F10 M5 RPi GTM Exhaust: With Fully Catless Downpipes Now! - (I went Full Retard)

[LACSTER]

WOW!!!!!!! That's awesome Motiv Concept is making these cause they specialize in FRS & BRZ.


I have thier exhaust tips on my F10.

[ScorpionT]

Originally Posted by Boss330

At 01:10-01:15 - Revving the car and then killing the engine - You are not treating your turbos nice. It's adviced to let the engine sit at idle for up to 1 minute before switching off the engine. The turbos need time to spool down and cool before loosing lubrication (when you stop the engine the oil pump shuts down, but the turbos are still spinning without lubrication...)

Quick bit of turbo tech:

Doesnt hurt to rev the car and shut it down. When the engine is off the turbos stop spinning within 2-10 seconds but still have enough oil pressure around the bearings to prevent damage. What really causes damage is coking. Oil in turbo applications undergoes temperature extremes and has a tendency to break down. If not cooled sufficiently carbon will precipitate from the oil and build up in the bearings, which over time causes damage.

[buildbright]

Would like to hear these downpipes on the Akrapovic exhaust.

[luigimaster24]

Sounds Amazing!!

Awesome write up and videos, thanks for taking the time to post up!!

Getting catless DPs installed next week on the M6 with Meisterschaft full exhaust.... Can't wait.

[Boss330]

Originally Posted by ScorpionT

Quick bit of turbo tech:

Doesnt hurt to rev the car and shut it down. When the engine is off the turbos stop spinning within 2-10 seconds but still have enough oil pressure around the bearings to prevent damage. What really causes damage is coking. Oil in turbo applications undergoes temperature extremes and has a tendency to break down. If not cooled sufficiently carbon will precipitate from the oil and build up in the bearings, which over time causes damage.

Not sure what you are saying here that is different from what I said?

Yes, heat (and lubrication) is the issue. That's why I said the turbos should be allowed to spool down and cool. If you rev the engine the turbos RPM is tremendously higher than at idle, hence taking longer to spool down. When engine is shut down oil and coolant pressure disappears (unless there is a "turbo timer" device installed). The turbos will then rotate for much longer without lubrcation and coolant flow through the turbo housing. This is bad for bearings and also accelerates/worsens the coking process.

Not a big issue with just some slight revving, but becomes a issue after a spirited drive if this is done repeatedly.

But, just to reiterate what I posted previously: The M5 have the Start/Stop functionality and I'm sure BMW has addressed this issue. So, probably not a big issue on this car.

[ScorpionT]

Originally Posted by Boss330

Not sure what you are saying here that is different from what I said?

Yes, heat (and lubrication) is the issue. That's why I said the turbos should be allowed to spool down and cool. If you rev the engine the turbos RPM is tremendously higher than at idle, hence taking longer to spool down. When engine is shut down oil and coolant pressure disappears (unless there is a "turbo timer" device installed). The turbos will then rotate for much longer without lubrcation and coolant flow through the turbo housing. This is bad for bearings and also accelerates/worsens the coking process.

Not a big issue with just some slight revving, but becomes a issue after a spirited drive if this is done repeatedly.

But, just to reiterate what I posted previously: The M5 have the Start/Stop functionality and I'm sure BMW has addressed this issue. So, probably not a big issue on this car.

Its a fair amount different.

If the car was started and revved up cold, the turbo bearings would be more likely to suffer damage as a result of low viscosity oil (from it being cold). If the car was warmed up, revving then shutting it off wont hurt it. Enough oil will still be in the lines and CHRA to prevent damage. Turbos dont spin for minutes after shut down, its a matter of seconds. If a turbo timer is present the engine isnt actually shut down (sounded like you were saying engine is shut down, but oil/coolant keeps flowing). Coking comes from the extreme heat and breakdown of oil, doesnt matter if the oil sits in the bearings or not, it will still coke. If the oil cools down it gets cleaned by the oil filter, preventing the carbon precipitate from building up in the bearings.

The start/stop only shuts down the engine for a short time, so very hot oil doesnt have the time to coke in the turbos. It will still be an issue for those that drive their cars hard and shut down with little to no cooling period.

[wisesoul]

Originally Posted by ScorpionT

Its a fair amount different.

If the car was started and revved up cold, the turbo bearings would be more likely to suffer damage as a result of low viscosity oil (from it being cold). If the car was warmed up, revving then shutting it off wont hurt it. Enough oil will still be in the lines and CHRA to prevent damage. Turbos dont spin for minutes after shut down, its a matter of seconds. If a turbo timer is present the engine isnt actually shut down (sounded like you were saying engine is shut down, but oil/coolant keeps flowing). Coking comes from the extreme heat and breakdown of oil, doesnt matter if the oil sits in the bearings or not, it will still coke. If the oil cools down it gets cleaned by the oil filter, preventing the carbon precipitate from building up in the bearings.

The start/stop only shuts down the engine for a short time, so very hot oil doesnt have the time to coke in the turbos. It will still be an issue for those that drive their cars hard and shut down with little to no cooling period.

