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Full Akrapovic with no power commander according to BMW!

72K views 99 replies 59 participants last post by  verrucktaxe 
#1 ·
Spoke for a good 20 min. today with the head Motorrad tech at my BMW dealer about full exhausts and power commanders/remaps.

Here's what he had to say....

According to him the ECU on the S1K is totally adaptive. The idea of over-riding the ECU with a map from a power commander is a bad idea (in his opinion).

He said that when you go with a full system the bike will learn it and remap itself in a way that is absolutely optimal.

He also claims that the idea of the bike running lean is absolute bull$hit considering how "adaptive" and real time the ECU will remap.

BMW sells Akrapovic exhausts as part of their catalog and fully support their products. On the other hand any modifications to the electronics such as a power commander piggy backing on the ECU is a great way to potentially cause warranty issues if a problem came up. Hence the reason BMW does not offer any power commander options of any sort nor do they in any way support it.

As a BMW corporate option they offer full Akrapovic systems without any type of power commander and there's a reason for that....

Not sure what to make of that but it seems like a valid argument!?

What do you guys think?
 
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#3 ·
I bought a full Shorty SS Akra Evo. I planned on putting on the exhaust, driving for a few weeks then putting on the PCV so I can comment on how much better it was. As it probably is more smooth, I haven't gotten a PCV yet... Runs great. No dyno yet
 
#5 ·
I agree, it probably doesn't, but it probably does have enough to make up for a free flowing exhaust...

A power commander (or any piggyback) will allow you to make more power, exhaust or not. It's going to allow you to optimize air/fuel and timing.

The OEM ECU has the ability to learn and make changes, however, these changes are in an effort to conform to the OEM fuel/timing map which is not optimal for power. Keep in mind, when a manufacturer creates a map, they have no idea what fuel you'll be using, what ambient temps you'll be in, what the altitude will be, what humidity will be, how much load will be on the bike, etc, etc. So, their target map is very "safe".
 
#7 ·
i also have the full Akra/long can, I took my PCV off for the BMW service and yes the bike ran fine, it was noticable that I had to twist the throttle more to get the same acceleration as with the PCV and I found the throttle stop a lot easier.

The bike however runs much better with the PCV fitted: in fact it's ballistic

I also run the autotune, I have narrowed the tuning band to +/- 5% now that the map is complete, one thing that is noticeable is depending on the ambient temperature the autotune trims can vary between these limits, sometimes they are all very close to +5% and other times -5%, that's nearly a 10% swing in fuelling
 
#8 ·
not that mileage is my primary concern (i drive a V8, not a hybrid), but it is a concern if riding through west Texas in the middle of the night like a few weeks ago. the PC kicks the mixture from the below-stoich ratio to a richer ratio if i recall correctly, so how does that affect the mileage from what you guys are seeing? i got 46 mpg if i was just cruising at 90 on the way to CO. just curious.
 
#11 ·
To answer your question about fuel economy and the PCV. When I first put on my PCV with AutoTuner, I went from about 39mpg (mixed riding) to about 36mpg. Later I went to a 6-gear map where I have a separate AFR target table along with separate fuel tables (and trim tables) for each gear. I put in target AFRs in my cruising RPMs in 5th and 6th gear that are a little leaner to get the fuel mileage back and focused the other gears/areas of the map for performance. The overall combination is that I am right around 39-40 mpg again (mixed riding) and I still got the advantages (power/smoothness/acceleration gains) from the PCV.
 
#9 ·
Nothing wrong with what he said, it will remap and get back to the stock ACU's target air fuel. But that is not good enough as the target is a compromise air fuel target. The only way to fix this (and get more drive and power) is with a HP race calibration kit (which BMW supply duh!) and of a PC or similar devise. That why you inmprove the power and torque as well as the direveabilty with the PC.

P.S. My bike picked up 9hp with a PC. And that is more or less what everyone is getting here at altitude.

N.



 
#13 ·
You can... there are two bungs available for O2 sensors. They are up on the headers. Unless you run the PCV, then just plug em w/the plugs provided but you knew that ;) :).
 
