243's on an LQ9 should gain even more than a LQ4, correct? Are you saying that's 20hp/20tq gain AT THE WHEELS? or flywheel? If so, damn! That might be a better mod than headers for me.

Also, what' so different about your comp 222/224 compared to a TR224? Do you get a lot of bucking/stalling with the 112lsa at low speeds? Or are you able to tune it so that it's smooth? Sorry for semi-derailing your thread!

 

Just bolting on 5.3L heads with stock cc chambers will take your 9.4:1 LQ4 up to 10.4:1 assuming a stock head gasket thickness. That's a good target compression ratio IMO, especially for a daily driver. Perhaps mill the 5.3L heads for a true mating surface only and end up with 10.5 or 10.6, somewhere in there.

I like the idea of 5.3L heads on an LQ4 with the goal of improving port velocity and low speed torque, especially with a stock-ish cam. If this is the case, I would then vote for #2 on the basis of practicality and simplicity, starting you off with a good base foundation if you end up with dyno #s. From there you could change the cam later, dyno again to see the gain. After that you could change to a 2.00" intake valve, dyno again to see the gain. Lastly you could then bolt on 243 heads after milling them for the same target compression ratio (to isolate only 1 variable being changed...the heads) and see if there's a gain to be had just from that.

Just starting with #2 and Zippy tuning it I wouldn't be surprised to see this LQ4 make 1hp/cubic inch. In fact, I had a similar setup spec'd out for me by one of the sponsors before I started out my 5.7L project and #2 was quoted to make 405hp and 415lb-ft of torque with a 218/224 custom grind. Not bad for the wife-mobile.

 

There really isn't much difference at all in the two cams. I just get a decent deal on the Comp Cams so I stick with them. As for bucking and stalling, none. My truck runs and drives as if it were stock. At part throttle you wouldn't even know it were cammed if you didn't stop to hear it idle. Feel free to question me. It's all good discussion.

I'm possibly thinking of doing it as you have put it Inch Up. That was one of my thoughts, just working them out. Engine will be here tomorrow.

Oh yeah, the hp gain. One of the test I have showed a 18hp and 23ftlbs of torque gain. Flywheel though. This was without tuning though. Tuning would have gained more.

 

So would most competent tuners be able to make a TR224 drive smoothly? I really want a 112LSA for the midrange (I want to be thrown back when I punch it), but I've heard it has horrible bucking/stalling at low rpms/with AC on. So if that was the case I thought I'd just settle for the 114lsa, eventhough I really want the 112. But now that you're saying it can be tuned out, that makes me rethink. I used to just want all low-end, but more recently I've been driving around in 2nd gear doing some WOTs. With just a cutout, 93 tune, and ported TB the LQ9 is pretty wicked up top, it just keeps pulling. I really considered the LS6 heads, but what holds me back is that when I go fishing out in the boonies, there's no guarantee that anything other than 87 octane will be available.

 

Damn, what a woman!

 

The higher compression would help even more getting rid of the problems associated with bigger cams. I'll try to get an in truck video of me cruising residential area at like 0-25mph. It took quite a bit of tuning to get it where it was calm as could be. Lots of timing helped. I took a couple of days with the wideband and running in open loop speed density to get it dialed in. Once the maf was turned back on it only took a touch more tuning and it was great. One more thing I really like, It runs even smoother on the E85.

 

GMCtrk the difference between cam A with a 112 lsa and cam A with a 114 lsa will be totally unnoticeable. The difference in driveability is in the tune, and there will not be a significant change in the power band between the two lsa's. Now jump from a 110 to a 118.5 given the same cam A specs and you'd probably notice the idle characteristics change a good bit along with peak torque occurring later on the 118.5 cam. Between said 110 and 118.5, given the same cam specs otherwise, you're looking at torque coming on maybe 400 rpms later. Look for dyno graphs over on LS1tech of the same motor testing many different cams with the only variable being the lobe separation angle. I haven't seen that post in a year or so now, but if memory serves the difference was very little when moving up or down 2 degrees of separation. The real difference came when they tested a 108 vs a 116, or something different like that.

Zippy when you said a test showed a gain of 18hp and 23lb-ft, what were your controlled variables and what changed?

 

if you just want to test it then go for it, but me personally i would stick with the 317's and mill them down.... my friend has a LQ4 with 5.3 patriot or wcch heads? with a 224/228 114lsa cam and has ran a 12.3 @ 108, he ran a tenth faster than me with and me with LQ4 with stock 317's, his 108 is higher than my 106mph though..... and both trucks are tuned with the same tuner, we have same boltons including same spec'd out converter, but i do believe his truck weighs in 200lbs lighter than mine raceweight.... i cant help you out with dyno cause we both havent tuned ours on a dynojet, mine put down 323rwhp on a mustang dyno.....

 

Engine is on the stand. Heads are at the machine shop.

 

Keep us posted, please. I'm itching to high Heaven to know how the beast works with the 5.3's 1.89" intake valves.......................