blew headgasket on dyno 300 shot
Thread Starter
Launching!
Joined: Mar 2009
Posts: 237
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From: new jersey
blew headgasket on dyno 300 shot had the c5 vette on the dyno - 402, 11:1,235 tfs,fast 92,wilson direct port,nitrous maximizer 2,stand alone fuel system etc .the question i have is on a 300 shot car made 860 rwhp on a mustang dyno on that pass air fuel crept to the 12.2 range changed fuel jets up 1 size and made 865 car shut off at 6k thanks to the fjo widwband but blew head gasket cyl 5 ! but the bigger problem is it also took out the block and head it was like a torch sliced a hole in both of them has any one seen this on a ls2 engine ,also with a properly tuned engine what is a safe nos level be ? p.s the bottem end is forged and has coated pistons,was thinking it burned the head because the piston coating was stronger than the block . any input would be great
You lifted the head and when the air/fuel/nitrous ignited in the combustion chamber it went in to the path of least resistance witch is where the "torch" marks are.
If you don't already have them, you need to get the bigger head studs and a set of MLS gaskets.
I also think 17* is too much timing for a 300 shot on your setup. I'd back it down around 13-14*
What did the plugs look like after the first pull when it made 860?
If you don't already have them, you need to get the bigger head studs and a set of MLS gaskets.
I also think 17* is too much timing for a 300 shot on your setup. I'd back it down around 13-14*
What did the plugs look like after the first pull when it made 860?
17*
That's more timing than I was running with a 200 hit. I'm not an expert, but I'll speculate that detonation and high cylinder pressures lifted the head and the heat and pressure cut like a torch.
That's more timing than I was running with a 200 hit. I'm not an expert, but I'll speculate that detonation and high cylinder pressures lifted the head and the heat and pressure cut like a torch.
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had the c5 vette on the dyno - 402, 11:1,235 tfs,fast 92,wilson direct port,nitrous maximizer 2,stand alone fuel system etc .the question i have is on a 300 shot car made 860 rwhp on a mustang dyno on that pass air fuel crept to the 12.2 range changed fuel jets up 1 size and made 865 car shut off at 6k thanks to the fjo widwband but blew head gasket cyl 5 ! but the bigger problem is it also took out the block and head it was like a torch sliced a hole in both of them has any one seen this on a ls2 engine ,also with a properly tuned engine what is a safe nos level be ? p.s the bottem end is forged and has coated pistons,was thinking it burned the head because the piston coating was stronger than the block . any input would be great
too much timing at peak torque for the kind of cylinder pressure you are seeing will torch a head, block and gasket everytime. Cylinder pressures are astronomical at peak torque man. what plugs were you running?
You lifted the head and when the air/fuel/nitrous ignited in the combustion chamber it went in to the path of least resistance witch is where the "torch" marks are.
If you don't already have them, you need to get the bigger head studs and a set of MLS gaskets.
I also think 17* is too much timing for a 300 shot on your setup. I'd back it down around 13-14*
What did the plugs look like after the first pull when it made 860?
If you don't already have them, you need to get the bigger head studs and a set of MLS gaskets.
I also think 17* is too much timing for a 300 shot on your setup. I'd back it down around 13-14*
What did the plugs look like after the first pull when it made 860?
Holy **** that gap is large for nitrous plugs batman. I would suggest a gap of around .024-.026 for that kind of cylinder pressures...And more like a 10 heat range plug then the 9's and run at least the 110 in tank and in the standalone. Thats another thing you have to consider...pump fuel in the tank will do this same thing that you described because its so volatile at that much power. We generally only shoot for about 700hp NA with pump. On a nitrous motor we dont even play with pump fuel after about 575hp as its so unpredictable when mixed with a standalone fuel setup for the nitrous only.
Thread Starter
Launching!
Joined: Mar 2009
Posts: 237
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From: new jersey
The fuel in stand alone was Q16 and had 93 in tank with 5 gallons ms109 -100 octane . It is a plastic fast 92 intake direct port with 2 wilson burst pannels,it seems like you guys think too much timming and a colder plug with less gap
Suprised it didnt burn it up on the 1st pull.
Q16 will make it even hotter.... on Q16 last year and a 350 shot we were running 4-5* of timing and NGK 11's
If you want to run that much timing try a colder plug and C23 in the main tank and stand alone.
Also FIRE who ever your tuner is!
Q16 will make it even hotter.... on Q16 last year and a 350 shot we were running 4-5* of timing and NGK 11's
If you want to run that much timing try a colder plug and C23 in the main tank and stand alone.
Also FIRE who ever your tuner is!
Last edited by ATVracr; Apr 20, 2009 at 07:30 AM.
The short answer...yes it can be done up to a certain extent..The quick answer is, its not worth ruining a motor on fuel that can be so unpredictable.
