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Discussion Starter · #1 · (Edited)
The objective of this post is to share with my friends from DC the journey I have undertaken to make my 2008 C6 Z51 Corvette compliant with current European specifications. I purchased this car during my 3 year expatriation to New York (2007-2010) and it had to be compliant before my return to France as Corvette parts are extremely difficult to come by in Europe.

Before I embark on this literary journey, I have a small, albeit important, disclaimer:

First, and foremost, I want to be crystal clear here, I am not expert in anything and bear no certifications what so ever in any domain related to vehicles, regulations and so forth. FWIW: I work in the IT department of a bank.

Secondly, this is my only car, I need it to go to work. So this project was a weekend only project and the car had to be operational come Monday morning; as a result it took more time.

Now that being said, let's get back on track here :smack

From a car regulations perspective there are mainly two regulations in the world: US regulations and EURO regulations (aka ECE Regulations).

The EURO regulations have been adopted by the United Nations and are the de-facto standard throughout the world; except the USA (and Canada to a certain extent).
The most significant difference between the two regulations is related to the lighting, in particular the shape of the light beam. The EURO beam provides more light to the side walk, which allows the driver to see pedestrians more easily, and generates less glare to oncoming traffic. My interpretation of this difference is that Europe is more densely populated than the USA (which is probably also why Europe is more stringent regarding noise emissions).
Interestingly enough, from a pollution perspective, the USA is more stringent.

Some countries accept the US regulations, such as Canada, but all accept EURO regulations - except the US. Although Canada is more tolerant it requires some local adaptations for an ECE compliant vehicle.

Anyway the core differences are the following:

  1. Headlamp washers: compulsory for HID lamps in EURO regulations, optional in the USA.
  2. Self levelling mechanism: compulsory for HID lamps in Europe. Actually the specification requires that the projected beam remain within a certain area, irrespective of the load in the vehicle.
  3. Lighting colour differences:
    • Europe: turn signal is orange (mandatory), DRL is white (when present). DRL will become mandatory in the near future, 2015 I believe.
    • USA: turn signal is orange or red (rear only), DRL is white or orange.
  4. Rear fog lamp, red, mandatory, distinct from breaks and turn signals. Distinct means at least 3 inches from any other light.
  5. Rear side lamp markers are red in the USA, orange in Europe.
  6. Front side lamp markers are orange and self lighting in USA. Europe just reflectors, no lights (well there are but in the headlamp, not on the side). Europe calls them park lamps, so people can see your car when parked in a not to well lit street.
  7. Dynamic and static noise must not go beyond a certain limit (74dB in dynamic testing).

I decided to undertake this task using the divide and conquer strategy and easing it over a period of two and a half years, from the easiest task (good for moral :D) and ending with the most complex:

  • Headlamps and pressure washer system.
  • Side turn signal repeaters
  • Car Noise reduction (in a separate thread)
  • Tail Lamps (requires BCM programming or electronic skills)
  • Engine Noise reduction (more on this later) - easy to do just for the certification.

To be accurate, I started this project in February 2008 and finished on October 25th 2010.

Post Project Termination Notes:

I would like to add that there have been recent regulation changes, in particular the rear view capabilities. For this reason, the new Grand Sport sold in Europe has different side view mirrors.

Here is the Euro Grand Sport (yuck if you ask me):

Compared to the US Grand Sport:


Premium Member
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Discussion Starter · #2 · (Edited)
Headlamps and Pressure washer system.

ECE Regulation 48 requires that headlamps be kept free of debris in order to not blind on-coming traffic from unwanted glare. This is mandatory for any low beam that is beyond 2000 lumen - this includes HID and some high power halogen units.

In the USA headlamps cleaning systems is permitted but not mandatory - so if you are ordering your Corvette, you may be able to ask for them: they are to my knowledge installed under the CE4 RPO.

