Rear light cluster

[steve1506]

Help please - When mounting the original 2B+ light clusters to the rear wheel arch. Does the face of the cluster need to be vertical when the car sits on the ground so as to meet the IVA requirement. It does not read as clear as for the rear fog light

Steve D

[IanS]

I think that the reasoning goes like this.

There is a mirror behind each bulb that focuses the light to some extent. This focused light should be aimed straight back to increase the distance that the light is obvious.

So my take is that the original light cluster needs to be vertical.

Production car rear light clusters internally make sure that this is achieved even though they appear to be sloped.

 

[nelmo]

I haven't read the IVA manual again but I'm pretty sure there is no requirement for the rear cluster to be perpendicular- I certainly didn't make any effort to do that,  unlike the fog light, and had no issues on the day. 

[IanS]

I am not saying that it has to be vertical, just saying that there is a case for making it vertical so as be seen a bit sooner.

There is IVA and there is see and be seen.

[Derek]

From SVA days....

My rear light cluster was on the wing and passed no problem, the mounting was curved so it would be vertical once on the wing. Like this but not LED

 

My fog light was on the rear panel and the tester allowed me to put a spacer behind it to make it vertical.

 

The good old days.

Edited August 16, 2023 by Derek

[Sparepart]

I have attempted to make sense of the IVA Manual sections 20 - 30. There is nothing about any lamps having to be mounted vertically. The requirement for all the lamps is specified by the "angle of visibility", both horizontal and vertical. Also the lamps cannot be tilted so far that less than 50% of their apparent surface is visible from anywhere in the required angle of visibility. I guess to be absolutely certain a lamp is acceptably mounted one would need some trignometry and a measuring stick vertically at a known distance from the lamp. Mark the horizontal height of the lamp on the stick and the distance above that gives the correct angle. Plonk the stick vertically on the floor at this distance and look towards the lamp from just behind the stick. More than 50% of the apparent surface of the illuminated lamp then must be visible at least from the bottom mark all the way to the top mark. Oh yes, you must then move this stick around in an arc to check that it satisfies the vertical visiblity at all points of the horizontal requirement. This is easy because you can fix the bottom mark on the stick to the bottom of the lamp and just move the stick around keeping the string taught. Sounds complicated ... but a low tech measurement. Oh yes, there is all the other stuff about height of lamps and distance from the sides of the body ... thats easy. The only place I had trouble with the old SVA was the front indicators, on the EXMO the build instructions were to place them on the suspension outrigger below but closer together than the headlights. This position failed the horizontal visibility check, as the nose cone obscured the full extent of the angle (45 dgrees I think). Anyway I was surprised as to how far out of the nose cone sides I had to mount them on stalks. Iv'e seen cars since that must fail this test, my guess is that it was changed as soon as SVA/IVA was passed.

Edited August 16, 2023 by Sparepart
spelling

[steve1506]

Thanks guys for all your comments

Steve D

 

[nelmo]

22 hours ago, IanS said:

I am not saying that it has to be vertical, just saying that there is a case for making it vertical so as be seen a bit sooner.

There is IVA and there is see and be seen.

There's a case for saying, with our cars being so low,  that they SHOULD point upwards. I mean, they are literally 15cm off the ground...pointing back at right angles to the road is great for snails but not Karen in her SUV

I added a 3rd high-level brake light exactly because I felt the standard ones were just too low.