It's simple....packages is the goal, you need all your parts to work together. If I have a 255 cam I have a build that is all about tq at 2000 to 4000 rpm so I want a pipe that works well at these rpms and the 2'' baffle does just that. If I have a 2.25 or a 2.50 baffle it will not work well in the lower rpms however at 4000 rpm and up they will work just fine. Personall yI can care less about 6000 rpm cause 99.999% of my customers don't ride there....they do ride between 2000 and 4000 so what do I have to gain with a larger baffle.
The other thing is the more back pressure I have the better the 02 sensors work and the better the tune comes out....I want the bike to run smooth from 750 rpm to 5500 rpm and the 2'' baffle works the best in that area.
Doc
Thanks Doc. I'm getting a lot of mixed messaged about the direction that I should go and I'm not sure what I should do. I don't want to spend thousands of dollars dyno tuning different parts combinations trying to find the right setup. I also don't want to be riding around second guessing my build (should I have done this instead of that). Like you, I want my power between 2K and 4.5K RPM.
I've got a 110 with:
- T-MAN CVO Street Performer Kit - Includes:
- CVO Street Performer Heads (2.130 intake and 1.630 exhaust valves)
- T-Man 555 Cams (same grind as T-MAN 625 but lower lift
- Forged Wisco 10.5:1 Pistons
- Cometic .040 Head Gaskets
- Final Static Compression Ratio set to 10.7:1
- Darkhorse Crank with Timken
- 50 MM Throttle Body with 4.35 injectors
- Fullsac C Pipe with 2" cores
My dealer tuned it with the SEPST and got 116 HP and 122 TQ (dyno chart attached - the names where changed to protect the innocent)
The tuner had to set the cubes to 145 and decrease the injector size from 4.35 to 4.3 to set the VE tables. The tuner just keep v tuning and changing cubes until he was able to get the VE table out of the red. However, the tuner never looked at or monitored the injector duration. I've since learned that the injectors are to small.
After a lot of research and consultation, I've decided to make the following changes:
- Install SE 5.3 g/s Injectors
- Install Fullsac Xtreme D pipe
What I am uncertain of is if whether or not the following would be beneficial or harmful in my build.
- 6.2 g/s Injectors
- SE 58mm TBW throttle body
- Fullsac 2.25" cores
I have all of the above mentioned parts on hand so I can choose to install some, all or none of them. What are your thoughts on:
1. Installing the SE 58mm throttle body. About 50% of the supposed experts that I've asked tell me that it will move the power to the right while the other 50% said that is more applicable to cable operated TBs and that the ECM on a TBW system will maintain good low RPM venture velocity by progressively opening the butterfly based on rpm and throttle position (won't open it fully regardless of throttle grip position until after 3K rpm). I no longer know what to believe and really don't want to spend the money on dyno time to find out. Since I'm sure you've seen it all during your years tuning, what are your thoughts on this? Stick with the 50mm or go for the 58mm?
2. Replacing the 2" cores with 2.25" cores. My thoughts are to tune it with the 2" cores installed and then while its still on the dyno, swap them with the 2.25" cores and see if they help or hurt.) I have two complete muffler set, 1 with 2" and one with 2.25" so the swap would be quick and easy.
3. Going with 6.2 g/s injectors instead of the 5.3 g/s. I want to right size these so I am thinking of retuning with the 5.3s and see whether the dyno shows that if I need to go larger.
I have a credit with the dealer that build the motor and did the initial tune so I am going to give them another crack at it. Once I'm confident in the parts combination, I'm going to make an appointment with you (have to travel across country to get to you so the parts combinations has to be right when I get there). I have both the TTS and SEPST (dealer is going to tune with the SEPST). I assume that you prefer to tune with the TTS which I am cool with.
Regards,