Isphius

For a third gen trans am, would i be better off starting with an ls1 or ls2 if i can find one, or build my own 6.0 lq4/l92 headed motor? I would like to boost in the future, so thats a consideration. How strong are the lq4 pistons? and how much compression do they make on the lq4 block? also, will the lsx cams, 3rd gen swap parts, headers, etc, work on the lq4? I would like to do the lq4/l92, with a cam, manifold, fuel injection gear, and accesories. Would this run ok? how much power would it make depending on what parts? what are the pros/cons of just shelling out for an ls2 vs building my own 6.0 motor? and before anyone asks or jumps on me, I do have some experience building and swapping motors, and can do all my own maintenance work on my trans am. This is also my 3rd f body and 2 or 3rd modded car in general

hookemdevils22

iTrader: (12)

LQ4 = 9.4:1 CR stock (w/ 72cc heads). I believe the L92s are 71 cc, so you'd be looking at about just a tick above that.

The rotating group is almost exactly the same between the non-LS7 LS-series motors. According to the 2008 GMPP Catalog: "Most Gen III and IV crankshafts are nearly identical in design... All but the LS7 are iron... The connecting rods are all very similar. All rods except the LS7 are powder metal steel, whereas LS7 rods are titanium... All LS pistons are very similar. All are made of hypereutectic aluminum and should not be used in applications exceeding 550hp. The biggest difference between them all is bore size."

There's something like 60-100 lb (depending on whom you ask) difference between the aluminum LS1/2 block and the iron LQ4/9 block. Obviously, the iron is heavier and stronger, and GM rates it to 500 hp vs. 450 for aluminum (remember, though, that that's their conservative rating).

As for the heads, the bone-stock L92s flow some ridiculous numbers and have stupid-big intake valves for being a "stock" head. Car Craft made 550 hp on an LQ4/L92 engine, although it was carb'd. They only real problem is the intake for them - the L76/LS3s are pretty much it for now. You could toss 'em on an LS2 and have the best of both worlds.

Isphius

thanks for the info. so basically with the lq4 im set, just the aluminum block is lighter? And i plan on building exactly what car craft did, I was just wondering if there may be any advantage to using the ls2 which i assumed was more performance oriented, mabye better for the sustained rpms. But it sounds like they arent much different. And cheaper+stronger is definatley an advantage to me

the_merv

iTrader: (88)

What do you plan to do and how big is your budget?

I got ahold of a LQ4, sold the internals out of it, and built a 402 Stroker out of it, using the L92 Heads. It did cost a little more, but the power is pretty nasty for what it is..

Isphius

The motor is going in either my monte ss or my trans am. Im planning on doing this over the next 2 years or so, aquiring whatever used parts i can, including the lsx swap parts for whichever car . I plan on spending whatever it takes, so its just time really. Not like I NEED a 500hp motor sitting around haha. I basically want to do a build identical to car crafts, but add some better bearings, ARP rod bolts, and whatever i need to help the motor live for repeadted passes on the track and racking up miles on the streets. I would like to keep the lower compression lq4 stuff, mostly to save headache and money. I dont want to have to get any machine work done on the block. Maybe some CNC ported L92s that keep popping up on ebay but thats about it. Ill really just have to buy the block and see where it goes from there. Just trying to gather as much info as i can!