Need help guys,2nd forged ls1 blown up this year.Whats my problem?
11-10-2010, 08:53 PM
#1
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Need help guys,2nd forged ls1 blown up this year.Whats my problem? Okay il try and keep this as short as possible. Running a kytp ac turbo kit with tc78 and 3inch dp,very large IC. Last year i melted piston 7 on a forged 348. It was on pump gas and it was really hot out and I hot laped it. That one made alittle sense. Had it rebuilt with mahle pistons,8.9:1 compression,tr6 plugs,ls6 intake,60lb injectors, 97-98 vette fuel rail with 1:1 regulator and dual 255 pumps. Went to the track 3 weeks ago and ran a 93 and 104 octane mix and it ran great, 10.4 at 133 with a 1.65 6o.
Ran it this last sunday on 93 and made it half way down the track before again piston on cyl 7 blew out another ring land, plug melted also. I was able to watch my wideband and it was at 11.0 afr just like on the dyno. Iat was 85 and fuel pressure at 71psi. Max timing is at 18 then ramped down to 16 for the majority of the run.
I had last years engine tuned at a sponsors shop then switched to another. Both big shops that know what they are doing. Both were tuned to raced on pump gas. My ideas, tr6 is too hot, ls6 intake design sucks and forces to much air in cylinder 7, stock volume rails maybe have an issue with cylinder 7.
Any other ideas would be great.
Alex
Ran it this last sunday on 93 and made it half way down the track before again piston on cyl 7 blew out another ring land, plug melted also. I was able to watch my wideband and it was at 11.0 afr just like on the dyno. Iat was 85 and fuel pressure at 71psi. Max timing is at 18 then ramped down to 16 for the majority of the run.
I had last years engine tuned at a sponsors shop then switched to another. Both big shops that know what they are doing. Both were tuned to raced on pump gas. My ideas, tr6 is too hot, ls6 intake design sucks and forces to much air in cylinder 7, stock volume rails maybe have an issue with cylinder 7.
Any other ideas would be great.
Alex
11-10-2010, 09:27 PM
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Okay il try and keep this as short as possible. Running a kytp ac turbo kit with tc78 and 3inch dp,very large IC. Last year i melted piston 7 on a forged 348. It was on pump gas and it was really hot out and I hot laped it. That one made alittle sense. Had it rebuilt with mahle pistons,8.9:1 compression,tr6 plugs,ls6 intake,60lb injectors, 97-98 vette fuel rail with 1:1 regulator and dual 255 pumps. Went to the track 3 weeks ago and ran a 93 and 104 octane mix and it ran great, 10.4 at 133 with a 1.65 6o.
Ran it this last sunday on 93 and made it half way down the track before again piston on cyl 7 blew out another ring land, plug melted also. I was able to watch my wideband and it was at 11.0 afr just like on the dyno. Iat was 85 and fuel pressure at 71psi. Max timing is at 18 then ramped down to 16 for the majority of the run.
I had last years engine tuned at a sponsors shop then switched to another. Both big shops that know what they are doing. Both were tuned to raced on pump gas. My ideas, tr6 is too hot, ls6 intake design sucks and forces to much air in cylinder 7, stock volume rails maybe have an issue with cylinder 7.
Any other ideas would be great.
Alex
Ran it this last sunday on 93 and made it half way down the track before again piston on cyl 7 blew out another ring land, plug melted also. I was able to watch my wideband and it was at 11.0 afr just like on the dyno. Iat was 85 and fuel pressure at 71psi. Max timing is at 18 then ramped down to 16 for the majority of the run.
I had last years engine tuned at a sponsors shop then switched to another. Both big shops that know what they are doing. Both were tuned to raced on pump gas. My ideas, tr6 is too hot, ls6 intake design sucks and forces to much air in cylinder 7, stock volume rails maybe have an issue with cylinder 7.
Any other ideas would be great.
Alex
11-10-2010, 09:42 PM
#5
How much power? Could be an issue with a stock rail. Timing is just what the car likes, but 18* on pump is quite a bit. Could be coils, open injector, lots of things. How does the blown piston look? I made 770rwhp on a LS6 intake with 19 psi, and I know that Mighty Mouse has made more power on the same intake.
11-10-2010, 09:50 PM
#7
bad injector that just happens to be on cylinder #7?
what type of manifold/header or is it a homemade setup?
right side has a "real" breather or is it just piped over to passenger side valvecover?
what type of manifold/header or is it a homemade setup?
right side has a "real" breather or is it just piped over to passenger side valvecover?
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11-10-2010, 09:54 PM
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It made 675whp and 705flbs on a mustang dyno through a locked auto and 9inch. Im sure back pressure is higher than normal. Im thinking of running a larger ar housing. Im running a .96 now. Running a truck manifold on driver side and c6 vette manifold on pass side. I hear ya on the leaded race gas. Ive just seen so many cars run fast on pump. Along with my self. Im thinking i got a bad tank maybe.
