It's a little more but hardly twice as much ... you can purchase it at a pretty good discount from the usual suspects.

Not better or worse IMHO, just different and like I said: a tool. The tune and the experience of the tuner is much more important IMHO. An extra $100 here or there is nothing compared to the joy of a well-tuned bike. I've got a PCIII, had a SERT previously, I like them both for different reasons. I'll never own one of those DFO or FuelPack or similar boxes. Simple is as simple does I say.

 

(PowerCommander or V&H fuel pack is the only way to go....quote)........ you must have a mostly stock scooot because i went pc3 and it was terrible with my 98inch 10.5 to 1 compression build.... the only way i could of used pc3 was to get a stage 2 flash from a dealer.....

i dont have close to 2 grand in the tune... and just so we understand... the Only thing a harley dealer was involved with was when i walked in and told them i wanted a sert........ then i went outside harley to someone "kevin" who has no affiliation with harleys, other than his personal ownership of one...there was not one "dealer" that had ANY influence on the route i took.... No Harley Traps here!!!

 

If the SERT will indeed allow use of the O2 sensors but it'll only allow you to run in closed loop mode (that's the mode that uses the sensors) at air:fuel ratios in the ballpark of 14.2:1 to the 14.7:1 the EPA wants you to use (to burn up your engine). You'll not get rid of much heat that way.

Is there a way of using a SERT and tune to an air:fuel ratio of 13.2:1 as mentioned, tune for ~13.2:1 and run the **** out of it.

Ordered a 08 streetglide either doing a 103 or 110 kit before I pick it up with D&D pipe, aircleaner, etc.

What do you guys think?

 

Yes, you can use the SERT to tune to even 10:1 if you want, but the closed-loop mode uses the O2 sensors to dynamically ensure the target ratio is maintained, and the sensors themselves are only good for about 14:1 to 15:1 (unless HD went with wide-band units for '08, but it's very unlikely that would yield EPA approval unless there were a way to totally ensure the 14.6:1 could be locked in for the normal operating conditions).

Getting out of the range of the narrow-band O2 sensors runs you in open-loop mode, which is how all(?) the piggy-back fuelers operate. Most for very much less cost and some with a great deal of control/adjustment capabilities.

 

Me too/neither. For the same reason I run Linux on the computer instead of Windows. I've used the phrase a few times now in the last couple of days but it's just so apt: they're (the "simpler" tuners and Windows) all like a car with the hood welded shut. I prefer the ability to open the hood, so to speak, and make changes from time to time.

 

You can make Big Horsepower with a PC3.We have multiple tuners in our area Cycle Rama.

 

Dear glens

Ok i understand fuel injection on cars to a ok degree, but how if you can tune the SERT to what ever air-fuel ratio how does the computer over ride it to run back to 14.2:1 or epa std. in what mode?

I need all of your guys input Call me stupid I am used to a carb.

 

Ok now im wondering what I want after reading all this...............lol dang it.

I got 07 SG stock, runs hot as hell, gonna get slip ons, air kit and either a PCIII or SERT. BUT when or if I do engine work which unit will still be usable?


Im asking, which unit will work for stage 1 AND engine work (110" kit, cams etc...). Or will I be buying 2 unts?


Granted these changes will be way apart in time.

 

Most modern fuel injection systems have two modes. Open-loop and closed-loop. Under normal driving conditions you are running in closed mode which is reading the O2 sensors.

While in closed mode, your ECU is attempting to run the bike as close to stoich (14.7 AFR) as possible. This will maximize fuel economy and reduce emissions, however it's too lean for optimal power (not to mention that it makes the motor run hot as hell). While in closed mode it will read the O2s and, if it's too lean (above 14.7 AFR), it gives it a bit more gas to meet that mark. If it's too rich (below 14.7 AFR), it will lean the mixture out.

When you hammer the throttle wide open (or when the motor is initially warming up), typically the ECU will switch to open loop mode. In this mode, the O2 sensors are ignored and the motor uses calibration tables to "guess" at what estimated AFR to apply given your current conditions (RPM, timing, etc,).

The PCIII is an open loop only system. The SERT can operate your existing O2s in closed loop mode. The range of the factory O2s are way too lmited though. They only measure a small range above or below 14.7 AFR. A system like the DTT or TMAT with wide-band O2s is the best way to go but is considerably more expensive. The PCIII is a great setup, but without a closed loop mode you will probably never get optimum fuel economy however, it has a large, friendly user community if you are going to try to tune it yourself. The SERT retains your closed loop ability and probably would give you better overall fuel economy, but is also mainly supported by a closed group of people (mostly dealers). You can program a SERT yourself, but it's not like a PCIII where you can post up a message looking for someone to send you a config for Rush mufflers, SE air cleaner, and V&H true duals.

The real question is who's doing your tuning? If you're having a shop do everything, a SERT might be better for you. If you are doing it yourself, you might find the PCIII user community to be much more friendly and helpful. If you want my recommendation, get a DTT or TMAT and be done with it in one swoop! For the do-it-yourself'er, you can't beat the auto-tuning functions on these two ECUs. Everyone asks about the price of the hardware, but "good" tuning costs big bucks for someone to spend 4-5 hours tuning on your bike. By the time you add up just purchasing the less expensive PCIII and adding just 2 hours worth of dyno tuning, you could probably have bought a DTT or TMAT unit.

Best of luck,
Drel

 

Thanks, Drel.

I very basically went over that back up in post #34.

What follows is my interpretation of what I've gathered in non-exhaustive study. I reserve the right to be wrong. And this is not meant in any way to cover all aspects of what's going on.

The Daytona Twin Tech and the similar Thundermax ECU replacement packages only use a two-dimensional lookup table while the Delphi (stock) unit uses a three-dimensional one. The way I'm using those terms is this:

They all use a lookup table which is a square grid having rows and columns, one each for RPM and Throttle Position values. The computer at any given instance takes both current values and pulls the injector on-time (or target AFR) value from the intersecting location within the grid.

The PC-III does the same thing within its own two-dimensional table to find any over-ride value with which to modify the main ECU's derived injector timing. (the reason I'm singling out the PC-III is because the user has access to its lookup table and can discreetly modify it; the other piggyback units have their "hoods welded shut" to varying degrees in comparison; also, the PC-III has similar capability with ignition timing, and can modify both it and fuel values for each cylinder independently)

The Delphi unit also has a third dimension to its lookup table (think of it as a cube full of values, instead of just a square grid). That third dimension is the intake pressure (usually a negative value) from the MAP sensor.

I could be running 8% throttle at 3500 rpm with any of the three main ECUs and they would all look up the appropriate injector on-time value (or target AFR) for that situation in their tables. What the Delphi ECU also does is look along its third axis to determine what the load on the engine is before making its final determination. I could be at that rpm/throttle_opening going down a hill or going up one. The fuel necessary for either of those situations, would it be the same or different? The Delphi can tell.

If the Delphi could make use of wide-band O2 sensors to enable closed-loop control everywhere (not just idle/cruise modes), or if the DTT/TMAX could make use of the MAP sensor, the best possible tuning control would be available to us. As it is, even with the SERT, they all offer us certain compromises. The SERT will, at least, allow us to "trim" the values its O2 sensors report such that we can get the closed-loop AFR down to the low 14s to 1. The DTT/TMAX can do closed-loop everywhere to any (reasonable) AFR target but don't take engine load into consideration.

Oh, I googled the Cobra unit and it's nothing more than a very-well-packaged Dobeck "techlusion"(sp?) unit.