BMW F800GS engine tuning

There are some guys on here who have one and like it, señormoto is one. Do a search and you'll find his posts.

Why exactly should the PC be a bad idea if tuned right?? :huh

I agree..... In reality, I have seen many state that they were going to do this, but none has documented any detail..... Like with or without autotune, dyno runs, before and after mileage. Too many people thinks it is just a matter of bolting the thing on, as the manufacture states in their propaganda. What most dont understand is that it is not just about more gas, and I think that any map enclosed, or written with autotune, will kill the great mpg. the 8GS gets. Only way to do this is with a reputable tuner...... dyno runs before, and after. With autotune, it is a bit easier, as it is more of a set and forget. When I do this, I will have a handlebar switch mounted..... ( I know...I know....another one...right...), and then match the stock map setup for economy, and then with a push of a button....power.

Thanks for the feedback guys!

I'm considering PCV with Autotune, having one constantly learning map and one more or less zero-map for economy-touring. Not sure if it's worth the effort though. I'm running an Akra with th Dbkiller in place, think it's too loud without it for longer rides. Also have a K&N ready for use.

It would be really interesting to get som mpg-numbers, before and after. I really like the fuel economy. Any thoughts about how much of a mpg-hit one would get?

Best regards,
Mats

If you plan on keeping the db killer in, I would suspect that you will see no change in power, as the engine need to accommodate more gas, it needs to flow better. MPG is just a guess.... but 5 mpg decrease in power mode.
Hej paa dej......

Tack för svaret Erling!

Maybe the IICE-stuff would be good enough - my main issue is the throttle response when manouevering at low revs in 1st and 2nd gear. More improvement is just a bonus!

I guess that for a real increase of power the cat and the DBkiller would have to go, but then again, we have no Planet B when this one gets too poisoned and I really don't need to disturb my neighbours any more. It's noisy enough when going for longer rides...

Best regards,
Mats P

Yeppers..... I agree..... and know how strict the "Bil og motorcykkel syn" are in Scandinavia. But in reality, if tuned right, i doubt you would pollute much more if any with the cat removed. Remember the FI systems are old and antiquated as compared with automobile systems.....and as far as unburned gasses.... they will occur with the cat in place if you change the a/f towards rich anyway. If memory serves me correct, they will come after you if you remove the cat, if it was installed from the factory. It would be great if you post your effort here, as we all would like to see this......

Will keep you posted!

Now i'm checking if the PCV+autotune will work on my F8GS. Bought new in march 2009 but when I checked the VIN it was manufactured in september 2008. And apparently the 2008:s should run a PC3, not a PCV. I didn't know that there was any differences betweeen the 2008 and 2009?!?!

Well, I've put the question to Dynojet. We'll se what the answer is!

That mostly is just a ordering boof....... They should take the same unit. That's how it goes many times when manufactures set's up internet ordering...... Bike is same.....

Hiya , yeah I have both , tho am thinking about taking the auto tune off and getting the bike dyno'd , adding the power commander was one of the best mods I have done . Previously I had done a booster plug was better but the difference with on the F8 with the pCV was immense , makes it a really nice bike to ride .
Cheeers
Magoo

What happened to your mpg? Can you still ride the bike and get low fuel consumption? Of course the consumption depends on your driving manners, but if the Autotune enriches the mixture on most rev's, you could get a lot higher consumption....

What kind of exhaust and airfilters do you use?

Best regards,
Mats

You dont need to take off the auto tune..... Just program the parameters leaner..... if this is your issue.... Autotune is your friend.... But a trip to the dyno is good, as you other why need to adjust....ride....adjust....ride.... etc..

Hi guys!

According to Dynojet all F800:s manufactured from july are considered "next years model". So, 2008:s made from july 2008 will work with the PCV.

Best regards,
Mats

You don't tune only for revs but also for throttle position. So you can get exactly the same mileage when you take it easy and then have more power available when you really give it some gas.

Good input!

It would be most interesting to see what ideal Autotune strives for and how many "inputs" it uses compared to the original. Of course one can study any pre-fabricated map and also see the exact target AFRs for different revs and so on. Since you have to replace the O2-sensor you will partially disable the original capacity to adjust...

