As some of you may know Im installing stage2 cams this week,Ill will most likely be using Hp tuners for any tuning requirements, my question is" do you think the tune would have to be more aggressive if I was to up the ante and purchase valve springs, in turn making the cams more aggressive? thanks

 

upgrading the valve springs won't really increase the performance of the cam. The upgraded springs would be stiffer, making it safter to wind up the motor and take advange of the upper rpm range without worry of "floating" a valve.

 

On the flip side...

More spring pressure at the seat means the valves, followers and possbily cam lobes wear faster.

Don't use any more spring pressure than the cam requires. Do they recommend upgraded springs with those cams? If so, find out which springs and use them.

 

This is entirely correct.

 

depending on the cam spec, there might be little "tuning" required. In fact, the only things i can think of that would actually need to be changed for "start and run" issues are the desired idle rpm, but this should only be an issue if you stalling at stoplights or idleing badly.

otherwise, maf, timing, pe is where the money is..

 

depending on how radical the cam is you might have to bump up some fueling in the lower rpm to keep the car from trying to chase its own tail with a bouncy idle etc...

other than that, your ve will have to be changed, (speed density mode if you have it will enable you to tune it better) pe tables will have to be radically changed timing will be different, possibly adding more timing, thats about all i can think of at 3am

 

Good luck with the 2.4 VE table...its a 5 dimensional mathematical model.

 

What are the 5 dimensions? How does it work, come on dan your not getting off that easy.

 

even tho i'd love to hear his explaination... no-one to my knowledge has worked with the matrices of these zones on the 2.4l. you seriously need a math degree to even feel comfortable talking about them.

 

http://www.hptuners.com/forum/showthread.php?t=8490

http://en.wikipedia.org/wiki/Fifth_dimension

http://www.tenthdimension.com/flash2.php

Dan

and im not a physics major so im not going to try to describe it

 

I know one. I can see him trying to explain it. It'll go right over my head. Maybe thats why he gets to work for NASA. Then again, that may be why he doesn't have a girlfriend either.

 

I'm kinda curious on the effects of the VE table to overall fueling. On an LSJ, we've seen, other than the p0068 DTC, the PCM doesn't reference the VE table in hardly any cases other than MAF failure, when it comes to fueling. However with the number of variables used in the LE5 fueling calculations (intake cam RPM, exhaust, plus all said coefficients, etc), I'm sure the VE plays a bigger part than the MAF does.

As of now, I can't find anyway to log cam phasing or be able to lock cam phasing with VCM scanner (although the option is there, its like the PCM won't support that function). Until 2 of the 5 dimensions as Dan stated are eliminated, locked to a constant, or zeroed, I don't see anyway to feasibly tune a 2.4 VE table.

 

So the 5 variables are....

RPM
MAP
Exhaust Cam Angle
Intake Cam Angle
The VE Coefficient.

VE = Constant + KMap².MAP² + KMap.MAP + KMapRPM.MAP.RPM + KMapEx.MAP.Ex + KMapIn.MAP.In + KRpm².RPM² + KRpm.RPM + KRpmEx.RPM.Ex + KRpmIn.RPM.In + KRpm.RPM + KEx².Ex² + KEx.Ex + KExIn.Ex.In + KIn².In² + KIn.In

If you changed your cams it woud be more like solving for K all over again. It's been a long time since matrix algebra for me and I didn't do that well, but if you could gather a a bunch MAF flow points at with MAP and RPM you could try to solve for K.

It's very complicated but a good math person could probably solve it (like someone who teachs math or do it for a living) I think MATLAB is what I used in college