MK5 Golf GTI
General => Product Reviews => Topic started by: RedRobin on April 14, 2010, 05:39:12 pm
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WHAT IS A SPLITTER?
As the front of a car slows down the air without a diffuser, this is the ideal place for an inlet. A splitter is commonly used here, serving to increase the amount of downforce at the front of the car. The airstream is brought to stagnation above the splitter by an air dam, causing an area of high pressure. Below the splitter, the air is redirected away from the stagnation zone and is accelerated, causing the pressure to drop. This, combined with the high pressure over the splitter creates downforce. The larger the area of the splitter, the more downforce is generated. In most closed-wheel race cars, the underside of the splitter smoothly integrates with the undertray, creating one large flat plane that is driven by the rear diffuser. [source: Wikipedia]
However, that is mostly in the context of a race car but inevitably performance road cars can benefit from having a splitter and/or diffusers. Also inevitably, there is an element of fashion which creeps into the equation and some aftermarket splitters can be purely cosmetic.
This is a good example of a race style splitter, also known as a spoiler, on a performance road car:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FCupraSplitter.jpg&hash=30840a49b056ed56e38ec7fd13d4ff79f9b815f5)
WHY BUY ONE?
Either because you hope to improve aerodynamics and downforce because you believe it will benefit you, probably mostly on track days. Or as a cosmetic improvement which makes your car look more purposeful and aggressive.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FRED_HeadOn.jpg&hash=21953492b30f0e6f2f4c61d60875401a216b2938)
^ Before OSIR carbon fog panels were fitted.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FCarbonfibre%2FRED_29Mar09.jpg&hash=cb392f10a2f90e21e50ddcdfb72c2a2c56ed85fb)
^ After OSIR carbon fog panels fitted.
WHY BUY AN OSIR SPLITTER?
Probably primarily for cosmetic reasons as I have seen no hard data to support there being any real aerodynamic or downforce advantages. That's not to say that there aren't any advantages but just that any claims are scientifically unproven at this moment in time. But neither have I seen scientific data to prove the effects of other aftermarket splitters for the Mk5 GTI.
It has to be said that cosmetically the OSIR splitter is the least aftermarket (none VW product) in appearance currently on the market for the Mk5 GTI. I say this because the shape and ducts blend with and match perfectly the styling of the ex-factory GTI front. Refer to Audi A4 to RS4 frontal styling differences to see the equivalent. OSIR's aesthetic design has been very well thought out, but that is Riso's strength as a designer. He was involved in some of the Mk5 American Thunderbunny styling exercises for Volkswagen and is well respected.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FOSIR-V3-splitter.jpg&hash=4bf2a958dd2e3b5676d1da7e33221b05e536ee16)
^ 2-part OSIR without centre section.
The first OSIR splitters were fibreglass but the current V3 is PU plastic, made of the same chip resistant material as the factory bumper. My professional bodyshop tells me that fibreglass is much easier to repair and even I have found I can successfully repair mine.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2Fprimer_offside.jpg&hash=76c6fb9ef4aac1b76b1022e045f7fa1e2f7366e9)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2Fpaint_nearside.jpg&hash=04a145cd15441d726aeefcc1aa166e565fb6c758)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2Fmasking.jpg&hash=8f82289097982021c0d0e5be7ff452ea3ae619f9)
^ Masking is the key to a good finish. By the way, a solid foam floor pad is invaluable for working comfort.
There are options available for the central splitter section: Two shapes in either carbon or plastic primed for painting.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FOSIR-DF1-centre.jpg&hash=639fed399731f9bb8e817a387232c5a831ca7d6c)
^ DF-1 centre section.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FSplitter_old.jpg&hash=1cc61a1883e7df96aa58669c5b19dbdf19feae68)
^ DF-1 centre section not easily visible when fitted.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FOSIR-DF2-centre.jpg&hash=e4e206684b932d1fbb2218e1bff867a949f5b9bc)
^ DF-2 centre section. Works as a functional splitter with an open back. Visible.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FMods%2FPUsplitter_1423.jpg&hash=178223a443720be45695d0536df1386456708c1c)
^ Version 3 PU splitter showing how the OSIR components fit together.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FMods%2FRED_1440v2.jpg&hash=0535f41b47e64ea61f9cdc641bfa60255882cbfe)
^ April 2012: PU version fitted to my car.