There are two possible mechanisms to clean the headlamps:

  1. A small motor-driven wiper blade - e.g Volvo S40.
  2. A high-pressure sprayer - e.g Corvette.

The headlamp washer system in the Corvette is composed of the following main parts:

  1. Headlamp washer high pressure nozzle for each headlamp
  2. Covers to hide the nozzles when not in use.
  3. Pipes for the pressurized water
  4. More pipes for the pressurized water
  5. Reservoir for European edition (not acquired, fixed the existing one)
  6. High pressure water pump

The headlamp washer system requires a dedicated wiring harness (the one from the famous CE4 RPO). This harness is not easy to get and requires patience - from order to delivery - I might add this is the case for any European compliant harness/part.

I specifically ordered the CE4 harness that had the European connectors for the Headlamps. The reason is that the EURO projected beam is different from the US projected beam - as such it is necessary to replace the Headlamps.

For reasons I do not understand the connectors for the European Headlamps are not compatible with the US headlamps, it is therefore necessary to replace the wiring harness. In my mind this kills cost reduction initiatives through scale ... and it also made my life harder because removing the cable is not an easy task.

Here is a photo of the parts received (note duplicate parts not on photo)

As you can see, some painting will be necessary, the headlamp covers are plastic black (lower left of photo) :thud:

So I ordered the GM touch up paint (three cans) and did some "touching up"

Note: ECE regulations also require self leveling HID optical blocks so as to not blind oncoming traffic due to loads that change the dynamic of the vehicle. Particularly when the trunk is loaded, the front of the car goes up. I have encountered many people who state that the Corvette will fail and get rejected because the Corvette does not have self levelling headlamps and is therefore none compliant.
This statement is incorrect: the Corvette is compliant and is sold in Europe without self levelling headlamps.

The reason being one of the following:
  • Suspension is so stiff any variation is within specifications (Z51 and Z06)
  • Magnetic Selective Ride controls the height of the vehicle.

As such, in Europe, the only Corvettes sold are the Z51, Z06, selective magnetic ride or the Grand Sport.

The specifications do not state the lamps have to be self levelling, the regulations state that the variation of the projected beam must be within a certain zone.
It is perfectly compliant if the car stabilizes it self via a dynamic suspension mechanism or if the suspension is so stiff there is no variation.

Looking at the hardware closer:

The pressure washer nozzle with the cover (requires painting) and the high pressure pump (which is significantly larger than the windshield pump)

Pressurized water hose

Mounted it looks like this

Here is a picture of the harness and all the EURO components attached to it:


Premium Member
4,611 Posts
Discussion Starter · #3 · (Edited)
Test Before Breaking Everything!

Before stripping the car and making holes, a small test to ensure that the hardware is functional is a good idea. The reason for this is that parts can get broken during the shipping :thumbsup:

So, as the electrical system is going to be impacted, I started by disconnecting the battery (minus first then the positive), which has a potential, rather annoying, side effect: the windows have to be re-indexed ... if you disconnect the battery too long.

Here is the battery of the Corvette:

Be careful, the red cable has this annoying feature of moving back into position, so if you put the cables like this:

They will fly back whilst you are busy on the other side of the car, I ended up dumping the + cable between the engine and the battery to ensure that it never came back to the terminal.

Before taking everything a part you need to have a clean work space and some things to hold nuts 'n bolts. I bought the 10$ cheapo magnetized receptacle that is cool:

Ok, now it's time to remove the existing harness at it's attachment point: that is to say the fuse box and to put the new harness in it's place. The point of anchor is called the X1 connector.

Here is the fuse box that holds the relays, and without the cover

Disconnect the cable that comes to the fuse box, which effectively powers the unit and loosen the 4 bolts. These bolts hold the underlying connectors (X1 to X4) and can't be completely removed unless the top part of the fuse box is separated from the bottom part.

You will find all around the fuse box, small latches that need to be removed in order for the fuse box top to come off.

So unscrew everything and remove the X1 connector (corresponding to the harness that goes to the headlamps and washer system), and pull out the X1 connector (easier said than done, damn thing :nuts:).