#14 ·
Full Akrapovic without Power Commander and K&N air filter

I have a Full Akrapovic without Power Commander and K&N air filter, my bike is running super rich, 70 miles per tank plus 30 miles reserve, I dyno the bike and I only got 160 HP LOL, the mechanic told me that the bike computer will not auto tune itself without the catalytic (OEM Exhaust) he told me that the only way to tune it is with a Power Commander with auto tune or do a custom map without the auto tune, that will give me 10-20 HP increase and like 30 miles more per tank
 
#15 · (Edited)
Let me share. I have dyno'd my S1k several times data logging the fuel trims via GS911. As I suspected, as you approach 80% "true" throttle, the fuel trims got to 1.0, this is common with the automotive world likewise. In addition, BMW has built in around 10% more fuel than needed in the 80-100 load range (Throttle position). Hence, as long as the stock 02s are hooked up, there is enough extra fuel built in to the fuel tables to accommodate after market bolt-ons at WOT plus the ECU can make adjustments in the part throttle tables. Just for giggles, I was given a PCV and I tuned mine with the stock exhaust only altering the 100% table. Picked up a good 6 wHP, so far.
 
#17 ·
Just for giggles, I was given a PCV and I tuned mine with the stock exhaust only altering the 100% table. Picked up a good 6 wHP, so far.
so...it looks like we all calling the head of BMW Motorrad a liar?:p
No one is lying... just different intents with the responses you're comparing. Just take a look at what Ransom found by using a PCV... Most folks that put on aftermarket systems like to get the full results (performance increase) from them... hence the use of a PCV. Do you have to, according to BMW, no... Do you want to? Well, that depends on if you want to realize the full gain from that expensive exhaust system you just bought :)
 
#16 ·
so...it looks like we all calling the head of BMW Motorrad a liar?:p

or they just want to sell their HP race power kit?:rolleyes:
 
#20 ·
D@mnit! Just when I was ready to pull the trigger on buying an exhaust without a PC V, I read this. I would like to install a PCV, but I have already been told that my warranty will be canceled If I install one.
 
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#23 ·
I installed full Devil exhaust and it was immediately popping a lot, etc. I let the ECU adapt to it as I was told to do so (15 minutes from cold start, running stationary, then driving it for quite a bit, stopping and letting it run another 5-10 minutes stationary). I was surprised how much smoother everything became. The bike will still spew fire if you pin the throttle suddenly (on kick stand) but backfiring when you downshift or close the throttle during a ride is a relic of the past.:D
 
#30 ·
You lucky bastard:D I wish my dealer was that mod friendly...
I just finished putting a full TI exhaust with a PC5 from Dan Kyle and believe me it took some serious thinking on my part due to the possibility of any future warranty issue's.
I'm happy for you, as far as your dealer is concerned, good luck and enjoy
 
#31 ·
Rest easy - I have had a PC5 with the full AK evo exhaust for the last year. The dealer repaired a transmission problem without any quibbles what so ever last winter.

The stock computer system uses the O2 sensors to adjust the computer to the current conditions (temp air press, humidity) at part throttle only. This allows the bike to meet emissions regs. The stock computer is setting an AFR of 14.7 to 1 at part throttle operating conditions. Maximum power on any 4 cycle engine occurs at between 12.5 and 13.5 to 1 AFR, therefore a better power output will always result if you are allowed to specify the target AFR in the stock computer. Unfortunately, to do this, BMW offers an option: The HP tuning equipment and software. (Please pay $5000).

Now, speaking of HP tuning kits, does anybody know if the stock computer can be reflashed to emulate the HP computer? I suspect that BMW has to sell a separate ECU as an HP kit part to satisfy the emissions agencies of our governments, who would not allow the stock computer to be re-tuned so easily. Maybe I am dreaming, but if I am right and if you could get a dealer to agree to flash the HP tuning codes into your stock ECU, all you would need to have an HP ECU is the HP tuning software.

Mike
 
#33 ·
Mike, i think Alpha Racing offers something similar on ebay, not that i'm going to buy it, but, would be interesting to get some impression from the forum member...

perhaps some dyno test that compares to PCV
 
#34 ·
Let me try and roll up 10 years or so tuning experience.