ALTERNATIVES:
- OEM Edition30 or Votex style: The splitter is moulded in and so air only feeds under the floor pan as the OEM GTI.
- Volkswagen Racing: Primarily functional. Black plastic but can be painted but will need much chip maintenance if painted.
- Reiger: Looks identical to the VWR but reputed to be less strong. Thoroughly tested and frequently broken by our very own Joe.
- Abt: Very fussy design and deeper than any of the others.
- There are others but mostly over designed and fussy in my opinion.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FMartin_VWRsplitter.jpg&hash=accd4049f6ed8bcdaef2b31016bb2b52b83885e6)
^ Volkswagen Racing splitter/spoiler.
SOURCING:
The TTshop Bedford are OSIR's officially appointed European distributor and give good aftersales support.
Web: http://www.ttsroadsport.com
Phone: 01234 855 555
Price: Liable to fluctuation dependent on currency exchange rates. Nothing from OSIR is cheap.
INSTALLATION:
A few screws and some wiggling = Easy. Best done on a ramp or lift for convenience.
PLUS POINTS:
- The inlets feed directly in line with the wheel arch openings for brake cooling. Hose ducts could be added if desired if you are a bit of a hardcore trackie.
- Stylish and purposeful in appearance.
- Except to the cognoscente, looks OEM, or at least looks like a factory option and suits the OEM side valances if colour coded.
- Very easy to repair if fibreglass. I don't have experience of plastic repairs - Joe?
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FCarbonfibre%2FCFfogs3.jpg&hash=05f8148d637cc9c07d6070d9672c6b413a1c819f)
MINUS POINTS:
- If combined with low suspension, road clearance becomes more limited and indoor car park ramps unapproachable.
- The DF-1 centre section will only be visible to baby bunny rabbits in their dying moments. The more visible DF-2 will decapitate them with that slicing leading edge. The blood and guts will at least exit out the back instead of remaining lodged ready for you to clean up. If in carbon, the DF-1 is a waste of money as it is hardly visible - Anyone want to buy mine?
- No scientific proof of aerodynamic performance available. But no proof to back claims from the rival products either.
- Obliges you to consider and probably change the colour, or style, of your side valances.. And then your rear spoiler. Which all adds to the overall expense. It's Slippery Slope time.
- It will not work as a snow plough. In fact it's asking for trouble as I later found out from hard ice pieces.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FSnow_RED_Askers1.jpg&hash=783417810bf6d50e3794d18327b29b53c87687c1)
SUMMARY:
I think I am currently the only one on this forum with an OSIR splitter fitted. I don't know what that tells you! There is a school of thought which says that Volkswagen's highly trained and experienced engineers and designers applied considerable time and expertise in evolving the OEM production car and that others should know better than to modify or interfere with the results. However, whereas their efforts should be greatly respected, their production solutions must meet a very wide range of criteria across a number of territories each with their own sets of very strict rules. And then there is production economics and the need for financial profit. The results can only be a degree of compromise and the individual car owner must make up his or her own mind whether to and what to modify.
My decision to modify the front end was essentially for cosmetic reasons initiated by my strong dislike of the OEM Ford Ka-like black plastic rear bumper which looks particularly naff on a red car (in my opinion). My desire to better hear the engine and the consequent purchase of a Milltek exhaust meant a colour coded aftermarket rear needing to accommodate quad pipes. This was done long before the Edition30 was launched, so then meant colour coding the sides, which in turn led to the question of front treatment and my choice of OSIR splitter which I instantly liked. You can see how easy it is to slide down the slippery slope of modifying.
