MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: AjayB on July 07, 2012, 09:19:21 pm

Title: MK5 without undertray
Post by: AjayB on July 07, 2012, 09:19:21 pm
I had to take my under tray off last week due to a brick absolutely ravaging it to pieces :( just wondering if the car will be ok with no under tray especially in this weather?

 Thanks in advance
Title: Re: MK5 without undertray
Post by: bacillus on July 07, 2012, 09:26:41 pm
Car will be ok without the undertray but underbody aerodynamics will be impaired.
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 02:45:58 am
Thanks for the reply mate! Much appreciated!
Title: Re: MK5 without undertray
Post by: RedRobin on July 08, 2012, 08:05:46 am

Car will be ok without the undertray but underbody aerodynamics will be impaired.


....I wonder how the UNIbrace UB affects underbody aerodynamics.
Title: Re: MK5 without undertray
Post by: DFish on July 08, 2012, 11:50:01 am
I wouldn't aim of the puddles, unless you want to wash the engine. ;)

I'd doubt the UB does much to be honest, as it's mostly just replacing the bars already there.

Fish
Title: Re: MK5 without undertray
Post by: apples12 on July 08, 2012, 03:23:45 pm
I'd look to replacing it ASAP...

that undertray not only serves an aerodynamic purpose but also keeps water away from a fair few of the components and likewise another brick from the components under there....
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 09:31:51 pm
I'd look to replacing it ASAP...

that undertray not only serves an aerodynamic purpose but also keeps water away from a fair few of the components and likewise another brick from the components under there....


Oh, ill have a look at ordering a new one then.. does anyone know the part number and cost? 2004 GT TDI..
Title: Re: MK5 without undertray
Post by: Andy on July 08, 2012, 09:35:03 pm
dont know the part number but i was told they are £250 from the dealers
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 09:36:58 pm
dont know the part number but i was told they are £250 from the dealers

 :surprised: So much? just for a bit of plastic? i've still got the old one.. will try patch that one up if this is the case!
Title: Re: MK5 without undertray
Post by: DFish on July 08, 2012, 09:40:09 pm
Breakers or ebay will be the best place by the looks of it then.

Fish
Title: Re: MK5 without undertray
Post by: donovan2123 on July 08, 2012, 09:43:29 pm
Surely water will still get to engine components with or without tray. I had a astra that ran over 2 years with out under tray and it was fine. Also it went through some tough climates such as snowy Germany at Christmas
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 09:45:27 pm
Surely water will still get to engine components with or without tray. I had a astra that ran over 2 years with out under tray and it was fine. Also it went through some tough climates such as snowy Germany at Christmas

I was told that it should be ok to run like this but i will look into it tomorrow by popping up to VW to ask. Don't want to cause any damage that would be prevented by not having an under tray.
Title: Re: MK5 without undertray
Post by: RedRobin on July 08, 2012, 09:49:29 pm
.
It's things like bits of branches etc which are usually washed onto the road in extremely wet conditions or storms. Lots of such instances on country roads.
Title: Re: MK5 without undertray
Post by: Tfsi_Mike on July 08, 2012, 09:52:38 pm
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 10:42:29 pm
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17

Cheers mike, that seems more reasonable lol. Are those dealer prices you just mentioned?
Title: Re: MK5 without undertray
Post by: bacillus on July 08, 2012, 10:59:48 pm
 Part number 1K0 825 237 P Undertray £26.24
Title: Re: MK5 without undertray
Post by: apples12 on July 08, 2012, 11:18:24 pm
Latest one according to my version of etka is 1K0 825 237 AE for a diesel engine,

I'd highly recommend 3 of 1K0 825 951 - those are the three Hex bolts which go into the rear of the tray into the subframe

Snap nut (the little metal thing) - not sure if the new tray would come with new ones of these - N 909 591 01

and etka states 8 of N 103 546 02 - those are the T20 Torx screws to secure it in place...

(now might be a good time to inspect your undercarriage for any other covers which may be damaged/missing and replace them and/or replace them with the more aerodynamic ones)

on a side note....it would appear according to etka vw also sell a metal skid plate assembly!

 :happy2:
Title: Re: MK5 without undertray
Post by: AjayB on July 08, 2012, 11:35:42 pm
Thank you guys. i really appreciate the information :D will get one ordered tomorrow!
Title: Re: MK5 without undertray
Post by: Tfsi_Mike on July 09, 2012, 08:38:19 am
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17

Cheers mike, that seems more reasonable lol. Are those dealer prices you just mentioned?

I bought my bluemotion undertray from the dealer in Germany as I lived there at the time. The aim was to improve fuel economy on my Cupra.

