely. Possibly no.3 pending inspection of my exhaust system!

What I've got so far:

Engine undertray
1K0 825 237 P  - x 1

1K0 825 951 – x 3 (bolts)

Rear covers from A3 or TT
1K0 511 539 E – x 1

1K0 511 540 C – x 1

8E0 825 267 – x 4 (what do I need to install these)

Rear axle cover as fitted to bluemotion
1K0 501 713 D – x 1

1K0 501 682 - x 1

What other parts do I need? I think I've listed the undertray, no.4 and the rear covers are 2a and 2b I think? I'm getting confused with part numbers and brackets/bolts/rivets needed!

What tools do I need to install? I.e. what type of rivet gun (assume they are pop rivets?) and I'm hoping I don't need to drill anything... Sorry if I've missed the information, it would be good to have it all in one place! Cheers guys

http://www.mk5golfgti.co.uk/forum/index.php/topic,22986.msg402475.html#msg402475

[malaroo978]

Thanks, sorry I completely missed this page. Got everything I asked for on that page!

Whats this part no. for?   3C0 501 713

Also, for all the rivets etc. what do I need to install and are the holes pre drilled?

Definitely getting the undertray, part no.4, 2a & 2b (not sure about brake line difficulty though) and I was hoping someone could tell me of the benefits of 1a & 1b?

Cheers again :)

[the bruce]

3C0 501 713 is the larger Passat rear axle cover - you don't need it.

1a and 1b are the small spoilers sitting on the rear of your already
fitted large undebody trays besides the tunnel. These can be retro-
fitted on all Mk.Vs which have already even smaller spoilers at that
place. Mk.VIs have toothed larger spoilers there so that 1a/b do not
fit.

1a/b originally are a part of the Volkswagen ''all terrain package''
available in some countries and they protect the rear axle against
stone chips, snow and ice parts.

[Richn83]

as the bruce states you dont want the 3c0 part number I got that by mistake and it needed to  be modified to fit and you need further brackets for the other side of the rear axle.

[malaroo978]

Thanks guys, thought it might be that.

With the stone protectors do they add any aerodynamic benefits? Ie downforce?

Thanks :)

[the bruce]

If you fit the rear axle cover and the A3 trailing arm covers I don't see
any need for them. Without a wind tunnel I cannot exactly tell the
difference with or without of course.

[malaroo978]

Sounds good to me, easier for me that way as I'm not that great at fitting. Thanks again for the advice and starting this thread :) I need to invest in a trolley jack and axle stands! I'll let you know results when I've got it done :)

[fuscobal]

I've ordered the front large undertray but cannot find a real aerodynamic purpose on the little bits from the rear. I'd better look into making an entire piece just like in front instead of all those small pieces !

[Richn83]

The rear parts especially the audi parts on the control arms are aerodynamically shaped and i don't think audi and vw strap bits of plastic to the bottom of the car for no reason 

[the bruce]

I've ordered the front large undertray but cannot find a real aerodynamic purpose on the little bits from the rear. I'd better look into making an entire piece just like in front instead of all those small pieces !

Great idea. I thought about that many times.

The problem is the heat caused by the exhaust, so that heat resistant material has to be used.

[Richn83]

The other problem with a single rear cover is the amount of consistent space you have to run a flat area of plastic at the same level or higher than the front end.

In front of the rear axle the fuel tank drops down below the line of the rest of the body on one side and the other you have the first silence.

Then you have the rear axle which gives you clear space and mounting points yet the exhaust comes through that area directly in the middle between the control arms if you look at the larger pass at part in my earlier photos the exhaust interferes with this.

Then between the control arms you have a gap of maybe 30 cm in the middle where you don't need clearance for the suspension to be able to fully travel.

Straight behind that you have an exhaust taking up the entire rear area before the number, the standard one if you could get a material that is temperature resistant could be boxed in and the cover made to bolt on to holes that are already in the rear bumper, but this could cause heat issues into the cabin.  So you would want a rear vent or something to draw air over the rear silence, and the larger miltek or after market exhausts all hang down lower so would be even worse.

I had a look into potential materials as well and stuff that's easy to work with like abs plastic generally has low melting points which leaves you with rigid materials like aluminium or harder plastics, or you could do a wet lay up in kevlar or heat resistant carbon fiber?

My thought on the best option would be a panel that comes from the rear of the fuel tank through the middle of the rear axle uptto the exhaust and then attach slightly curved upward material to the control arms to flow air up behind the car to reduce rear drag at higher speeds

[the bruce]

This one has a real working duffuser:



The professional built racing Mk.Vs have no rear muffler and different lower arms not to disturb air flow.

[Duke]

Quite interested in this, especially as I take mine on track.

How hard are the parts to fit generally? Can I do itself by jacking the car up or does it need to be done on proper ramps (i.e get garage to do it)?