Difference between lq4 and lq9 6.0L
03-15-2007, 06:46 PM
#1
Difference between lq4 and lq9 6.0L What's the difference between them and if one of them is better for an upgrade from a 5.7 to 6.0L for a Procharged car?
Last edited by Mike Cordero; 03-15-2007 at 06:47 PM. Reason: make a correction.
03-15-2007, 09:10 PM
#6
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Compression is the difference. I am not sure how they changed it but I would assume it would be the heads.
I think you need a 4.0 inch bore to use the L92 heads, Hot Rod or Chevy High Tech performance just did an article on it. They used a 6.0 liter block.
I think you need a 4.0 inch bore to use the L92 heads, Hot Rod or Chevy High Tech performance just did an article on it. They used a 6.0 liter block.
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03-15-2007, 09:35 PM
#8
Originally Posted by My1st Truck
Compression is the difference. I am not sure how they changed it but I would assume it would be the heads.
I think you need a 4.0 inch bore to use the L92 heads, Hot Rod or Chevy High Tech performance just did an article on it. They used a 6.0 liter block.
I think you need a 4.0 inch bore to use the L92 heads, Hot Rod or Chevy High Tech performance just did an article on it. They used a 6.0 liter block.
some people bore it to 4.03 or even 4.08 ....
03-16-2007, 10:35 AM
#10
Wow, a lot of misinformation here.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
03-16-2007, 10:40 AM
#12
Originally Posted by LostCauseZ06
LQ4 has shorter head bolts 
03-16-2007, 11:16 AM
#13
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Originally Posted by 12secSS
Nope! Heads bolts are the same for all Gen3 engines, around 2003 GM changed the length to be the same. Earlier engines had two corner bolts shorter then the rest.
03-16-2007, 11:27 AM
#14
lq4
Originally Posted by 12secSS
Wow, a lot of misinformation here.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
03-16-2007, 11:46 AM
#15
Originally Posted by LostCauseZ06
your right, but most LQ9's that are around (unless you buy a new GM one) were built before 03.... mine had the short corner bolts... i think pretty much all LQ4's were built after 2003 and have the different head bolts.
LQ4 was introduced in 1999 with iron heads.
Don't believe me, do a search ... this is how I found out about the 2003 change, plus I have personal experience with this (head bolt) issue (see sig).
Originally Posted by Mike Cordero
Ok, if the blocks are the same, why you prefer one (LQ4 for boost up to 6 psi) over the LQ9. LQ9 will hold more boost?
LQ9 (10.4) = 6 PSI safe boost limit
LQ4 (9.5) = ~10 PSI safe boost limit
03-16-2007, 12:12 PM
#16
Lq4
Originally Posted by 12secSS
LQ9 was introduced in 2001 with the 317 aluminum heads (replacing the LQ4 Iron heads).
LQ4 was introduced in 1999 with iron heads.
Don't believe me, do a search ... this is how I found out about the 2003 change, plus I have personal experience with this (head bolt) issue (see sig).
With boost, you want a lower compression ratio to reach higher boost levels. Both will take the same amount of power, but with the 10.4 or the LQ9, you will be boost limited. The connecting rods can only handle so much combustion chamber pressure. Plus you read it wrong.
LQ9 (10.4) = 6 PSI safe boost limit
LQ4 (9.5) = ~10 PSI safe boost limit
LQ4 was introduced in 1999 with iron heads.
Don't believe me, do a search ... this is how I found out about the 2003 change, plus I have personal experience with this (head bolt) issue (see sig).
With boost, you want a lower compression ratio to reach higher boost levels. Both will take the same amount of power, but with the 10.4 or the LQ9, you will be boost limited. The connecting rods can only handle so much combustion chamber pressure. Plus you read it wrong.
LQ9 (10.4) = 6 PSI safe boost limit
LQ4 (9.5) = ~10 PSI safe boost limit
03-17-2007, 07:41 AM
#18
Lq4
Originally Posted by LS1NOVA
actually 12secSS, the facts are:
stroke 3.622
LQ4 compression 9.4
LQ9 compression 10.0
both have 72cc heads
So, buy either and upgrade the pistons and at least the rod bolts.
stroke 3.622
LQ4 compression 9.4
LQ9 compression 10.0
both have 72cc heads
So, buy either and upgrade the pistons and at least the rod bolts.
03-17-2007, 09:36 AM
#19
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Originally Posted by 12secSS
Wow, a lot of misinformation here.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
LQ9 and LQ4 are identical, except for the pistons. The LQ9 has flat top piston to reach 10.4 or so CR, while the LQ4 has dished pistons to reach 9.5 CR. Both use the same heads, 317 with 76cc chambers (which flow similarly to LS6 243 heads). The bore is 4.00" and the stroke is the same as an LS1 3.89". For a boosted application, you would be better served using the LQ4, unless you are staying at 4-6 PSI (then you can go with the LQ9).
Oh, and yes you can use the L92 heads on an LQ4/9.
Speaking of mis information, the stroke of an LS1 is 3.622 inches. The bore is 3.89 inches (for an LS1). The LQ4/9 have the same stroke and a 4.0 inch bore.
AJ
03-17-2007, 09:42 AM
#20
lq4
Originally Posted by ArrestMeRed99Z28
Speaking of mis information, the stroke of an LS1 is 3.622 inches. The bore is 3.89 inches (for an LS1). The LQ4/9 have the same stroke and a 4.0 inch bore.
AJ
AJ
