Help with LQ4 install!!!!
01-01-2008, 08:47 AM
#1
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Help with LQ4 install!!!! Hey guys, this is my first post on here, hopefully to be a good one. I have used the search bar and gone through posts to scramble any information, I can find towards this topic. I have a 1995 Chevy Impala and I am swapping it out with a LQ4 motor. Supposedly it is the same as a LQ9 and LS2 minus Aluminum block and lower compression. Since the motor is out, I'm looking for what heads and cam setups I can run on this car that will get me into the 450-500 rwhp range N/A. I am also looking for other little mods like pulleys and places to get them. I am coming from the LT1 game and this LS motor is foreign to me. I am not asking you guys to build my car for me but point me to the right direction. I am in the direction of getting a L76 intake with L92 heads. I am leaning this way so it will clear the stock hood since the truck manifold won't. I would like to know if there are any companies that sell a head and cam package for what I'm looking for? Thanks
01-01-2008, 12:18 PM
#4
Any parts that fit an LS1 will work on an LQ4. For your power level, and depending on what you consider driveable on the street, I would suggest a T-Rex, MS3/4, G5X3/4 or anything along the lines of upper-230/mid-240 duration. You will need great flowing heads like either those L92 or aftermarkets. LQ4 can easily achieve 500rwhp with a great heads/cam setup. Any of the sponsers to the right will have what you need. 
As far as CR variances from different LSx engines:
LS1 = 10.1
LQ4 = 9.5
LS2 = 10.8
LQ9 = 10.5
As far as CR variances from different LSx engines:
LS1 = 10.1
LQ4 = 9.5
LS2 = 10.8
LQ9 = 10.5
01-01-2008, 12:47 PM
#5
Any parts that fit an LS1 will work on an LQ4. For your power level, and depending on what you consider driveable on the street, I would suggest a T-Rex, MS3/4, G5X3/4 or anything along the lines of upper-230/mid-240 duration. You will need great flowing heads like either those L92 or aftermarkets. LQ4 can easily achieve 500rwhp with a great heads/cam setup. Any of the sponsers to the right will have what you need.
As far as CR variances from different LSx engines:
LS1 = 10.1
LQ4 = 9.5
LS2 = 10.8
LQ9 = 10.5
As far as CR variances from different LSx engines:
LS1 = 10.1
LQ4 = 9.5
LS2 = 10.8
LQ9 = 10.5
01-01-2008, 05:26 PM
#7
the lq9 is only 10:1 compression..
however, the problem with the lq4 engine is the dished piston (hence lower compression). it uses a -6.5cc dish vs. the flat top style in the lq9. the problem with using L92 heads on these engines is the simple fact that generating compression is a big issue without switching pistons. you can't mill the head to more than about 67 cc because of the huge valves, not to mention the odd valve angle causing problems with cylinder wall to valve contact. i bought an lq4 engine with the intent of milling the L92 head, but after extensive research i figured out that i won't be able to get compression without a different piston. you won't see 450-500 whp through a stalled auto using the stock shortblock lq4 without a KILLER combo. probably involving some valve reliefs and a carb style intake.
my advice - either lower your expectations from the stock shortblock, or use different pistons. also, the L76 intake isn't proving to be very productive above 6,000 rpm, so using a cam in the 240s duration will be a waste.
also bear in mind that you cannot mix and match the accessories as the lq4 style parts stick out farther than ls1. so if you're going to use the lq4 waterpump or whatever, you won't be able to use an ls1 style underdrive pulley, etc. and vice versa.
however, the problem with the lq4 engine is the dished piston (hence lower compression). it uses a -6.5cc dish vs. the flat top style in the lq9. the problem with using L92 heads on these engines is the simple fact that generating compression is a big issue without switching pistons. you can't mill the head to more than about 67 cc because of the huge valves, not to mention the odd valve angle causing problems with cylinder wall to valve contact. i bought an lq4 engine with the intent of milling the L92 head, but after extensive research i figured out that i won't be able to get compression without a different piston. you won't see 450-500 whp through a stalled auto using the stock shortblock lq4 without a KILLER combo. probably involving some valve reliefs and a carb style intake.
my advice - either lower your expectations from the stock shortblock, or use different pistons. also, the L76 intake isn't proving to be very productive above 6,000 rpm, so using a cam in the 240s duration will be a waste.
also bear in mind that you cannot mix and match the accessories as the lq4 style parts stick out farther than ls1. so if you're going to use the lq4 waterpump or whatever, you won't be able to use an ls1 style underdrive pulley, etc. and vice versa.
Last edited by s346k; 01-01-2008 at 07:31 PM.
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02-22-2009, 05:02 PM
#8
I'm running L92 Heads on a LQ4 Block without a problem, and they have been milled .025". The Cam I have was spec'd to 6500 RPM's, and with a stock L76 Intake it pulls hard to that RPM. Maybe it's cause I have a stroker..but mine has plenty of power to 6500 RPM's.
There are stock displacement 6.0's out there with the L92/L76 setup making some pretty good power for what they are.
There are stock displacement 6.0's out there with the L92/L76 setup making some pretty good power for what they are.
