AKZ71

iTrader: (1)

Okay, I am a little confused here as to the difference between the standard LQ4 and the LQ4 which GM puts in the Denali.

The standard LQ4 puts out 300hp@4400rpm and 360tq@4000.
The Denali LQ4 puts out 325hp@5200rpm and 365tq@4000.

Would this be a difference in cams? If not does anyone have an idea what is making the power difference? I cannot seem to find much on the internet regarding the stock motors.

Thanks,

Kevin

1BADHD

Exhaust........

AKZ71

iTrader: (1)

How is the exhaust different? I wasn't aware that you could squeeze that much hp out even with a decent aftermarket exhaust?

cstchevy

yes I believe its the manifolds and exhaust with a computer adjustment. their really isnt any difference in the actual engine

BigTex

iTrader: (16)

Different manifolds? Thats the first I've heard of that. I think there is very little difference in them. Internally, they are the same. Programming is probably a little hotter and the exhaust could be better.

cstchevy

dont listen to me, I am talking out of my butt why I am trying to work. manifold what was i thinking. sorry about the error.

AKZ71

iTrader: (1)

Any ideas who might have an idea???

F8L Z71

If those are the actual specs then i would be more concerned why peak HP is at 4400 on one motor and at 5200 on the other. I didn't think exhaust could change it by so much.

Yelo

The answer is kind of hard to give....primarily because GM seems to be BS-ing us when it comes to stock dyno numbers. Here are some good examples

ALMOST ALL stock 300hp 6.0's dyno at 268-275rwhp, assuming a 23% loss for the transmission that works out to 340hp, The driveline loss is actually closer to 27% for the 4L80E...and since those transmissions tend to be in the trucks with the 6.0's the actual engine output may be closer to 350hp...from an engine supposedly rated at "only" 300hp.

GM hasn't shown ANY good explanation for the 300hp, 316hp, and 325hp differences between the Trucks, H2's and Denalis...there are no physical differences in the engines that the HP increase could be attributed to. Also, the "High-Performance" LQ9 in the Escalades "supposedly" makes more power (345hp) due to a higher compression ratio (.6 CR bump) and a slightly reviesd programming but I've NEVER seen a .6 CR bump make 45hp....5hp maybe, and a tune by a professional tuner is good for about 15hp MAX so a "revised tune" by GM is good for about another 5hp (total of 10hp over that LQ4). you just can't convince me that the LQ9 engines REALLY make that much more power than the standard LQ4

What all this is leading up to is: GM is playing the same game with the 6.0's that they were playing with the LT1's and LS1's...underrating their horsepower to keep insurance rates down......the've been playing this game since the early 60's

If that seems like BS to you think about it this way......for 2004 a 295cid motor (4.8) makes 285hp, and a a 325cid motor (5.3) makes 295hp, but a motor 40cid bigger (364cid - 6.0) only makes 5hp more ??....somehow I just doubt that

AKZ71

iTrader: (1)

Well thats why I thought it might be a different cam. I couldn't really think of anything that would change it that much. Besides I asked on the board a while back and was told my exhaust was the same as a 6.0l 2500hd???? When I bought the truck I drove a 6.0 2500 ext cab, compared to the Denali it was a dog. There shouldn't really have been a whole lot of weight difference between the two. Maybe the difference was between the 4L80E and the 4L65.