Now I'm back in England and have also damaged my undertray I will be getting a new one very soon.  Probably from tps via AKS tuning.
I'll get a price for both the normal shorter tray and longer bluemotion one.
Title: Re: MK5 without undertray
Post by: Tfsi_Mike on July 09, 2012, 08:47:33 am

http://bit.ly/MUqsXe (http://bit.ly/MUqsXe)

Quick eBay search
Title: Re: MK5 without undertray
Post by: vag12 on September 16, 2012, 06:41:25 pm
My undertray is missing I just found out, would like to replace with blue motion part, anyone have part number please and price?
Cheers
Title: Re: MK5 without undertray
Post by: Tfsi_Mike on September 16, 2012, 06:45:23 pm
My undertray is missing I just found out, would like to replace with blue motion part, anyone have part number please and price?
Cheers

Do a quick forum search for "improving aerodynamics with oem parts"  :happy2:
Title: Re: MK5 without undertray
Post by: itismebigd on September 16, 2012, 07:06:21 pm
is it not true that you need to remove some of the undertray to fit a forge twintercooler,ie the forge pipes,reason that i say this is that i have some of my undertray missing to accommodate the forge pipe work,if this is not the case then my tuner is in hot water lmao
Title: Re: MK5 without undertray
Post by: vag12 on September 16, 2012, 07:09:40 pm
My search has narrowed down to a part number ending with P which also needs 3 bolts, is that all that is needed to fit it on? Also has anyone seen any benefits after fitting the blue motion undertray?
Title: Re: MK5 without undertray
Post by: E30Dom on September 16, 2012, 08:33:05 pm

Car will be ok without the undertray but underbody aerodynamics will be impaired.


....I wonder how the UNIbrace UB affects underbody aerodynamics.

It acts like an undercar wing/diffuser sucking the car to the road... :pomppomp:
Title: Re: MK5 without undertray
Post by: RedRobin on September 16, 2012, 09:11:53 pm

....I wonder how the UNIbrace UB affects underbody aerodynamics.


It acts like an undercar wing/diffuser sucking the car to the road... :pomppomp:


.... :surprised: Really? :surprised:
Title: Re: MK5 without undertray
Post by: bacillus on September 16, 2012, 09:15:40 pm

....I wonder how the UNIbrace UB affects underbody aerodynamics.


It acts like an undercar wing/diffuser sucking the car to the road... :pomppomp:


.... :surprised: Really? :surprised:

I think he's just being sarcastic RR.
Title: Re: MK5 without undertray
Post by: RedRobin on September 16, 2012, 09:18:02 pm
^^^^
But you know how gullible I am - Look at all those mods I've got  :grin:
Title: Re: MK5 without undertray
Post by: Phil Miller on September 16, 2012, 10:06:29 pm
i took mine off almost 2 yrs ago and havent re fitted it yet, also not all mk5s have the complete undertray, 1.6 FSIs only have a small one, TBH its doesnt make a blind bit of difference, but if anyone wants a full undertray ive got 2 or 3 :star:
Title: Re: MK5 without undertray
Post by: itismebigd on September 17, 2012, 06:31:11 am
At last some one has came along and finally put this one to bed,personally i didnt think there would be much of a difference,thank you Phil :congrats:
Title: Re: MK5 without undertray
Post by: jimojameso on September 17, 2012, 12:10:04 pm
I just found out mine was missing one so fitted one last week. I go on the motorway everyday and the fuel consumption is exactly the same so doesnt increase drag not having one. I never had any problems without one but i was advised by amd to fit one before the snow, etc, comes as it can knacker the ac pump, etc if you dont have one and crap gets up in it.

My advise would be get one  :happy2:
Title: Re: MK5 without undertray
Post by: the bruce on September 17, 2012, 12:18:31 pm
I does increase drag even if you don't recognize it. Otherwise VW would have saved
the money for it.

To me there's not only one point against the (large) undertray, but many points for it.
All GTIs should have come with the ... 237 P from factory.

On the motorway aerodynamic drag is the main factor.

http://www.mk5golfgti.co.uk/forum/index.php/topic,22986.msg307333.html#msg307333



(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FMy_Leon_Cupra%2FMini_mods%2FPhoto0792.jpg&hash=b746bc70d3f228146e6acacb30e0aec27e7881a8)
Title: Re: MK5 without undertray
Post by: RedRobin on September 17, 2012, 12:39:37 pm
^^^^
The one point against the complete frontal undertray is that it will conceal any fluid leaks until they become far worse.

