E34 M5 mechanical audibles

[Fordkoppie]

I would like to ask a few questions regarding acoustics of the e34 M5.

Firstly – The viscous fan blade – mine works perfectly as it should ie; - loud when starting up for a few seconds and thereafter quieting down, disengages @ 3000rpm when hot ect, but I hate the sound when it is operating. It sounds like a Toyota bakkie. The other thing is that these things have a tendency to explode when getting old, so I would like to replace while I am still ahead with no dents in the bonnet. Now my question is, can I fit an e46 diesel fan blade? It is also 420mm and fits onto the s38 viscous clutch but it has a “ring” around the 7 blades that makes it a lot more robust.
Would it be quiet?
Would it create sufficient cooling?
Would it still work like the std 11 blade fan that disengages @3000rpm with the OEM viscous?
I don’t want an electric fan.

Secondly – Exhaust – the middle silencer just in front of the diff starts to rot. Now bearing in mind that I don’t want this car to sound like a race car, can I just replace the middle muffler with straight pipes? Having said that, I would like for it to be a little louder in order to hear that glorious 6, but not too much.
Should there be an X pipe if I do replace that middle silencer with straight pipes?
How much louder would it be than std?
Would it rasp? That is the last thing I want.
Would I lose power, as I have read that the OEM exhaust can’t be improved upon?

Thirdly - Timing chain tensioner – I think I am imagining that I can only sometimes hear chain clatter for a second upon startup. Could this already be happening @ 57 000km?
If this car were yours and still keeping the low mileage in consideration, would you replace the tensioner with an S50b32 upgrade?

 

[maximus]

Reckon all the E34's viscous fan is noisy Not too sure about anything else :mmm:

 

[Nic_s]

My viscous is just as noisy, although I've kinda gotten used to it. Although... now that I think about it, I can shift gear at around 1000rpm while the M5 tends want more revs. Either way I've thought about it a lot and decided that sticking with the stock parts is just best.

Normally if you want to have a less noisy fan you have to go bigger. A bigger fan can give you the same rate of air at a lower rpm and thus less noise. Also, more fins tend to be less noisy from what I gather. I'm no expert and should maybe Google some of this, but I'm a bit to busy right now.


If I remember correctly, Richard's car had one box missing so he should be able to tel you want the sound was like. I do remember him saying that he had a little less power because of it. My car has the center box replaced with straight pipes, but it's a V8. I can tell you that I prefer the noise over the power

 

[maximus]

My viscous is just as noisy, although I've kinda gotten used to it. Although... now that I think about it, I can shift gear at around 1000rpm while the M5 tends want more revs. Either way I've thought about it a lot and decided that sticking with the stock parts is just best.

Normally if you want to have a less noisy fan you have to go bigger. A bigger fan can give you the same rate of air at a lower rpm and thus less noise. Also, more fins tend to be less noisy from what I gather. I'm no expert and should maybe Google some of this, but I'm a bit to busy right now.

Curved blades :thumbs:

 

[rick540]

I would like to ask a few questions regarding acoustics of the e34 M5.

Firstly – The viscous fan blade – mine works perfectly as it should ie; - loud when starting up for a few seconds and thereafter quieting down, disengages @ 3000rpm when hot ect, but I hate the sound when it is operating. It sounds like a Toyota bakkie. The other thing is that these things have a tendency to explode when getting old, so I would like to replace while I am still ahead with no dents in the bonnet. Now my question is, can I fit an e46 diesel fan blade? It is also 420mm and fits onto the s38 viscous clutch but it has a “ring” around the 7 blades that makes it a lot more robust.
Would it be quiet?
Would it create sufficient cooling?
Would it still work like the std 11 blade fan that disengages @3000rpm with the OEM viscous?
I don’t want an electric fan.

Secondly – Exhaust – the middle silencer just in front of the diff starts to rot. Now bearing in mind that I don’t want this car to sound like a race car, can I just replace the middle muffler with straight pipes? Having said that, I would like for it to be a little louder in order to hear that glorious 6, but not too much.
Should there be an X pipe if I do replace that middle silencer with straight pipes?
How much louder would it be than std?
Would it rasp? That is the last thing I want.
Would I lose power, as I have read that the OEM exhaust can’t be improved upon?