Negotiating speed bumps is very rarely a problem - I just have to go dead slow, like everyone is supposed to, and annoy those following me. But those same people get annoyed when I stick to 30mph in a 30 zone and subsequently wonder what's going on when I suddenly boot it on arrival at the NSL sign, aka the GLF sign (Go Like Feck!) and usually leave them as smalls dots in my rear view mirror. As already said, I don't even bother entering indoor multi-storey car parks. Such compromises are largely due to my low suspension setup but that has been done professionally and delivers awesome handling which gives me great pleasure. It's a trade-off I'm very happy to accept.
I think it's supportable to say that the side inlet slots must improve brake cooling. Any aerodynamic or downforce advantages are incidental if indeed there are any. It would be nice to know of any aero benefits but I am confident no harm is being done and my car is still stable at full maximum speed in the 130-140mph (GPS) range (driven on German unrestricted autobahns).
The bottom line is that I still love the look of my OSIR splitter and the way it's in visual harmony.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FRR%2FRR_TshirtGolfMod.jpg&hash=c5573bc81fbc453f85b4c1db6523c7b8b7edd949)
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I think I am currently the only one on this forum with an OSIR splitter fitted. I don't know what that tells you!
Probably the only flaw in the entire review! :signLOL:
mojo has one too I believe. Or that's what he told me.
Did you repair it yourself? Quite impressed given that you tend to avoid monkeying around like that.
How much of a drop could you get before it becomes impossible to drive up indoor carpark ramps?
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^^^^
Yes, I repaired it myself but started off having guidance from Simon at VWR:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FRED_INK%2FUnderConstruction.jpg&hash=172ee6030bddf2a03ccf2dac5409bfda444c8e2c)
I must admit that I quite impressed myself doing it.
How much drop before indoor car park ramps probs? - Depends on the individual ramp cos some are vicious, so could be a problem on a few even with oem drop. It's the GTI's relatively long frontal overhang from the front wheels which doesn't help.
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as ever RR :notworthy:
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you can add me to the list of "haves" as of first week in may wooohooooo
nice review RR as usual!
matsu
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you can add me to the list of "haves" as of first week in may wooohooooo
nice review RR as usual!
matsu
....It'll be nice to see some pics of yours in this thread in due course. :drinking:
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Will do boss!
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:happy2:
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they look great the spitters
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they look great the spitters
I Don't like spitters! :laugh:
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they look great the spitters
I Don't like spitters! :laugh:
....Yeah, most of us prefer swallowers :evilgrin:
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lol diffuser then ?
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Where you resprayed it robin...was that with a can of VW tornado red, followed by a coat or two of lacquer?
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Where you resprayed it robin...was that with a can of VW tornado red, followed by a coat or two of lacquer?
....Yes but I haven't bothered to lacquer as well or I would have to spraycan the whole splitter instead of just where repaired.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2Fprimer_offside.jpg&hash=76c6fb9ef4aac1b76b1022e045f7fa1e2f7366e9)
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Thanks Robin :) thats cleared that one up for me!
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^^^^
Surely that doesn't mean that you're thinking of getting an OSIR splitter!?
I like the Ed30 ones and you can get a carbon 'centre lip' or wrap it. I'm very happy with my splitter in spite of needing to repair it a couple of times a year and having to be extra careful on speed bumps and not being able to risk indoor car parks. OSIR's later version is plastic but I reckon that my fibreglass one is easier to repair?
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I had a good look, but no im not planning to get one :signLOL:
More so, was planning to give mine a quick blow over as its more white than red at this point in time!!
Fibreglass is generally easier to repair, as with plastic, it has to be plastic welded which can be quite destructive if not done correctly.
I have contemplated carbon wrapping the centre section on mine...might get some to try it and out see what the finish is like.
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^^^^
Gloss black vinyl wide centre section would look good too - Would match the piano black nose and B-pillars. Carbon vinyl is very good but rather matt. IIRC Saint Steve once had his wrapped.