On the floor of my car's batcave (garage without electricity) I keep pristine brown cardboard under the whole area of the engine. Consequently I can immediately spot any drops of fluid. I caught a faulty DSG oil plug seal that way and before it became a serious problem.

In the UK, unfortunately without unrestricted speed autobahns, I don't consider the underfloor aerodynamics of a VW Golf hatchback to be that important.

I think that you are something of an expert on the aerodynamics of the Golf and so I am very interested in your thoughts about the UNIbrace UB regarding underfloor drag etc.

(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FMods%2FUNIbrace%2FUB_1972.jpg&hash=afae850eebe9eec70fbc344dd5cc5400128dc08b)

Also whether a Golf which is lower on suspension has any aerodynamic underfloor advantages or disadvantages  :happy2: (Mine has 95mm overall ground clearance)
Title: Re: MK5 without undertray
Post by: the bruce on September 17, 2012, 01:13:47 pm
... of my car's batcave (garage without electricity)

 :happy2:  :signLOL:


I think that you are something of an expert on the aerodynamics of the Golf and so I am very interested in your thoughts about the UNIbrace UB regarding underfloor drag etc.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FMods%2FUNIbrace%2FUB_1972.jpg&hash=afae850eebe9eec70fbc344dd5cc5400128dc08b)

From theory almost any protruding part will increase drag (almost, cos spoilers that prevent
the air hitting other 'draggy' parts do not). The amount of drag won't be significient.


Also whether a Golf which is lower on suspension has any aerodynamic underfloor advantages or disadvantages  :happy2: (Mine has 95mm overall ground clearance)

Again from theory lowering is a good thing from the view of aerodynamics as less air will
flow underneath the car. This will almost always reduce both drag and lift.

Same with a splitter/air dam (Osir/VWR/Votex): This also reduces the amount of air flow.
Title: Re: MK5 without undertray
Post by: RedRobin on September 17, 2012, 01:45:09 pm
^^^^
Thanks, Bruce  :happy2:

Either way, I'm extremely happy with my handling mods but it's nice to understand something about how things work and to know if I'm doing something importantly wrong.
Title: Re: MK5 without undertray
Post by: the bruce on September 17, 2012, 02:06:26 pm
I'm pretty sure you didn't do anything wrong, mate.  :wink:
I strongly believe your GTI is handling great and gives way more driving pleasure than stock.
Title: Re: MK5 without undertray
Post by: jimojameso on September 17, 2012, 02:14:27 pm
I does increase drag even if you don't recognize it. Otherwise VW would have saved
the money for it.

Yes i know it does affect drag but the point im making is it will not really affect the car on the road. If you were roaring around a track at 150 mph then it would make a lot of difference but for most people who use there golf on the road it wont make the slightest bit of difference. It is mainly needed to protect the engine components from dirt. I actually work in aerodynamics so i know a thing or two about it.
Title: Re: MK5 without undertray
Post by: the bruce on September 17, 2012, 02:21:24 pm
True, mate. The main advantages are:

- protecting engine bay components from water, dirt, salt, stone chips
- some slight reduction in drag at motorway speeds
- on a TDI: damping the awful Diesel noise
Title: Re: MK5 without undertray
Post by: rdfcpete on July 05, 2014, 02:50:03 pm
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17

Ancient one I know Mike, but - does the BlueMotion undertray fit all MK5 platform cars i.e. my 8P3 Audi A3 does anyone know?

Cheers.
Title: Re: MK5 without undertray
Post by: betty_swollox on July 05, 2014, 03:53:31 pm
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17

Ancient one I know Mike, but - does the BlueMotion undertray fit all MK5 platform cars i.e. my 8P3 Audi A3 does anyone know?

Cheers.


http://www.mk5golfgti.co.uk/forum/index.php/topic,85541.0.html


Might help :happy2:
Title: Re: MK5 without undertray
Post by: rdfcpete on July 05, 2014, 07:23:12 pm
dont know the part number but i was told they are £250 from the dealers

A blue motion (see the improving aerodynamics with oem parts thread) undertray, cost me about 20-30€
A standard (bit smaller / doesn't go as far back) Leon / golf undertray is around £20
Ive seen one on eBay recently for £17

Ancient one I know Mike, but - does the BlueMotion undertray fit all MK5 platform cars i.e. my 8P3 Audi A3 does anyone know?

Cheers.


http://www.mk5golfgti.co.uk/forum/index.php/topic,85541.0.html


Might help :happy2:

Cheers fella, it's given me the part number which is as good a start as any. I'll do some general reading up...  :happy2:

(I did use the search, it didn't retrieve that thread)