Unusual power loss after 20 minutes
08-20-2016, 08:04 AM
#1
Unusual power loss after 20 minutes
I have been driving my Z06 in this summer in VA with temperatures hovering around the 100 mark.
After about 20 minutes of driving when I try to moderately accelerate from low RPMs (below 2500), the Z06 lacks powers and the engine will struggle and surge until the supercharger comes on at about 3,000 RPM. The Z06 runs great and normal until this 20 minute window.
It feels suspiciously like vapor lock due to a heat soak problem. I've also suspected that the intercooler may also have reached high temperatures and become ineffective. An air leak passed the throttle body has also been considered.
I have a Dewitt after market intercooler which has more cooling capacity the the OEM, but I don't see how that could affect the problem.
If anyone in Corvette land has had this problem or can suggest a cause and solution, I would be grateful. I have a great dealer mechanic, but he seems to be at a loss to explain what's going on so I tune to the Forum.
After about 20 minutes of driving when I try to moderately accelerate from low RPMs (below 2500), the Z06 lacks powers and the engine will struggle and surge until the supercharger comes on at about 3,000 RPM. The Z06 runs great and normal until this 20 minute window.
It feels suspiciously like vapor lock due to a heat soak problem. I've also suspected that the intercooler may also have reached high temperatures and become ineffective. An air leak passed the throttle body has also been considered.
I have a Dewitt after market intercooler which has more cooling capacity the the OEM, but I don't see how that could affect the problem.
If anyone in Corvette land has had this problem or can suggest a cause and solution, I would be grateful. I have a great dealer mechanic, but he seems to be at a loss to explain what's going on so I tune to the Forum.
08-20-2016, 08:05 AM
#2
If it's happening due to high IAT's (after running it hard a couple times) try this: https://www.corvetteforum.com/forums...ler-video.html
08-20-2016, 09:58 AM
#5
Hi Gary. I had my car seem really low on power one very hot day but it seemed to be that way from the start. It was the day after I was at the track so I thought maybe I broke something. I was about to take the car to the dealer and things improved so I didn't bother. To this day I'm not sure if it was just my imagination, the heat, or some transient issue.
If you want to try logging some things like IAT2 or fuel trims I have one of these you can borrow. https://www.obdsoftware.net/scantools/obdlinkmxwifi. You'll need to get one of the apps but it seems to work pretty well.
If you want to try logging some things like IAT2 or fuel trims I have one of these you can borrow. https://www.obdsoftware.net/scantools/obdlinkmxwifi. You'll need to get one of the apps but it seems to work pretty well.
08-20-2016, 02:18 PM
#10
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I think what you are feeling is bypass valve surging. You say moderate accel and low RPM, look at your boost gauge and see if it says 0-2 psi give or take. You are in a gray area and it is building a small amount of boost and the stock bypass valve isn't very good at relieving pressure in that midrange airflow level, IMO. It will hold boost fine if you floor it and it will vent pressure fine if you are very light or off throttle, but if you are building a little tiny bit of boost at low RPM it will flutter.
If you get 20-25 minutes into your drive and just floor it all the way, does it feel powerful and smooth?
The intercooler cavitation issue is evident under road course conditions, this sounds like a perceived power loss on the street at normal RPMs, but I am not sure you have a power loss, rather a strange drivability characteristic.
If you get 20-25 minutes into your drive and just floor it all the way, does it feel powerful and smooth?
The intercooler cavitation issue is evident under road course conditions, this sounds like a perceived power loss on the street at normal RPMs, but I am not sure you have a power loss, rather a strange drivability characteristic.
08-20-2016, 09:20 PM
#11
Would installing a Vitesse Controller help in this situation?
08-20-2016, 11:53 PM
#12
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08-21-2016, 11:10 AM
#13
Got It
Poor-sha...
Thanks for the reply. I have an app and can monitor the IAT. I just haven't done that yet, but I will.
I will be at TPC next week to purge and fill the intercooler. Mike did it once, then I replaced the intercooler radiator and didn't do it a second time. May be the nature of the problem.
I'll let you know if that solves it. I haven't had the Z06 on the track since I left VITR early in the Spring. One problem after another al engine related, some self induced. I am targeting an Audi event at Dominion in mid-september. Hopefully cooler and all problems solved.
Thanks for the reply. I have an app and can monitor the IAT. I just haven't done that yet, but I will.
I will be at TPC next week to purge and fill the intercooler. Mike did it once, then I replaced the intercooler radiator and didn't do it a second time. May be the nature of the problem.
I'll let you know if that solves it. I haven't had the Z06 on the track since I left VITR early in the Spring. One problem after another al engine related, some self induced. I am targeting an Audi event at Dominion in mid-september. Hopefully cooler and all problems solved.
