Wondering about a stock LQ4 LQ9 under boost
05-14-2010, 12:00 PM
#1
Wondering about a stock LQ4 LQ9 under boost okay so I have seen the threads on how a stock LS1 (bottom end) and 5.3 would hold up/live under FI. Now I would like to know about the stock iron blocks (LQ4/LQ9) have lived under boost. I have one that has a approx CR of 8.8 and I am only on 5#'s and looking to go higher. So I want to see if anyone has tried this and what limit they got to. So I would like to see what FI you went with, CR, how long it lived from install, HP/TQ, if you broke it & most importantly how you drive the car. We might as well know what all LS type blocks are capable of. Think of this kinda like knowing how much HP you can run knowing you're close to breaking that stock 10-bolt.
05-14-2010, 01:13 PM
#4
It was on 15 psi for a good while also. What killed it was when I raised the rev limiter over 6K. 2nd pass @ over 6K RPM it put a rod out the side of the block. I was running consistant 10.0's @ 130ish but couldn't make it to the traps with my gearing (3.73's at the time). Was coasting thru on every pass. Finally I had all the bugs worked out and was ready to forge the bottom end so I went out with the intentions of running a 9 or blowing up. It ran like a 10.005 or something on the pass that it let go but it broke before the finish line. I had intended to just blow it up but I ended up blow it apart.
05-14-2010, 01:19 PM
#6
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My 6.0 iron block lifted the heads with only about 14 psi boost and 8.5 compression Wiseco dish pistons. What happened is that two ARP studs pulled the threads out of the block. I had copper head gaskets and o-ringed heads. I dicsovered that this is common. I ended up buying a LS2 ERL Performance 427 ci block and am using 6 bolt Trick Flow heads from Total Engine Airflow with 1/2" main studs and 3/8" 5th and 6th studs. I am running double o-rings now cut in the head and block. I also expect to run up to 30 psi on race fuel.
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fastfreddy77 (10-10-2019)
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05-14-2010, 03:12 PM
#8
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My stock lq4 with ls6 springs and pushrods put down 623 at 15lbs and 16 deg of timing on e85. I drive it like I stole it, and have for the last 4500 miles. It did push water at anything over 13.5 lbs. I switched to a gt2-3 cam, patriot duals,ls9 gaskets, and studs and so far haven't pushed any water.
05-17-2010, 11:07 AM
#15
My 6.0 iron block lifted the heads with only about 14 psi boost and 8.5 compression Wiseco dish pistons. What happened is that two ARP studs pulled the threads out of the block. I had copper head gaskets and o-ringed heads. I dicsovered that this is common. I ended up buying a LS2 ERL Performance 427 ci block and am using 6 bolt Trick Flow heads from Total Engine Airflow with 1/2" main studs and 3/8" 5th and 6th studs. I am running double o-rings now cut in the head and block. I also expect to run up to 30 psi on race fuel.
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fastfreddy77 (10-10-2019)
05-17-2010, 11:27 AM
#16
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800 ish rwhp here.
14 psi
Twin T70 turbos
Stock pistons
Stock rods with arp bolts
Stock Crank
Stock main bolts
Stock bearings
Stock rings
Custom grind comp cam
Stock timing set
Stock oil pump
Comp 850-16 lifters(stock replacement)
ported 317 heads
94 octane pump gas/meth
Regularly saw the 7200 rpm rev limiter.
No pushed water. 9.51@147 with a shitty 60 foot, LOTS of street miles/pulls.
Its all in the tune up, they do NOT like timing and they like to be a little fat.
14 psi
Twin T70 turbos
Stock pistons
Stock rods with arp bolts
Stock Crank
Stock main bolts
Stock bearings
Stock rings
Custom grind comp cam
Stock timing set
Stock oil pump
Comp 850-16 lifters(stock replacement)
ported 317 heads
94 octane pump gas/meth
Regularly saw the 7200 rpm rev limiter.
No pushed water. 9.51@147 with a shitty 60 foot, LOTS of street miles/pulls.
Its all in the tune up, they do NOT like timing and they like to be a little fat.
05-17-2010, 12:24 PM
#17
You have a stock one with 8.8 compression? How did you get that? I just rebuilt a stock LQ4 and i looked it up and it said the compression was 9.4 and i think an LQ9 is higher. right? Im guessing mine is an LQ4 by the dished pistons, I think LQ9s are flat.
