how high do u rev?
People keep stating numbers that they have there specific car set @, but there are more variables then whta someone else's car shifts at IMO. Get it on a dyno and find out where you peak then set it accordingly. If you peak @ over 6600 then look into getting ARP rod bolts. Just my .02
Originally Posted by zspot98
People keep stating numbers that they have there specific car set @, but there are more variables then whta someone else's car shifts at IMO. Get it on a dyno and find out where you peak then set it accordingly. If you peak @ over 6600 then look into getting ARP rod bolts. Just my .02
word i wouldnt go past 6600 with factory rod bolts, cause they will stretch and will break if u push the motor to far.
My trex makes peak power at 6,600 and my rev limiter is set at 6,900. I usually shift at 6,800 to 6,900 or bounce it off the rev limiter. It's hard to tell when to shift because my tach is so slow it says 6,500 when its really a lot higher. My friend shifts his MS3 zo6 at 7,200.
here is how you figure out where to shift.
get on a dyno, get a complete power curve for your engine (NOT just the peak, go a bit farther). Find one of the calculators that shows you speed vs engine RPM based on gears, tire height, etc and make sure it accounts for transmission gear (heres a decent one: http://www.camaroz28.com/services/calcs/) Calculate what your HP is at say 6500RPM. Then calculate what the RPM will be if you shift into the next gear FROM THE RPM YOU USED FOR THE FIRST CALCULATION. If your HP after the shift is lower than your HP before, you need to shift at a higher RPM. Basically you should lose no HP from shifting. Do this for every shift, and you are good to go. For many people this means you will be shifting a lot higher than your comfortable with...such is the downside of the big *** cam you bought
EDIT: just noticed that camaroz28.com has a shift point calculator based on this theory right on that page...wicked
get on a dyno, get a complete power curve for your engine (NOT just the peak, go a bit farther). Find one of the calculators that shows you speed vs engine RPM based on gears, tire height, etc and make sure it accounts for transmission gear (heres a decent one: http://www.camaroz28.com/services/calcs/) Calculate what your HP is at say 6500RPM. Then calculate what the RPM will be if you shift into the next gear FROM THE RPM YOU USED FOR THE FIRST CALCULATION. If your HP after the shift is lower than your HP before, you need to shift at a higher RPM. Basically you should lose no HP from shifting. Do this for every shift, and you are good to go. For many people this means you will be shifting a lot higher than your comfortable with...such is the downside of the big *** cam you bought
EDIT: just noticed that camaroz28.com has a shift point calculator based on this theory right on that page...wicked
here's a shocker...this is using a stock LS1 dyno, however I had to estimate the 7500+ numbers so it may drop a lot faster than that...
Bowling's Optimum Shift Calculator
Input Parameters Are the Following:
* Transmission Ratio One = 3.06 to 1
* Transmission Ratio Two = 1.62 to 1
* Transmission Ratio Three = 1.00 to 1
* Horsepower = 70 at 2000 RPM
* Horsepower = 150 at 3000 RPM
* Horsepower = 185 at 3500 RPM
* Horsepower = 225 at 4000 RPM
* Horsepower = 275 at 4500 RPM
* Horsepower = 325 at 5000 RPM
* Horsepower = 340 at 6000 RPM
* Horsepower = 275 at 7000 RPM
* Horsepower = 160 at 7500 RPM
Computation Results:
Using the Criterion for Maintaining the Same Horsepower Before and After Shift:
Finding Best Shift Placement Points For Ratio 3.06 to 1.62:
# Found optimum shift RPM at 7308, which achieves 214 horsepower and lowers the RPM To 3869 after shift
Finding Best Shift Placement Points For Ratio 1.62 to 1.00:
# Found optimum shift RPM at 7082, which achieves 261 horsepower and lowers the RPM To 4372 after shift
Maximumizing the Area Under the Horsepower Curve:
Finding Best Shift Placement Points For Ratio 3.06 to 1.62:
# Found optimum shift RPM at 7480, which achieves maximum area under horsepower curve, and lowers the RPM to 3960 after shift
Finding Best Shift Placement Points For Ratio 1.62 to 1.00:
# Found optimum shift RPM at 7355, which achieves maximum area under horsepower curve, and lowers the RPM to 4540 after shift
Bowling's Optimum Shift Calculator
Input Parameters Are the Following:
* Transmission Ratio One = 3.06 to 1
* Transmission Ratio Two = 1.62 to 1
* Transmission Ratio Three = 1.00 to 1
* Horsepower = 70 at 2000 RPM
* Horsepower = 150 at 3000 RPM
* Horsepower = 185 at 3500 RPM
* Horsepower = 225 at 4000 RPM
* Horsepower = 275 at 4500 RPM
* Horsepower = 325 at 5000 RPM
* Horsepower = 340 at 6000 RPM
* Horsepower = 275 at 7000 RPM
* Horsepower = 160 at 7500 RPM
Computation Results:
Using the Criterion for Maintaining the Same Horsepower Before and After Shift:
Finding Best Shift Placement Points For Ratio 3.06 to 1.62:
# Found optimum shift RPM at 7308, which achieves 214 horsepower and lowers the RPM To 3869 after shift
Finding Best Shift Placement Points For Ratio 1.62 to 1.00:
# Found optimum shift RPM at 7082, which achieves 261 horsepower and lowers the RPM To 4372 after shift
Maximumizing the Area Under the Horsepower Curve:
Finding Best Shift Placement Points For Ratio 3.06 to 1.62:
# Found optimum shift RPM at 7480, which achieves maximum area under horsepower curve, and lowers the RPM to 3960 after shift
Finding Best Shift Placement Points For Ratio 1.62 to 1.00:
# Found optimum shift RPM at 7355, which achieves maximum area under horsepower curve, and lowers the RPM to 4540 after shift
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I shift at ~6800 and my limiter is 7000. I have the same problem with the tac being about 700 rpms too slow. I have my shiftlight set at about 6700. Stock bottom end here with a 228/236@.50 588 lift on a 114 LSA cam, stage 2 ported stock heads with dual valve springs and a retainer kit.
93k on stock motor shifting at 7200 in the camaro. cam makes power till like 7300 on the dyno. i just think shifting at like 7400 is a little excessive seeing as im prolly rattling the hell outta the bolts now. when the new cam goes in im intrested to see where im gonna have to shift it! 245/250 cam in a 346 a4
