bodykits: purely cosmetic?

Which kit is that, Meat?

Sometimes, aftermarket brand parts can add aero to a car. To a certain degree of course. Even though many (most) of the parts aren't wind tunnel tested, the people who made and designed them could have some general idea of how things work, from past/previous designs from other cars, etc.

I think that only the expensive ones would help

90% or more of kits bought are aesthetic and add more drag than anything

SloppySRT said:

Which kit is that, Meat?

Click to expand...

The one VW Motorsports used on their 24 hours cars at the Nurbugring:

http://www.bildon.com/catalog/SubCat/body/G5kitcar.cfm?Nav=3


Pricey though, nearly 10k plus it takes a lot of work to prep and fit it properly.

If you're wanting to race at a speed that modifications to the body have a noticeable effect, I'm going to go ahead and say you need a different car then a VW GTI.

saab actually did put the time and effort into their kits.

the regular NG900


the viggen


ng900 owners put the viggen kit on their car and they say its like night and day for high speed stability. and it is true that saab did take the time and effort to make the viggen body kit more aerodynamic.

Doctor7474 said:

If you're wanting to race at a speed that modifications to the body have a noticeable effect, I'm going to go ahead and say you need a different car then a VW GTI.

Click to expand...

Lol you have a good point there, the GTI doesnt go fast enough on the track for you to notice the effects of the body kit

Meat said:

The one VW Motorsports used on their 24 hours cars at the Nurbugring:

http://www.bildon.com/catalog/SubCat/body/G5kitcar.cfm?Nav=3

Pricey though, nearly 10k plus it takes a lot of work to prep and fit it properly.

Click to expand...

Thats one of the nicest wide bodies available for the GTI as of now

I know at least two splitters that have been proven in a wind tunnel:


VOLKSWAGEN RACING UK (looks like 'Rieger'):




VOLKSWAGEN VOTEX:





If you don't like huge wings there two 'factory looking' parts:


the more effective Mk.VI rear roof spoiler:




the even sharper edged VOTEX:




or just adding a ZENDER WINGLIP:



:wink:


You may know them. But that's not all. There are also some parts that are:


- cheap
- defintely developed in the wind tunnel

but: you can't see them. :biggrin:



The design of the underbody is 40 % of the total drag of a modern car !!
A flat underside will always reduce both drag and lift. So the stock underside of the GTI creates both.
Without a wind tunnel we cannot state the amount of improvement but it it will be
an improvement. Flatter is better in this area.
We cannot exactly state the resulting lift front and rear (but I promise at 200 km/h
it's around 0 front and 250 N rear). No real downforce of course, but better than stock though.


At high speeds ''aerodynamic drag'' is the main drag factor. Reducing it by a low margin
has large effects on dynamics and economy. Also there is ''aerodynamic lift'' causing
instability.

Lift isn't any problem the Golf's front. :wink:
It's got nearly no lift (about 50 N/5 kg @ 200 km/h) at front. The rear is an unequal problem
like it is with all hatches. The stock Golf V GTI produces about 350 N/35 kg lift @ 200 km/h,
the Mk.VI as well.

That's much more important because the cars's tail is lightweight and when braking hard it's
even much more light. Some of You may have experienced that by their own.

:driver:

Dont' expect wonders, but there's a slight improvement possible for very low budget.

There are some OEM parts from Audi TT, newer A3 and Golf BlueMotion that fit the
Golf V + VI GTI easily:


- larger underbody engine/gearbox cover (instead of smaller one, looks like TDI cover)
- small deflector between rear axle and muffler
- some smaller parts to come later (more complicated)


There are no downsides like higher Oiltemperatures !! I measured with the Kufatec
E-MFA an increase of oil temperature of just 1° C after full throttle for several minutes.
The engine compartment is also much cleaner since then. :happy2:

Note: only the ''... ... 237 P'' has three ''NACA''-style vents. Two for the gearbox,
one for the turbo.


Example Audi A3 (almost identical to Golf V/VI):



Between fuel tank an rear exhaust there's the ''Hinterachsverkleidung'' = rear axle cover.


Installation is made in 5 - 10 minutes each, plug & play !!




part number 1K0 825 237 P:




1K0 501 713 D Trim for Rear Axle:





There are even some more, but these are the easiest to install parts:




Engine undertray
1K0 825 237 P Noise Insulation £28.84
1K0 825 951 Hex headed bolt (Combi) 89p (need 3 according to above list)

Rear axle cover as fitted to bluemotion
1K0 501 713 D Trim for Rear Axle £26.73
1K0 501 682 Retaining bracket £1.89
N 905 483 05 Not on Stamm
N 901 838 02 Not on Stamm

Rear covers from A3 or TT
1K0 511 539 E Stone chip Guard £5.37
1K0 511 540 C Stone Chip Guard £6.75
8E0 825 267 a spreader rivet £0.12 (need 4 so x4)


Nr.12 is ''Hinterachsverkleidung''. 7 - 9 is mounting hardware:




Nr.1 und (1) are mor kind of ''all terrain protection'':




2a and 2b comes from Audi A3 and TT 8J (fwd only).
Nr.3 comes from TDI BlueMotion and is best to be used with an non-resonated exhaust.
Nr.4 is ''Hinterachsverkleidung'' from TDI Blue Motion.