How you reach the targeted AFR has very little to do with the result. Bazzaz, PCV, HP kit will all result in the same increase if you only alter the fuel trims. Now, the HP kit will alter the timing tables which gives you ability to change timing to match internal engine mods and fuel used. Without getting into a thesis of flame fronts, spark timing, compression ratios, piston design, cam design, cam timing, and achieving max power; if you only use pump gas of "correct octane" or lower octane race fuel (MR12) on a stock engine, you will not achieve much at all, if any, by changing the timing curve. In addition, you really have to change a lot internally that would require a lot of timing changes. Forced Induction or Nitrous would be some of those changes requiring a change.
 
#36 ·
low rev range is the issue for me (Akra + PCV)

as a newbie to this forum I must say that the dialog on this thread has been incredibly helpful and largely objective - keep up the balanced discussions !! :)

after running my '11 for over 6 months and 1. knowing that there was surely a larger monster to be unleashed and 2. not being happy with the CBR400 type soundtrack coming out of the rear, I fitted an Akra shorty full system. My trusty mechanic (non BMW) suggested that I run the Akra without the PCV as he had a number of clients say that the PCV hadnt made 'much' of a difference. Ive had a lot of bikes over the years (R1, Gixxers, Hayabusa) where almost by default i've fitted a combo of an Akra and PC - all have had amazing results :D . After running the bike for a few weeks I'd observed that it was definitely producing a lot more raw power but wasnt running that crisp - ie throttle response was a bit lazy. I then installed the PCV and have fairly mixed views. Above approx 5k revs, throttle response is good n crisp. Below 5k its not so responsive and this particularly noticeable on downshifts where its really hard to inject a blip of the throttle to match gears on the way down.

So, for the moment forget warranty, and understanding that ive been the beneficiary of this great Akra + PC marriage for years ( ie I know this combo will get more out of the bike than the biassed suggestions of BMW), what in your opinion is happening at the low rev range ? Do i take the bike back in and just have it re-mapped - or is there something impeding it at this rev range ? :confused:
 
#37 ·
as a newbie to this forum I must say that the dialog on this thread has been incredibly helpful and largely objective - keep up the balanced discussions !! :)

after running my '11 for over 6 months and 1. knowing that there was surely a larger monster to be unleashed and 2. not being happy with the CBR400 type soundtrack coming out of the rear, I fitted an Akra shorty full system. My trusty mechanic (non BMW) suggested that I run the Akra without the PCV as he had a number of clients say that the PCV hadnt made 'much' of a difference. Ive had a lot of bikes over the years (R1, Gixxers, Hayabusa) where almost by default i've fitted a combo of an Akra and PC - all have had amazing results :D . After running the bike for a few weeks I'd observed that it was definitely producing a lot more raw power but wasnt running that crisp - ie throttle response was a bit lazy. I then installed the PCV and have fairly mixed views. Above approx 5k revs, throttle response is good n crisp. Below 5k its not so responsive and this particularly noticeable on downshifts where its really hard to inject a blip of the throttle to match gears on the way down.

So, for the moment forget warranty, and understanding that ive been the beneficiary of this great Akra + PC marriage for years ( ie I know this combo will get more out of the bike than the biassed suggestions of BMW), what in your opinion is happening at the low rev range ? Do i take the bike back in and just have it re-mapped - or is there something impeding it at this rev range ? :confused:
For what its worth my bike has no PC and only a shorty slip on Akrapovic muffler with the standard factory headers and cat system, and i get the same feeling at low rpm. Especially when giving it a blip of throttle on downshifts, with it sometimes not really even registering that ive blipped it on the downshift. Its as if i have to really give it a firm twist to get the revs up to hear it on downshifts.
 
#38 ·
The BMW tech is wrong.

BMW does sell the slip-on with no strings attached.

The full system is only sold in combination with a HP ECU, which provides a new engine fuel/ignition mapping, as well as a revamped DTC setup. The installation of this HP package also incorporates the removal of the O2 sensors and the exhaust valve servo's.
 
#42 · (Edited)
That's funny...here is what my Dealer's service manager told me about upgrading exhaust/performance: Go with a full system of your choice and put a PCV on it that they would tune for our location....He said the HP kit isn't appropriate unless you are a serious racer and need tuning option for different tracks...just sayin.
 