Very well said And if turbo timers could work without the engine being on, that would be pure magic lol.

[Boss330]

Originally Posted by ScorpionT

Its a fair amount different.

If the car was started and revved up cold, the turbo bearings would be more likely to suffer damage as a result of low viscosity oil (from it being cold). If the car was warmed up, revving then shutting it off wont hurt it. Enough oil will still be in the lines and CHRA to prevent damage. Turbos dont spin for minutes after shut down, its a matter of seconds. If a turbo timer is present the engine isnt actually shut down (sounded like you were saying engine is shut down, but oil/coolant keeps flowing). Coking comes from the extreme heat and breakdown of oil, doesnt matter if the oil sits in the bearings or not, it will still coke. If the oil cools down it gets cleaned by the oil filter, preventing the carbon precipitate from building up in the bearings.

The start/stop only shuts down the engine for a short time, so very hot oil doesnt have the time to coke in the turbos. It will still be an issue for those that drive their cars hard and shut down with little to no cooling period.

Still don't see that your previous post was any different to what I said, but it might be due to English being my second language

I'm not sure I agree to what you are saying about revving turbo engines and not letting it idle though. First of all, a turbo can spin for at least a minute after shutting the engine down. Even more if you revved it first. The turbo might be rotating at 50.000rpm if you revved it (a modern turbo spins at 150.000rpm (or more) at full load). It won't stop from 50.000rpm in a few seconds (unless the bearings are covered in sticky gum...

As regards the Turbo Timer subject. I'm aware of the old school turbo timers that would have to keep the engine running to provide cooling and lubrication (and shouldn't the fact that HKS developed a specific product to let the engine run at idle indicate that there is a point to idle a turbo engine?).

Modern engines have electric water pumps and can even have supplementary electric oil pumps that take care of cooling and lubrication after engine shut down. The part # for the supplementary waterpump for the turbos on the M5 is: 11517629916

Anyway, your advice that there is no need to idle a turbo engine (after revving or a spirited drive) is contrary to what experts are saying:

There has been many topics discussed around how long to let a turbocharged car idle before shutting off the engine. First we will tell you why your car needs to cool down before turning off the key and also why it is not good to allow a car to idle for a longer period than needed for proper turbocharger life. We know that a turbocharger operates at a very high rotational speed and it is fed lubricating oil from the engine, so it only makes sense you want to slow down the turbo's speed and also provide it with oil before shutting the car down. Once you turn off the engine in your car, the turbocharger will continue to spin for up to a minute or more and during this time oil is not being delivered to the turbochargers bearings, causing wear. To help prevent this from happening, we have been told in the past to let the engine idle for a few minutes prior to turning off the key. The good thing that happens during this time is in fact the turbo will slow down, but if allowed to idle for to long the temperature of the engine compartment, engine oil and the turbocharger will start to increase. The reason for this is today's car is designed to be moving while it is operated, allowing air to pass through the radiator and engine compartment, keeping it cool. The best thing is to drive your car as easy as possible when you are getting close to your destination. Once you are safely in your parking spot, allow the car to idle for no more than 2 minutes. This time will be adequate for both the turbochargers speed to slow, and for the temperature not to increase in the engine compartment.

http://www.turborepair.com/index.php...202&Itemid=154

But, let me once again say that this is not a major issue on the M5 as it has at least supplementary water cooling (which basically eliminates the need to idle the engine).

[Boss330]

Originally Posted by wisesoul

Very well said And if turbo timers could work without the engine being on, that would be pure magic lol.

I'm aware of the old school turbo timers that would have to keep the engine running to provide cooling and lubrication.

Modern engines have electric water pumps and can even have supplementary electric oil pumps that take care of cooling and lubrication after engine shut down.

The part # for the supplementary waterpump for the turbos on the M5 is: 11517629916

Not sure I would call it pure magic, but clever engineering maybe

[ScorpionT]

Originally Posted by wisesoul

Very well said And if turbo timers could work without the engine being on, that would be pure magic lol.

Would be nice. Ive used electric oil pumps in some applications, but the added complexity usually isnt worthwhile for street cars.

Originally Posted by Boss330

Still don't see that your previous post was any different to what I said, but it might be due to English being my second language

I'm not sure I agree to what you are saying about revving turbo engines and not letting it idle though. First of all, a turbo can spin for at least a minute after shutting the engine down. Even more if you revved it first. The turbo might be rotating at 50.000rpm if you revved it (a modern turbo spins at 150.000rpm (or more) at full load). It won't stop from 50.000rpm in a few seconds (unless the bearings are covered in sticky gum...

As regards the Turbo Timer subject. I'm aware of the old school turbo timers that would have to keep the engine running to provide cooling and lubrication (and shouldn't the fact that HKS developed a specific product to let the engine run at idle indicate that there is a point to idle a turbo engine?).

