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Discussion Starter #1
Is there a way to data log or monitor with a app like Carly or Torque to record and view a comparision between Fuel Pressure requested vs Fuel Pressure actual, Or perhaps Torque requested vs Torque actual?

I am trying to see if my M is putting out the power it should. It just feels sluggish especially below 3500rpm.
I dont know how a brand new M5 would feel, but at 500hp it just feels slugish compared to my 300 hp tuned 335d.

The 335d feels way faster upto around 50mph or so, then the M5 is in the higher revs and pulls strong.

It's the low revs i'm concerend about. In either P400 or P500 modes. it feels sluggish. On dry pavement I cannot get wheel spin in 3rd gear (below 4kRPM,

I don't have any codes what so ever. My vanos valves, 3 of them are above 0.6 (0.65, 0.7, 0.75 or so), the 4th is 0.6.


Thanks for the inputs!
 

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Try the basics first. Try to reset adaptations. Make sure you on 93 octane. If not. When is the last time you did a tune up? Air filters, plugs and another issue alot of M5 enthusiasts forget to do with time is the fuel filter (driver side). Gets sluggish as it clogs. Your dual pumps will work harder. I use AutoEnginuity for logs, resets etc as I work on Bimmers it's a shop tool but a good investment.


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Your vanos sounds like its still in working order... As mentioned, basic maintenance, check for codes, shadow codes can be stored without setting off a light on the dash, can be a tell tale sign of something going wrong.. The s85 loves it some plugs, every 37K miles is the bmw default interval for changing them, sooner if your modded imho..
Datalogging would be the best way to check if she is running at her best..
 

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Like others said, start with the basics like plugs, fuel filter, air filters, clean/replace MAFs, new pre-cat O2s. What made a world of difference with my E39 M5 with 95k miles, compared to the aforementioned items which I changed in the same timeframe, was running two cans of BG Air Intake System cleaner with their special injection tool. I bought the apparatus myself because it was cheaper in the long run, but a competent shop can do it and costs about $180-200. I picked up 1mpg, got a throatier exhaust sound, and it feels much peppier and smoother around town. I was actually exhaust shopping until I did the treatment, now I think it sounds perfect with the stock system. I have two cans of their Fuel Injection System Cleaner that runs through the injectors with the fuel pump disabled; that should also help with carbon buildup, but haven't had time to run it through yet.

I actually pulled my plenum off and hand sprayed each throttle body for a 10-15 seconds each, repeating until both cans were used. I found that inserting the nozzle in the intake resulted in pooling of the treatment in the manifold.

No affiliation with BG, just sharing my experience.
 

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Sounds like the car is quite normal. At 3500 rpm you've probably got around 200 bhp. A tuned 335d will have far more power at low engine speeds.
 

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Discussion Starter #7
Thanks for all the suggestions fellas..

Try the basics first. Try to reset adaptations. Make sure you on 93 octane. If not. When is the last time you did a tune up? Air filters, plugs and another issue alot of M5 enthusiasts forget to do with time is the fuel filter (driver side). Gets sluggish as it clogs. Your dual pumps will work harder. I use AutoEnginuity for logs, resets etc as I work on Bimmers it's a shop tool but a good investment.

Adaptations have been reset. I use 93 everytime I fill up. Some stations have 94, so I buy this if I am at these sations.
I dont know about the last "tune up"
I changed a few plugs, coils and air filters about 6months ago. I have been pondering doing the fuel filter, but it's a little expensive, so I would like to datalog or compare requested vs actual fuel pressures, before I keep replacing stuff.


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When was the last time the throttle actuators were replaced / rebuilt?

I believe I'm still on the originals... Where can I find a rebuild kit for these?

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Your vanos sounds like its still in working order... As mentioned, basic maintenance, check for codes, shadow codes can be stored without setting off a light on the dash, can be a tell tale sign of something going wrong.. The s85 loves it some plugs, every 37K miles is the bmw default interval for changing them, sooner if your modded imho..
Datalogging would be the best way to check if she is running at her best..
Yes, Data logging... What programs are out there, what apps to use?

Like others said, start with the basics like plugs, fuel filter, air filters, clean/replace MAFs, new pre-cat O2s. What made a world of difference with my E39 M5 with 95k miles, compared to the aforementioned items which I changed in the same timeframe, was running two cans of BG Air Intake System cleaner with their special injection tool. I bought the apparatus myself because it was cheaper in the long run, but a competent shop can do it and costs about $180-200. I picked up 1mpg, got a throatier exhaust sound, and it feels much peppier and smoother around town. I was actually exhaust shopping until I did the treatment, now I think it sounds perfect with the stock system. I have two cans of their Fuel Injection System Cleaner that runs through the injectors with the fuel pump disabled; that should also help with carbon buildup, but haven't had time to run it through yet.

I actually pulled my plenum off and hand sprayed each throttle body for a 10-15 seconds each, repeating until both cans were used. I found that inserting the nozzle in the intake resulted in pooling of the treatment in the manifold.

No affiliation with BG, just sharing my experience.
Pre-cat O2's, I have to look into these... would they not set a code if they were begining to fail? or give false readings to the DME?
 

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The S85 isn't know for it's torque, the diesel has definitely spoiled you there.
 

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Coming from a JB4 335I I feel your pain, almost thought about selling at one point. With a Pulley, Corsa, Brentune I'm more content. Just have to drive the M5 differently. Next mod 3.91 diff.
 

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Pre-cat O2s will degrade slowly over time and eventually trip a CEL when they get bad enough. I don't know how much yours cost, but a set for my E39 was only $85 from Bosch on Amazon. Cheap relative to a lot of other things that can go wrong.
 

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Check the age on your plugs. The stock intervals are 37K but they really should be replaced about twice as often to maintain optimal performance. They make a serious difference, especially at lower RPMs.
 
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