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Instructed at the SVT/Cobra Superfest at VIR this last weekend. During the second session on Saturday I set my personal best lap time of 2:03:49 and this was with number 8 cylinder misfiring through most of the session and the next two sessions. At the end of the day checked with HP Tuners and number 8 had misfired 521 times and number 3 had misfired 2 times. On top of that the PDR video kept on doing what it did three weeks ago freeze every so often. I had a different SD card inserted and that along with the fact you can hear the audio playing during the video pause and the speed data is recorded right through the video pauses. I used Pi Toolbox to graph speed and it didn't show any interruptions.
Watch the video from about the 15:10 mark as I am going up the bridge straight and let a track prepped Fort GT 40 pass me at the entrance to the uphill Esses. If number 8 hadn't been misfiring I may have been able to keep closer to him.
Here is a picture of speed data during the 2:03 lap and you can see it doesn't pause when the video pauses.
Car goes to the dealer tomorrow. This time I will be pushing for them to replace the coil, plug wire and plug for cylinder number 8. We have bled the intercooler enough over the last 6 months and it still hasn't resolved the high speed misfire problem. The car sent me an email stating it had an emissions issue while I was out on track during the afternoon. That is when the CEL lit. The misfire has gotten bad enough that passengers can feel it now.
Great driving. I know you have had the misfire issue for a while. Did they replace the wire and plug on #8 when you first mentioned it?
No. It didn't do it at low rpms and GM Engineering believed the issue was due to air in the intercooler circuit that kept the intercooler from sufficiently cooling the intake charge into cylinders number 7 and 8 so they directed the dealer mechanic to bleed the system several times. The last direction was to use the new ZR1 bleeder since it supposedly gets more air out. We had to wait until the mechanic received his ZR1 training before he could get the tool. The misfire seems to be getting worse and the fact that cylinder number 8 misfired 521 times on Saturday makes me and others think the problem is ignition related. In the old days when you had just one ignition coil on an engine when the coil started to break down you would get high rpm drop off in ignition voltage and the engine would literally quit until the rpms dropped down to a point the coil could fire the plugs again. This is very similar to that except with one coil per cylinder the failure doesn't show up as drastically. This has been going on for close to two years. At first it was just a drop off in power that only I would notice when driving, then a few P0300 codes started to be thrown, then a P0308 and a CEL followed by more P0300 codes. It isn't particularly heat related since oil and coolant temps were low over the weekend. Although it didn't seem to misfire during the first session of each day. The ambient temps when we were on track then were in the mid 40s. After that they climbed into the mid and upper 60s. This is what the engine temp data looked like:
Great driving - Sean is going to have to up his game with the ZR1!
I forgot SVT was at VIR last weekend, otherwise I would have asked Tony if he needed instructors
Was the turnout decent?
I know in February, the turnout was very low & Tony was griping. I don't know why more people don't run with this club since the track is essentially empty (unlike NASA, Chin, BMW, etc...).
I hope you get your car sorted soon.
Where do you think you made up the time this time out? I know you were trying a different braking zone through 16A...
Esit: Holy hell that green Mustang in T10. I saw him enter mid-track & thought 'this isn't going to go well'. How he kept it together was quite impressive.
Great driving - Sean is going to have to up his game with the ZR1!
I forgot SVT was at VIR last weekend, otherwise I would have asked Tony if he needed instructors
Was the turnout decent?
I know in February, the turnout was very low & Tony was griping. I don't know why more people don't run with this club since the track is essentially empty (unlike NASA, Chin, BMW, etc...).
I hope you get your car sorted soon.
Where do you think you made up the time this time out? I know you were trying a different braking zone through 16A...
Tony griped to me about the potential attendance as well. That was when I posted some info about the event on the forum. I don't know if that got any takers but others did the same on other forums and we had over 100 drivers for the first time in a long time. When I got in line to enter the track on Friday afternoon there was Toter ahead of me. I didn't know what was in it but I sure did when they finally unloaded:
The last couple pictures are of the Ford GT I was trying to keep up with on track.
I think the time was made up all over the track. I had the MRC Calibration update installed a couple of months ago and I think it has helped. I am not as fast as others going through the uphill Esses but I am trying to maintain a more constant speed so I am not losing as much time. The other thing the power loss due to the misfire did for me was make me drive deeper into the braking zone to make up some of the difference. As for getting through 16a sooner I think trail braking was helping but I was inconsistent in applying it. I do think there is a 2:02 in me if I can get the misfire fixed as my top speeds on the straights was at least 10 mph less than when the car is running right. I am beginning to suspect I don't really know if the car is running right when it runs better. The misfire may just be much less but still cutting speed. That would explain why my speeds at the end of the straights seems to be down just a little from other cars.
I have another video from Sunday morning where another forum member in a C7Z and I were chasing the GT40. That was a hoot. When I pulled into the pits I was out of breath from all of the exertion.
Bill
Last edited by Bill Dearborn; 04-24-2018 at 10:05 PM.
Tony griped to me about the potential attendance as well. That was when I posted some info about the event on the forum. I don't know if that got any takers but others did the same on other forums and we had over 100 drivers for the first time in a long time. When I got in line to enter the track on Friday afternoon there was Toter ahead of me. I didn't know what was in it but I sure did when they finally unloaded:
The last couple pictures are of the Ford GT I was trying to keep up with on track.