Ta about the repair info, young Will - Am now doubley glad I got fibreglass. :drinking:
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APRIL 2012:
Well, although happy with the fibreglass version I don't have ramps etc to make repairs easy and so I bought the PU version I was kindly offered by RoMocop. I'm hoping that it will flex more and be less susceptible to damage than the fibreglass one. The problem is not with it being fibreglass but with my car being so low and therefore easier to damage.
I have updated my original review.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FMods%2FRED_RedDevil.jpg&hash=50be2034679a8066c1e9f1fec47d179a90c99cd1)
^ OSIR V3 PU splitter with DF-2 carbon centre fitted April 2012.
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Really like the look of this splitter and hoping to be getting the V4 this year, as alot of people are getting the edition 30 splitter.
Your car looks :drool:
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I like the fog light covers,what colour ate the fibre ones come in??
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I like the fog light covers,what colour ate the fibre ones come in??
....The fog light (LED DRL's in my case) panels are carbonfibre but you'd need to check out OSIR's web site to see what's currently available: http://www.osirdesign.com/
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i like the racing splitter, where can you get this from?
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i like the racing splitter, where can you get this from?
....Do you mean like this one?:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fneilmelvin%2FBuild%2F8-4.jpg&hash=ef4e22e4ada42b5840c6bf99ea167aa4905d2fc9)
Rieger: http://www.rieger-tuning.de/shop/article/details/artno/00099727
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i like the racing splitter, where can you get this from?
....Do you mean like this one?:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fneilmelvin%2FBuild%2F8-4.jpg&hash=ef4e22e4ada42b5840c6bf99ea167aa4905d2fc9)
Rieger: http://www.rieger-tuning.de/shop/article/details/artno/00099727
No the one on the red car, the thick deep one
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^^^^
That red Leon belongs to Tfsi_Mike. PM him for info.
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top review and a cracking looking car :pomppomp: :jumpmove:
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Got mine on now
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ff204%2FShabba168%2Fea83cc14.jpg&hash=85c64e56fe345f445abc7f904a912fee46bb98d4)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ff204%2FShabba168%2Fa9597bc5.jpg&hash=bdc7dcdf91cdb02b178a121c576c6261f4272cc4)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ff204%2FShabba168%2Fdbac74f8.jpg&hash=6d32c7ce36c08b34f3bdf13325f0bc715a550bcd)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ff204%2FShabba168%2F23c80c05.jpg&hash=f1db14b39834855a9297b95b1d8b3d2735d8eb13)
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Ff204%2FShabba168%2F283449a3.jpg&hash=cdc33ce93535d5c58fc0fbe7e5baf0a7ad4fc39f)
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Looks ace :happy2: The carbon sets it off nicely. Got mine sitting in the spare room while i wait for my sideskirts to arrive :sad1:
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^^^^
Great, Dan! :happy2:
That brushed up well, especially the carbon [this used to be my old OSIR splitter, folks].
Suits the car in Steel Grey.
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How does the removable center bit stay in place? i have lost the screws/bolts to hold them in place and picking the car up tomorrow, the 2 center bits i have are away getting wraped so i cant see how they hold in place. Has anyone got a picture of them?
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How does the removable center bit stay in place? i have lost the screws/bolts to hold them in place and picking the car up tomorrow, the 2 center bits i have are away getting wraped so i cant see how they hold in place. Has anyone got a picture of them?
....Hopefully this pic will help. Otherwise, if you ask me questions referring to this pic I may be able to help you further.
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2FRedRobin_05%2FMods%2FPUsplitter_1423.jpg&hash=178223a443720be45695d0536df1386456708c1c)
^ The two halves (yellow) of the main body slot and lock together - They are laid on the ground upside down in this photo.
^ The centre piece (black and shown right way up) then bolts through the slots you can see in the yellow main body when it's assembled into one piece.
I'll find a pic of the sides and upload it if you need more info.
Here's another pic which may or may not help:
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fdaz.co%2Fmedia%2Fb308%2FRedRobin_05%2FSplitter_undersideJPG.jpg&hash=17453e5a6017a392f43481ee299293fb698e738f)
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Thanks RedRobin that helps alot. I guess i can just use some other bolts that will fit to hold it on place. Is it hard to change the center section without removing the whole splitter?
