A Royal Enfield forum for the people

[gashousegorilla]

My personal thoughts on what I think you would be happy with and get where you want to be ?...

...lots of good advice follows...

And any questions, don't hesitate to ask . Always happy to help another Enfield guy out if i can.

Many thanks for your advice and willingness to share your expertise. I'm probably a couple months away from doing anything (other than throwing on a modified Harley muffler) but want to start preparing the budget.

One question, though. You removed the O2 sensor (or at least faked out the PC with a resistor) - I was thinking it would be better to retain it, since the PC will address the overly lean running. Just seems like keeping that loop closed would provide useful information. I don't doubt I'm wrong, but when you get a moment, could you explain the logic there?

Thanks!

No problem swamp.

OK, the Narrow band sensor on these bikes is there as a pollution control devise and really that is it. It is there to bring the air fuel mixture as close as it can to 14.7:1 ... the ideal air fuel mixture for complete combustion in a lab setting. It is not the ideal air fuel mixture for power . And at 14.7:1 you are also very near the HOTTEST combustion temps. And remember , this an air cooler motor. No water Jacket to keep temps under control. 14.7:1 also plays nice with the catalytic converter. So basically for me , and this air cooled motor , not to mention the legions of modified similar Harley air cooled motors out there . The stock NARROW band sensor just gets in the way of tuning the air fuel ratio's to ideal for power and Engine cooling.

A NARROW band sensor does just that... it operates in a very NARROW range, around 14.7:1. And the farther away from 14.7:1 the voltage seen by the ECU gets , the less accurate it is. It's basically just a switch between a little too lean and a little to rich.. FOR a stock bike. It can not accurately get to the richer air fuel ratio's that one is shooting for when tuning for power and better throttle response. So ... we stick in a cheater to just trick the ECU into thinking that a Narrow band sensor is " THERE" , so you don't get a mil light. This puts the ECU into a fixed Map, then we intercept the signals coming back to the ECU from the sensors with the PC-V. And correct then to ones needs with a SUPER accurate WIDE band sensor . Which can put you exactly where one want's to be , at any throttle position and RPM.

A PC-V CAN be used with the stock Narrow band sensor . But you will have no control of the air fuel mixture when the ECU is in closed loop, or when using the Narrow band sensor. When would this be ? Well, when throttle is in a fixed and steady position... because the Narrow band sensor act's slow and is just a switch it needs time to work . A good example I think would be ? Your cruising or blasting down the highway in the summer, in a fixed throttle position , the air fuel ratio will be very near to 14.7: ! . You'll save a little bit on fuel , but your power will be down and you motor will be running HOTTER. One should remember also , that here in the states , most of our fuel has 10% Ethanol in it . So it requires a richer air fuel mixture ... more like 14.1:1 . This may not sound like a big difference, but it is for an air cooled motor. Not so much for a water cooled car motor , or like how most of the modern bike motors are now. What may apply to a modern Japanese water cooled motor , does not apply here. Engines are different, with different system's and what my apply to one , may not apply to another.

And depending on how deep you go or what steps you take with your mods... you might be beyond the range where the stock narrow band sensor can compensate. Certainly Cams and head work . And Every pipe , muffler or intake flows different and will require a different adjustment, to get to ideal. I can tell you that a very small air fuel adjustment between 12.8 and 13.2 :1 for instance can make a big difference in power and fuel economy... and be the difference between a fouled spark plug or not. I usually tune in the AFR range of 13.2-13.5 on these motor's . 14.7:1 ?! Is WAY out of the picture for me ...

