Blew my LS9 Headgaskets mid pull?! **5 MORE PICTURES PAGE 3**
03-18-2013, 05:40 PM
#22
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You didn't list your compression. Key factor here. Those milled heads do suck. Maybe they lifted to let some pressure out and prevented even more damage? 
There is a table in your ECM for timing for IAT. I pay attention to the IAT's I see on the dyno and street while tuning the car. I progressively pull timing out for IAT's that are seen beyond what I did while tuning. Your coolant temps are pretty much irrelevant.
Long freaking pulls on 93 octane should be just fine if your tune, compression, boost, plugs, fuel are right.
I made back to back pulls like you said, even grabbing 5th on 28" tires this past weekend, and I haven't pushed a drop of water. 950rwhp on pump/meth. 23psi. 8.8:1 comp, tr7's, and IAT's going from 80 to 110 on a very long pull.
There is a table in your ECM for timing for IAT. I pay attention to the IAT's I see on the dyno and street while tuning the car. I progressively pull timing out for IAT's that are seen beyond what I did while tuning. Your coolant temps are pretty much irrelevant.
Long freaking pulls on 93 octane should be just fine if your tune, compression, boost, plugs, fuel are right.
I made back to back pulls like you said, even grabbing 5th on 28" tires this past weekend, and I haven't pushed a drop of water. 950rwhp on pump/meth. 23psi. 8.8:1 comp, tr7's, and IAT's going from 80 to 110 on a very long pull.
03-19-2013, 05:32 PM
#24
those head are advertised 58-63 cc.
would put your compression at 10.8-11.5:1 depending on the actual cc of your heads.
either way, im suspecting it was too much for pump gas and just let go.
have you considered e85. there are a couple of gas stations that sell it close to you.
03-19-2013, 06:47 PM
#25
those head are advertised 58-63 cc.
would put your compression at 10.8-11.5:1 depending on the actual cc of your heads.
either way, im suspecting it was too much for pump gas and just let go.
have you considered e85. there are a couple of gas stations that sell it close to you.
would put your compression at 10.8-11.5:1 depending on the actual cc of your heads.
either way, im suspecting it was too much for pump gas and just let go.
have you considered e85. there are a couple of gas stations that sell it close to you.
yeah he said he was running "stock" compression... I know heads vary by CC even if they are the same casting..
bump to find out his actual CR
03-22-2013, 10:57 PM
#28
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Fuel pressure was base set pressure at 55'ish psi... 1:1 rising rate regulator... The entire pull is 10.9-11.0:1 AFR... It's a speed density 3 bar map sensor tune so when it gets hot outside (around 80 degrees) the AFR goes to 11.5:1 but when it drops 20-30 degrees outside it goes to 10.9-11.0... During these pulls were 11.0'ish:1....
No idea on compression 100% exactly but its factory bore stroke 346ci LS1 block with the 5.3 CNC casting heads... I don't know the exact casting number as PRC changed the "casting number" with "stage 2.5" so no idea... Prolly 706's?
The car has dual aeromotive stealth 340's in tank pumps running through a -6AM feed going to the aeromotive regulator and then out to the factory ls1 rails. Then the regulator returns with a -6AN back to the tank.
I heard -6AN line and my 80lb injectors are far to
Small for E85... So I think I'm going to go the pump and Meth route...
The car has BR7EF's in it gapped to .027"...
No idea if timing is pulled if IAT's skyrocket.. I need to ask my tuner...
Oh and no idea on my ring gap but my builder did set it up loose as he knows its a turbo motor...
I need to pull my Downpipe to make sure the turbo is unhurt.
Is E85 better than Pump/meth on my set up? It just seems like meth is the MUCH cheaper and easier way to go.
I just purchased my 317 heads and soon will purchase my ARP head STUDS and go from there... Then machine shop to make sure block is ok, and if so change the piston and put her back together and then fresh tune and let her rip!
No idea on compression 100% exactly but its factory bore stroke 346ci LS1 block with the 5.3 CNC casting heads... I don't know the exact casting number as PRC changed the "casting number" with "stage 2.5" so no idea... Prolly 706's?
The car has dual aeromotive stealth 340's in tank pumps running through a -6AM feed going to the aeromotive regulator and then out to the factory ls1 rails. Then the regulator returns with a -6AN back to the tank.
I heard -6AN line and my 80lb injectors are far to
Small for E85... So I think I'm going to go the pump and Meth route...
