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I recently purchased a 2014 c7 stingray convertable with the z51 package (manual transmission). The car is all original, no mods. I am not sure that I have a problem or not, however I seem to be experiencing the top end power of each gear flattening out (especially 2nd and 3rd gear). It has plenty of low end torque. Is this normal? I expected more power from the top end.
I am in the market for upgrading the cold air intake and exhaust system, any suggestions would be appreciated. Thanks for your time and information.
Thanks for your reply. To answer your question is when I reach a certain rpms in each gear the power flattens out. I should have noted the rpms, I will have to record that the next time I have it out. Once I reach the point where the power flattens, I literally have plenty of pedal left. As I place the pedal to the floor I get no throttle response.
Car should pull strong up to redline, however this engine is not a screamer - it makes tons of low to mid range torque and thus is happiest in that range. There isn't much in the last 1K of revs...
And a cold air intake does pretty much nothing to the non-supercharged LT1 engine. While an x-pipe will not add any power either really it sure sounds better so I recommend one as a starting point.
Are you unhappy with the throttle mapping or is the engine actually losing power?
Elk, the engine is not loosing power. Once I reach a certain rpms beyond the low end torque (n/a until I do another test run) the power tends to flatten out until I shift into the next gear. I am not all familiar with the power dynamics from a Corvette, first timer. I just expected more top end power and top end throttle response through 1-3 gears. Maybe I am not allowing the rpms to reach the power curve before I shift, that maybe the problem. I will test soon, thanks.
Car should pull strong up to redline, however this engine is not a screamer - it makes tons of low to mid range torque and thus is happiest in that range. There isn't much in the last 1K of revs...
And a cold air intake does pretty much nothing to the non-supercharged LT1 engine. While an x-pipe will not add any power either really it sure sounds better so I recommend one as a starting point.
Thank you. I was hopeful to gain more horsepower by adding a better air intake system (ex. AFE) and a better flowing exhaust system (Borla or a Corsa - prefer the Borla for the deeper throaty sound). However, either would be great. Thanks for your reply. Great chart by the way.
Last edited by Timscherer; 10-01-2020 at 12:05 PM.
I am not all familiar with the power dynamics from a Corvette, first timer.
This may be it as much as anything.
The engine is tuned to provide linear response. There is no sudden deliver of extra power at higher RPM. Rather, the engine just smoothly pulls as the RPM increases.
Thanks for all your advice, I took the Vette out today and attempted a no lift method shifting at a higher rpms than what I normally shift at. I definitely noticed a stronger pull shifting from one gear to the next shifting in the "power band" between 5k to 6k rpms.
When just cruising around I was expecting a stronger pull at lower rpms. I need to take in consideration that it the manual transmission utilizes its power differently than an automatic transmission. I am extremely impressed with the low end torque, the C7 is an impressive vehicle.
Regarding your "still have pedal left" comment, that relationship is only somewhat correct when the car is turbocharged (so more fuel creating exhaust might increase boost if the boost is not limited already), or on diesel engines. Most of the time, you already reach most of your max power at that RPM level long before you're at 100% throttle.
As noted before, these cars' power generation taper on the last 500-1000 RPMs, but for max performance, you'd still need to hit close to redline before shifting, since that would get you to a better spot (i.e. higher RPMs) once you shift to the next gear.
Regarding your "still have pedal left" comment, that relationship is only somewhat correct when the car is turbocharged (so more fuel creating exhaust might increase boost if the boost is not limited already), or on diesel engines. Most of the time, you already reach most of your max power at that RPM level long before you're at 100% throttle.
As noted before, these cars' power generation taper on the last 500-1000 RPMs, but for max performance, you'd still need to hit close to redline before shifting, since that would get you to a better spot (i.e. higher RPMs) once you shift to the next gear.
That makes complete sense, that is what I experienced.
Thanks for your reply.
09-30-2020, 08:58 PM
Performance question - C7 manual transmission
