3" Turbo Down Pipe Clamp

Hello All,

I need some feedback on how people are mounting / hanging their modified exhaust systems?

My 1994 940T wagon has some minor modifications; IPD Turbo cam, chipped ECU, chipped ICU, manual boost controller, larger injectors and a 3" downpipe / cat with a 2.5" pipe to a single Magnaflow straight through muffler (#11216), just before the rear bumper.

The 3" pipe is wrapped with fibreglass tape from the turbo to the cat. I've used the original turbo downpipe clamping point (bell housing bolt), for a metal band wrapped around the fibreglass pipe wrap. Next I modified the original mount from an AW71L automatic to fit the O/D housing on the M46 gearbox (I swapped out the AW71L for the M46 with O/D). Again, I used a metal band wrapped around the fibreglass tape. This mount is about 12" further back than the original location with the AW71L. From the cat to the rear bumper the exhaust system uses the original 'rubber' hangers.

My logic for the above set-up is to ensure the downpipe is held very tight to prevent vibrations from stressing the exhaust manifold, turbo and all the mounting studs. But allow the remainder of the exhaust system (cat to rear bumper), to move around on the rubber mounts.

I have a slight 'buzz' between about 1800 and 2200 RPM that I'm certain is the exhaust system. It will even create a very slight buzz in the instrument cluster during part of this rpm range.

So, I'm open to suggestions as to what changes I should be making?

Looking forward to your feedback.

Look in my project thread

Hello MadDog_945,

Quite the project you undertook with your 945. I shudder to think how many hours you have in it. Definitely a labour of love.

I found your exhaust system pictures on page 19 of your project. I was pleased to see you used a piece of flex pipe in your system - I was thinking of going down that same route.

I noticed you initially (??) had the flex pipe just after the steel clamp to the bell housing bolt. It appears you latter moved it further along the pipe but before the hanger you made. Is this correct?

If so, this means your set-up is rigid up to the bell housing clamp and then allowed to flex after the welded in flex pipe. You added an additional flexible hanger just before the cat to for some additional stability before the first muffler hangers.

I found the Urethane hanger set up welded to pipe ahead of the cat was a very simple but effective solution.

Did you find this set-up was relatively vibration / drone free?

It is completely rigid and nothing rassles or vibrates.
That additional hanger before the cat adds stability to the whole system and prevents the cat from hanging to low.

Hello MadDog_945,

Thanks for the quick reply. To be clear, you removed the flex pipe but retained the metal band clamp at the bell housing? The remainder of the exhaust system is free to move around on the Urethane and rubber hangers?

It is like shown in the pics maybe the first flexpipe is not necessary but I had it laying around

Hello MadDog_945,

Vielen Dank - will start working on an updated exhaust system soon.

i am curios how it turns out no problem mate!

Check my build thread.... 3" DP and a commercially available clamp system to fix the vertical section in the same location as the factory 9 series / late 7 series DP (never worked on a early 7 series, so I can't say how they were attached). No vibes and the pipe is properly supported so no concerns about the OE stud size at the turbine housing mounting to the 90+ exhaust manifold.

Hello DET17,

Appreciate the feedback. Your exhaust system solution aligns with my thoughts as well as the feedback from MadDog_945. I won't be able to get at my exhaust system for at least a month due to other conflicting projects, main one being the 1988 Merkur Scorpio I picked up for my better half. She is looking forward to driving it once winter is behind us.

BTW, I noticed your AC condenser is for a normally aspirated (NA), car. The NA version had the 'notch' in the upper right corner for the air filter housing snorkel. If you want slightly better condenser performance go for the turbo version. For example, under the 940 turbo section of Rock Auto they show two condensers; APDI/PRO 7014736 (correct one) or a Nissens 94216 (incorrect - this is for a NA version). Rock Auto also has some errors regarding the AC compressors for the 940s - in 1994 the angle of the fittings on the back of the compressor changed and won't work for a 'pre '94' model.

Hope it helps.