SSplaytoy Posted May 3, 2005 Report Share Posted May 3, 2005 I know it has been a debate, but I read that I had the LQ4 because the 8th digit of my vin is an N. But they say the LQ9 is better for boost. So my question is, who has what and what are the differences? Just the heads? Link to comment Share on other sites More sharing options...
BenKey Posted May 3, 2005 Report Share Posted May 3, 2005 If it's a SS, it's a LQ9 motor. The heads on both are the same, the only difference is in the pistons. LQ9 motor has flat top, LQ4 dished pistons. The LQ9 is 10:1CR, with the LQ4 being 9.6:1. The LQ4 is better for boost due to the lower CR. Link to comment Share on other sites More sharing options...
tawss04 Posted May 3, 2005 Report Share Posted May 3, 2005 If I remember correctly the LQ4 is the 6.0 non HO and it is the heads are different thats why the HO is 345hp and the other one is 300hp. The LQ9 heads are the same as the Z06 heads but the combustion chambers are larger to get the 10.1to1 CR. The GM hightech magazine had an artical about it a few months ago. SSplaytoy if you want to be sure call Alex at Maroone, he has both a LQ4 and a LQ9 he is building. Link to comment Share on other sites More sharing options...
BenKey Posted May 3, 2005 Report Share Posted May 3, 2005 If I remember correctly the LQ4 is the 6.0 non HO and it is the heads are different thats why the HO is 345hp and the other one is 300hp. The LQ9 heads are the same as the Z06 heads but the combustion chambers are larger to get the 10.1to1 CR. The GM hightech magazine had an artical about it a few months ago. SSplaytoy if you want to be sure call Alex at Maroone, he has both a LQ4 and a LQ9 he is building. <{POST_SNAPBACK}> That's not totally right. The LQ4 is the non-HO 6.0L, yes. However, the heads are exactly the same. It is the pistons that effectively change the CR. The combustion chambers on both heads are 71cc. If they were any larger on the LQ9, then that would drive down the CR. Link to comment Share on other sites More sharing options...
TurbochargedBerserker Posted May 3, 2005 Report Share Posted May 3, 2005 Ben's right. Both use 317 castings with 71.xx cc chambers. LQ4 = dished pistons, LQ9 = flat top Link to comment Share on other sites More sharing options...
detjoe Posted May 6, 2005 Report Share Posted May 6, 2005 bigger combustion chamber=higher compression Link to comment Share on other sites More sharing options...
BenKey Posted May 6, 2005 Report Share Posted May 6, 2005 bigger combustion chamber=higher compression <{POST_SNAPBACK}> No. Larger combustion chamber = a lower compression ratio. Link to comment Share on other sites More sharing options...
zippy Posted May 6, 2005 Report Share Posted May 6, 2005 man, don't get bigtex in here on this. it's bad enough that people come up with their own assumptions on the differences in the two. he has more than a few times pointed out that the heads are the same. is there some reason you didn't just search for the info that has been posted many times? on top of this, for no reason. why would you think you don't have the same engine as the rest of the SS trucks? special SS? Link to comment Share on other sites More sharing options...
TimC3 Posted May 8, 2005 Report Share Posted May 8, 2005 the HO is 345hp and the other one is 300hp. <{POST_SNAPBACK}> I think there must have been a couple different versions of the LQ4 then.. My C3 has the LQ4 with 325HP.. But I think some of the HD's from a few years ago had a 300HP 6.0L.. Was it still an LQ4? or a different code? Link to comment Share on other sites More sharing options...
PewterC3 Posted May 9, 2005 Report Share Posted May 9, 2005 the HO is 345hp and the other one is 300hp. <{POST_SNAPBACK}> I think there must have been a couple different versions of the LQ4 then.. My C3 has the LQ4 with 325HP.. But I think some of the HD's from a few years ago had a 300HP 6.0L.. Was it still an LQ4? or a different code? <{POST_SNAPBACK}> just tuning. the LQ4 came in 300hp and 325hp versions. The Denali's (C3, Sierra Denali, Yukon Denali) all got the 325hp version while 2500 trucks, HD's, etc. got the 300hp version. Link to comment Share on other sites More sharing options...
TimC3 Posted May 9, 2005 Report Share Posted May 9, 2005 I thought so.. Thanks PewterC3 Link to comment Share on other sites More sharing options...
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