What do you guys think about the tr6 glowing and causing the detonation? Or does the stock fuel rail starve cyl 7 more than the others? Should I even consider a victor jr intake or is that a waste of money for me?
What do you guys think about the tr6 glowing and causing the detonation? Or does the stock fuel rail starve cyl 7 more than the others? Should I even consider a victor jr intake or is that a waste of money for me?
11-10-2010, 09:58 PM
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The driver side is a real breather, I have the ls6 valley plate open to atmosphere. Just wondering why that has been brought up here. Can this cause an engine to blow up,not having enough crank case pressure relief?
11-10-2010, 09:59 PM
#10
I'd definitely go with a bigger rail, but it sounds like an octane issue if you're fine with higher octane gas. That is a lot of power/tq for pump gas and beating on it at the track. The intake (unless it's damaged) is not your problem. I don't see how your duty cycle on 60's isn't excessive, I had 75's way maxed out at 770rwhp and the dinky 50's were at 156% on the first WOT pull with them making 640rwhp.
Octane is taken on average and if you're getting gas that's E10 your stoich changes, I'd just not run on pump gas or get a meth kit for added insurance (do not use it as a fuel substitute).
Octane is taken on average and if you're getting gas that's E10 your stoich changes, I'd just not run on pump gas or get a meth kit for added insurance (do not use it as a fuel substitute).
11-11-2010, 05:08 AM
#11
TR6's are a blow torch at that power level. You need a colder non projected tip plug. I don't trust pump gas over 14 degrees of timing without meth. A #7 or even #8 heat range is a better idea if you are pushing it on pump gas NGK BR7EF.
Last edited by Nitroused383; 11-11-2010 at 05:15 AM.
11-11-2010, 05:33 AM
#12
I thought the Mahle was the weakest of the forged pistons and lots of guys don't recommend them for boost. I would suggest a bigger rail like others have. Also I don't see any issue with running a TR6 plug as that is what I have been running with no issues. I do think your timing might be a little high if you don't have meth
11-11-2010, 08:17 AM
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I third the motion of bigger rails.
The LS6 intake is not your problem and has nothing to do with #7.
I agree with Trust, sounds like an octane problem. another member, Mr. Powell, has the computer software and hardware in his 996 to know, and hes had 2 tanks of 93 that werent actually 93 and the only way he knew was because of his gadgets. he knew the instant he made full boost that the tank of gas was no good, so it makes sense that at WOT you wont make it far before it goes boom.
The LS6 intake is not your problem and has nothing to do with #7.
I agree with Trust, sounds like an octane problem. another member, Mr. Powell, has the computer software and hardware in his 996 to know, and hes had 2 tanks of 93 that werent actually 93 and the only way he knew was because of his gadgets. he knew the instant he made full boost that the tank of gas was no good, so it makes sense that at WOT you wont make it far before it goes boom.
11-11-2010, 08:23 AM
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It made 675whp and 705flbs on a mustang dyno through a locked auto and 9inch. Im sure back pressure is higher than normal. Im thinking of running a larger ar housing. Im running a .96 now. Running a truck manifold on driver side and c6 vette manifold on pass side. I hear ya on the leaded race gas. Ive just seen so many cars run fast on pump. Along with my self. Im thinking i got a bad tank maybe.
What do you guys think about the tr6 glowing and causing the detonation? Or does the stock fuel rail starve cyl 7 more than the others? Should I even consider a victor jr intake or is that a waste of money for me?
What do you guys think about the tr6 glowing and causing the detonation? Or does the stock fuel rail starve cyl 7 more than the others? Should I even consider a victor jr intake or is that a waste of money for me?
11-11-2010, 08:47 AM
#15
I thought the Mahle was the weakest of the forged pistons and lots of guys don't recommend them for boost. I would suggest a bigger rail like others have. Also I don't see any issue with running a TR6 plug as that is what I have been running with no issues. I do think your timing might be a little high if you don't have meth
11-11-2010, 11:21 AM
#18
There's absolutely no reason to run a TR6 at that level. It may work for some but has caused many issues for others. There is essentially zero side effects to running a colder plug.
It sounds fuel related to me as well. Melted usually indicates lean whereas just plain busted would indicate knock. I'd start by getting your injectors checked, or just move to larger ones altogether.
It sounds fuel related to me as well. Melted usually indicates lean whereas just plain busted would indicate knock. I'd start by getting your injectors checked, or just move to larger ones altogether.
11-11-2010, 12:30 PM
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There's absolutely no reason to run a TR6 at that level. It may work for some but has caused many issues for others. There is essentially zero side effects to running a colder plug.
It sounds fuel related to me as well. Melted usually indicates lean whereas just plain busted would indicate knock. I'd start by getting your injectors checked, or just move to larger ones altogether.
It sounds fuel related to me as well. Melted usually indicates lean whereas just plain busted would indicate knock. I'd start by getting your injectors checked, or just move to larger ones altogether.