hirdlej

iTrader: (31)

Ok, so had my truck dyno'd today with the new 6.0L. Timing dialed in to 27 deg total on pump premium and AFR close to 13.0-13.1:1 during the whole run. Look at the whacky dyno run below. Here's a rundown of my combo.

2004 Silverado Reg Cab Short Box 2wd
5-Speed manual transmission
3.73 gears with 255/70/16 tires
6.0L
10.6:1 Compression
Hand ported 243 heads
Truck intake manifold
Truck Intake tube/box
8.1L Multec II 44/lb hr injectors
Custom Comp 218/224 .563/.581 lift with a 114 LSA +2 deg advance
OBX brand stainless long tube headers without cats going into a single 3.5" catback magnaflow.

Do these curves look right to you? If you say "no", why? I just thought this seemed a little off. Has anyone seen a motor built like this put numbers out like this? I'm wondering if the dyno wasn't calibrated right, if I was sent the wrong cam (never degreed it) or if the heads were screwed up when the local guy hand ported them. He went real easy on them and only cleaned up the area around the valves and the bowls.

hirdlej

iTrader: (31)

Also for what it's worth, here's an automatic truck with a bone *** stock LQ4, TR224 cam and long tube headers. Look how long his powerband runs on. By upping the intake lobe 6 degrees it wouldn't cause this drastic of a difference, would it?

dre2013

iTrader: (7)

looks like that motor has hella torque...hp does seem a tad low though. are you 100% sure the heads were milled down the correct amy to give you that 10.6:1 comp ratio? that cam is pretty small for a 6.0 motor though as well. im assuming its been tuned already?

hirdlej

iTrader: (31)

Yeah, the head work was done by a reputable guy here in town. I wouldn't doubt any of the work done on the heads. I just wonder why there's such a difference in power curves between a 218/224 and a single pattern 224 in almost the exact same setup.

PREDATOR-Z

The HP curve doesn't look right. Peaked way early, with a IVC of 41 it should peak closer to 6000. on yours it peaked before 5250

WYATT318MOPAR

iTrader: (28)

What kinda valve springs are you running?? Looks to me like premature drop off due to coil bind or float out...If you have aftermarked springs already you may want to check setup height to make sure your running enough seat pressure..Could be the reason for the quick drop off..

hirdlej

iTrader: (31)

I know, strange right? I never degreed the cam to confirm its actual specifications but here's the cam card I got from COMP that matches the serial number on the cam. Why would my power fall off so early? Do you think the cam I was shipped was mis-labeled?


cam card:

SPEC CARD

PART #: 54-000-11 ENGINE: LS1 CHEVY LS1/GEN III

GRINDING INSTRUCTIONS 1

"" "" 2

"" "" 3

GRIND #: LS1 3712R /3722R HR114.0

SPC INST 1:

SPC INST 2:

J. DIAM: STD INT EXH

VALVE ADJUSTMENT HYD HYD

GROSS VALVE LIFT .562 .581

DURATION @ .006

TAPPET LIFT 271 273

VALVE TIMING OPEN CLOSE

@ .050 INT 3- 41

EXH 48 4-

SPECS FOR CAM INST. @ 112.0 CENTERLINE

INT EXH

DURATION @ .050 218.00 224.00

LOBE LIFT .331 .342

LOBE SEPARATION 114.0 FIRING ORDER LS1

ROCKER ARM RATIO 1.70 1.70 REQ SHIP DATE

hirdlej

iTrader: (31)

The valve springs are actually patriot dual golds. I checked the install height, I don't think they are the problem.

hirdlej

iTrader: (31)

What are you gathering from looking at the dyno then Predator? If the power falls off that fast do you think I was shipped the wrong cam? Do you think the head flow was screwed up? Do you think the dyno operator screwed up because the torque is so high but the HP is so low? He had me driving the truck, he just ran the buttons on the controller that's all.

odarabla

iTrader: (1)

This is one thing you might want to check.. I had this same issues and didn't know what could be causing it until I did my H/C/I install. When I was all bolt ons my dyno #'s looked just like yours did. After 4000 it was real jagged and dropped off fast right after 5,000rpm. While pulling out the stock cam we found that the timing was set 1* degree off. That meant that the person who had the car before me had a cam in it and before selling it he put the stock cam back into the motor but didn't put it in right. Just food for thought.. Hope this helps..

hirdlej

iTrader: (31)

You know, this brings up an interesting point. Before tearing into things, wouldn't a compression test reveal this? I haven't done one yet but maybe I should. Also, when you refer to 1* off, are you referring to the fact that you had your cam gear off 1 tooth or that the cam was degreed wrong? Mine is supposed to have 2 degrees advance built into it. I never did degree the camshaft but who's to say that between the cam, timing chain and gears that they're all perfectly timed? How many degrees does each tooth on the cam gear account for? Let's say I had it 1 tooth off, then you take the 2 degrees advance built into the cam, I could potentially have the camshaft advanced we'll say 6 degrees??? This would make for great low end power but fall on its face later on? The truck seems to run great though in the upper RPM's but the butt-o-meter could be off compared to the real world. Maybe I should contact the vendor in which I bought the cam through (non-sponsor) and show him the numbers and see what he thinks. The question is here I think is the DYNO wrong or is there something wrong with the cam or valve timing that would be causing this? Everything else in the combo should be setup right. The truck does idle very nicely after being tuned and the shifter only has a slight intermittent shake to it every now and then. I think the cam timing is on as far as lining the dots to dots up, BUT who's to say the cam was ground properly at comp?

hirdlej

iTrader: (31)

No one else sees any other possible way it could be off, do they? It's either a false dyno reading or something wrong with the cam timing? I was thinking of putting a dial indicator on the rocker and turning the engine over to see what the lift is. If it matches the cam card then it must be the right cam, right? I don't think you can do less than a .581 lift on a 218 dur lob, or a .561 lift on a 218 lobe, can you?

PREDATOR-Z

To check if cam is installed properly you'll have to degree it (this lets you check specs as well)
If dyno is messed, only way is to go to another dyno and see if results are the same.

hirdlej

iTrader: (31)

Meh, I'm going to go to another dyno this week and just get 1 pull in. After that, I just may end up going to a single pattern 224 cam. The extra 6 degrees on the intake side should flatten and extend everything out.

odarabla

iTrader: (1)

This is what I meant, it was one tooth off.. I know my car made really good low end but fell over on it's face on the top end. The car would run 12.60@107mph with a 1.68 60ft but on the highway I had a damn Mazda Speed 3 running right on side me. I didn't start pulling away until a little over 100mph. Oh. How I wish I could find him now!!!!!!!