Do you know all the original sensors/inputs and how the ECU will suffer from the loss of the O2-sensor and that you have to plug the extra airhose for burning exhausts?

Ideally one should be able to get better mileage when driving calmly and better hp/torque when driving aggressively, but with a mpg-hit... But everybody that writes in forums about the PVC on F800s seems to get a lot higher fuel consumption

Best regards,
Mats

I would like to caution a little. The a/f ratio for max power will be around 13.5....give and take one unit...... The stock map on the 8gs, I have heard that it rolls as high as 17..... which will not yield max power, but sort of dangerous lean mix. I don't think any tuner would incorporate this in a power map, as it is too lean. But by saving two maps, and capable to toggle between then with a say handlebar switch...... You could set one to say 13.5 a/f ratio....and then hover the other map to h leaner mix...perhaps mimicking the stock map.....less the idle takeoff, to minimize the bunny hopping, and your golden.

I will go out on a limb here, and say that is because of their tuners..... Think about it.... You show up at a tuner, with a bike,,,,PV5/AT.......most tuners will not focus on economy..... but rather ...max power. It is quite simple to get both, but first you have to sniff the a/f ratio of several stock runs, to get an idea of where it runs...... Then just mimic those parameters in the second map.

I don't understand your reasoning Erling.

If I tune the bike to inject more fuel when I open the throttle more, say above 50%, but leave the lower TPS positions stock, how would that be dangerously lean, any more so than a stock engine? :huh

There is no point to having a map for 13.5:1 throughout, you are just wasting fuel if the engine is not under load.

Really interesting!

I'm going to dive into the AFR-tables in Dynojets published maps for the F8GS and see what the values are.

My concern is - if I use a zero map but have disconnected the original O2 sensor and plugged the airhose - will the bike use more gasoline than before? The ECU will get less input. If this causes the bike to use more gasoline it would explain why everbody that mounted a PCV w/wo Autotune seems to take a mpg-hit! Or do they just drive more aggressively after mounting the kit?

Best regards,
Mats

Well.... if everything works perfect....then you could just do that..... at less than 50% throttle set it to a high a/f ratio, and then anything above 50% throttle transfer to 13.5%.... But what I was eluding to was that running as lean as it does stock, to achieve the great fuel economy as it does..... You need to be very careful with all parameters. That is what the stock map is good at.....and it is engineered to be. I am not sure of the exact parameters of the stock map..... But I would approach "copying" said map with caution, as you can destroy that engine very fast. Combining it into one map..... I would not do, as there might be times below say 50% that you wanted to run a richer mix....like for the bunny hopping, and other trail side excursions. The biggest thing to take away here is to align yourself with a reputable tuner, that understands your goals. Then he/she spend some time sniffing the stock map....work out the bunny hopping kink out of that.....then store those parameter as a economy map..... then goes on to create a max power map....... I have a tuner lined up here in the states in Denver,CO..... But I will do mine with a set of remus or arrow headers first.....and money are a little tight right now. It would be interesting though to see what my fellow Scandinavian comes up with...... Last dyno graph I saw for the 8gs....had no a/f ratio, so to me...it was just a set of lines....

I am guessing the increased throttle response is what gets you..... The throttle response is slow on the 8gs......but only for a second...or two. I suspect that is from the stock map.... which manifests itself as the "bunny hopping" off idle....which is one of the biggest reasons I am eventually doing this. When you ride a race bike with lightening fast throttle response...... You get bitten. When I need the thrill, outside our aircraft,....I ride this.....


With lightening fast throttle response, as 55 rwhp, this 300 pound enduro will get to 80 km/hr before even many sport bikes will.... and I think... yet still get 55 mpg.... as of the implications with a zero map.... I would be cautious running that with the o2 disconnected. If you are going to this do yourself..... Then plug in the pc-5 and the auto tune..... with it's o2 sensor.... The run that at zero input...... and only change one thing at the time. If you can rig a setup with a laptop...... you can see the a/f ratio's as you ride under different throttle positions.