You should have something looking like this now:

So now we have disconnected the old harness - but not removed it from the car - we can connect the new harness. Here is a photo of the X1 connector, new harness (T90 + CE4):

and here is the new X1 connector in the fuse box, along side the existing, disconnected X1 connector:

Next step is connect the ground of the harness, very important step, here is an example of a ground outlet:

As for me, I didn't spend 24 hours connecting them, I put all ground outlets to the same grounding bolt up front for the test:

Once that is done, you can connect the new hardware and test it out:

Before testing, make sure there aren't short circuits in the system, you will cry your eyes out if there is a short ... with all the electronics in these cars, shorting anything will end up being extremely expensive ... :smack

Here are some photos

You can test the lights with the stalk at the steering wheel but don't start the car for this test because a lot of systems have been disconnected.

For now, the headlamp washer pump can't be tested because it requires programming the BCM.​

There is also a side turn signal repeater that is not on the photos but was installed and tested.

As I mentionned previously, the European headlamp has a park light instead of having a lighted side reflector. The photo hereafter shows the switched on park light:


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4,611 Posts
Discussion Starter · #4 · (Edited)
Jacking The Car and Removing The Panels.

Well now that I am sure that everything is working, I was able to do quite some work as this past weekend was Columbus weekend.

First things first, mounting the baby safely (thanks to grumpy for the tips :thumbsup: )

Loosen the wheels, jack the car and put permanent jacks at the recommended jacking locations:

In order to remove all the panels of the car, which is necessary for:

  • Removal of US Headlamps and installation of Euro headlamps
  • Drilling the front bumper to install the pressure washers
  • Drilling a hole for the repeater side turn signal

The front wheel liners (front and back of the front wheels) have to be removed.

These liners are held by simple pins that expand like a classical wall plug, here is a photo of one that has been removed, and a photo of a plug just before removal from the car

In order to remove the central piece, I used two flat screw drivers, I know some use wire cutters but I wasn't successful with the wire cutters.

Of course there are a couple of screws to remove here and there, here is the rear liner of the front wheel removed. We will see it again when the time comes to take out the washer reservoir and make a hole in it.

Now with all the screws and plugs that are going to be removed I put everything into the yoghurt pots that my kids eat and put labels on them so that nothing is mixed up, each to his own though ...

The front liner of the front wheel is more painful to remove, I understand that the manual states to remove each part individually. However I find that removing both parts together in a single step is way more easier and less of PITA

In the first photo, on the left there is the front liner and on the right there is the rear liner of the front wheelhouse.

Once the liners have been removed, the body panels need to be removed, in the following order:
  • Front bumper
  • Left and right wing panels

Removal of the front bumper is relatively easy and pretty straight forward, the trick is finding the right screws and plugs to remove :D

Normally at this point, if you have followed the steps indicated above, there should only be 6 screws to remove from the top of bumper (in the engine compartment), 2 screws below at the bottom (the other screws hold various parts together because the bumper isn't in one part) and 4 plugs.
The 4 plugs are located at the air inlet, a pair being on each side of the inlet, as illustrated in the photo hereafter - plugs already removed:

Here is the picture of the bumper that has been removed, you can see in the bumper the various parts held by the other screws:

Please note that there are cables that require removal in order to take the bumper off. As it is extremely simple and evident when you remove the bumper, I have skipped these details so as to not overload the explanation. As an example, the cables that power the fog lamps have to be detached prior to removing the bumper. I didn't know this ahead of time and did it as I progressed.

Next panels to be removed are the wings, very easy from a theoretical standpoint, however there is one screw that is a nuisance to remove. That screw is located just in front of the door hinge, you can see it in the following photo, it is just below the top front hinge:

Additionally, there is one screw that is hidden below the rubber at the level of the wind-shield:

Be careful: the wings are mounted with 3 different screw types, depending on the type of material the screw goes into. Try not to mix the screw types, you will see when you unscrew them, they are noticeably different. The major difference being the thread.

Once you have removed all the screws, the wings can be removed quite easily. Bear in mind that there is a small pin on the top of the headlamps, so you need to raise slightly the front part of the wing before removing the panel.

This is how the car looks like at this point:


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Discussion Starter · #5 · (Edited)
Replacing the Headlamps - part 1

Step 1: Taking note of the beam position

At this point in the operation, it is a good time to take note of the headlamp positions - because once the US headlamps have been removed, it will be tough to guess the correct position. :laughing:

Unless you have the appropriate material to set the lights according to regulations, this wasn't my case.

