Power Loss with camshaft on LS3

[HsvR86.2]

Hi Guys,
Long story short.
Got my Clubbie 6.2l ls3 with full exhaust system HM headers and twin 3 inch exhaust and tune made 290rwkw with 850nm rw torque back in 2013.

Since then, got the cam installed, I believe the cam is VCM 480 ran on dyno today and made 271rwkw with on 480nm rw torque? How is this possible? Attached are the 2 dyno graphs.

 

[HsvR86.2]

Other dyno with 290rwkw

 

[someguy360]

Dyno readings can vary a lot between dyno brands/workshops etc. One of those tests was with a Mainline dyno and one was with a Dynotech. Mainlines are known to be a little.....generous.


That being said I highly doubt the original dyno run was accurate, an LS3 with an exhaust isn't going to make anywhere close to 850nm at the wheels (and I mean, absolutely nowhere near it).

I'd expect a bit more on the post cam dyno run, sounds like either the tuner is useless or the cam wasn't degreed properly and the cam timings off. It only takes a tiny bit of cam timing being out to wipe off power. Or it's possible that you are now maxing out your stock fuel system and the tuners gone conservative. That is, if that dyno is in any way accurate.

Just remember throwing a cam in an otherwise stock engine isn't going to transform it into a beast, you'll be up for probably 40kw at the fly more with a good tune on a stock LS but it's not going to be earth shattering. A different brand of dyno or an improperly calibrated dyno is going to take up that slack.

Either way, you shouldn't be using a dyno graph as the be all and end all measure of your cars performance, it's mainly for P platers wanting pissing contests at car shows. Does it feel faster than it did before?

 

[lmoengnr]

2 different dyno's?

 

[HsvR86.2]

Car definitely feels better to drive no doubt. What should be the average power output of an ls3 with Orr, tune, twin 3 inch exhaust and 1-78 headers? And then with cam I would of Atleast expected 300+

 

[someguy360]

Car definitely feels better to drive no doubt. What should be the average power output of an ls3 with Orr, tune, twin 3 inch exhaust and 1-78 headers? And then with cam I would of Atleast expected 300+

I'd expect 290-320rwkw for that particular cam on an LS3 depending on how competent the tuner is for a safe street tune.

I'd say the tunes lacking or theres something deeper at play like cam timing or fuel system.

 

[HsvR86.2]

2 different dyno's?

Yes and years apart.

 

[HsvR86.2]

I'd expect 290-320rwkw for that particular cam on an LS3 depending on how competent the tuner is for a safe street tune.

I'd say the tunes lacking or theres something deeper at play like cam timing or fuel system.

Spoke to the tuner today and he said the afr's everything looked good. Forgot to ask him how much timing it was running.

 

[someguy360]

Spoke to the tuner today and he said the afr's everything looked good. Forgot to ask him how much timing it was running.

cam timing and ignition timing is completely different from each other.

If the cam wasn't degreed/dialled in correctly when the cam was installed it will never be right.

A lot of workshops will just use the dot to dot method of setting up the timing chains/sprockets etc, rather than degreeing the camshaft in correctly which is how it should be done.

 

[MrBags]

If it feels better but shows less power that tells you something about the first dyno numbers.