I think the time was made up all over the track. I had the MRC Calibration update installed a couple of months ago and I think it has helped. I am not as fast as others going through the uphill Esses but I am trying to maintain a more constant speed so I am not losing as much time. The other thing the power loss due to the misfire did for me was make me drive deeper into the braking zone to make up some of the difference. As for getting through 16a sooner I think trail braking was helping but I was inconsistent in applying it. I do think there is a 2:02 in me if I can get the misfire fixed as my top speeds on the straights was at least 10 mph less than when the car is running right. I am beginning to suspect I don't really know if the car is running right when it runs better. The misfire may just be much less but still cutting speed. That would explain why my speeds at the end of the straights seems to be down just a little from other cars.
I have another video from Sunday morning where another forum member in a C7Z and I were chasing the GT40. That was a hoot. When I pulled into the pits I was out of breath from all of the exertion.
Bill
Your car is definitely running a good 10 MPH off on the straights; that GT checked out on each one. I did see you exited 9 at the same speed you entered 7 in at least one lap (120), which is moving at the top!
Good job in that section!
You also caught the GT in several sections like 11/12.
You definitely can get a few more seconds I think without driving on the ragged edge.
Why don't you just try to diag it for GM, since so many of their dealers are incompetent .
Swap plugs between 7 and 8, swap coils between 6 and 8, and plug wires between 5 and 8. (or whatever combos you choose). Go run the car hard again and see where the miss comes back. If it follows one of those parts then you know what's bad. If it's 8 again, check compression. If ok, that leaves bad injector which could also be swapped around, but not home friendly, or intercooler issue as noted initially
Great track weekend with tons of open track and good driving. This used to be a Corvette invasion and I tried together some more of those pesky E30’s in there for test and tune. Late April at VIR is prime time.
Pirelli Scrubs. 305/660/18 front and 315/680/18 rear. I have looked at swapping components. However, cylinder number 8 is on Bank 2 and that is hard to get to. There are several fluid lines that have to disconnected, the cover over the coils has to be removed and the under hood electrical center has to be removed. If I am going to swap parts around I might as well replace them due to the work of getting to the items. Hopefully, they will agree with me tomorrow. The mechanic said he would replace those items under warranty if GM said to do so. So far all they have been doing is saying bleed the intercooler better. I just think if it was a problem with air in the intercooler that it would affect cylinder number 7 just as much as it does number 8. They have already said both of those cylinders have higher combustion temperatures than the other 6. The PDR problem is another one that has them scratching their heads. I am instructing at a private event at VIR on May 17th and hope I can have everything running OK by then.
I don't know if the new Ford GT went on track. Somebody said it did but even with full coverage the minimum 10% deductible would still leave somebody with close to a $50K bill if they totaled it.
Several GT 350s lost their engines at this event. My student's friend had his lose oil pressure and he pulled off the track right away. When they took the oil filter apart it was full of metal shavings.
Bill
Last edited by Bill Dearborn; 04-25-2018 at 01:22 AM.
Well done for sure! Nice drive! Anxious to see a new Ford GT battle with a C7Z but doubt we will ever see one on track other than parade laps.
The closest you will get is comparing Mero's lap vs Fords race driver running the GT at VIR . I stopped caring about how fast "supercars" are since the owners just treat them like jewelry and I pass them every time on a canyon run.
I don't know if the new Ford GT went on track. Somebody said it did but even with full coverage the minimum 10% deductible would still leave somebody with close to a $50K bill if they totaled it.
Bill
Lockton has a $150k liability limit I believe, which would leave someone severely exposed in the event they wrecked their Ford GT...
But I guess if you have those kind of pockets, ain't no big thing.
Pirelli Scrubs. 305/660/18 front and 315/680/18 rear. I have looked at swapping components. However, cylinder number 8 is on Bank 2 and that is hard to get to. There are several fluid lines that have to disconnected, the cover over the coils has to be removed and the under hood electrical center has to be removed. If I am going to swap parts around I might as well replace them due to the work of getting to the items. Hopefully, they will agree with me tomorrow. The mechanic said he would replace those items under warranty if GM said to do so. So far all they have been doing is saying bleed the intercooler better. I just think if it was a problem with air in the intercooler that it would affect cylinder number 7 just as much as it does number 8. They have already said both of those cylinders have higher combustion temperatures than the other 6. The PDR problem is another one that has them scratching their heads. I am instructing at a private event at VIR on May 17th and hope I can have everything running OK by then.
I don't know if the new Ford GT went on track. Somebody said it did but even with full coverage the minimum 10% deductible would still leave somebody with close to a $50K bill if they totaled it.
Several GT 350s lost their engines at this event. My student's friend had his lose oil pressure and he pulled off the track right away. When they took the oil filter apart it was full of metal shavings.
Bill
I agree Bill. There is no sense swapping parts. Go with a new coil, wire and plug for #8. Seems to be the logical thing to do considering the repeated misfire keeps showing up. Even if they don't foot the bill, you're not talking about huge $$$ here. Good luck.
I agree Bill. There is no sense swapping parts. Go with a new coil, wire and plug for #8. Seems to be the logical thing to do considering the repeated misfire keeps showing up. Even if they don't foot the bill, you're not talking about huge $$$ here. Good luck.
I did some more digging in the FSM. Not only does all that other stuff have to be removed but the coolant has to be drained and the coolant reservoir removed. Obviously, they didn't consider ignition maintenance when they laid out the engine compartment packaging. If I don't do it myself the cost of labor will probably exceed the cost of parts.
04-24-2018, 06:36 PM
New personal best at VIR this last weekend