First from a bolt perspective, there are 3 bolts under the headlamps that have a lot of leeway, it is a good idea to note the positions of these bolts with a marker/pen. Technically you can position the headlamps later on down the road, but I suggest keeping note of the position of the initial headlamps.

You can mark the projection of the headlamps against the wall - or a fixed element. In my case as I don't have a clear wall, I put two planks and noted the beam against the planks (don't forget to note the position of the planks, learnt the hard way :laughing: )

This is what I have done in my case, don't forget to mark the high beams because the Euro high beams have to be set:

Note: those who have the GM Service Manual (one of them is on the photo behind the planks), they indicate how to set the headlamps. However, in order to correctly apply the technique defined by GM the wall has to be perpendicular to the floor. My garage floor is inclined and the wall is dubiously vertical ... :smack

Furthermore, this technique has it's limitations because the form of the projected beam in Europe is different from the USA. When you get to France/Europe, you will need to get the headlamps positioned according to European specs.

The difference between the beams is clearly distinguishable, the shape is night and day in difference of form.

Step 2: Replacing the electrical harnesse

First and foremost, please be careful: this electrical harness commands many important functions such as the impact sensors. As such don't rip out this stuff like a red-neck :thud:

Before removing the cable, you need to remove the battery. Be careful, it's quite heavy and my index has witnessed the weight and lack of space around the battery. :WTF

Here is a photo without the battery in the car:

The next thing to do is detach the fuse box completely because the harness that is to be removed goes beneath it.
The fuse box is held by 3 screws, two on top and one hidden attachment screw for the fuse box that is located in the front right wheelhouse.

Here is a photo with the screw that has to be removed, is has been slightly unscrewed so that you can see it and another with the box completely detached

From a personal standpoint, I completely removed the fuse box from the car so as to have more working space and be sure that I don't damage the top components, mainly constituted of relays.

Here is the bottom of the fuse box with the harnesses that are located in it:

Once you have done that, you will need to remove the air intake in order to be able to the cable out, and I suggest also removing the plastic on top the radiator:

In the event that you are clumsy like one of my friends or just happen to have large fingers, I suggest removing the radiator pipes too because the harness is located below them. Accessing the attachments points of the harness is going to be a finger cutting experience. I am rather lucky to have fine fingers so I took my chances with the pipes in place.

Side note the harness at the level of the radiator is attached to the hood release cable, don't forget to the attach them together later ... :laughing:

Pulling out the cable is rather easy, it takes a bit of time though ...

Based on the layout of the cable within the engine compartment, the easiest way from my perspective is to pull it out by holding the X1 connector and pulling.
This is a figure of speech, if you hold the X1 connector and yank it you are sure to break everything.

Once that is done, this is how the engine compartment looks like.

By the way, large images are available, just substitute the medium keyword by large in the image link.

The new cable was put in by doing the reverse operation of the removal procedure. Do take note of what goes where when you yank out the harness so that you reconnect everything later on.

Before removing the SIR connector you can practice on the new harness because there is a safety mechanism to prevent unintentional removal.

Premium Member
4,611 Posts
Discussion Starter · #6 · (Edited)
Replacing the headlamps - part 2

Step 3: Installing the headlamps

After having installed the new harness and connected the existing components, such as the SIR sensor, the first thing to do is install the new headlamps. This is an easy and straightforward process if you have adequately marked the position of the previous headlamps:

Contrarily to the US version, the Euro headlamp high and low beam need to correctly set. This is done via turning the screws on the inner side of the headlamps (the side facing the engine).

These screws make the projected beam go up or down but not side ways. The side way converge or divergence of the beam requires loosening the bolts that hold the headlamps.

In my case as I not noted the position of the beams and the bolts on the car, it was an easy process.

Step 4: Installing the repeater turn signals

The next thing to do is install the side turn signals, and this will require some drilling in the side wings.

