dry_kill

iTrader: (12)

whats the difference between a LQ4 and a LQ9 and also what vehicle does a LQ4 come out of? i know the LQ9 comes out of the escalades and VHO but what about the LQ4? thx

03NHSilvy

iTrader: (1)

the LQ4 is the stardard 6.0 in the HD trucks and some others

dry_kill

iTrader: (12)

so how much hp does the LQ4 put out?

99Silver6.0

iTrader: (1)

LQ4 is 325 with dished slugs. LQ9 is 345, has flat top pistons, bushed rods and bigger con rods.

dry_kill

iTrader: (12)

ooooooo, hey this is kinda off topic but 99Silver5.3, u got a 2/4 drop right? im think about putting a 2/4 drop on my truck but im worried about bottoming out, is it easy to bottom out with a 2/4?

99Silver6.0

iTrader: (1)

Yea, its a Hotch 2/4. I have yet to bottom out. Im running cut stock bump stops too.

.T.

LQ9 has higher compression too

hog

the LQ4 for 2005 and 2006 is actually 300 hp at 4400 rpm and 360 lb/ft of torque also at 4400 rpm. It used to be 325 hp but I dont know why the 25 hp loss. My guess is that it always did make 325 hp and probably does still but due to CAFE reasons GM decided to lower it from 325 to 300.

CAFE is an acronym for Corporate average Fuel Economy, every auto maker MUST have a certain CAFE to be able to produce cars in North America, for every gas pig truck truck GM makes they must also offer some sort of fuel miser Economy engine to balance the CAFE.

If the govenment stated that my company HOG Automotive needed a CAFE of 30 mpg abd all my company built was 20 mpg trucks and 40 mpg cars, and my total production for this year was 100,000 cars and trucks total. I would need to build 50,000 trucks that got 20 mpg and 50,000 cars that got 40 mpg.

See GM is really bad for underexagerating thier HP levels. The 98-02 f-bodies were rated from 305-310 hp with the LS1 engines, they regularly dynoed at 300+ rwhp or roughly 360 hp at the engine.
It wouldnt surprise me if teh LQ4 engine always had made a tad more than 325 hp and even with the derating still makes exactly the same hp as it did before.

The LQ4 is only found in 3/4ton HD trucks and other heavy vehicles.

Another possible reading is that the SAE (society of automotive engineers) has changed the way that NET hp is rated in North Amercican sold cars and trucks. A few Japanese cmpanies have lost around 10 net HP while some NA built cars have gained up to 10.
The supercharged 4.4L Cadillac XLR roadster went from an OLD rating of 435 net hp to a NEW net HP rating of 460 hp.
The new SAE NET rating system has evend the playing field for ALL entrants. the older spec said that some Asian makers could run lower crankcase oil levels and different exhaust manifold for testing, now everything has been standardized.
the North American automakers have seen to come out on top.

the first North American engine to use the new SAE rating technique was teh awesome LS7 7.0L Corvette ZO6 engine, it WAS rated at 500 hp@6200 rpm with 475 lb/ft, the new standard has it at 505 hp @6300 rpm and 470 lb/ft.

It would seem to me that the LQ4 having lost 25 hp maybe is a move to further the LQ4 from the LQ9 as the LQ9 is part of the NEW GM truck Vortec Maxx Package. The 3/4 ton LQ4 being at 325 hp would amke the new 345 hp Vortec Maxx package seem like a waste of money for only 25 hp and 20 lb/ft of torque.

Whoo knows, all I know that GM is offgicially saying LQ4 is 300 hp 360 torque and LQ9 is 345hp and 380 lb/ft of torque.

Wasnt the LQ4 of 1999 with iron heads also 300hp???????????

peace
Hog

99Silver6.0

iTrader: (1)

Its in the tuning. There was only 2 6.0's in the trucks.

whitt1

The LQ4 and LQ9 both use the same 317 cylinder head and the same cam.The LQ9 has a 10:1 compression ratio while the LQ4 is 9.4:1,the main difference in power is the PCM tuning and exhaust systems packaged with the the different applications.With just a engine swap and equal tuning there's probably not a 10hp difference.