Installed dual Hella horns

[PBNB]

The other day, I went to use the horn and thought for a moment that I was driving a Ford Pinto.

I was given a Hella dual horn set for Christmas and finally decided to install it on the weekend.

The horns are very cool sounding with a (Euro) sound.

Here is a video made by Phil H https://www.youtube.com/watch?v=DYEoiMYjZ0w on how to do this.

 

[Obioban]

My real complaint with the i3 horn is that it seems to have lag, and you can't give a friendly/polite, quarter second "beep beep"

 

[robthebold]

My real complaint with the i3 horn is that it seems to have lag, and you can't give a friendly/polite, quarter second "beep beep"

Yes. I just don't get that. Although maybe not as time-sensitive as braking, why should there be a time delay when honking the horn? It is a piece of safety equipment, after all. The technology for "instant honk" has existed since the squeeze bulb.

 

[alohart]

Although maybe not as time-sensitive as braking, why should there be a time delay when honking the horn? It is a piece of safety equipment, after all. The technology for "instant honk" has existed since the squeeze bulb.

Apparently, the horn button isn't electrically connected directly to the horn as has been true in cars made for decades. Instead, the horn button and horn are connected to a data bus that receives a signal from the horn button which activates power to the horn. Unfortunately, there is a response delay on this data bus that results in the horn not honking immediately when the horn button is pressed. This seems like a poor implementation on BMW's part.

 

[robthebold]

This seems like a poor implementation on BMW's part.

You can say that again. CAN bus is designed to be real-time and prioritized. If the horn has such a low priority that the human operator notices the delay that's a big deal. Parking sensors and collision avoidance and automatic braking go over CAN. So BMW can (that's a pun ) and should make sure response time is instantaneous. I've "requested horn activation" to warn of an impending collision only to have the horn sound after the situation had passed. Yelling is considerably faster, I've found.

 

[Anonymous]

Unfortunately, there is a response delay on this data bus that results in the horn not honking immediately when the horn button is pressed. This seems like a poor implementation on BMW's part.

My horn honks immediately when the horn button is pressed - no lag whatsoever.

 

[robthebold]

Unfortunately, there is a response delay on this data bus that results in the horn not honking immediately when the horn button is pressed. This seems like a poor implementation on BMW's part.

My horn honks immediately when the horn button is pressed - no lag whatsoever.

Well this suddenly got more interesting. Before reading your post I thought we were dealing with a "feature" not a bug. But if there are i3s that don't have the horn lag -- you know, like every other car ever -- this changes things.

 

[vreihen]

I can't tell you what my horn does, since they usually rust away from lack of use in any of my vehicles. Other than the annual test that's part of the state DMV safety inspection, it is dead weight in my cars that sees zero use.....

 

[Anonymous]

Before reading your post I thought we were dealing with a "feature" not a bug. But if there are i3s that don't have the horn lag -- you know, like every other car ever -- this changes things.

https://youtu.be/Cuv4ft81L_c

 

[Sarahandr]

Which kind of Hella horns is that? I can’t figure it out from the video. Is it the Twin Trumpet edition or the Super Tone? I installed a loud marine horn on my X3. Stock horns were not making enough noise when on a highway. I decided to keep them but also to add a separate button for new horns. These are used when I see someone who doesn’t know how to merge properly into high-speed traffic. Now my original horn sounds too weak, so I'm thinking about Hella Twin Trumpet.

 

[frictioncircle]

https://youtu.be/Cuv4ft81L_c

Yes, the first press of the horn button does seem to sound at the bottom of the button's travel.

However, for the following four horn button presses, the horn does not sound until AFTER the horn button is released and has returned to its resting position.

Watch the clip at a playback speed of 0.25x. For presses two to five, the horn button can be heard moving back to its end stop after which the horn sounds.

Terrible performance, BMW, for a safety-critical device.

 

[JohnnyCakes]

Which kind of Hella horns is that? I can’t figure it out from the video. Is it the Twin Trumpet edition or the Super Tone?

Super Tone = https://www.amazon.com/gp/product/B000CRZXPI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

The most difficult part by far is supporting the horn while getting the OEM mount notched into the tab and getting the bolt started.

Instead of using washers, I cut a box tube (Lowe's) cut to size and also just cut threaded rod (also Lowe's) to size rather than mess with a bolt and a bunch of washers. There's a lot of room to the driver's side of the OEM bracket so I mounted both horns on the driver's side of the bracket.

OEM Bracket > Spacer > Horn > Spacer> Horn
The spacers are required so that the horns don't bump into each other or the mount.

Underneath access is by removing six screws holding the under skirt on. It also lets one person hold the horn from underneath while the other person positions the bracket and screws it in (hardest part). While the video in post #1 was super helpful, he completely skipped over the part of attaching the horns to the car.

Here's what mine ended up looking like:

 

[RhodyDave]

Kudos to the OP! Just completed install of a pair of Hella horns following your YouTube closely. Used a longer (3") bolt and some nylon spacers. The business about reusing the OEM plug was genius, once I figured out how to remove it from the horn and plug the bullet connectors into it! Hellas work great and sound very authoritative. Mine have no detectable delay attributable to the CAN bus. But why would BMW have installed the original wimpy horn on a car with a $51,645 sticker price (my 2018)? Great fix for $48 and a few hours of my time.

One question only: My Hellas came with a horn relay, but you didn't use it and neither did I. Wonder what the capacity of whatever (solid-state switch, relay, etc) is hooked up to the CAN bus that actually drives the horns? Have anyone's horns burned out the actuator?

 

[Rattler]

My real complaint with the i3 horn is that it seems to have lag, and you can't give a friendly/polite, quarter second "beep beep"

Definitely a down side, plus you know, time matters if you're actually using it to avoid someone merging into you or something like that.

 

[1960euroVWbug]

That is a very cool, and much needed upgrade. Thank you for posting the clear how-to video.

The other day, I went to use the horn and thought for a moment that I was driving a Ford Pinto.

I was given a Hella dual horn set for Christmas and finally decided to install it on the weekend.

The horns are very cool sounding with a (Euro) sound.

Here is a video made by Phil H https://www.youtube.com/watch?v=DYEoiMYjZ0w on how to do this.