Wow, excellent, thx for posting! I had no idea factory had these parts available.

Looks like these parts can be ordered here with exception of the Bluemotion part numbers (3 & 4).

My 944T with all the underneath shields installed (most are missing on many of these cars now) made the car extremely stable at speeds of 160+, it works.

I need to replace my undertray after a little run-in with a cone:



I may have to look into that extended version.

No question these parts have no effect at Auto-Xing and very little effect on daily driving when speeds are very low.
Also the effect can not be as significient as huge wings. They just reduce the factory given amount of lift and drag.
As above I presume a reduction of lift from 50 N @ 200 km/h on front to about zero and from 350 N to 250 N (with better spoiler ~ 200 N) on rear.
That's good results for a street car !!





Zender 'Winglip':

the bruce said:

The design of the underbody is 40 % of the total drag of a modern car !!
A flat underside will always reduce both drag and lift. So the stock underside of the GTI creates both.
Without a wind tunnel we cannot state the amount of improvement but it it will be
an improvement. Flatter is better in this area.
We cannot exactly state the resulting lift front and rear (but I promise at 200 km/h
it's around 0 front and 250 N rear). No real downforce of course, but better than stock though.


At high speeds ''aerodynamic drag'' is the main drag factor. Reducing it by a low margin
has large effects on dynamics and economy. Also there is ''aerodynamic lift'' causing
instability.

Lift isn't any problem the Golf's front. :wink:
It's got nearly no lift (about 50 N/5 kg @ 200 km/h) at front. The rear is an unequal problem
like it is with all hatches. The stock Golf V GTI produces about 350 N/35 kg lift @ 200 km/h,
the Mk.VI as well.

That's much more important because the cars's tail is lightweight and when braking hard it's
even much more light. Some of You may have experienced that by their own.

:driver:

Dont' expect wonders, but there's a slight improvement possible for very low budget.

There are some OEM parts from Audi TT, newer A3 and Golf BlueMotion that fit the
Golf V + VI GTI easily:


- larger underbody engine/gearbox cover (instead of smaller one, looks like TDI cover)
- small deflector between rear axle and muffler
- some smaller parts to come later (more complicated)


There are no downsides like higher Oiltemperatures !! I measured with the Kufatec
E-MFA an increase of oil temperature of just 1° C after full throttle for several minutes.
The engine compartment is also much cleaner since then. :happy2:

Note: only the ''... ... 237 P'' has three ''NACA''-style vents. Two for the gearbox,
one for the turbo.


Example Audi A3 (almost identical to Golf V/VI):

Between fuel tank an rear exhaust there's the ''Hinterachsverkleidung'' = rear axle cover.


Installation is made in 5 - 10 minutes each, plug & play !!

part number 1K0 825 237 P:

1K0 501 713 D Trim for Rear Axle:

There are even some more, but these are the easiest to install parts:

Engine undertray
1K0 825 237 P Noise Insulation £28.84
1K0 825 951 Hex headed bolt (Combi) 89p (need 3 according to above list)

Rear axle cover as fitted to bluemotion
1K0 501 713 D Trim for Rear Axle £26.73
1K0 501 682 Retaining bracket £1.89
N 905 483 05 Not on Stamm
N 901 838 02 Not on Stamm

Rear covers from A3 or TT
1K0 511 539 E Stone chip Guard £5.37
1K0 511 540 C Stone Chip Guard £6.75
8E0 825 267 a spreader rivet £0.12 (need 4 so x4)


Nr.12 is ''Hinterachsverkleidung''. 7 - 9 is mounting hardware:

Nr.1 und (1) are mor kind of ''all terrain protection'':

2a and 2b comes from Audi A3 and TT 8J (fwd only).
Nr.3 comes from TDI BlueMotion and is best to be used with an non-resonated exhaust.
Nr.4 is ''Hinterachsverkleidung'' from TDI Blue Motion.

Click to expand...

Thanks for taking the time to write all of that up, I might look into some of this later!

part number 1K0 825 237 P:
is from the MKV R32, just looked it up on ECS Tuning and they want $77, not bad if you are missing/destroyed your current piece.

$56.64 at Ciocca parts.

One has to think these parts made more sense for German market, since Autobahn carries a *slightly* higher speed limit than our idiotic highways.

On 1K0 825 237 P, not clear where those three rear holes would bolt into.