Dynojet PC-5, with Autotune, and full exh. system Tune...

So..... It is official..... Got the notice that I will get a tax refund again this year, so I thought about starting the thread a few weeks early, as I have some questions to the lurking motor tuners here. I am ordering a set of arrow headers as soon as the refund gets here. I already have a full open pipe on it, but the stock headers are restrictive, and will be replaced. I will then hop the gs on the trailer, and take the fam to Denver,CO, and have a go at Sisneros Speed Works. The owner Eddie is a wizard in tuning big singles, and his riders have taken several titles at the PPIHC. I have known him for a while now, and he build my 55hp Susuki DRZ 470. As I arrive up there, we will first dyno the bike as a base line. I wanted to pop the stock pipe on it, and have a stock base line, but with all the crap I have on it, it would be impossible for me to start with the stock headers. So unfortunately the dyno will start with arrow headers, and open pipe. Sorry, but I dont have a shop with me, and dont want to bother Eddie with all the r&r. Then we will install the PC-5, and auto tune, and then another dyno run. Here is my concern. There have been several people doing this, but none have gotten any before and after dyno graphs.... and more importantly, not talking much about it. I also remember Joel mulling something to the fact that he had little success, or have seen none to not much gain with that setup. All that talk, is leading me to the question to you wizzards out there..... Not the ones that think they know, but the real wizzards..... Many times when you have a stock set of cams....designed for a stock restrictive exhaust system, when you open up the exhaust with out re-camming it, it will loose some torque at specially low rpm. Then it will take off at mid to higher rpm. The stock lobes are groud to satisfy the somewhat restrictive exhaust system, and now when opened, it does not work good. Thus the need for aftermarket cams. Reason I think it will work in the case of the 800, is a few indicators. First, the 800 revs very fast to start with, but is somewhat flat untill 4000 rpm, where it picks up. A race bike rips from the getgo. As my drz will leave the 8gs in the dust....until about 55 where the 8gs will pull away. The real ( to me) indicator that this should work fine, is when a fellow inmate took his 650 twin ( 798cc) and stuck the cams in there, from a 8GS..... Although it ran, you could hear the now more aggressive lobes made that thing run hard at idle, and at pick up. Sort of like a race engine. Very rough idle. When I saw that video, I had a feeling that the lobe grind of the stock 8GS came are good enough to open up the exhaust. We shall see, but whatdayathink.....

(ps) Thanks to DWS underneath, for pointing this out. I forgot to mention that we will also focus on the intake side, as I clearly thinks that the 8gs is restricted with those long funky snorkels. So one dyno run in the end with the airbox cover off, should decide that.

I think you will see some gains. I can't imagine a custom tune doing anything but making gains for you.

Have you done or thought about any intake upgrades? Better flowing exhaust is all good, but more air/fuel typically means more power. The power commander should get you the extra fuel, but what about the extra air? A different cam might help with that but it doesnt sound like an option

Hhhhmmm.....ohhhhhh....uhmmmm.....gee whiz Erlng, you know what you need to do. Can't turn your back on it, if you really want to know. And I can tell, you definitely know...you got to have a full-monty stock baseline to answer this question definitively. Just ain't no way around it. Take the time to put the stock pipes back on and do it right.

If you don't, you'll always wonder if you made the right move.....and you'll never really know. Otherwise, its just bench racing speculation. 4-strokes are odd this way. Sometimes you see improvement, sometimes setbacks. And I've had a fair bit of PCV + AT, Dyno Tuning, & head work experience.

HF

Yeppers.... Yes I have. Thanks for mentioning that, as I clearly forgot to mention it in the beginning. I will edit it. I think the snorkels are restrictive. It is a very long distance the air have to travel before even entering into the airbox. As such, we will do a dyno run after the pc-5 w. at is installed, removing the airbox top. If there is any gain, and the at will adjust instantly, then My plan is to design another air intake, also higher located, as to a higher forging depth. I have fiddled with opening up air box inlets, on several scoots, and cycles, and it is a necessity. None of the ones I worked on had as long and restrictive intake tunnel as the 8gs has. I agree there is some to be gained there, but the dyno will tell. I too think the grind on the stock lobes will be fine.

Arrrrggggg..... I know I know.... But But..... I am certain that there will be improvement with the arrow headers, and wanted to focuss on the pc-5, as if I start naked, it will cost me lost more $ in the r&r of the equipment, as I most likely will not be allowed to do that myself. I agree with what you are saying, and will ask Eddie if I can borrow a corner on their parking lot...or so..... Would be really cool to have the graphs from naked....

I seriously doubt the F8 has any intake airflow restrictions. It's one of the best designs I've seen for abundant fresh air. Simple atmospheric pressure (14.7psi+\-) will instantly fill any void, not to mention the additional benefit of air pressure created by forward motion. Don't jack with it, especially not before a Dyno run. I predict it will not be a factor.

