What went wrong??Supercharged my C6 and blew motor on dyno.
09-07-2014, 11:36 AM
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What went wrong??Supercharged my C6 and blew motor on dyno.
A&A supercharged kit installed and only 4.5 lbs of boost made 500 rwhp. Tune shop said I needed more cam,stiffer valve springs and 8 rib pulley set up with 10% under drive on a 3.47 supercharger pulley. Only 6000 miles on stock ls2 bottom end. Afr 205 heads, long tube headers and corsa exhaust. Spent the money and went with all their recommendations. Did 3 dyno runs, and on the third run something went wrong. Pulled plugs and 3 tips smashed down to the diode. At the time of the final run, she made 654 rwhp at 13 psi of boost with 14 degrees of timing. They are saying injectors (which were brand new 60lbs) failed and leaned out the 3 cylinders causing the failure, which blew the motor. Please chime in our all your thoughts and experiences. Obviously, I have to rebuild the motor, and just want to keep it from happening again
Last edited by travis1693; 09-10-2014 at 02:12 PM. Reason: added pictures
09-07-2014, 12:15 PM
#2
Burning Brakes
A&A supercharged kit installed and only 4.5 lbs of boost made 500 rwhp. Tune shop said I needed more cam,stiffer valve springs and 8 rib pulley set up with 10% under drive on a 3.47 supercharger pulley. Only 6000 miles on stock ls2 bottom end. Afr 205 heads, long tube headers and corsa exhaust. Spent the money and went with all their recommendations. Did 3 dyno runs, and on the third run something went wrong. Pulled plugs and 3 tips smashed down to the diode. At the time of the final run, she made 654 rwhp at 13 psi of boost with 14 degrees of timing. They are saying injectors (which were brand new 60lbs) failed and leaned out the 3 cylinders causing the failure, which blew the motor. I don't think thats the case, I think they hit it with too much timing and boost on 92 octane which detonated the 3 cylinders. Please chime in our all your thoughts and experiences. Obviously, I have to rebuild the motor, and just want to keep it from happening again
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
09-07-2014, 12:31 PM
#3
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How many miles? Never seen a plug close up like that. Are you sure valve train was good and valve didn't float? I would rule out mechanical failures first.
Who the hell is dumb enough to put a under drive on a blower car? Did you mean over drive? If so 3.47 10% OD is way over a si-trim or t-trim max speed.
Who the hell is dumb enough to put a under drive on a blower car? Did you mean over drive? If so 3.47 10% OD is way over a si-trim or t-trim max speed.
09-07-2014, 12:46 PM
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Soooo many variables here that need to be covered. Couple of questions:
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
09-07-2014, 12:53 PM
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How many miles? Never seen a plug close up like that. Are you sure valve train was good and valve didn't float? I would rule out mechanical failures first.
Who the hell is dumb enough to put a under drive on a blower car? Did you mean over drive? If so 3.47 10% OD is way over a si-trim or t-trim max speed.
Who the hell is dumb enough to put a under drive on a blower car? Did you mean over drive? If so 3.47 10% OD is way over a si-trim or t-trim max speed.
09-07-2014, 12:58 PM
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Soooo many variables here that need to be covered. Couple of questions:
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
09-07-2014, 01:12 PM
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Soooo many variables here that need to be covered. Couple of questions:
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
1- who was watching the fuel pressure gauge during the runs? Was there a decrease in pressure?
2- who was watching the air fuel meter while the pull was happening? Did it show a sudden upward spike?
3- was there meth involved in this setup? 13PSI on a stock bottom end is definitely pushing it.
Thanks!
2- a/f was constant throughout the run with no spikes,(see dyno pic)
3- No meth, and I didn't want it, just wanted a safe set up with good hp and was very specific not to push it to the limit of risking the lower end.
09-07-2014, 01:17 PM
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Safety Car
That's a overdrive pulley not underdrive. Any head damage?
09-07-2014, 01:30 PM
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09-07-2014, 01:39 PM
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So do you think that it detonated in 3 of the cylinders at thats why the plugs look like that. Compression test on the 3 cylinders shows 0 compression.
Last edited by travis1693; 09-10-2014 at 02:14 PM.
09-07-2014, 01:55 PM
#14
Burning Brakes
It looks pretty classic honestly... 13lbs of boost, no meth and a 12:1 A/F ratio? You've unfortunately become a statistic. 
you really want the A/F around 11.5 to 1, sometimes a bit more rich and have meth there supporting the timing advance.
Just my opinion, I'm not an expert
you really want the A/F around 11.5 to 1, sometimes a bit more rich and have meth there supporting the timing advance. Just my opinion, I'm not an expert
09-07-2014, 04:37 PM
#18
Drifting
So do you think that it detonated in 3 of the cylinders at thats why the plugs look like that. Compression test on the 3 cylinders shows 0 compression.
I too thought that there was too much timing for 92 octane. As far as the overspinned blower, I put my faith in the race shop that they new what they were doing and all they work on is LS motors. Keep in mind that they disagree with me about the boost level and are adamant that the motor could handle much more than 13 psi on a stock bottom end. Obviously, they don't want to accept responsibility for the motor failure, and because it was on the dyno, the responsibility is on me.
I too thought that there was too much timing for 92 octane. As far as the overspinned blower, I put my faith in the race shop that they new what they were doing and all they work on is LS motors. Keep in mind that they disagree with me about the boost level and are adamant that the motor could handle much more than 13 psi on a stock bottom end. Obviously, they don't want to accept responsibility for the motor failure, and because it was on the dyno, the responsibility is on me.
I am almost positive that the combination of pulleys are pushing the boundaries of the max recommended spin on that blower. I personally would have not put that much boost on 92oct and no meth. Yes, they may be able to handle that much boost but not without enough octane. That's just asking for trouble. I'm not a tuner but I know enough to know when something is not right and I do all my work except tuning.
09-07-2014, 10:49 PM
#19
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Unfortunately, I see you mentioned a Stg 4 heads, cam, LT's package prior. Stock LS2 is 10.9 CR and I'm afraid your heads may have bumped your CR even more. Then maxing out the boost running only pump gas looks like the stock pistons didn't like that for long.
09-08-2014, 07:14 AM
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Unfortunately, I see you mentioned a Stg 4 heads, cam, LT's package prior. Stock LS2 is 10.9 CR and I'm afraid your heads may have bumped your CR even more. Then maxing out the boost running only pump gas looks like the stock pistons didn't like that for long.
Thanks for all the help.
Last edited by travis1693; 09-10-2014 at 02:14 PM.