LR4 with 799 heads and ls9 gaskets with boost
LR4 with 799 heads and ls9 gaskets with boost I put together a 2005 LR4 4.8l short block with a set of very low mile 799 heads. ARP bolts holding it down. I bought the 799 heads with the impressions it would lower the compression ratio, thinking I would like that.
The truck has two smaller turbos, the goal was to spool early and make low end power.. It idles pretty well, and will actually make boost, after 30 seconds or more going from 1200 to 2000rpm.
Once boost came on the truck started to make all sorts of power. But it took FOREVER to start to build it up, and something feels off.
Did I lower the compression too much ? Or is this some other problem completely?
I still have the stock heads, but I would like to take the 799's and maybe mill them down if thats possible with them. And how much is possible?
Also should I ditch the ls9 gaskets? and do something else, or with having those, should I take the heads down even further?
Some HPTuners cfg and log files.. if they say anything/
my tuner's config - http://goo.gl/kkuid -hit the download arrow in upper left corner
6.19 First log - http://goo.gl/8qazX
6.19 second log - http://goo.gl/KFAlz
Thanks to anyone willing to help
The truck has two smaller turbos, the goal was to spool early and make low end power.. It idles pretty well, and will actually make boost, after 30 seconds or more going from 1200 to 2000rpm.
Once boost came on the truck started to make all sorts of power. But it took FOREVER to start to build it up, and something feels off.
Did I lower the compression too much ? Or is this some other problem completely?
I still have the stock heads, but I would like to take the 799's and maybe mill them down if thats possible with them. And how much is possible?
Also should I ditch the ls9 gaskets? and do something else, or with having those, should I take the heads down even further?
Some HPTuners cfg and log files.. if they say anything/
my tuner's config - http://goo.gl/kkuid -hit the download arrow in upper left corner
6.19 First log - http://goo.gl/8qazX
6.19 second log - http://goo.gl/KFAlz
Thanks to anyone willing to help
Last edited by asb2106; Jun 20, 2013 at 10:08 AM.
gt35 chinese specials and ls9 cam
Compressor trim: Compressor Wheel diameter: 54.28 /71.32 Turbine Wheel diameter: 55.79 /63.36 Exhaust Trim: .63ar
Compressor trim: Compressor Wheel diameter: 54.28 /71.32 Turbine Wheel diameter: 55.79 /63.36 Exhaust Trim: .63ar
Last edited by asb2106; Jun 20, 2013 at 10:41 AM.
found this comparison..
Casting Number 243 (and if Im reading this right the 243 is the same as the 799)
Head: 2001 LS6 5.7 Liter Passenger Car
Material: Aluminum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183
Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174
**********************
3.3 cc extra on top of the 7 layer MLS gasket.
Is that chamber size even relevant? considering its going on an engine not usually for it? Or is that the chamber size of the head itself?
Casting Number 243 (and if Im reading this right the 243 is the same as the 799)
Head: 2001 LS6 5.7 Liter Passenger Car
Material: Aluminum
Part Number:
12564243
Combustion Chamber Volume: 64.45cc
Compression Ratio: 10.5:1
Intake Port Volume: 210cc
Exhaust Port Volume: 75cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 64.45 cc-------0.100---0.200--0.300--0.400---0.500---0.550---0.600
Intake 210 cc------------62------126----184----224-----251----256----257
Exhaust 75 cc------------57------108----143----163-----176----180----183
Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches
Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174
**********************
3.3 cc extra on top of the 7 layer MLS gasket.
Is that chamber size even relevant? considering its going on an engine not usually for it? Or is that the chamber size of the head itself?
Last edited by asb2106; Jun 20, 2013 at 11:06 AM.