HF

Yes it will not be jacked with, until all other equipment is installed, as I need for the fi to adjust. I disagree with your assessment on the intake. While after the filter looks great, flow, angle...etc..... It is the pre filter area that I dislike. I have a few issues. First and formost, the small inlet holes. It is a small area for a 800cc bike. Most race 400-450 mx'ers have an intake area of roughly 3x3 inches. No matter of how you bend it.... static or dynamic it is small. Only reason I can come up with, knowing BMW's funny ways to design things, is to minimize intake noise, with a high snorkel. And that is just a guess. Second, the negative tapering of the intake. I don't know much of this on the intake side, but are aware of the pulse effect achievement you can have on the exhaust side. I would caution, that air will slow down as it moves through the intake and hits the filter. Third, the 90 deg. bend. Simple aerodynamics, it creates resistance.... and potential shock waves. All that is purely speculation on my behalf, and perhaps I would be wrong. The dyno will show. But I have seen this again and again. The manufactures want's no intake noise.....specially with a high snork. BMW is no different. They have shown us that they are capable of great design, but have omitted many features this bike really needed, and settled for..... " we think this is good enough for you" We shall se amigo.....we shall se.

(ps) I have heard of people knowing someone at BMW, stating the dynamic effect of the intake system achieves at highway speeds. All I can do is laugh, as it is so very funny. We picture Mad Max's intake to the blower on his hood, and while it sounds good, those tiny holes getting hit by all that crappy turbulence your face gets hit with, get's nothing added as a dynamic effect. Simply too small.

You know I bet a turbo would solve any air-flow problems...

Ha ha...yes..... but then I would have problems with holdontightous......

Will altitude have any effect on the performance or does OBC take over adjustments of the fuel / air ratio at Denvers 5280 ft

I'm just askin caus I don't know

The stock computer, will adjust the mixture according to the map loaded. The problem , with fine tuning is that that computer only uses the O2 sensor at idle to say 1/8 throttle...... and wot. Everything in between is closed loop....Ie... air, and fuel is metered according to the map installed, the temp sensor, and perhaps a little learning from the driving. But perhaps I have missed this......there are no OAP sensor ( outside air pressure ) and if that is the case it will not directly and accurately adjust. With the pc-5 and auto tune. It will bring the total system in to a wideband system, not unlike a car, where the O2 sensor is used through out the whole power band. Regardless if the stock has a OAP sensor or not, it runs with out using the O2 sensor most of the time, and depends on the stock map, and as soon as you vary stock configuration with say open pipe.....headers.,.....etc... then you are going to be off.... Hope this helps, and don't confuse you more....

(ps) After reading your question again..... I would like to add this.... that even with the computer adjusting to high altitude, you will loose some power, as air gets thinner the higher you get, and the computer subsequently schedules less fuel, and you see that as less power available.

Is there a inmate that can lend ebrabaek his or her Boosterplug and or that other one so that we can have a definitive end all independent test?

Can't wait for the results, i want to get rid of that twitchyness myself so i found a local dyno shop but not yet sure if that is the best route to go, is kinda spensive

Why don't you find a Denver inmate to bring a stock F8 by and run it on the dyno for a baseline.... Just a thought.

I thought of that, but as no bikes are the same.... each could vary 3-4 hp, and as such, you really would not get the whole story. As HF stated, the right thing would be to dyno from the start. Unless you just want to focus on the pc-5, with AT..... I will report back as I talk with the tuner.

I actually have an extra one on the shelf. It's for an upcoming project, but I won't need it while there's snow on the ground here in Ohio.

I am not getting the connection.... Please elaborate. Once the new custom maps are loaded, we can tinker with the a/f fuel ratio off idle. As the BP and the other one ( one being made in my home country of DK) enrichens the mixture just a little through out the range, the custom map wil do the same, but only off idle.... Or so I plan it...

Well i must be honest since you wanted to do the definitive end all test to stop the bullshit and do some hard science i became extremely interested in your results . You wanted to baseline and then tune, hopefully not just for more power. I am very interested in getting the bike to perform better economicly and remove this fucking surging because its a pain in the ass. Power increase to me is not that important, i would rather have a nice smooth bike, it goes as fast as it should already.

I want science, not raving reviews that show's the surge in the rpm band and it gone. I want information about how much the fuel/air mixture changes at what rpm. Adding +6 percent to everything is but a hack solution. A workaround rather than a true fix.
That's why i made my cheeky post and hoped you would fall for it.

I am in full agreement of what you say..... I truly are. I was just eluding to the boosterplug, as it is a band aid, more so than adressing the real problem.... imho. OK I am not wanting to bash the BP, because as a band aid stops the bleeding, the BP does cure the monkey hop.... I just dont like the way it does it. But back on track. To work the BP on the dyno, has no real interest for me, as it would just cost more for me, and I have no interest in it. Even as it originates from my home country of DK...... I am how ever considering to fork out the extra few hundreds of $ it would take to begin with a stock system as a base line for the first dyno run, then header, or perhaps header and pipe, then pc-5 with AT....then lastly airbox off. Or so is the plan. There are some method to the madness, as this could be a usefull package solution to all the 8gs around the world. As if this works out as forcasted, pc's could be programed by Epic motorsports/Sisneron Speed Works, along with the at, and shipped out to customers...... If EMS/SSW decides to play along. I am sure I will get to the bottom of this...... I just need to decide how low I want to start.....With the dyno config.

works for me too! :)

Soooooo... I talked with Eddie, and without going into too much detail...... The goal is two maps.... One for HP.....and one for economy....with the monkey hop of idle corrected.