The car has BR7EF's in it gapped to .027"...
No idea if timing is pulled if IAT's skyrocket.. I need to ask my tuner...
Oh and no idea on my ring gap but my builder did set it up loose as he knows its a turbo motor...
I need to pull my Downpipe to make sure the turbo is unhurt.
Is E85 better than Pump/meth on my set up? It just seems like meth is the MUCH cheaper and easier way to go.
I just purchased my 317 heads and soon will purchase my ARP head STUDS and go from there... Then machine shop to make sure block is ok, and if so change the piston and put her back together and then fresh tune and let her rip!
03-23-2013, 07:52 AM
#29
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I missed the part where you had e85. You either have a tuning issue or a fuel issue. E85 is great, but you need to be sure of the ethanol content or tune very conservative in case you get some e70 by accident. You don't even need head studs at that power level. It's detonation that lifts the heads unless they just have a super thin deck.
03-23-2013, 08:26 AM
#30
He was running 93 pump.
He is asking which is better 93/meth or E85. I would run E85 if I had it more abundant around me but I use 93/meth and it works great too.
No reason not to use head studs if its apart. Build it once and do it right. He can sell the ARP bolts to offset the cost of studs.
He is asking which is better 93/meth or E85. I would run E85 if I had it more abundant around me but I use 93/meth and it works great too.
No reason not to use head studs if its apart. Build it once and do it right. He can sell the ARP bolts to offset the cost of studs.
03-23-2013, 09:23 AM
#31
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What pistons? That would help figure out comp ratio. Unless you were at 10.0 or higher i don't see why this happened. Lots of people run pump gas on forged motors at 13psi. **** even stock motors at 8 to 10psi are ok. There has to be more to this.
03-23-2013, 11:27 AM
#32
heres his build thread
https://ls1tech.com/forums/forced-in...-pictures.html
looks like his forged shortblock ended up being just forged pistons..
my guess is he was at 10.5:1 - 11:1 CR Like said a few posts up ^^ depending on Cc of head and piston Comp height...
Im buying a meth kit before I even start my car, I don't want an accident to happen
03-23-2013, 01:52 PM
#34
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He was running 93 pump.
He is asking which is better 93/meth or E85. I would run E85 if I had it more abundant around me but I use 93/meth and it works great too.
No reason not to use head studs if its apart. Build it once and do it right. He can sell the ARP bolts to offset the cost of studs.
He is asking which is better 93/meth or E85. I would run E85 if I had it more abundant around me but I use 93/meth and it works great too.
No reason not to use head studs if its apart. Build it once and do it right. He can sell the ARP bolts to offset the cost of studs.
I made 750rwhp for a very long time on a stock ls6 with a cam with 19psi at 6800rpm. Never pushed a drop of water, and heads never came off. I use meth/water, then 100% meth, and then much more meth as it progressed. That is 10.5:1 for those that don't know. I now make 950rwhp+ on pump/meth at 23psi with pump/meth at 8.8:1 comp. Again, never pushed a drop of water. I'm pushing it on some long runs as well.
To the OP, let your tuner diagnose this for you. If it doesn't add up, find a better tuner. More often than not there is just too much timing in the motor when all else checks out.
03-23-2013, 11:06 PM
#35
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You will get people telling one is better than the other on both sides. I like and have had great luck with the 93 and Meth combo (for street). Meth is your friend and spray a lot of it.
03-24-2013, 09:57 PM
#37
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Here is the new plan:
Make sure the 5.3 CNC heads I have are OK, and then sell them.
just bought some 317 heads..
Make sure motor checks out ok, change piston + whatever else...
new LS9 headgaskets
Buy Meth kit
ARP Head studs + Sell the ARP head bolts...
throw it back together... have my IAT's to pull timing significantly if they go higher than normal...
This motor had like 2,000 miles on it!!!!
03-24-2013, 10:05 PM
#38
why the hell are u using 706 casting prc 2.5 heads on a boosted engine with HEAD BOLTS? those heads are milled! u should have just went with some stock 317s and head studs or some 243s/799s with head studs!!!
03-26-2013, 09:26 PM
#39
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I was using the 706's because they were already on the car from my previous all motor/n20 set up... I knew they weren't ideal but I went ahead and used them anyway...
video of the car blowing up...
pics of piston and stuck on side of highway...
video of the car blowing up...
pics of piston and stuck on side of highway...
