Re: Lq4 Cam/ motor input ???
 

You make no sense. First you say LSA has nothing to do with sound then you do. Which way is it?

Re: Lq4 Cam/ motor input ???
 

look dude I was not saying that it did not make a difference. what I was getting at is that ls engines are not like old school engines that run 106-110 duraration. the point is that just because the cam does not have a lot of overlap does not mean you wont hear it. believe me I know what makes power and I know the difference between usable power and max power. most people like my buddy with the 2010 ss Camaro go for #S and for the radical sound. and they end up with a ride that is almost impossible to drive everyday. he has to keep his foot in it to keep from having slow speed stall and dying issues. but the sound and dyno #s are rad. most people on the net are looking for advice and most want that cam sound. and most jake legs tell them oh you need a 228-232 cam with a 112 and those are good if you want to deal with some drivability issues and put out for a $$$ stall that will run your tranny hot in regular traffic. yes I know for ls even those are med cams. but most people who have been doing it a while will tell you that a mild cam is a lot more fun to drive and the tq in the low speed gives a great seat of the pants feel expecially if you have a good set of gears. if you have a heavy truck or any kind of heavy vehicle. your better with less overlap and more slow speed tq. I was just proving you can have a good sounding truck even with a mild cam! Also before anyone else blowes up this thread I like the 228-230 ish cams. infact if you can get a stall id say the best all around is the 228R much bigger than that for the street and you are peeing in the wind. just my .02

Re: Lq4 Cam/ motor input ???
 

I agree but I thought he already had the heads. If not, then it will be cheaper to do the L92 swap bc the heads can stay stock and move alot of air. 799/243s are the best stock cathedral port heads you can get, rectangle ports are a totally different beast.

Re: Lq4 Cam/ motor input ???
 

I'm not attacking you, sorry, I'm very direct…we're on the same page.
A good tuner can make even the big/nasty cams easy to drive.
My LS2 GTO had a MS3, 237/242 on a 111. I daily drove it in the summer. FWIW, that car made 452 to the tire, stock 243's and short block - cam, FAST 90, MS3, Kooks LT's.
A friend had a 427/solid roller 99 SS that I tuned, it was tame as a kitten(literally reach in and tap the key and it'd sit and idle till it ran out of gas) despite idling like a pro-mod. It made 510rwhp N/A and ran bottom 10's.

With those bad manners your friend's camaro exhibits he needs to find a new tuner.

OP - your plan sounds great. The only thing I'd think about would be a little more converter. I think you'll regret going rectangle on the heads, the ports are just too big to provide sufficient velocity at low RPM. They do flow more and will make more peak HP, at the expense of grunt.

Re: Lq4 Cam/ motor input ???
 

What about where the OP will drive it most? If he's making frequent highway trips the low end power may not matter as much to him. Opposite if its all around town driving.

Re: Lq4 Cam/ motor input ???
 

I keep hearing about how bad the rectangular port (L92/LS3) heads are on 6.0's...yet GM configured motors that way, as in the LY6 and L76 (plus 2 hybrids?). Now I can't speak to how the LY6 would run in stock form as I never ran it that way....its 1st spark was w/o the VVT setup and running a Comp 223/231 .610/.617 112 LSA cam and the required supporting gear....but having run it with both a carb setup and more recently with efi it has run very strong at lower rpm's and has always pulled very well. I compare to the old 383sbc it had previously as well as my 400hp/400tq LS2 powered and 4.10 geared TrailBlazerSS....and my cam'd LY6 powered truck pulls considerably harder.

just sayin...

Re: Lq4 Cam/ motor input ???
 

The ly6 starts off with like .2-.3 more compression, and the ls3's were like 10.7-10.9, so the only thing I can think of is that the lack of compression and huge flow mean that it needs to get up a few r's....making it lose a few under the curve.

With the difference on the ls3 it makes sense I suppose, but I'm surpised that the .2-.3 difference between the lq4/ly6 would make as big a difference as some folks feel it does. I wonder if comparing the lq9 would eliminate most of that.

I'd still go l92, so when you get bored you don't have to go back and say "well I Coulda gone with the l92s" Room to grow, like buying kids shoes a half size big.

Re: Lq4 Cam/ motor input ???
 

Agreed. Not to mention, how come everyone is saying the l92s are too big, but the 1-7/8" headers aren't too big? Don't get me wrong, I run them on my stock lq4 for the same reason mentioned above, room to grow, but I thought they were less efficient on mild engines than the smaller primary version. Why get better flowing headers and not do the heads too?

Re: Lq4 Cam/ motor input ???
 

Think about what you're saying here.
Highway = cruising at 2-2500. Rectangle ports won't pull ahead of cathedrals until 5k+ and then it's only @ WOT…highway PULLS, not cruising.