#46 · (Edited)
I think if you check with the dealer, you will find that when purchasing an exhaust system (Akra) from BMW, part of the installation includes a computer flash from BMW. The system that they (BMW) sell is a package.

They have 3 different systems.

The first package comes with a full Ti Akra system, no cat and no flapper valves. It also includes a new race ECU and activation code. This one costs approx $4600.

The second package comes with a full Ti Akra system, small fist sized cat and flapper valves that hook up to the stock cables. There is NO new ecu, but there is a reflash that needs to be done. This is done by BMW. This system costs approx $2600.

The third package is just the Akra slip on. I'm not sure if a reflash is needed with this one. This slip on cost between $700 and $800.

When you buy an Akra system from anyone other than the dealer, thats when an a PCV or Auto Tune is needed.

I would prefer to purchase from a vendor of my choice, but BMW makes it a little difficult because their reflashes are specific to their supplied systems.
 
#47 ·
On the "To PCV or not" question I wish to report as follows:

I bought the Akrapovic full exhaust (race) for installation on my otherwise stock S1K, relying on comments on this forum to the effect that no fuel mapping device such as the PCV was required since the OEM BMW ECU was adaptive in it's operation and given some miles would "adapt". And only for those desiring the maximum benefit from such a full exhaust, would the fuel mapping device be required.

Upon presenting my shiny new exhaust system to my BMW service rep for installation and hearing him exclaim to the effect that the bike was going to run like s.... at other than heavy throttle loads (where I rarely, if ever ride), I thought it best to revisit this question.

I have been informed by the people who sold me the Akrapovic system that there was a 95% likelihood that the bike would require something like the PCV to make the exhaust perform correctly. In other words you have about a 5% chance that you can operate satisfactorily without a fuel mapping device. Indeed it appears that BMW's own Akarapovic full system requires some ECU management.

I ordered a PCV.

Cheers,

Curtis
 
#49 ·
About the engine warranty .....
it is valid as long you don't open the engine , and when problem happens for no immediate reason the warranty will cover it , but if the problem is from a misuse then the owner is responsible even if the bike stock and under warranty.
Remember , warranty terms and articles has to abide with the law , no commercial entity can enforce their terms , that's why all the legal agreements has to go through legal check and approval by the court of law.

About PCV & BAZZAZ & RAPIDBIKE .....
The only reason BMW dealers worn us from installing aftermarket A/F units because of the conflict of interest , they want to sell you the ECU/AKRA kit that they have.

I installed full ti akra evo shorty with bmc filter and Bazzaz , I also installed BST and ceramic ballbearings and full OHLENS front and back , I also replaced the steering damper with ohlens and the quickshifter with HM , I also eliminated the emission system .... and many other goodies.. The power the bike produced was great and I thought of sharing it with you on the following video...

ps. I think I posted the video before but it wont hurt to repost I guess

CHEERZ :)

skip to 4:00


https://www.youtube.com/watch?v=j1v32yj6SSU&list=UUi5in99agb9tuCWRZMsrcrA&index=3&feature=plcp
 
#50 ·
About PCV & BAZZAZ & RAPIDBIKE .....
The only reason BMW dealers worn us from installing aftermarket A/F units because of the conflict of interest , they want to sell you the ECU/AKRA kit that they have.
Haha, nice conspiracy theory, but no.

The only reason dealers, and including the one i work in don't advice you to install a PCV is because of our experience with those. Usually **** gets hooked together and thrown under the tank, people set it up themselves and blow up their engine, and especially with those crappy powercommanders, 1 drop of rain and you're stranded.

I've seen too many **** ups in the installation and programming of those units to really stand behind them. If i install a A/F module, it's a RapidBike and i do it myself. Coating all connectors with dielectric grease and properly routing cables. The tune is done by someone close by who has proven to be a good tuner.

And finally, the reason BMW scraps your warranty when you install a (for example) PCV is because the engine software is no longer a 'BMW job', and thus, BMW does not want to be liable in case an engine blows (which again, i've seen happen due to a ****ed up installation). Which is nothing short of logical?
 
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