Thirdly - Timing chain tensioner – I think I am imagining that I can only sometimes hear chain clatter for a second upon startup. Could this already be happening @ 57 000km?
If this car were yours and still keeping the low mileage in consideration, would you replace the tensioner with an S50b32 upgrade?

There are two viscous fans you can get, there is a thinner 9 blade one used on the E30 320i. I bought one of these by mistake at the beginning and it worked perfecty in the heat of summer and was much quieter. In fact I will be putting it back on as when I fitted the wide blade fan the noise was really noticeable.

When I had to do roadworthy, to get the car passed as a temp fix I cut out the centre box fitted straight pipes and the car sounded fantastic, growly and not noisy at all it. At idle it sounded exactly the same and at 3000rpm it sounded 6 pot sweet "maybe lost a teensy bit of power but not significant. I wish I had not replaced that centre box, so that is also something I will undo soon.

 

[maximus]

There are two viscous fans you can get, there is a thinner 9 blade one used on the E30 320i. I bought one of these by mistake at the beginning and it worked perfecty in the heat of summer and was much quieter.

Interesting...maybe will consider this blade and then a new clutch for mine.

 

[Fordkoppie]

There are two viscous fans you can get, there is a thinner 9 blade one used on the E30 320i. I bought one of these by mistake at the beginning and it worked perfecty in the heat of summer and was much quieter. In fact I will be putting it back on as when I fitted the wide blade fan the noise was really noticeable.

When I had to do roadworthy, to get the car passed as a temp fix I cut out the centre box fitted straight pipes and the car sounded fantastic, growly and not noisy at all it. At idle it sounded exactly the same and at 3000rpm it sounded 6 pot sweet "maybe lost a teensy bit of power but not significant. I wish I had not replaced that centre box, so that is also something I will undo soon.

I see the 9 blade e30 (pre 87) one is the same dia than the 420mm item in the M5. Did it bolt to the viscous directly, or is it different all together?

AFAIK you said you cut out the 2 small resonators (the 2 small ones below the gearbox). The one I am referring to is the large one between the diff and the gearbox that has a bend halfway in it.

 

[Legacy]

If this were my car (haha I wish) I would leave the viscous as is, yes it is annoying but its only to 3000 rpm so there is at least another 4000 rpm left that does not sound like a bakkie.

In the case of the exhaust I would cut out the box and fit straight pipes and see what it is like and then decide from there.

Regarding the timing chain tensioner when I have talked to you about it you have always said that it is extremely important to change it to the s50b30 one since its only a matter of time until the timing jumps and you smack some valves. To be perfectly honest I would go with rather safe than sorry.

 

[Fordkoppie]

so there is at least another 4000 rpm left that does not sound like a bakkie.

Ahem, cough..... 4300rpm :rollsmile:

The exhaust I would only want to be done by Van der Linde. But they are $$$.

Yeah, I guess I should just get my lazy ass in gear and do the tensioner swap. That and the fact that the S50 item usually results in chain whine also puts me off slightly

 

[rick540]

so there is at least another 4000 rpm left that does not sound like a bakkie.

Ahem, cough..... 4300rpm :rollsmile:

The exhaust I would only want to be done by Van der Linde. But they are $$$.

Yeah, I guess I should just get my lazy ass in gear and do the tensioner swap. That and the fact that the S50 item usually results in chain whine also puts me off slightly

In my case I kept the old tensioner and replaced the chain.

I had my head in that engine for six weeks and I can gaurantee you they only jump when the chain is badly stretched. I also do not like the fact that the S50 tensioner has no hydraulic damper. that thing is there to prevent snapped chains.

The original tensioner with damper is still available from BMW and I would rather go with a new one from them than with an idea from some dude on a USA forum that because it fits it's "better"

It's just better for a stretched chain

 

[Fordkoppie]

In my case I kept the old tensioner and replaced the chain.

I had my head in that engine for six weeks and I can gaurantee you they only jump when the chain is badly stretched. I also do not like the fact that the S50 tensioner has no hydraulic damper. that thing is there to prevent snapped chains.

