I can almost see the eyes rolling, but in all my years, here, I have never seen anyone make this comparison.
Assuming that I can use the stock PCM to accommodate the VVT*, or an earlier PCM since/if the VVT will no longer be an issue (I'm not afraid of either one.) ...
Obviously (unless I've had my head in a dark place) there are no performance cams available for the VVT engines.
There are plenty of performance cams available for the earlier engines. The retrofit to the LZ9 requires inserts to tighten up the cam clearance for the cam journals. Those inserts are also readily available. The one notable exception is the LNJ 3400 ('08 Equinox) that also uses a fixed, large journal cam. Obviously, it's not a performance piece. Guessing it can be reground, but it seems like a waste of effort.
The question is, which method will provide the best performance, with a manual trans? I liked the way my Crane 272 sounded in my 3.4, and it pulled like a train on the top end, but I also have a VVT 3.5 in my G6, and GM did such a good job with it that it seems a shame to mess with the VVT, even if it doesn't have the slightly lumpy idle.
I'm not averse to doing a bit of porting to the intakes, and changing throttle bodies. I don't really want to do a bunch of head work, though, other than really basic stuff. The engine will remain N/A. Will those mods help the performance of the VVT motor as much as they will the "fixed cam" motor option? Can the VVT cam use all that air flow?
Thanks.
*And yes I know that "VCT" is actually what's happening, but "VVT" gets used a lot more frequently.
Thank you sir! I just figured there was someone here who had built out an N/A LZ9, with deleted VVT, and maybe could give me an an idea what to expect.
I would keep the VVT but it would take a fair amount of research work and tuning to maximize its performance. But once done, it would likely have a wider power band, better fuel economy, and fewer compromises than the single fixed cam setup. You could even make it chop at idle with some timing parameter changes in the tune. I would start with a custom cam with 10-15 degrees more duration and lift that allows use of peak head flow and then focus on the range limits and VVT adjustments to the cam to maximize idle, cruise, and WOT power up to 7000 rpm.
If all you want is a peak power, then you can install a fixed camshaft designed to reach that goal, but idle, fuel economy, and low rpm torque/drivability will suffer.
Thank you sir! I just figured there was someone here who had built out an N/A LZ9, with deleted VVT, and maybe could give me an an idea what to expect.
i may be wrong, but it just doesn't seem to me like there are that many LZ9 builds. its the engine i'm wanting to do when i get around to swapping, and there doesn't seem to be all that much information specific to them on this forum. i would think it would be a popular swap, close to the same output as the 3800SC, but on reg gas and N/A. sure its got its techy stuff like the VVT and variable intake, but those can be deleted without *too* much work.
everything i've seen suggests its a pretty strong engine. there was a guy(slowv8fiero) who boosted his to 600hp on stock bottom end, so i would think ~350hp would be pretty achievable.
i may be wrong, but it just doesn't seem to me like there are that many LZ9 builds. its the engine i'm wanting to do when i get around to swapping, and there doesn't seem to be all that much information specific to them on this forum. i would think it would be a popular swap, close to the same output as the 3800SC, but on reg gas and N/A. sure its got its techy stuff like the VVT and variable intake, but those can be deleted without *too* much work.
everything i've seen suggests its a pretty strong engine. there was a guy(slowv8fiero) who boosted his to 600hp on stock bottom end, so i would think ~350hp would be pretty achievable.
600 HP on a stock bottom end. Maybe. He's done some nice stuff, and knows his way around most any 60 degree V6. Doesn't mind breaking stuff to find out what works. Although he makes that 600 claim, I've yet to see a dyno sheet. Although, to be fair, I haven't looked really hard. (He's the one that used to troll V8 owners about posting a dyno sheet or time slip. Yeah... that guy. Irony. )
Originally posted by Raydar: 600 HP on a stock bottom end. Maybe. He's done some nice stuff, and knows his way around most any 60 degree V6. Doesn't mind breaking stuff to find out what works. Although he makes that 600 claim, I've yet to see a dyno sheet. Although, to be fair, I haven't looked really hard. (He's the one that used to troll V8 owners about posting a dyno sheet or time slip. Yeah... that guy. Irony. )
I think that 600 hp is what Shaun estimates at the flywheel based on the wheel horsepower measurement.
yeah i knew it wasn't that exact, and i did forget to mention it was his claim to be a stock bottom end. he did wind up blowing it up im pretty sure though haha
I think that 600 hp is what Shaun estimates at the flywheel based on the wheel horsepower measurement.
That's with a junkyard LZ9 engine and LNJ camshaft.
Well... okay. Fair enough. I stand corrected. Thanks! I never saw that. I guess I figured that if they weren't posted on one of his YouTube vids, they didn't exist. But he's running a stock cam, since he's boosted to a fare-thee-well. I'm not interested in boosting. At least not at this point. But at least it proves the sturdiness of the LZ9 bottom end.
there is a 3rd option that you don't appear to have explored yet, and that would be having a stock cam reground. Material can be removed from the bas circle of the cam, to increase lift and duration to some degree. I think this could be a compromise between the options you are exploring, not quire the all out performance of a dedicated performance cam, but also not removing VCT. you will NEED to check piston to valve clearance as well. I think you're somewhat local to me, and therefore possibly somewhat local to Powell Machine, who does offer cam grinding, it may be worth a phonecall.
I've been extremely interested in making a performance VCT cam for a LZ engine, it could be alot of fun!
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
https://youtu.be/vdTY9J9crQw These boys from Canada did a good job on showing what an NA 3900 can do. I think they use the LNJ cam also.
they used a stock LNJ cam, they also had a few cooling system issues that weren't very well sorted, for some time, their thermostat didn't have a bypass, so water wouldn't have been flowing through the block, they ended up removing the thermostat for at least a couple of their races, I'm not sure what they have done since then, I'm fairly certain their truck wasn't ready for the start of their race season this go around.
there is a 3rd option that you don't appear to have explored yet, and that would be having a stock cam reground. ...
It did cross my mind (and Guru also suggested it), but I didn't know of anyone who even might be able to do it. Now I do. Thanks for that! (I messaged a sort-of local shop who does lots of fancy sh!t with LS motors, and asked about 3900 stuff. Head porting and such. Never even bothered to reply. Figured that nobody wanted to touch it.)
I am in west-middle GA. I can almost throw a rock and hit Ranburne AL. But yeah... Powell's is definitely do-able. Not exactly local, but at least they're not in Indiana or something. I really don't mind the VVT. I really like how the LZE (3.5) in my G6 runs, but more power is just about always better.
Thanks again! And thanks for the vid, LaFiera. I'll check it out.
[This message has been edited by Raydar (edited 07-21-2023).]
