swathdiver

2009 GMC Yukon XL 4WD with LC9 Motor and 3.42 gears.

Except for a tune, no other mods are planned.

Going to remove AFM and considering the 2007-2008 version of the LS2 camshaft, 12593206. Seems similar to GM Performance 88958775 camshaft marketed for crated LC9s. Would like to increase low end torque and have no desire to lose bottom end power for top end gains.

Is there a better cam than this or will it work fine? I was also considering the LY6 stock cam, the 12625439/40 but cannot find their specs anywhere.

LS2 - 12593206 - 204 211 - .525 .525 - 116
GMP - 88958775 - 203 212 - .526 .525 - 117.5
LC9 - 12625436 - 196 201 - .467 .479 - 116

FFDP

iTrader: (2)

Go larger, otherwise I feel you'll regret it.

Find a cam in the 212/218 range or very similar, will make more power and torque over the LS6 cam no problem while still being mild and letting you keep the stock stall converter.

RPMSpeed Tech

I know it may seem like you are looking for a "budget" cam and prob want to use ls6 springs, but youre losing out on so much.
I would recommend the TSP STG1 LOW LIFT
and upgrade to the pac1218 spring.
We have that kit right now for $500 shipped.
Still super easy on the valve train but will bring up that tq significantly without losing any bottom end.

swathdiver

I am concerned that those longer duration and lifts above .525 will kill the LC9s bottom end torque.

This truck weighs 5900lbs on the scales empty and will be towing a TT soon. It's also going to take us across country and back.

The "tune" I'm told will offer the most bang for the buck and the AFM is coming off, necessitating the cam change, for long term reliability. If there weren't so many options, I'd put an original spec cam back in.

I rarely spin the motor past 3500 rpms.

Anyone here with a Yukon XL or Suburban running that TSP Stage 1 Low Lift camshaft? I originally considered this cam, thanks for bringing it back to my attention.

RPMSpeed Tech

Adding more lift on the same duration doesnt kill torque. Using the same duration @.050 but more lift you will increase tq. A stock cam will barely see a tq bump vs that stg 1 low lift or stg 2 high or low lift. It wont lose anywhere in those durations. We have personally seen zero issues in hundreds of dynos with them. As well as TSP on their engine dyno.

A tune on the gen4 engines is worth 20-30 but add in the cam youll see even more. The tsp dynos are on a gen4 5.3 as well. So youll see whats to be expected with your setup.

They also use a stock computer and hptuners to make the tunes so they arent wrung out or strung out for max hp either.

The point of diminishing returns for bottom end on a truck is about 220 intake and mid 220 to upper 230s exhaust and anything wider than a 114 really doesnt help either. broadens the power band and can cut down on early tq production for a later peak. 110 - 112 is a sweet.

swathdiver

Why do the more popular aftermarket cams ground with equal intake and exhaust lifts, or favor the intake lift (being higher) when the factory camshafts usually have higher lift on the exhaust side, just as their durations on the exhaust side are larger?

RPMSpeed Tech

There are so many theories you are stepping in to deep water there lol.
We like either even lift (due to certain variables like springs and lobe aggressiveness) but other than that we build them traditionally with a higher exhaust lift.
The "torquer" cams you see with a really large intake lift and smaller exhaust rely on that large intake lift to keep the valve open longer at higher lifts to allow the most air in without using huge duration to do it.
Normally adding lift on the same lobe with the same @.050 duration will add more @.200 duration and promote more power and allow for higher airflow to increase power with no drawback. The ones that add lift but use the same or lower duration above .050 get pretty aggressive and can be noisy or hard on springs. TSPs lobes (which we like to use and grind our high lift hot cam, asa, and trex cam lobes we developed) have more adv and @.200 duration to keep the valvetrain quiet and stable yet make more power with no real drawback.

madmann26

iTrader: (7)

Your spark map can be tailored to make up any difference you think you may lose.

Stock tunes are extremely conservative. That take off feeling, can be adjusted with spark tuning.

I run a Howard's Cam. 226/232, .578/.587 @ 115 and you'd think it was a smaller cam while driving. That's what Kyle @ TMS put in my longblock.

Some people favor certain cams. Some people swear by certain specs and duration. At the end of the day, it's the lobe that matters.

Another thing to take into consideration is DCR.

RPMSpeed Tech

You can only add so much timing down low before you hit issues esp when you run into the throttle. At a certain point all you are doing is hammering the bearings with too much cyl pressure. Above 220s intake youd want a stall anyway as the power below 2k starts to fall off. Mid 220 in a 5.3 are not good without a stall and anything above 228 int dur a stall is nearly mandatory to tune right and not give drivability issues.
Erring on the side of caution is fine but that 5.3 will take the stg 1 low lift or stg 2 hi lift with no issue and make great power. Esp off the tsps designed lobes. Since you are so concerned about any loss the stg1 would be best with a good bump in power.

madmann26

iTrader: (7)

True.

I ran a Comp LSR 265 in my old 5.3. That was a fun cam and I had 0 issues out if it and had plenty of grunt.