I put some masking tape to protect the paint and reduce chipping. The tape also helped me mark the layout of the lamps. I based myself on a photo of Euro vette to position the lamps, as shown on the picture hereafter:

The dimensions/positions are marked in mm and not inches, sorry :D-

Once the hole drilled, I glued the side lamp turn signal support, not the lamp per say, just the white plastic support. I also put in some silicone to make it water proof. Don't know yet if it is a good or bad idea, but it's done.

Now it's time to put back the side wing onto the car and connect the electrical harness.

The two photos show the side repeater turn signal lamp off and on, as you can see it is not very visible:

My personal impression is that it is truly beneficial at night, I have doubts of the practicality of such a small lamp in the daytime.

Et voila, the front part of the lighting is done. Of course, it is necessary to have the beams of the headlamps adjusted before claiming victory!
The front part of the Corvette will be finished from a mechanical pespective once the headlamp pressure washer has been installed.

Premium Member
4,611 Posts
Discussion Starter · #7 · (Edited)
Installing the headlamp washer system

Installing the headlamp pressure washer system is very simple from a mechanical perspective:

  1. Install the high pressure pump onto the reservoir, including the electrical harness connection (comes with CE4 RPO harness)
  2. Install the high pressure nozzles onto the bumper
  3. Install the high pressure water pipes from the reservoir to the front of the car
  4. Paint the nozzle cache to match paint of car
  5. Put bumper back into place.

Step 1: Installing the high pressure pump

The first step is to install the headlamp washer pump on to the existing reservoir.

It's a very simple process, you empty out the reservoir as you can see on the photo hereafter:

Be careful there's about 2 gallons of liquid if it's full, don't get stuck on a shortage of milk containers. Clean them first though :laughing:

To remove the reservoir, you must start by removing the top plug that holds the neck of the reservoir. I just pushed the pin out from the wheel house. Then there are a couple of bolts to unscrew.
To pull it out you will need to remove the black cap on top, otherwise it won't go out.

Once it's out, put it on a nice stable table and drill a hole for the headlamp washer pump, in my case I took a 13/16" drill bit:

Don't forget to clean out everything in order to make sure that you get a clean reservoir :D

Once that's done, you can put back the reservoir back in and reconnect everything

Before closing up everything, I suggest filling up the reservoir to ensure there are no leaks in your circuits. You can also take a 12V power supply and connect it to the pump (which I ultimately did to ensure that were no leaks).

Step 2: Installing the high pressure nozzles

Next step is to install the headlamp washer system on the bumper, in order to do that all you have to do is drill some holes in the bumper just below the headlamps.
You should get something that looks like this for the hole, and with the headlamp washer installed:

As for the pipe per say I stuck it in the bumper as you can see on the photo:

I did not fully mount the pipe, which is in fact constituted of three parts. I put the two parts that connect to the nozzles in the bumper and the third pipe I attached to the pressure pump. I joined the pipes once the bumper had been put back into place and I then clipped the pipe firmly into place so that it doesn't move around.

Step 3: Install the high pressure water pipes from the reservoir to the front of the car

This is a very simple and straight forward operation; the pipe runs from the high pressure water pump to the front left pressure washer.

It is attached to the CE4 harness that powers the high pressure water pump, this electrical harness runs along the structural beam that supports the engine and the car.

The CE4 harness has special pipe attachments installed at the factory.

The high pressure pipe is visible in the photos hereafter between the alternator and the over spill reservoir, right next to the new harness:

Here the pipe is dangling at the front end of the car

Here the pipe has been attached to the harness:

Step 4: Painting the nozzle covers

The next step consists in painting the covers, with the base, the color coat, and the clear coat:

Once the paint is nice and hard you can put clip it on, once you clipped them one, you can remove the white tag on the headlamp washers that prevents them from going completely in.
This tag is just a packing/shipping thing, to be removed once installed.

Now it is important to understand that installing the headlamp washer system doesn't mean it will work. The BCM requires programming in order for the headlamp washer system to be enabled.

Step 5: Re-installing the bumper

Now at this point in time the bumper should be installed back on the car and the high pressure piping should be firmly attached to the harness and chassis of the car.

