Corvette Z06 Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
803 Posts
Discussion Starter #1
I’ve been thinking again (Sometimes I sits and thinks – sometimes I just sits). I have suggested that I think substantial gains are in a cam change. Too bad the cam is so difficult to get out of these machines.

The ground rules:
Use Performance Trends, Engine Analyzer Pro (aero-thermal) modeling software.
Use LS6-01 valve and spring data to allow all LS6 motors to use the same cam.
Retain stock ratio rockers.
’01 pup cats must go.
Baseline performance is ’02 cam 204/211 degree I/E duration on 116 degree lobe separation, installed 4 degrees retard (events: IO –18, IC 42, EO 37.5, EC –6.5). Valve lift is .551 for I and .547 for E.
Attempt to gain HP above 4500 RPM because that is the after shift condition.



Results:
Interestingly, the only timing event that had any significant affect on produced power was IO. Advancing the IO event all the way to 10 degrees takes advantage of inertia charging. The specs for the first try cam are: 232/211 degree I/E duration on 109 degree lobe separation, installed 3 degrees advance (events: IO 10, IC 42, EO 37.5, EC –6.5). Intake and exhaust lift were held to .525 inch. Notice the HP loss in the low-mid area. That should make launches easier. The ’01 injectors will handle the fuel flow but the ’02 will not (duty cycle ~ 89%). The valve open overlap dwell is increased by 28 degrees to 63 degrees. This cam will have a serious rump rump but be streetable.

I am not comfortable with the model definition that I currently have for the LS6. I will rerun the model when better data is available. Andrews has ground custom cams for me before. They have a direct digital grinder. I would expect the cost to be around $500. The blank to do this grind is not out of the ordinary.
 

·
Registered
Joined
·
132 Posts
Roger, I have business dealings with a company in your area who could probably help you with equipment, blanks, etc, they may have already developed LS6 cams. Not sure about that, but I do know they develop many performance cams for drag & street cars and have years of knowledge and experience in this field. Company name is Camcraft located in Easton, Maryland. Talk to Charles Reichard. Good people. Keep up the research, I always follow your posts.
 

·
Registered
Joined
·
803 Posts
Discussion Starter #3
Do you know if Camcraft has a direct to digital grinder? For low volume production, the cost of 1000% masters is prohibitive.
 

·
Registered
Joined
·
132 Posts
Roger, I'm not sure. They are closed this week, but if you are interested,call them after new years day @ 800 426-2261 or 410 822-2122 loc.
 

·
Registered
Joined
·
5,414 Posts
You may have said it

And I just didn't comprehend........but, the '02's have LONGER valves, so they would need to be changed correct??.
Or, is this what you meant by, using '01 data so that all could use same cam??:-?
 

·
Registered
Joined
·
5,414 Posts
Roger

What about these specs??
224/224/561/561/114.........................
What would this combo do??.
How would it compare to what you have put up?.:)
 

·
Registered
Joined
·
2,459 Posts
J-Rod said:
Hey Roger, what about your new cams specs, but with the '02s lift?
Only problem with that is it will only work on an '02 (or an '01 with updated valves/springs). He wanted to make one that would work with either the 01 or 02 without swapping parts around.

I take on it: it takes a bunch of work to pull the cam, might as well make it big and nasty cuz it won't be much more work to get the heads off and have them updated (and ported/polished and larger valves installed).
 

·
Registered
Joined
·
1,811 Posts
That TR224 cam would be sweet, Z06LS6....I had the same cam in my Firehawk (but on a 112 LS), and was extremely happy with it.

In fact, in my hunt for a cam, it was between that very one, and the one I ended up going with. The one I went with is significantly bigger and nastier, probably to the tune of only about 5-8 rwhp though.

You would be very happy with that cam....and really, it's not all that hard to swap the cam in these things, I mean, come on! The intake and heads stay ON the car, you don't even have to evacuate the AC system! :cheers:
 

·
Registered
Joined
·
5,414 Posts
Tamu........Roger for some reason got this thread started, and let his part die???.....dunno......I think he was really ONTO SOMETHING HERE......
I know nada about this stuff.....except I can install one......;)
The problem, as I see it is STILL emissions, and driveability.....
A really well thought out cam sway( alone) would net at least 20/30 rwhp........add a great Porting job on the heads, and you got 50 easy...........
If this could be accomplished without making the Rump/Rump too noticeable, and alerting the warranty police.....it would be MUST do swap for the '01's & '02's........
IMHO, this is EXACTLY the area GM is going to tackle, to get the 450 HP model....it's too easy for them NOT to......it ( along with Long tubes), is the same place those of us with '01's, '02's, are going to have to go to get the 450+, needed to compete with the C6, and 2800#'s, and 450//////////////
 

