I have been reading this forum for some time as I am in the market for an EFI change on my 2007 Roadking as I am installing new pipes/ac and cam. My main goal is to have a setup that will be good for two-up touring. The problems I need to solve involve the heat issue of this motor and hesitations at low speed. I have boiled this down to three choices. Thundermax with autotune, Harley’s Sert or PowerComander PCIII. Before I purchase any of these I still have a some EFI questions the first one is about running in closed loop mode for each of these. If I understand correctly in order to get an AFR of say 13:1 in the lower rpm range I will not be running in closed loop mode with either SERT or PCIII. I will need to run SERT in openloop in the lower RPM range and closed loop in the upper ranges, with PCIII I Would need to run O2 eliminators to get this AFR putting me in openloop mode in the upper ranges also. Thundermax should allow me to stay in closed loop at all rpm’s. The next questions invlolves SERT and VE could someone explain how this established following engine mod’s. I was told thundermax I may have slight problem with two-up riding as this system reads throttle position to sense load and is not as good as the stock Delphi unit that sense air flow has anyone else heard this.

Thanks for any info.

 

Low end hesitation can be caused by the cam and pipe selection along with a badly tuned motor, so my question to you is what cam and pipe did you select...mater of fact what are your all mods going to be?

The SERT (with 02 sensors) runs in closed loop from 20~80 kpa on most maps today, this means as long as the AFR table has 14.6 in the grid thatgrid is running in closedloop and any grid that has anything else other than 14.6 is in open loop. The 90~100kpa area will not allowyou to set the AFR any leaner that 13.2 so there is no way you can run in closed loop on top end. If youchange the AFR table to 13.2 like you suggested it will no longer be in closed loop where these changeshave been made, the bike will run good but the mileage will be VERY poor. The bike is not under a load in the cruise area, even two up, so to take it out of closed loop isn't necessary to get a little richer fuel. You can alter theClosed Loop BiasTable....this table controls the 02 Switching Device voltage that the ECM uses to decide the AFR in the closed loop area. In other words a voltage of .450 would be 14.6, a higher voltage like .550 would be 14.4, a voltage of .650 would be 14.2 and maxed out voltage of .798 would give you an AFR around 14.1 or so in the closed loop area .With maxed out Bias Voltage every where the AFR is set at 14.6 will actually 14.1 or so AFR and this is rich enough for any cruising you will be doing and it will run cooler that it did before. The down side to maxing out the Bias Voltage is the 02 sensor switching device is at it's learning limit and this will shorten it's life span to 6000~10,000 miles. If you maxed out the CLB table andyouexperience the bike running hot again it's possible the 02 sensors need changed out. Or you could simply set the cruise area at 14.1 and leave it......the map will be out of closed loop at this time so there will be no more 02 data for the Adaptive Fuel learning. (another long subject)

How does the SERT get the correct VE with Mods done.....well it's the tuners job to tell the ECM how much air is traveling through the motor, he does this with a process of synchronizing the AFR table to the VE table which is more of an explanation than I want to get into here. I will tell you tihis, if the tuner doesn't do this step in every throttle position which is very time consuning the tune is worthless.This is why the tuner plays such a big part in the way the bike will act allthrough the map. The Delphi system does not sense air movement, there is no mass air sensor on a Harley so again the Tuner has to tell the ECM there is more air flowing through the motor after mods are done.

Now as far as the TMax goes....all I can say about this is it is two dementional, it uses throttle position and rpm not a map sensor to sense load on the bike. I sure some of these TMsx guys will chime in to give you better information on it than I can.

Hope this helps

_____________________________

HDMD TUNING CENTER
352-242-9616
hdmd88@yahoo.com

 

Doc,

Your a great resource in this forum and I thank you for your explanations.
In answer to your questions as to the mods I will perform. I plan on RUSH pipes with
Fuel moto baffles or Supertrapp SE, SE AC and SE255 cam I believe. Some of my misunderstanding could have come from a combination of places. I ride with someone
Who has the Rush pipe and cam setup and has had the hesitation/heat issues at or around idle using Se race tuner and has been looking into Tmax. He has had this setup dynoed three separate times with little to no change in the overall rideabilty. The first dyno tune was a portable unit and he thought this might have been the problem. But as it turned out this may have been the best of the three. The other was preformed by a HD dealer, but come to find out had the dyno had been installed with in a month of his tune. The dealer says there is not much that can be done for the heat because of the o2 sensors. But from what you seem to be telling me this can be reduced.
I would prefer to use Se race tuner but issue here is getting a knowledgeable tuner to work though the issues.

Thanks for helping the ill informed,

 

The 255 cam will retain some heat at the lower end rpms mainly because this is the only performance cam that has all its power between 2000 and 3500 rpm. No this is good for a person that doesn't twist the throttle that much because this camfall on it's face at 4000 REALLY hard....I mean it's done at 4000 and drops like a rock......! A Fat Cat would great with this cam because the Fat Cat also produces more tq at 2000 to 3500rpms than I ever seen. I cant see the hesitation here with these cams....they start too early to cause problems off idle.....if you have off idle problems you call me and we will go through a process to set the DBW back to Zero.

As far as a tuner you guys have one of the BEST in a man that calls himself ''GRock'' from th 'V-Twin Forum.com' or you might get Dave from JD's Cycle Works in Pa above Philly in Bethelem....he's real good too. You might have to travel a while to find who you need. Both these guys would be worth the trip.

Doc