Even on a bone stock UCE , with stock intake and exhaust. You guys ever notice everyone is talking about what plug to use on that other Forum ? .. Hehehehe . " Oh that stock plug is crap and this and that... ya gotta put in an NGK plug !" " " My stock plug was always fouling !" Well that stock Bosch plug ain't the best , and it has duel electrodes for India's crap fuel . So they stick in a little hotter Running NGK and things are mostly better . Because it keep the plug cleaner . But it ain't the plugs doing it . It's the air fuel ratio on these bikes ! These bikes take for F'ing EVER to warm up and get to operating temp . Especially in the cool weather. Mostly to do with the ridiculously and overly rich air fuel mixture at start up and until they can get hot enough to even get in closed loop. They run at air fuel ratio's of between 10.0:1 and 11.0:1 !! Crazy rich ! And it can take a good 10-15 minutes at idle to get the motor near operating temps. Remember , That Narrow band sensor can not make WIDE and accurate air fuel corrections , until the motor is stable and at operating temps. At 10 or 11:1 is too far away . With a PC-V , you can pull out all that wasted and unnecessary fuel going in there at start up and idle. These bikes run VERY rich again ,when you crack crack open the throttle. The air fuel ratio dips down rich again to that 10 or 11 area .. and then lean out as the RPM's come up. Again , this can be straightened out with a PC-V...

[swamp2]

Thanks for the treatise, Doctor! Yeah, I guess I pretty much get the narrow band vs wide band stuff. Do you have a wideband sensor on the bike now, or does it just get used on the dyno to figure out what the maps should be? I've had PC's on a few of my bikes over the years, but never fussed around with a dyno - just loaded pre-existing maps that were allegedly close to the configurations I was running. Perhaps slightly less than optimum, but I've never been dissatisfied with how the bikes ran.

What is the logic behind the factory making the bike run so rich when cold? Never even need to use the bi-starter thing,

[gashousegorilla]

Yes , I have that Dynojet AT-200 with the Wide band sensor , add on hooked up to the PC-V's on my bikes. And I keep it active even after I am done and satisfied with the tune on the bike ... but you don't have to . So in effect , I'm always running in "closed loop " , and the wide band will adjust the AFR's on the fly a bit. I just narrow down the adjustment range. Going to a Dyno , as I'm sure you know , every time I want to try or do something different is crazy expensive and time consuming. I did that for a while , before I got smart . Hahaha ! So now I can do this out that to my bikes , and basically just ride the thing and it gets it to were I want it to be pretty darn quickly. And it's more fun this way .. to me anyway.

Why did they tune them so Rich in certain area' s ? Not sure , maybe just a scatter gun approach type thing ? They export these bikes all over . And I believe that the Export ECU are or where all the same. Different fuels , different climates , altitudes and etc ? Try to get it as good as they can fro everywhere type thing, and meet different emission standards. The rich start up and idle might not be as big of a deal in places like Australia where it's hot most of the time and the fuel vaporizes much quicker . And OK here in the summer , but not quite as good in the colder months . Use the By-starter type thing as a compromise , when it's needed. And you need it rich when you roll on the throttle ... but not that much richer as they have it ? I don't know ... maybe it's that transition from when the bike is in closed loop working off the narrow band sensor , and it just goes real rich until it can correct it's self. You don't crisp throttle response that way ..

Anything you do to these motors , as far as intake or exhaust.. Cams , head work and etc. I have found anyway, will cause this rich start up and idle to be come worse , and even get richer for the first 1 or 2000 rpms . And the greater the change is , the worse it is. I find my self pulling out bucket loads of fuel out down low. I believe that these effects are caused by the different readings that the MAP sensor on the throttle body no see's . This in a Speed Density based EFI system ,... i'm pretty sure anyway . So any change in the manifold pressure will have the ECU " thinking " , that the motor is still stock, and it needs more fuel and perhaps more timing. Or that is just goes beyond or outside of the range whic is pre-programmed into the ECU based on a stock bike. You might have the same throttle position, your engine temps are the same , But the manifold pressure is now different..

[swamp2]

Thanks for the additional feedback. I have to ask, is the stock intake/filter really an impediment to breathing? Seems like the filter has a lot of surface area, more than the pod filters. I can see disconnecting the crankcase breather from the airbox but other than that, I don't see where the gains would come from.

Also... been researching the PC-V and Powertronic things. On the surface, it looks like the Powertronic is a better value, with a bit more functionality for less $. I see it listed for a C5, is there any reason it wouldn't work on my G5?

