Poor low RPM performance (first post)

[Rilot]

OK, I have now fitted a TRE (did the 15k resistor mod rather than shell out for the ready built) and this has really sorted it out at under 2000RPM. The difference is unbeliveable. No more hesitation. No more spluttering. There is still a little hesitation at 2200RPM ish but I will get this sorted with more Dyno time and a re-map. I made the mod switchable with a SPDT switch so I could really compare the difference while out riding.

If anyone else is having anything like this problem then I can highly recommend fitting the TRE. It has made a world of difference. I was laying huge darkies from 1500RPM in first on my ride this evening

Thanks for all the help and advice tracking this problem down. Glad I didn't have to pull cam shafts.

 

[Narcissus]

It is always something simple.

Since you made it switchable, you can tell just how much of a difference it makes. I sometimes forget to activate mine, it does make a huge difference.

Now, if I can just figure out how to reprogram these chips and do away with needing a TRE altogether......

 

[SierraFlyer]

Can you tune it out? My guess - and I have no proof of this - is that the Power Commander type unit only fixes adjusts fuel mix/and overall timing advance and not timing retard. The ECU retards the first three gears at low RPM (under 5K) for drivability. The TRE tricks the ECU to think its in 5th or 6th gear depending on resistor value and therefore bypasses the retarded maps in gears 1-3 . The power commanders take the ECU signals and adjust them to effect the performance needed. Here is what I don't understand yet - if you adjust the PC 2(or3 on newer bikes) to correct the timing at lower RPM in gears 1-3, then won't it advance the top end too much at the same time?
To get rid of the TRE you would need to remap the timing in the ECU and get rid of the retard completely. Factory makes a reprogrammer that may do this but it is about $600. If you want to get into the Busa remapping business it might be worth it?

Like you I made a switchable TRE. It is great! The first thing you notice is the sound is different. Low RPM stock is a rumbling kind of sound. With TRE, the exhaust almost crackles. What was the best part for me was the power surge problem was gone. Now when in a turn, barely cracking the throttle at about 5k won't cause the front end to lift up suddently when the ECU comes out of retard to full advance unexpectedly. Low PRM quick throttle openings don't result in the bog and then surge syndrome either. You get a more consistant throttle response at every RPM. To get this without TRE would require a total ECU remap I THINK. Hopefully other with more experience will sound off.

 

[race24x]

I thought the PCII did not adjust timing until the PCIII came out I understand the Yosh box does though