The original tensioner with damper is still available from BMW and I would rather go with a new one from them than with an idea from some dude on a USA forum that because it fits it's "better"

It's just better for a stretched chain

Rick – I am not trying at all to convince you or nitpicking your way of thinking but consider this:

1. The later s38b38 also changed to a tensioner design that resembles that of the s50 with no damper/accumulator.
2. One can’t argue with the fact that the design of the original is stupid as it can retract very easily when there is no oil pressure causing the chain to go slack.

Now I agree that while the engine is running (and oil pressure is up) that the original one is very good since it has the damper, but these engines usually self destruct @ startup. It only needs to backfire once and you have had it. The moment the engine turns anti clockwise and with no oil pressure to maintain tension the guide will simply push back, the chain will skip timing teeth and the valves mate with the pistons. This is where the S50b32 item is way better in that the chain is always tensioned up and the possibility of skipping teeth should the engine rotate backwards is drastically reduced.
My car’s chain is not stretched yet, so no need for replacement, but it does sometimes rattle upon startup until the oil pressure stabilize. It is perfectly quiet after 2 seconds from startup.

 

[rick540]

In my case I kept the old tensioner and replaced the chain.

I had my head in that engine for six weeks and I can gaurantee you they only jump when the chain is badly stretched. I also do not like the fact that the S50 tensioner has no hydraulic damper. that thing is there to prevent snapped chains.

The original tensioner with damper is still available from BMW and I would rather go with a new one from them than with an idea from some dude on a USA forum that because it fits it's "better"

It's just better for a stretched chain

Rick – I am not trying at all to convince you or nitpicking your way of thinking but consider this:

1. The later s38b38 also changed to a tensioner design that resembles that of the s50 with no damper/accumulator.
2. One can’t argue with the fact that the design of the original is stupid as it can retract very easily when there is no oil pressure causing the chain to go slack.

Now I agree that while the engine is running (and oil pressure is up) that the original one is very good since it has the damper, but these engines usually self destruct @ startup. It only needs to backfire once and you have had it. The moment the engine turns anti clockwise and with no oil pressure to maintain tension the guide will simply push back, the chain will skip timing teeth and the valves mate with the pistons. This is where the S50b32 item is way better in that the chain is always tensioned up and the possibility of skipping teeth should the engine rotate backwards is drastically reduced.
My car’s chain is not stretched yet, so no need for replacement, but it does sometimes rattle upon startup until the oil pressure stabilize. It is perfectly quiet after 2 seconds from startup.

I hear you and I do understand what you are saying.

My comments came from the fact that after I changed the chain I could turn the engine backwards with no oil pressure and the chain would not skip, it just isnt long enough.

But ja, thinking about it if my chain was old I would seriously consider it.

I am curious about your startup rattle from the chain as I didnt have that even when the chain was worn

 

[Fordkoppie]

I am curious about your startup rattle from the chain as I didnt have that even when the chain was worn

It doesn’t always do it, but if the car was driven till the oil was hot and then from there on parked without moving for 2 weeks, it would sometimes rattle for a second or 2 after starting. It is like the accumulator would sometimes leak/drain back into the engine and then doesn’t have any pressure left until it has “recharged”.

 

[Legacy]

so there is at least another 4000 rpm left that does not sound like a bakkie.

Ahem, cough..... 4300rpm :rollsmile:

The exhaust I would only want to be done by Van der Linde. But they are $$$.

Yeah, I guess I should just get my lazy ass in gear and do the tensioner swap. That and the fact that the S50 item usually results in chain whine also puts me off slightly

I know just checking haha :fencelook:

 

[Fordkoppie]

So over the weekend I tried one of these fans to see if it might be quiet, since the guy I borrowed it from said it was…….

BTW – it is the one that can be found on the e46 330d.

I bolted the blade to my current viscous and golly, it is even worse. Sounded like a Harvard trying to take off.
It simply doesn’t provide enough torque to disengage the viscous even @ 7k. Screwed my old blade back on and it works perfectly again, bar the noise up to 3000.