·
Registered
Joined
·
1,811 Posts
No bones about it - the dealership WILL know there is a cam in there if you put in that TR224.....:D
 

·
Registered
Joined
·
1,321 Posts
Stole this post from SWCDUKE on Corvetteforum


-----------------------------------------------
Just do the heads and leave the cam alone. CNC ported heads should yield about ten percent more top end power and won't effect the bottom end, idle, or drivability.
The LS6 cam is very different from typical high performance cams. Timing is 12-85/71-33 and the points of max lift are 120/115, inlet and exhaust. These are NOT the "lobe centers" because the lobes are highly asymmetrical.

The exhaust timing is fairly conventional, but the inlet lobe is retarded about ten degrees from a typical high performance cam. This reduces overlap to virtually nothing and is the reason headers won't do that much. The cam was designed specifically for the low restriction OEM exhaust manifolds. Good top end volumetric efficiency is derived from strong inlet inertia tuning with the late closing inlet valve, and the minimal overlap keeps the bottom end strong with a smooth idle and excellent emissions performance.

Chevrolet really did their homework on the LS6 cam and valvetrain. I'm still amazed that the torque curve is as high and as flat as it is; 300 lb-ft at 1000 revs, 400 peak and 405 HP is an amazing feat for a 346 CID pushrod engine without variable valve timing or inlet geometry.

Production costs place some limitations on the port coring due to considerations for core shift, and it's just too expensive to CNC machine the ports in production. Reworking the heads is the BEST modification you can do to the LS6 and is the ONLY mod I would ever consider. Get the heads CNC ported by someone who knows what they're doing (has proven the process with flow bench testing) and leave the cam alone.

Duke



The limiting factor on pushrod engines is ALWAYS the heads, and pushrod engines will always respond best to head work. Four-valve DOHC heads are usually pretty good as cast so there's not as much to gain.
Most aftermarket cams have too much overlap. They will kill low end torque while degrading idle quality, driveability, fuel economy, and emissions. The LS6 is superbly system engineered and everything works together to create great synergism, but the realities of a pushrod head - having to wrap the ports around the pushrod passages and the limitation on port core sizes and geometry due to core manufacturing tolerance and core shift considerations make the inlet ports the limiting factor in top end power, and they are the first item to work on if you want more top end power.

When system engineering a pushrod engine, I select the valve timing to achieve the low end torque characteristics I want, then work the heads and inlet system to get as much top end power as possible.

Duke

Duke

----------------------------------------------------------

Roger, I thought some of the cam info in that post might be useful....
 

·
Registered
Joined
·
283 Posts
Just by doing the heads you will not gain 10% - 34 rwhp...you would be lucky if it was 5% - 17. I did the heads and did not gain much at all, when i would race a stock 01 with my heads, vortex and my B&B shorties i was a little quicker and with the 02 is was even.

:guiness:
 

·
Registered
Joined
·
803 Posts
Discussion Starter #15
Thanks for the info.

I can run the model for any of the cams listed - and for any head flow, however, until I get better definition for the LS6 components I don't feel comfortable with the results.
 

·
Registered
Joined
·
1,321 Posts
Hey Roger,

How about playing with your model again???


I have a question. What would happen with the stock camshaft with more duration. Same LSA, etc using the model you have defined...
 

·
Registered
Joined
·
5,414 Posts
J Rod,
I'm with you on this...........RR, started it and just let it D_I_E...........
It was really interesting.....and I wish he would finish his thoughts.................call me :-?
 

·
Registered
Joined
·
1,321 Posts
Roger, do you need someone to measure the intake runners on the head and the intake. If so, let me know exactly what you are looking for, and I will try to get that done....

I'd really like to see what an "ideal" model cam would be for both stock, and modified...
 

·
Registered
Joined
·
803 Posts
Discussion Starter #20
I'm remiss in answering my e-mail. Sorry! Been off doing other fun stuff - drag boat, motorcycles, dyno, & Sea-doo.

J-Rod -
I would like centerline length measurements and minimum port diameter (vertical & horizontal) for the intake manifold, head (intake & exhaust), and exhaust manifold.
 
1 - 20 of 22 Posts
Top