Modern engines have electric water pumps and can even have supplementary electric oil pumps that take care of cooling and lubrication after engine shut down. The part # for the supplementary waterpump for the turbos on the M5 is: 11517629916

Anyway, your advice that there is no need to idle a turbo engine (after revving or a spirited drive) is contrary to what experts are saying:



http://www.turborepair.com/index.php...202&Itemid=154

But, let me once again say that this is not a major issue on the M5 as it has at least supplementary water cooling (which basically eliminates the need to idle the engine).

No problem, your English is still good.

In the case of the OPs video, the car idled for a bit before shut down. The turbo will stop spinning in less than 15 seconds, the RPMs arent high enough to keep it going for long. The compressor and turbo are lightweight and have fairly low inertia, allowing them to spin up and slow down pretty quick. The larger a turbo the longer it can continue to spin, but these small twins wont go for long.

Turbo timers have their purpose. The longer and harder you push a car the more time it needs as a cool off period. Revving the car hard a handful of times isnt enough abuse to get the oil temps hot enough to cause coking.

[M5 Orthodox]

Thank you for making my stock M5 feel so inadequate ... jerk.

On a serious note though, phenomenal job on capturing the essence of the upgrades. You, sir, are a gentleman and a scholar.

[RPiM5]

Originally Posted by M5 Orthodox

Thank you for making my stock M5 feel so inadequate ... jerk.

On a serious note though, phenomenal job on capturing the essence of the upgrades. You, sir, are a gentleman and a scholar.

How did u know?!

I'm actually graduating tomorrow with my Masters Degree.

[info@trinityautosport]

Originally Posted by RPiM5

How did u know?!

I'm actually graduating tomorrow with my Masters Degree.

[leletyM3]

Nice set up!

[mstmng]

Dave, absolutely amazing job and sound!

just picked up my m5 less than 2 weeks ago and can't wait to change from stock exhaust!

i have couple of questions, if you don't mind answering.

I am thinking of getting GTM exhaust, which is mufflers free and resonators free (please correct me if i am wrong)?! Were you getting any engine faults when you had it, before you changed DP's? and did you upgrade your ECU with GTM exhaust?


what would you recommend to go for? GMT or fully straight pipe as yours now?) I had race eisenmann on my e90 and it was not loud enough for me

[boots]

I got the same kit except gts with gtm. Dave has gt with gtm plus dp. I have no drone lots of power and great sound. The gtm has resonators. No exhaust gives you cel but the dp will. If you want a rpi go gtm. It's all the way live. (Isley bro)
The more I drove and broke it in the more I liked it. If this what you want trust me you will like it.

[Timberwolf]

Originally Posted by RPiM5

How did u know?!

I'm actually graduating tomorrow with my Masters Degree.

Grats on graduating. Btw does you car shoot flames? Sorry if someone already asked you this.

Thanks,

Greg

[mstmng]

Originally Posted by boots

I got the same kit except gts with gtm. Dave has gt with gtm plus dp. I have no drone lots of power and great sound. The gtm has resonators. No exhaust gives you cel but the dp will. If you want a rpi go gtm. It's all the way live. (Isley bro)
The more I drove and broke it in the more I liked it. If this what you want trust me you will like it.

now you confused me buddy

what do u mean by saying "i have gts with gtm" and "Dave got gt with gtm" ? sorry about that, i thought GT, GTS and GTM are 3 different systems, where:

GTS: Full system with resonators and with mufflers.
GT: Full system with no resonators and with mufflers.
GTM: Full system with no resonators and with no mufflers.

thanks!

[boots]

Originally Posted by mstmng

now you confused me buddy

what do u mean by saying "i have gts with gtm" and "Dave got gt with gtm" ? sorry about that, i thought GT, GTS and GTM are 3 different systems, where:

GTS: Full system with resonators and with mufflers.
GT: Full system with no resonators and with mufflers.
GTM: Full system with no resonators and with no mufflers.

thanks!

No problem::: I originally purchased the Gts system. Then I replaced the rear section with Rpi's straight pipe version that they call the Gtm. So yes, it has the resonators and now has no mufflers. I can see where the confusion came from. Sorry..lol So now I see they sell their Gtm with no resonators which basically is the Gt system with the Gtm rear.

[mstmng]

thank you!

i then i will definitely go for GTM and when software is available i will go "Full Retard" as well
just cant stand warnings and symbols flashing all around the car

[RPiM5]

I got another dyno done with my full straightpipe setup.

Unfortunately this time my engine blew a rod...

[JPMD]

Originally Posted by RPiM5

Yes, there is odor from the engine fumes now. BUT!!! It is not nearly as bad as the E60 V10's straightpipes smell. The fumes from catless F10 V8 are about 80% less obtrusive than the E60 V10's fumes.

You can only really smell the fumes on the F10 M5 when stopped at a traffic light. On the V10 you couldn't even hang out in your garage for a minute after shutting off the car, on the F10 M5 you can hang out all day. It's really not nearly as bad at all.

Hi found this old thread.
Are you still running the RPi DPs?

When stopped you mentioned you notice the fumes; is this also the case if the windows are up?

Your car sounded ridiculously awesome but if one wanted a less aggressive sound how do you think the RPis would sound with the comp pkg exhaust?