Hi Gary. I had my car seem really low on power one very hot day but it seemed to be that way from the start. It was the day after I was at the track so I thought maybe I broke something. I was about to take the car to the dealer and things improved so I didn't bother. To this day I'm not sure if it was just my imagination, the heat, or some transient issue.
If you want to try logging some things like IAT2 or fuel trims I have one of these you can borrow. https://www.obdsoftware.net/scantools/obdlinkmxwifi. You'll need to get one of the apps but it seems to work pretty well.
If you want to try logging some things like IAT2 or fuel trims I have one of these you can borrow. https://www.obdsoftware.net/scantools/obdlinkmxwifi. You'll need to get one of the apps but it seems to work pretty well.
08-22-2016, 08:44 PM
#15
I'll let you know if that solves it. I haven't had the Z06 on the track since I left VITR early in the Spring. One problem after another al engine related, some self induced. I am targeting an Audi event at Dominion in mid-september. Hopefully cooler and all problems solved.[/QUOTE]
Especially since you track it, mind letting us know what these problems have been. And any remedies?
Especially since you track it, mind letting us know what these problems have been. And any remedies?
Last edited by DLC7; 08-22-2016 at 08:48 PM.
08-22-2016, 08:46 PM
#16
I'll let you know if that solves it. I haven't had the Z06 on the track since I left VITR early in the Spring. One problem after another al engine related, some self induced. I am targeting an Audi event at Dominion in mid-september. Hopefully cooler and all problems solved.
Last edited by DLC7; 08-22-2016 at 08:47 PM.
08-22-2016, 10:05 PM
#17
Another question Gary, is this issue repetitive all the time after the 20 min. or does it come and go over a period of time?
I am asking these questions because I had the exact same problem at the track a few weeks ago and the temps were not high. Same symptoms that when I applied light to moderate throttle the engine seemed to bog down (no power), floor the pedal and after a few seconds the engine would go to full torque. Brought the car in the pit shut it down for around 10 min. went back out and same issues. No messages or engine lights were present. Brought the car back in and an hour later took it out again and the problem never reoccurred.
Later in the day I even pushed the oil temp to 285 and car ran smooth. We are really having a problem figuring out what happened.
To add to the confusion, I have tracked the car more than 20 days and several this summer during the heat and this is the first time I have ever had an issue of any sort.
Let us know your outcome.
Thanks
I am asking these questions because I had the exact same problem at the track a few weeks ago and the temps were not high. Same symptoms that when I applied light to moderate throttle the engine seemed to bog down (no power), floor the pedal and after a few seconds the engine would go to full torque. Brought the car in the pit shut it down for around 10 min. went back out and same issues. No messages or engine lights were present. Brought the car back in and an hour later took it out again and the problem never reoccurred.
Later in the day I even pushed the oil temp to 285 and car ran smooth. We are really having a problem figuring out what happened.
To add to the confusion, I have tracked the car more than 20 days and several this summer during the heat and this is the first time I have ever had an issue of any sort.
Let us know your outcome.
Thanks
08-22-2016, 11:53 PM
#18
Drifting
The intercooler pump is probably garbage. I had one fail at 2200 miles and the dealer refused to change it... Said they couldn't duplicate the problem after having the car for a month. Needless to say, i changed out the pump with a zr1 pump and it ran awesome again!
08-23-2016, 11:46 AM
#19
I got some IATs from the three sensors yesterday, after my surging problems began.
OAT: 92
IAT 1: 95
IAT 2: 130
IAT 3: 210
I was noticing as I drove today in 84 degree weather that the IAT 3 Temps continued to rise and after about 30 minutes hit 180 degrees. I also noticed fluctuations of about 20 degrees up and down as the temps climbed.
I have no idea what is normal range is for the IAT sensors. Can someone give me a clue what would be normal?
OAT: 92
IAT 1: 95
IAT 2: 130
IAT 3: 210
I was noticing as I drove today in 84 degree weather that the IAT 3 Temps continued to rise and after about 30 minutes hit 180 degrees. I also noticed fluctuations of about 20 degrees up and down as the temps climbed.
I have no idea what is normal range is for the IAT sensors. Can someone give me a clue what would be normal?
08-23-2016, 01:28 PM
#20
Can someone explain what IAT3 is as well?
Gary, on the road the couple of times I've looked at IAT2 it's been around 20 degrees above of IAT1 (as I recall). That assumes the car is moving under normal driving. A +35 delta in street driving seems high to me.
I can try to get some comparison data tomorrow but as you know it's cooled off a lot.
Gary, on the road the couple of times I've looked at IAT2 it's been around 20 degrees above of IAT1 (as I recall). That assumes the car is moving under normal driving. A +35 delta in street driving seems high to me.
I can try to get some comparison data tomorrow but as you know it's cooled off a lot.