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From digest.v7.n843 Mon Dec 29 16:38:12 1997
From: Stephen Rowe <>
Date: Mon, 29 Dec 1997 13:56:21 -0500
Subject: Horn upgrade

I am not trying to resurrect the horn thread, but I agree that the standard OEM horns are less than ideal in this era of extra insulation and high amperage stereos. I have wanted to do this upgrade for a while and the previous discussion got me motivated. Last Friday, while my wife was bargain shopping, I got a chance to more thoroughly exam the horn layout on my 525i. I had ordered the Hella Supertones (highway horns) about a month ago and the Hella OE (local horns) size horns arrived on Christmas eve and with the extra time and nice weather I decided to undertake the upgrade on Friday. And do the kid watching too.

The Hella OE sized horns (more volume than stock) went into the same location as the originals and the Hella Supertones (great sound) were attached to the lower radiator frame via two small holes that were drilled.

The wiring was a little more interesting. The original wiring has a positive and a ground so I used both to drive the relays. The passenger side horn wiring was used to actuate the local horns via a relay attached by a blind clip and screw through a hole in the original horn mounting bracket. This in not the best location since the relay is exposed to the elements and is not hanging down, but it is up and out of the direct flow of air and it keeps the wiring distances short. The highway horns use the drivers side wiring to actuate the relay which is attached via the bolt that hold the hood release mechanism. This one too is still exposed to the elements but is hidden from a majority of the airflow by the horn.

I used 10ga red wire off of the battery, attaching it via a bolt on the positive terminal, then feeding it through the fender area until behind the passenger's side lights. There I spliced in two 16ga fuseplugs (water proof

  • -one for each relay) and fed each line to its respective relay.

The cost of this upgrade was around $88. The Hella local horns were $36 from PUMA (Performance Unlimited Motoring Accessories), The Hella Supertones were $69 from Imparts, the fuses were $2 each and maybe a $2 for the wiring. But I also sold the OEM horns for $25: ) I used my 4 year old daughter to do the testing from the drivers seat. She did not like to volume of sound, but I did: ) I noticed that you can see the Supertones but not the local horns. Total time was 4 hours including lunch and requisite kid chasing.


R. Stephen Rowe
Pacific-Sierra Research Corp. <> 703-516-6334 Fax 703-524-2420
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