PDA

View Full Version : LQ9 engine


FU
11-24-2013, 12:55 PM
Looking LQ9 engine vin N in Cadillac only. Also a 4L80E for a towing project. Let me know if anyone finds something.

Thank you.

Hog
11-29-2013, 01:39 PM
The LQ9 was available in other vehicles besides the Cadillac. It was rated at 345hp/380 lb/ft torque. It came in the 2wd and AWD Silverado SS and in the 06-07 GMC/Chev trucks that had the Vortec Mx package, also came in the 2004-2007 rpo B4V Vortec High Output(VHO) trucks aka the Texas trucks.

The LQ4 and LQ9 share exactly the same block, crank, heads, cams, intakes except the LQ4 has a dish piston for 9.4:1 compression and the LQ9 got the flat top piston for a 10:1 compression. There were slight rod differnces from 204 and back, but from 2005+ even the rods were the same.
If you take an LQ4 and maximize teh tune you get about 370 hp at teh crank, if you do teh same for a LQ9 you get slightly more about 373-375hp as the only difference is the 0.6:1 compression difference.

The LQ4 was rated at 300hp/360 lb/ft torque as it was installed in the 99-2007 GMT 800 1500HD, 2500,2500HD and 3500hd trucks using iron heads, in 2001 they got aluminum heads. In teh C3 and Sierra Denali the LQ4 was rated at 325hp/370 lb/ft as it uses more agressive PCM tuning. The HD truck tuning is very held back as its designed for WOT throttle for sustained periods with very heavy loads either being towed or hauled.

I thought I'd inform you , just in case you didnt know. The LQ9 usually pulls premium prices and the LQ4 cheaper prices, although they are almost the exact same engine.