lq4 vs lq9

[davidomilligan]

Maybe be a dumb question but someone she'd some light please. I'm doing a swap in my camaro and looking at the lq4 which happens to be quite popular in Sacramento right now so it's been a task finding one. Lq9 I have seen a few of. I know the lq9 runs a higher compression because of the flat pistons but is that the only difference. I'm building my car for auto cross if that helps at all. What do you guys suggests what are the pros and cons of the lq4 and the lq9 ? And my newb question what does the higher compression affect ? I know my motorcycle have higher compression requiring higher octane fuel. But that's about as much as I've researched that so far

[davidomilligan]

Screw you autocorrect and my lack of proof reading ....

[Schwartz Performance]

Higher compression is higher horsepower. You may need to run premium with the lq9 but the computer will compensate with whatever octane you throw in it.
Lower compression is better for boosted applications. Go with the lq9 if you don't plan to put power adders on it.
The hp difference isn't all that much though between the two.

-Dale

[garys 68]

There are some other differences but the increased compression is the main difference giving the LQ9 about 30 more hp. I'm running one in my 68 vette. If you're autocrossing, you'll want to run 91 or 93 octane. On hot days when I'm running hard it will retard the timing to prevent detonation and you can actually feel it. The LQ9s are in high demand so you'll pay a premium price for it.

[davidomilligan]

Hmm I've seen them going cheaper here at the auto wrecking yards I might have to go that route then

I heard putting a ls2 cam in a lq4 or lq9 really beefs up the hp too. Have you had any experience with that ?

[Thephranc]

LS cam comparison.

http://www.carcraft.com/techarticles...st_comparison/

[Schwartz Performance]

LS7 cams do well in the LQ and Ls3's, you'll need to change the valve springs out though too.

-Dale

[davidomilligan]

Ok from what it looks like the ls2 cam looks like a fairly good choice to increase torque and hp on higher rpm and lose minimal in the lower rpm range . Correct me if I'm wrong

[Bonehead]

Wow. Cant believe I just read that. lol

For me, all depends on what I can get at the best price. But I turbo mine, and higher compression isn't exactly fun on the street when I run pump gas. Higher compression is relative. It doesn't automatically equal higher HP. Its all relative to the limitations you set, like mine running pump gas. I spray meth with a high HP tune and do well with under 10:1 CR. Currently building a LQ4 that I'm looking to limit the HP to 700 at the crank with less than 15lbs of boost. Will be an under 9:1 CR motor. You can always change pistons, heads to get to your set limitations. Its like any other build. I start where I want to be when its all said and done, and then backwards plan from there to piece it all together.

[garys 68]

Keep in mind the LQ9 is already running the LS1 cam. You'll get a little more top end, but might be limited by the intake on the 6.0. My suggestion, drive it as is.

Ok from what it looks like the ls2 cam looks like a fairly good choice to increase torque and hp on higher rpm and lose minimal in the lower rpm range . Correct me if I'm wrong

[ADiCarlo]

Keep in mind the LQ9 is already running the LS1 cam. You'll get a little more top end, but might be limited by the intake on the 6.0. My suggestion, drive it as is.

Another option is swapping LS3 heads on the LQ9 block. Then you get rectangular ports and can run the much cleaning LS3 manifold.

[garys 68]

Great minds think alike...lol
I put an LQ9 in my 68 vette. With exhaust and mild tune alone it puts out 400hp.
Plan was to upgrade LS3/L92 heads, LS3 intake, cam, etc to aim for around 480hp. But as is, the LQ9 will overdrive the stock tires. I saved some money, just left it stock.

Another option is swapping LS3 heads on the LQ9 block. Then you get rectangular ports and can run the much cleaning LS3 manifold.

[davidomilligan]

Running an lq4 with ls3 heads would not be a bad way to go then?

[Rod]

My suggestion, drive it as is.

THIS! run it stock,,,,,,thanks finally

[garys 68]

It would be a great way to spend another $2-3k for the 80hp over the stock LQ9. But the stock 400hp motor/exhaust/tune only cost me $2k. Your choice.

Running an lq4 with ls3 heads would not be a bad way to go then?

[davidomilligan]

Alright rod stock for now .... I'll play with it later

[Rod]

Alright rod stock for now .... I'll play with it later

the LQ4 or 9 will both have enough HP as a stock engine for you to be competitive and win at many autocrosses, and more than enough HP on a poorly setup car to be uncontrollable, and once you start to race then decide...more HP, better suspension, umm driving school! and so on

[davidomilligan]

Rod Where's a good place to pick up a Ls swap kit for a second gen camaro so I don't have to piece everything together . Unless you have a list of the parts and brands you recommend.

[CampbellshotrodsAZ]

Not enough difference between the 2 I'd imagine to limit your search for LQ9 only, especially as they have been out of production for awhile, with the LQ4, and finding one that doesn't need a rebuild is more difficult every day. If you can find a low mileage version of either, snag it up! Otherwise, if you're rebuilding, get a cheaper LQ4 and put in premium higher compression pistons, as the factory pistons were junk IMO anyways. I've seen too many of them come apart at the ring lands.