They're not BAD per se, there's just no reason to go to them when cathedral ports will easily get the job done.
Now, if you're starting from scratch and are going to be shooting for the moon then by all means do it. I'm not stating they won't make more power than cathedral port heads just that for a street motor that's going to run stoplight to stoplight they won't provide as good a result as cathedral heads.

You need to remember that LY6's/L76's and LS3's have VVT advancing and retarding the cam…When I was messing with the tune in our new Sierra Denali I locked it out and it made a HUGE difference in the midrange.

Big tube headers aren't going to gain much on an LQ4 but they will help out up top. I had them on my GTO and was glad I didn't get the 1-3/4 version.

Re: Lq4 Cam/ motor input ???
 

Idk what gears you have, but with my 4l80 and 3.73s I'm usually in the 27-2800 range on the highway, still not way up there sure, but when you need to get around someone on the highway you won't be putzing about.

Regardless, what we're saying is that if you are building the engine and you have the choice of rectangle or cathedrals, why choose a "stage" cathedral over a stock rectangle? You're definitely not saving any money.

Re: Lq4 Cam/ motor input ???
 

The "VVT / LS3" thing is tricky, because NOT all ls3's had vvt. M6 cars didn't come with AFM or VVT because of misfire detection problems.

The cars also had fly-cut relief in the pistons, changing their PTV clearance and making what works on one not necessarily work on the other. IIRC the version was the L99.

Billett- I run just a tad lower 24-2600, tho sometimes getting to 2800 closer to 75. This is through a 12bolt / 3;73s, my 4l80e, and a pair of heavy wheels with MT 325/50's



*woo I'm over 3k posts....

Re: Lq4 Cam/ motor input ???
 

There wasn't an LS3 with VVT. It's the L99 like you said....but the LS3 itself has no VVT (or AFM). It's the off-shoots of that generation that have those features. LY6/L76, L92, L99, etc


............and if your on the fence just build your LQ4 with its OEM 317 heads and you'll be fine. If you decide you want more you can always add some L92's/LS3's later....maybe even get you some CNC'd LS3's....

Re: Lq4 Cam/ motor input ???
 

This^ I think this thread has gotten way off track so let's bring it back, since I'm pretty sure we all agree anyway.

OP, if you have the stage 2 heads already, there's no point discussing this. Do it up and post pics! If you are just freshening the engine up and plan to keep it stock for a bit, keep the stock heads. If you plan on pushing some power through it, and plan to tear it apart, go for l92s.

Re: Lq4 Cam/ motor input ???
 

I am very curious, who that has commented in this thread has actually:

Built or helped build combos using similar combos using both a cathedral head and a L92 type head?

Have put multiple different cam shafts in the same motor only to see the results different valve events have on said combo?

Have dyno and track tested these different combos? Including tuning them?


I am not pointing at anyone specific, but it sure is easy to regurgitate what one reads on the internet.


I'm not going to get in a pissing match, but there is a lot of bad info with a little bit of good here.

Re: Lq4 Cam/ motor input ???
 

What are your thoughts then? Not trying to start anything either, I'm curious because if what I've read is wrong I'd like to correct it.

Re: Lq4 Cam/ motor input ???
 

Going back to your original post. I built a similar combo that I wanted to share. Differences are in blue

This made 37x rwhp / 36x rwtq and maintained a stock LS6 cam's power band. This was a solid high 12 second combo @ 3,900lbs even with the overly tight converter.


LSA does not specifically dictate a cams chop, nor is it tied specifically to overlap. It has to do with valve events as a whole.

Not getting in to the L92 vs LS6 vs aftermarket head debate as it is way to long to type out. But short answer, it depends on your goals.

Re: Lq4 Cam/ motor input ???
 

Yep, tho not track tested.

Re: Lq4 Cam/ motor input ???
 

Am I the only one who has noticed that this thread is pushing a year old and the OP hasn't replied since 3-6-13?

Re: Lq4 Cam/ motor input ???
 

I did not catch that :)

Re: Lq4 Cam/ motor input ???
 

:lol:

his profile shows he hasn't seen/been here since August!
:lol:

Re: Lq4 Cam/ motor input ???
 

As long as there's still useful info being discussed, who cares?

:lol:

Re: Lq4 Cam/ motor input ???
 

I've been reading with interest. Just picked up a 6.0 last week. Got a torquer 3 cam but may not use it now. Just seems too big for a street truck and not enough compression with a LQ4 and stock 317s.

Don't really want to change heads at this point in time as then I'm opening up a new can of worms in comparing stock motor and turbo vs h/c/i.

Re: Lq4 Cam/ motor input ???
 

True, I just thought it was funny how people kept refering to the OP like the thread was new. :lol:

Re: Lq4 Cam/ motor input ???
 

Nope, I had no idea. I remember posting way back when, but didn't realize it had been so long.

Re: Lq4 Cam/ motor input ???
 

Opinions are just that. I now realize the thread is old but if I see something I don't agree with I will state it and my logic for why. With the search function I consider it important to post regardless of age of post.