I strongly suggest doing a pressure test to ensure that the everything is installed correctly and that there are no leaks. The high pressure pump is a 12V pump, as such providing 12V to ti's terminals will make it work - be careful not to invert the polarity :)
I purchased for 10$ a connector to do the testing but it is perfectly feasible without.

Installing the front bumper is easy and straight forward - doing the reverse of the removal procedure.

I proceeded by putting into place the bottom part of the bumper into place and finished with the top part. The upper lip is subtle to put into place because it is necessary to find the correct position of the engine hood in order to slip it in.

Anyway you should have something looking like this now:

That is to say a fully installed and euro compliant front headlamp lighting system - from a mechanical perspective. The issue being that in order to enable the headlamp pressure washer the BCM needs to be reprogrammed.

Usually installation of a new component requires a VCI from GM. A VCI is the abbreviation for vehicle configuration index, I think so, and allows you to enable/customise the behaviour of the car. Unless you have connections, my experience is that this is simply not possible.

To my knowledge, in Europe, most people install an Opel headlamp washer that is triggered every time the windshield washer is activated. This is a perfectly legal installation, however it is not how the Euro Corvettes behave.

The OEM Corvette Headlamp Pressure Washer system that has been installed is activated for every three impulses of the windshield washer pump.
For every activation of the high pressure washer system, an initial spray of 2 seconds is followed by a longer spray, with a slight delay between the two.

This washing system is handled by the BCM and it therefore needs to configured in order for the Headlamp Washer system to be enabled.

At this point I would like to draw your attention on an extremely important problem. The turn signals in Europe are distinct from the DRL and as such are not designed to function continuously: they will overheat and melt.

So unless you reprogram the BCM you need an electronic circuit or you need to switch the DRL off during the day time.

Some people have installed the side repeater turn signals because of the looks without reprogramming: this is a big NO-NO here.

It is possible to install a set of orange LED but this requires some modification to the housing. If the incandescent light bulbs are left in the housing it will melt! I know I tried. :lookinup:

However I do not know how reliable and durable the LED will be.

Clearly the front turn signal housing is not designed in the European model to be used as a DRL: the following photo illustrates the differences between the US (metal prong) and the Euro model (plastic prong)

The Euro socket lasted about a month of DD, in US mode, before it got so burnt that the bulbs ceased to function.

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Discussion Starter · #8 · (Edited)
Installing the rear tail lamps.

The European compliant rear tail lamps are different from the US tail lamps for the following reasons:

  • Turn signal lamps have to be orange and distinct from the other lamps
  • The rear fog lamps have to be distinct from the other lamps. This includes a minimal distance from the other lamps.
  • The brake, or stop, lamps have to be distinct from all other lights.

As it is the case for the front lamps, the Euro rear lamps connectors are different from the US rear lamps. This requires purchasing a specific harness or modifying the existing harness.

Step 1: Removing seat and upholstery

In principle the harness that needs to be changed is only in the trunk of the car. Depending on the model and year of the car it may be necessary to change the harness that goes from the BCM.
The BCM is located in the passenger footwell, changing the harness from there requires removal of passenger seat (careful when disconnecting the seat airbag).

In my case, it was necessary to do a little thinking because my seats are power seats. It is mandatory to disconnect the battery before removing the seat due to the presence of the airbag. I only realised this when it was a bit late in the process :smack

There are four bolts holding the seat down, the rear bolts are in plain sight, however the front bolts are hidden by a plastic cache. This plastic cache needs to be taken off.
It is held by a pin just like the interior wheel liners, as you can see on the photo hereafter:

Once the pin is removed, slide the cache towards the front of the car, do not pull it up.

Once the seat has been removed, you will have to remove the carpet. For this you have unfasten the emergency door release and remove the door sill (black plastic thing)

With the carpet removed, the passenger area should be nice and clean. With a clear view of the BCM that is located in the passenger foot well:

A little work around the BCM is required to install the electronics related the rear fog lamp (unless you go the Die Hard route and replace the US stalk with the Euro stalk). This is a little bit technical and at this point, I'm not to sure if it's of interest to the audience.

The Euro stalk is distinct from the US stalk because in Europe the rear fog lamps are commanded indepently of the front fog lamps.

