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Going 1 to 1

ArizonaBOSS

Because racecar.
Moderator
8,552
2,392
Arizona, USA
Shifting at redline in 4th gear will put you into 5th at around 5500RPM. If you want to land on the torque peak in 5th (4400RPM?), you want to shift about 5800 in 4th, which seems WAYYYYYYY too low for this engine.
 
I can only tell you that I typically shift between 7000-7500..........I can't tell you if that's necessarily optimum though. The car definitely makes its power up top and below 4500 it doesn't pull that hard.
 
Thanks, I shifted the most just about 7K but tried everywhere from 6K on up. Did not feel a big difference but I did not have time to study the guages. I felt pushing it to 7500 was not helping but wanted to see what you guys were doing. Guess I will continue to shift around 7 for now, thanks.
 

ArizonaBOSS

Because racecar.
Moderator
8,552
2,392
Arizona, USA
Shifting at 5800 is not wise in my mind as you lose out on all your top end power (and give up about 25mph worth of gear!) in 4th.

Just play around with 7000-7500 and see what feels right.
 
1,255
2
GA
My Bullitt redlines at 6500, and I always take it up to at least 6000 before shifting (My power starts leveling off at about 6300 so I usually don't bother going past that). The Boss engine is supposed to pull all the way to 7500 and has beefed up internals to handle the sustained high RPM, so don't leave any power on the table and only shift when necessary.
 
OK that is about what I have been doing. It seems the Boss is still making power to at least 7500 but from some of what I read it starts to level off a bit above 7. The big question is where does it stop making power 7.5 7.8 or 8k? I was thinking if it starts to levels off above 7 then it would be better to shift before the 7.5 mark and pick up again in fifth. I am just not good enought at this point to drive and study guages so it is hard to tell the small differences.
 
Reading between the lines in the 5.0 article, the engine was designed to make power up to 7800 rpm but the electronic signals got blurred after 7500rpm. So even if the HP line flattens out at 7000 rpm, the engine will still pull all the way past the redline. Only if the HP line drops off significantly would you want to short shift. So run it as close to the redline as you dare without hitting the rev limiter. ;D The only reason to shift early is if you need to get a shift in before a high speed sweeper.
 
BossJockey said:
Reading between the lines in the 5.0 article, the engine was designed to make power up to 7800 rpm but the electronic signals got blurred after 7500rpm. So even if the HP line flattens out at 7000 rpm, the engine will still pull all the way past the redline. Only if the HP line drops off significantly would you want to short shift. So run it as close to the redline as you dare without hitting the rev limiter. ;D The only reason to shift early is if you need to get a shift in before a high speed sweeper.
This
 
2012Boss said:
ArizonaGT said:
We need some DYNO GRAPHS! :)

Not me ::) maybe we can get Gary to do it - he'll do anything ;D

Actually I read your post wrong A-GT so you are saying 5800 is good or not enough RPM"s?
The only thing I'm waiting for is TracKey! I planned to dyno it right away with both the street and TracKey tunes so we can see where it makes power. I also thought about doing it with and without discs but not sure if I'll bother with that since my discs are out for good. Now if I consider axle backs or a different exhaust, then I'll do the comparison. I just don't want to spend the time and money to put it on the dyno until we have TracKey since that's the only tune I'll want to study for track use.
 

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