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Thanks RedRobin that helps alot. I guess i can just use some other bolts that will fit to hold it on place. Is it hard to change the center section without removing the whole splitter?
....Always a pleasure to help if I can on this forum :grouphug: and thanks for the Thank You :drinking:
Yes, I'm confident bolts can be fairly easily found but I don't specifically know what threads they are etc. The whole assembly is pretty quick and straightforward such that my VW dealer's bodyshop did mine (and prep and painted it!) for free while they did my wings rust repairs :notworthy:
Which version is yours? Earlier fibreglass version or PU plastic? Post a pic here when done :happy2:
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.
By the way, when fitted, don't expect a perfect central join line between the two (yellow in my pic) sections. But when you start looking that closely on any Golf you'll see lots of uneven or imperfect body section join lines.
The centre piece helps to lock everything into a more rigid whole.
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Thanks RedRobin that helps alot. I guess i can just use some other bolts that will fit to hold it on place. Is it hard to change the center section without removing the whole splitter?
....Always a pleasure to help if I can on this forum :grouphug: and thanks for the Thank You :drinking:
Yes, I'm confident bolts can be fairly easily found but I don't specifically know what threads they are etc. The whole assembly is pretty quick and straightforward such that my VW dealer's bodyshop did mine (and prep and painted it!) for free while they did my wings rust repairs :notworthy:
Which version is yours? Earlier fibreglass version or PU plastic? Post a pic here when done :happy2:
Not a problem :happy2:
Hopefully i will get the two center bits back next weekend so i will have a search to see what bolts will fit. That was pretty nice of them.
My version is the V4 and made of PU plastic. Will be sure to post a pic as i dont think i have seen a reflex silver one on here yet :grin:
I have seen a small gap in all the pics i have seen of the splitter but doesnt worry me to much.
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^^^^
Yes I was thinking exactly the same about yours being a silver - It will look the part, as it does on Shabba's Steel Grey car. I think I was the first in the UK to fit the OSIR front splitter to a Mk5 GTI and I chose it very much based on thinking that it looks OEM+ rather than stick-on aftermarket body kit. The vents line up with and match the GTI's foglight panels.
I can't see from your sig pic whether your side valances are the original black or have been colour coded, but if still black, I wager that you'll be wanting to colour code them so that they blend in better with your OSIR front splitter when viewed from the side. Then you'll be probably looking at your rear valance options for the way they look with the sides :grin:
Do you have a build thread or a member's ride thread on the go? I may even have posted in it but forgive me for not remembering.
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^^^^
Yes I was thinking exactly the same about yours being a silver - It will look the part, as it does on Shabba's Steel Grey car. I think I was the first in the UK to fit the OSIR front splitter to a Mk5 GTI and I chose it very much based on thinking that it looks OEM+ rather than stick-on aftermarket body kit. The vents line up with and match the GTI's foglight panels.
I can't see from your sig pic whether your side valances are the original black or have been colour coded, but if still black, I wager that you'll be wanting to colour code them so that they blend in better with your OSIR front splitter when viewed from the side. Then you'll be probably looking at your rear valance options for the way they look with the sides :grin:
Do you have a build thread or a member's ride thread on the go? I may even have posted in it but forgive me for not remembering.
Yer we have got red and grey and soon silver. It does look OEM and doesnt look as deep as other so i can so lower on my coilovers when i get them fitted. They arent painted in the sig pic but i have new rieger side skirts going on atm. (was posted in recent purchases where there was confusion to wether they were real carbon or not) and as for the rear i have gone for an R32 rear which is smoothed (was vicks) and have got an R32 Blueflame style cat back.
This is my build thread. Not alot there because i moved alot over from my GT TDI.
http://www.mk5golfgti.co.uk/forum/index.php/topic,48705.0.html
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bolts are M5 roughly 20mm long.
My center join meets really well. Took half hour trimming the mounting points on the bumper to get it sat just right.