Here is a picture of the Euro stalk:

I did not install the Euro stalk because it requires purchasing the Euro harness from the IPC to the BCM and that costs 2k$.

It is not mandatory to have the front and rear fog lamps being independant of one another; so I connected the rear fog lamps to the front fog lamp command.

Step 2: Removing the rear panel

In order to correctly install the rear Euro harness it is imperatif to remove the carpet in the trunk and the rear panel.

Removal of the rear panel is similar to the removal of the front bumper in the sens that the wheel liner has to be taken out.

The reason for this is that the rear bumper is bolted to the side panels - in addition to being screwed on the top:

Here is a picture of the rear panel, once it has been removed:

Step 3: Replacing the harness

Once the car seat, carpets and the rear panel have been removed, replacing the US harness with the Euro harness is very simple and straight forward.

The rear harness for the Euro tail lamps (T94 RPO) is located at the rear trunk wall. This harness comes from the passenger side of the car, behind the right rear speaker and over the wheel well.

The other part of the T94 harness is attached to the rear panel shown in a previous picture. Replacing this harness is child's play compared to the rest of the things that have been undertaken to this point.

Step 4: Slap everything back together

And go for a ride in the snow :partyon:

In the above photo, the side reflectors are the US red reflectors and not the Euro orange reflectors because the car was still been driven in the US at the time of the photo :D

Actually once everything is put back together, the BCM needs to be reprogrammed so as to take into consideration the changes that have been performed.

From a technical perspective all you need is a Tech2 and the related software. Given the price of the Tech2, I assume that those who have it know how to perform the task. :thumbsup:

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4,611 Posts
Discussion Starter · #9 · (Edited)
Concluding Notes

The conversion of the Corvette to European specifications has been a lengthy and solitary road - the support of my fellow Corvette owners has truly been appreciated.

It has been satisfying knowing that at the end of the day, the job has been done correctly (I have some pretty bad stories from colleagues who handed their cars to "pros"). It has also been for me an excellent opportunity to discover and understand my car to it's fullest - even if there were moments of concern, in particular when things didn't work out very well.

Along the line of learning about the car and it's behaviour, as some may know, I have taken my car to a snow driving school and regularly drive on the snow with it.

Driving the Corvette in Snow

Parting comments:
With respect to the conversion process itself, at one point in time I installed an SCLM - what a mistake. This component is installed in all export Corvettes, even to this day.
This is the worst decision I ever made in the entire conversion process, I strongly suggest never ever installing the SCLM, to the best of my knowledge, it is not needed to be ECE compliant..

I suffered - hence spent money - to revert the installation of the SCLM and get it out of the car.

The SCLM brought nothing but headaches and worries; I really don't understand why it is installed. I know that in Australia it is mandatory to pass the inspection process but, to the best of my knowledge, they are the exception.​

At this point in time the Corvette has been fully converted to European mode without installing any none GM products. All components such as the Headlamp Washer are fully functional, the radio is working in Euro mode.

I wish the best of luck to all those who wish to wonder in this endeavor, it is truly an opportunity to get to know and understand your car :thumbsup:

All my photos are located here:

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In addition to lighting constraints, ECE Regulations also stipulate the maximum amount of noise a car may produce; these noise rules are designed with the pedestrian in mind.

The basic idea is that a car that is driving normally in a densely populated area should not bother pedestrians; such as those having an espresso on the side-walk or just enjoying the view in Paris, after a hard day of work:

So the law is that a passing car, driving at city speeds, should not produce more than:

  • 80dB if registered for the first time before 1990
  • 77dB if registered for the first time between 1990 and 1996
  • 74dB if registered for the first time from 1997 to this day

When not specifically stated, noise levels are provided for a stock US 2008 Corvette C6 Auto Z51 with a 6.2L engine. The dynamic noise test for this car gives 87dB; a stock US Corvette Z06, 7.2L, produces 91db.

Bearing in mind that every increase of 3dB is equivalent to doubling the amount of noise ... that is seriously over the legal limit and a lot of noise to get rid of.

High performance vehicles such as the Corvette have a tolerance of 1 dB in addition to the 1 dB given for lack of precision in the instruments; another 1dB tolerance is given for inclement weather. As such a Corvette can slide through at 77 dB if the inspector is in a good mood.

