Benefits of an LS Cam Upgrade
Benefits Of An LS Cam Upgrade
Cam upgrading your LS engines be it an LS1 or a LS3 or even an LSA or LS7 can give incredible performance improvement.
The factory cams in some cases leave a huge amount of performance gain ready to claim. The worst cams being in the L76 and L77. These were used in the VZ 6L, early VE 6L automatics and all 6L since the VE series II including all VF 6L. These cams create very low valve lift and have short durations. The LS3 and LS2 cams are the best standard cams and when used in the other engines give decent performance improvement.
Any good upgrade camshaft will have longer duration of valve opening events and also create more valve lift. Depending on the combination this will result in a different spread of torque across the rpm range. Some camshafts give more low down torque than any standard cam and make more power everywhere in the rpm range. Other streetable cams make relatively less torque until beyond 3600rpm and then make a huge gain with peak power at 6700rpm. It is ofcourse possible to build LS engines with cams that rev to 7500rpm and beyond that make their torque and power even later.
When cam upgrading an LS it is a must to upgrade the valve springs, we prefer to use dual springs, sometimes we use lightened spring kits that have extra light titanium retainers on the tops of the springs. It is also important to use chromoly pushrods (instead of the thin steel factory versions) to stabilize the valve/pushrod/rocker/spring , we use thicker chromoly pushrods as well. While doing a cam upgrade it is better to take the cylinder heads off, clean them up , fit the springs and take the opportunity to fit new lifters and lifter buckets, We have experienced good reliability statistics from genuine LS7 lifters and their buckets. Both the lifters and lifter buckets will likely be worn on almost any engine and this is a great chance to refresh them.
It is essential that whenever heads are removed new gaskets and new head bolts are used.
You can at this stage swap the heads for CNC Ported factory design and get a modest gain in power usually after 4000rpm. It is possible to shave the heads and increase compression, but this can give away piston to valve clearance. Many bigger cams have no spare clearance to give away.
Aftermarket designed heads are even better, many give better p to v clearance and make much more solid power gains. But yiou pay a premium for these heads.
It is possible to upgrade the throttle body to larger one but unless the hole in the intake manifold is larger this is a waste of money. Upgrading the manifold is an option. There are a few versions of FAST Manifolds for LS engines, Some versions work very well like the ones used on LS1 and LS2 Cathedral Port Heads. The LS3 L98 L77 L76 version doesnt work as well unless used with the big throttle body and combined with heads upgrade and a big cam. On a small cam this manifold/TB gives almost no gain.
It is recommended to upgrade the rocker trunion bearings to a rocker bush which we source from CHE. These on a the factory rocker have been spintron tested and make them much more reliable and smoother in movement. This may result in more power.
The factory harmonic balancer is also unreliable at high rpm and is recommended to be replaced with a 25% underdrive balancer kit. These give a small amount extra power as well.
The other simple mandatory modifications for an effective cam upgrade are Performance Exhaust and OTR Cold Air Intake.
We prefer the VCM OTR kit and exhaust that includes large 4 into 1 primaries in 1″7/8 or 2″ (big cam/heads), high flow cats and a twin 2.5 or twin 3″ catback.
We have seen a manual 6L with Heads and Cam make as much as 400 rwkw and peak torque 606Nm. the same model with a L77 engine standard often makes around 230 rwkw. A recent stock cammed car made 267rwkw adn 459Nm peak torque and many cars with our LSV cam make around 327rwkw with peak torque near 538Nm or our bigger cams 340-350 rwkw with peak torque near 550Nm.
Below is a dyno comparison between a VF 6L LSV and VF 6L stock cam, both with full performance exhaust and OTR. Torque is the top chart, Power at the bottom