M04 9-5 Aero gets dual Hirsch exhaust!

Photo: Hirsch

For a while ago I got the chance to buy a Hirsch exhaust system for my 9-5, the only problem was that the system was not fully compatible with my car. The system we talk about is the fancy dual exhaust for 9-5 M02-M05, but NOT for the M04-M05 Aero and car with the M04-M05 Aero-look (which is a very popular visual upgrade for M02-M05 here in Scandinavia). My 9-5 is just an M04 Aero sedan, and basically that not will fit is the rear bumper layout. The Hirsch webpage says “Please order the single pipe exhaust system instead”… But at this stage I already decided, I want this and would give it a shoot. I have always liked this exhaust system,  from the moment I saw it on a full Hirsched 9-5 Aero with the 305hp package at ANA Trollhättan back in 2003.  After I ordered the system from Cardyourcar.eu it became clear that the middle pipe from the cat to the Y-pipe wasn’t in stock, but luckily Cardyourcar managed to find some more middle pipes. Since it took a while from I ordered the system to I got it delivered I got plenty of time to thinking how to solve the fitting in a optimal way. In the end I decided that if the system absolutely didn’t fit, I would change to a compatible bumper from a standard 9-5, and use the Hirsch “diffuser”.

So, a few days ago I got four large parcels delivered, and the fun could begin! The system is built up by four parts, it starts with a 3″ middle pipe with a silencer and a flexi part. Then we have a 3″-2.5″ Y-pipe, and two tailpipes with a silencer on each pipe. Before I had Maptuns 2.5″ sports system mounted on the car about 2 years/40 000km’s so the disassembly was not a big issue, as it otherwise tends to be when replacing the exhaust system. If we look away from some mounting components that was pretty rusty the disassembly went quick. The biggest issue was the bolts that link the downpipe and the flexi-pipe, but with some special equipment (cutting disc) the assembly could begin. When I mounted the Maptun system I thought it had a very good fit and everything went pretty well, but the Hirsch system is perhaps slightly better! Obvious I began from the front with the mounting the middle pipe and the Y-pipe without completely tighten the screws so I have a opportunities for adjustment later, before I took a cardboard and marked out the opening for the tailpipe with a ink pen. Then I mounted the rear silencer on the left side, before the custom work on the right side started.

Hirsch_avgas9-5_fästeThose of you who have mounted dual exhaust on a 9-5 know that the bracket for the right pipe is missing, and that I think Hirsch has solved in a good way. In the kit Hirsch has attached a U-profile with fixings to be welded in place, with a very good fit. At this stage I chose a different solution then the instructions said, Hirsch want me to weld three spots on the top of the U. I chose to drill three holes on each side of the beam, and spot weld it there. After that was ready, I sealed around the U-profile with some sealant (Sikaflex), before I spay in- and outside with thin and thick rust protection in several steps.

Now it was time for the tricky part, cutting of some of the bumper plastic. We (me and my dad) was going for a simple tactic, we simply hope for the best, and marked up where the new oval hole was starting end where it would end with the cardboard as help. We was also marking out the top of the new hole before starting to cutting by eye. The new oval was after a few adjustments quite okay, but I hoped we had managed to get the lower profile in the bumper a bit more similar the original on the left side.
Maybe I will fix this in a better way later, with some special plastic glue and that way get a smooth surface. Another thing to do now, which I obviously forgot the first time, is to cut out a lite bit of the bumper beam, otherwise there is a high risk that the tailpipe is touching the beam when driving on gravel roads and so. Now in the end it’s “only” to mount the right silencer and adjust it, and enjoy the wonderful sound 😀

Visually it don’t look entirely as a original fit, but I think it’s right okay. I will wait and see now for a while, maybe I switch to a standard bumper later. Now I will drive a few more km’s, and fine tune the exhaust before I’m taking a decision. So far I’m quite happy with the sound, at idle it give a deeper rumble than the single Maptun system, but at acceleration you got a rather nice exhaust note. It isn’t in any way “too much” sound in my opinion, with this system you can drive hour after hour without being distracted of loud exhaust sound. In other words, just as I want it, much similar to the old single-system from Maptun. The biggest difference is that the sound is deeper all over, the Maptun system gives more “snarl” at acceleration.


If you has been inspired, and want a new Hirsch exhaust system, or some other Hirsch-stuff, check out www.cardyourcar.eu!

7 thoughts on “M04 9-5 Aero gets dual Hirsch exhaust!”

  1. Trond, you have inspired me to go ahead too. I’ve always loved the twin exhaust system, now it’s time to make the move. Watch this space.

    • I see what I can do, I tried with my Xperia Z1, but the recording had poor quality :/ But I guess it’s best live 😀

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