There are two tests that are performed: static noise measurement and dynamic noise measurement.

Static Noise Measurement:

The static noise measurement is a reference value used to see whether or not the car has been modified since the last legal test. There is no legal limit for the static test, it is a pure reference point for any law enforcement officer doing routine street controls.
The microphone is placed in the axis of the exhaust, at a distance of 50cm (19 inches) from the tip. The engine is revved at 75% of max RPM. There are a few variations of this scenario that are sometimes done but these are not of importance in my mind because there is no limit ... so who cares?

If the exhaust tips are slanted (downwards or upwards) the microphone is placed in the axis of the tips. This was initially defined for trucks but once the maximum noise level was set to 74dB, manufacturers started turning the tips of the exhaust away from the microphone, for the dynamic test, to gain a few decibels.

For example, here is the exhaust of a French car that is oriented downwards:

Instead of straight out exit:

Note: in the case of the Corvette there is a protection, when no gear is engaged, that limits revving at 4 000 RPM. This is noted on the car papers, in my case, it is noted [email protected]

Now this value is used because a LEO can pull you over, ask you to rev at 75% of max RPM and measure the amount of noise your car produces. If it is over the limit officially registered ... you are in trouble ... in the best case you get a hefty fine ... in the worst case, you walk home because the vehicle is impounded. :thud:

Dynamic Noise Measurement:

This is the tough one and where many people have great difficulties.

The test is as follows and executed on normalized asphalt:

  • Car cruises at 50km/h (31mph). This is most common city speed limit (25mph in the US)
  • Start of measurement zone reached. The car goes WOT in third gear (third gear engaged before entering the zone).
  • End of measurement zone reached. End of WOT for the car

The picture hereafter illustrates the general layout of the test:

Are measured:

  1. Exit speed
  2. Max noise produced in the measured zone

The measurement zone is 20 meters long (21.8 yards): so the car goes WOT over that distance.

Two microphones are placed halfway (10 meters from start of WOT), off axis by 7.5 meters (8.2 yards) at a height of 1.5 meters (4 feet and 11 inches).

The most noise the car is allowed to produce at this test is 74dB so as to not inconvenience pedestrians. 74 dB is the amount of noise you have in any restaurant with people talking ... which is to say not much. :WTF

Dynamic noise testing has shown that three elements produce the major part of the noise, in the case of my Corvette:

  1. Car tires
  2. Exhaust noise
  3. Engine noise with air intake

Driving at 50km/h (31mph) with stock GoodYear RF Summer tires inflated at 30 PSI, the car produces 64 to 67dB of sound; the engine at this speed is inaudible. The variation is due to the asphalt type and weather conditions.

Going WOT, the major part of noise increase comes from the air intake and the exhaust.

Noise from the engine and tires can be reduced, as explained here: DIY - C6: Sound and Heat insulation

Some countries within the European zone are more or less stringent on the 74dB sound limit. In France, for a high performance vehicle the limit is 77dB and, unless you have connections, it is stringently enforced.

In Switzerland, there is an additional constraint that is imposed where the Corvette fails: air/fuel ratio on a cold startup. Apparently the Corvette, on a cold startup, has an air/fuel ratio which is too rich resulting in failure of the test.

It is therefore necessary to program the ECM to have a more lean startup in order to be compliant with Suisse regulations. In France I did not have this issue, except for the noise, the car as I converted it, was compliant straight out of the box.

Mandatory Front Tow Hook

I do not know if this a Euro regulation requirement or a French requirement, in any case, in France a car needs to have a front tow hook that can be removable.

I am not sure about the driver behind this requirement, however it is there.

Not having the ability to weld a removable tow hook and at the time I didn't find many solutions, I purchased and installed the Pfadt racing hook which meets minimum requirements.

Pfadt Racing Tow Hook

Since then the market has improved and it is easy to find removable tow hooks. For example: EZ C6 Removable Front Tow Hook.

I strongly suggest going the removable tow hook route if possible as it is a protruding object and the inspector may hassle you.
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