Thread: vvl switchover

Is there any real benefit from switching the IN/EX cams at different rpms?
I know you may be able to find a little more power on a dyno,from what I have read,but what about a daily driver?
Reason is ,I am removing my mss and just putting a msd 8950 rpm switch instead.
Both cams will be switched at the same rpm.

I got pills for 4600,4800,and 5000

The big advantage is that with the MSS you can set your shut off RPM lower than you could with the Greddy MSS so you will nevar fall out vtec yo. sorry couldn't help myself.

based on most dyno graphs, when solenoid activates power drops noticeably. now separating activation points compensates this sudden drop of power/torque. just an observation.

hmmm...sounds reasonable,but is it really that bad?

Well im running the MSD box and the power does drop when the high lobes kick in. Now idk if activating them at different times will smooth it out a bit but I think some good tunning should fix it abit if not eliminate the drop.

why r u changing from the greddy mss.....is it that its defective.....

if the mss is still working the just adjust it to trigger at the same time and see how it feels

You should have your cams activating when they are needed.

"Dropping out" of vvl has nothing to do with making the best power, you are only switching to the low lobes because the vvl lobes are no longer efficient.

Switching the lobes at the same time might make a little larger initial drop in power, but it can be tuned pretty smooth on the dyno.

Get it tuned, set it to the best point where the graph is smoothest, and forget about it. Nothing else you can do. If you are dropping "out" then you can consider a different tranny or a higher shift rpm. Nothing else should be altered.

My .02

Dudeman

If you have access to a dyno shop, I would do two separate runs. One run with both high cams deactivated completely, and one run with both high cams activated at a very low RPM (like 3k). Have the dyno operator plot both torque graphs on top of each other. Where the two torque curves intersect should be about where you want the cams to change. After that I would fiddle with things like how far apart the exhaust cam should come on and fuel/ignition tuning.

This is all theory but it makes sense to me.

Luke