[Tim]

I would spend the extra money for the Power Commander. They are top of the pile in my opinion, also they have tech support on staff.

[swamp2]

Ok, what's the prevailing wisdom on the Dobeck EJK?

[gashousegorilla]

Ok, what's the prevailing wisdom on the Dobeck EJK?

The guy who started Dynojet , actually moved on after he sold the company and started EJK. It's a less expensive, less complex and " Dumbed down" alternative to the to the PC-V... you get what you pay for. Probably " OK" , if all you are ever going to do is just change the intake and exhaust.. stage 1 stuff. You can only " tune" in a few area's ... low , mid , top end and acceleration I believe. With the PC-V, you can tune in every throttle position and rpm .. and gear if you so choose. You can not take fuel OUT with the EJK, you can only add fuel. The PC-V, you can do both. You can not adjust the ignition advance or the rev extension with the EJK, with the PC-V you can. EJK recommends a separate AFR gauge and wide band sensor to get things perfect, to rent or buy. ... you basically ride around and watch your AFR's on the gauge , then start hitting buttons on the thing trying to dial it . Withe PC-V, and the auto tuner hooked up to it.... you type in your target AFR's , and as you ride the bike, it automatically adjusts to those targets. And you can accept or clear those changes, or narrow or broaden those changes .... complete and full control with the PC-V and auto tuner. The EJK... not so much.

[gashousegorilla]

Target AFR G5 zoomed.PNG (510.1 KiB) Viewed 513 times

I'll give you some examples here of tuning with an auto tuner hooked up to the PC-V. As mentioned earlier , it uses a wide band sensor to tune ... just like they do on a Dyno. And the software is very similar.. if not the same. They use an auto tuner on a Dyno as well, to get them close and then they might tweak it a little bit here and there , based on what they see as far as power output .. but your just doing the same thing on the road , without the benefit of actual seeing what kind of power your making. You can always take it and put it on a Dyno , if..." you just gotta know what it is ! " type thing. Taking your bike and putting it on a Dyno to just see what kind of power it is making , is a fraction of the cost of having it TUNED on a Dyno. Actually KNOWING what the new power output is, is not a MUST , unless your curious.

Anyway... This is an example of how you set your Target Air fuel ratio's. And these numbers work well with the Enfield's I have found. With super unleaded, 10% ethanol laced pump piss....

[gashousegorilla]

OK, after you have punched in those Target numbers... you take the bike for a ride . It might take several rides actually, and the more throttle positions and RPM's you hit, the better. You want the motor tuned across the whole range. But the idea here is to is hit them all. They do the SAME thing on a Dyno ... hit the different throttle positions and rpm's , hold the throttle in that position for a few moments , and it auto tunes them in. It just quicker on a Dyno . But on the road, you are doing it in real world conditions ... real world loads and how YOU ride the bike. Anyway... when you get back from your ride , you take a look at your trim table. Fuel Trims are the amount .. in a percentage of an air fuel ratio.... that has changed, to get you to where you want to be. For example ... if you see a "5 " in one of those little boxes. That means it added 5% to whatever the air fuel ratio WAS as stock , to get you to your target AFR. A "-5" would be a percentage taken OUT. 5% is really next nothing as far as AFR's go, but just an example here.

Anyway, you get back home and take a look at your trims and they might look something like this... Notice how there is fuel added and TAKEN OUT in various places ? It ain't ALL about ADDING fuel.

Trims G5.PNG (314.08 KiB) Viewed 511 times

[gashousegorilla]

OK, after you looked at your trims to see what went on, and your happy with how the motor performed. At this point you can accept those trims , and it will change your fuel map.. or fuel table in this case. And your bike will run off of this current fuel table if you so choose. OR .. you can keep the auto tuner active and continue to tune . ... It's to up to you. And you can narrow or broaden the percentage change per riding session ... or leave it active. But usually what I do , is take it for a good three rides and I'm there . I accept those changes after each ride . When I'm done.. I just narrow down the adjustment range to 10%, and it will continue auto adjust a little back and forth in that range. I'll post that image tomorrow or later....