C7Z Suttering Hesitation Moderate Acceleration
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Instructor
Joined: May 2018
Posts: 120
Likes: 5
C7Z Suttering Hesitation Moderate Acceleration
2015 C7Z M7. Tuned, headers, exhaust, mgw, TMTB, 18% lower.
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Racer
Joined: Jun 2013
Posts: 339
Likes: 126
From: Missouri
2015 C7Z M7. Tuned, headers, exhaust, mgw, TMTB, 18% lower.
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Burning Brakes
Joined: Nov 2017
Posts: 800
Likes: 326
Remember, we have a supercharger. The boost is always there with no build up like a turbocharger.
I personally consider 2k RPM the minimum, even for cruise. Other than starting from a stop in 1st gear, where there is no choice, I would not floor it until the RPM is well above 2K. Why? I have rebuilt a lot of cars with damage from lugging. At lower RPM the cylinder pressures are extreme and the oil supply is marginal. It's hard on rings, bearings and pistons. If you pay attention, automatic trannies will not let you floor a car below 2k RPM...they will downshift to a higher engine speed. Try not flooring it at 2k RPM and see if it doesn't like it better!
I personally consider 2k RPM the minimum, even for cruise. Other than starting from a stop in 1st gear, where there is no choice, I would not floor it until the RPM is well above 2K. Why? I have rebuilt a lot of cars with damage from lugging. At lower RPM the cylinder pressures are extreme and the oil supply is marginal. It's hard on rings, bearings and pistons. If you pay attention, automatic trannies will not let you floor a car below 2k RPM...they will downshift to a higher engine speed. Try not flooring it at 2k RPM and see if it doesn't like it better!
Tech Contributor
Joined: Jan 2015
Posts: 5,692
Likes: 1,451
2015 C7Z M7. Tuned, headers, exhaust, mgw, TMTB, 18% lower.
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Just noticed tonight that if I’m romping around town I get a pretty annoying hesitation with the car under moderate acceleration. Say 3rd gear about 2k rpm if I give it 75-80% throttle it’ll bog, take off, build boost, then it starts to stutter/hesitate. It feels like the engine is pulling timing or something. You can ride through it and it’ll clear up when RPMs increase. It almost reminds me of how the car acts when traction control comes on. You can definitely hear it in the exhaust. No codes or anything on the dash which makes think maybe normal and I just never noticed? Happens in 4th gear too.
Car runs strong in all other cases. I can do a proper pull and not notice any hesitation. It’s just the low RPM high boost condition that I notice this. Really when I roll into the throttle heavy at low RPM. Any ideas?
Advanced
Joined: Jan 2017
Posts: 73
Likes: 13
From: US
I had the same thing on my heads/cam Z. No codes but felt like something was pulling timing. Turned off traction control and had the same issue.
turned out I had a cracked spark plug. Replaced and has been fine ever since
turned out I had a cracked spark plug. Replaced and has been fine ever since