Owner of the fan – YOUR VISCOUS COUPLING IS BROKEN, but thanks for lending the blade to me

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I will just have to do an electric fan conversion if i want to get rid of the toyota inside

 

[Raybimmer]

M5 Harvard....:roflol:
That should add value , very scarce model ....Hello Gumtree :thumbs:

 

[Peter@AEW]

I cannot answer on the silencer box but I could possibly assist on the fan as well as the chain rattle.

A fan from an Audi 2,7T (A6) as it will fit directly on the 3 bolt viscous and it has a shroud around the blades. The blades and I speak from memory are also narrower so you will not get that noise.
Normally very quiet and the cars use the same viscous coupling so it will engage and disengage correctly.

As to the rattle on start up mine does it even if it has stood for a day and my motor is not over 7000km yet and everything is new.
They only kiss pistons on start up if the chain is over 100k and lubrication quality has been poor.
I am seriously reluctant to encourage you to deviate from the chain tensioning system as designed for the engine as the guide rail is extremely long and is loaded across its length. Changing " chain/piston tensioning design" is a leap of faith into the unknown. What may help is if you remove the system clean it up change the washers and see if it improves failling which you may require a new piston and spring (which obviously comes as a kit with the barrel) Does yours have a damper at the end as some came without the damper.

 

[Gizmo]

Now you see why I did it to my dad's car. I installed an early model e36 318is 80/88deg thermostat switch along with a 18" electric fan mounted to the radiator. The new fan was wired to the front AUX fan stage 1.

---

We used to nickname the viscous powered m5 as the bus!

 

[Fordkoppie]

Now you see why I did it to my dad's car. I installed an early model e36 318is 80/88deg thermostat switch along with a 18" electric fan mounted to the radiator. The new fan was wired to the front AUX fan stage 1.
We used to nickname the viscous powered m5 as the bus!

Thanks Warren. Do you perhaps have a partnumber for that 80/88 deg thermo switch?
Another thing I would like to know is that if you wire up the fan from the AUX1 and it should heat up enough to reach AUX2, wouldn't it switch off the radiator/custom fan completely?

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I cannot answer on the silencer box but I could possibly assist on the fan as well as the chain rattle.

A fan from an Audi 2,7T (A6) as it will fit directly on the 3 bolt viscous and it has a shroud around the blades. The blades and I speak from memory are also narrower so you will not get that noise.
Normally very quiet and the cars use the same viscous coupling so it will engage and disengage correctly.

As to the rattle on start up mine does it even if it has stood for a day and my motor is not over 7000km yet and everything is new.
They only kiss pistons on start up if the chain is over 100k and lubrication quality has been poor.
I am seriously reluctant to encourage you to deviate from the chain tensioning system as designed for the engine as the guide rail is extremely long and is loaded across its length. Changing " chain/piston tensioning design" is a leap of faith into the unknown. What may help is if you remove the system clean it up change the washers and see if it improves failling which you may require a new piston and spring (which obviously comes as a kit with the barrel) Does yours have a damper at the end as some came without the damper.

Thanks for the fan advice.
I will check out Goldwagen for the Audi A6 item. I assume you are referring to the C5 A6 2.7T ???

One of the reasons I consider doing the tensioner swop is because I have read about it on the M5 board with 10ths or maybe even 100ths of members that have done it without any ill effects afterwards.

I have personally fitted one of those s50 tensioners to the M88 of my ex e28 M5 with 157000km on the clock and it is still running. I have also fitted one of those s50 tensioners to the s38 of my previous e34 and I drove that car for +/-15000km with the tensioner before selling it without any issues. New owner only had it for 6 hrs before it dropped a valve, but that is hardly the tensioner’s fault and a topic for another day.
However, on both the s38 and M88, the engines had a slight chain whine after the install, but the startup rattle was completely eliminated.
Here is a good write-up.
http://www.m5board.com/vbulletin/e3...32-chain-tensioner-upgrade-s38b36-s38b38.html

I am not trying to persuade you, or to justify my way of thinking, but merely stating what I have read and my own previous experiences.

Oh and yes, mine is the one with the accumulator/damper behind the piston.

 

[Gizmo]

Aux 1 doesn't switch off when aux 2 is reached.
DOUBLE TEMPERATURE SWITCH 80/88CEL UP TO 03/1997 61318361787