Originally Posted by Pully Police

EXACTLY! This is not like the old style V-TEC where you change to a different cam profile at a certain RPM level. Like skykapp said: The cams are constantly being phased to deliver the bet mix of economy and usable power throught the RPM band based on engine load and a number of other factors.

IF you were to trace the VE of this engine through a normal drive in the country, you would have to wrap your head around the computer monitoring a point in the fifth dimension which gives you simulatnious access to all possible lines (running conditons) in the 4th dimension, which, in turn, would give you access to every cell on every VE table existing in the third dimension AT THE SAME TIME. Yeah...it is a bit if a mindblower

Originally Posted by Red2.4SS

Pretty crazy! I thought that the 5 dimensional VE table was only for speed density mode?

Originally Posted by Pully Police

Correct - I am sure that the MAF works in the same way. MAF tuning uses tables very similar to speed density. Now, I dont know the ins and outs of these ECUS specifically, but I DOUBT that they are using one "midpoint" master table and only multi level fuel trims to correct the AFR to get away with not having a 5-D MAF table....but they could be...it is definately simpler.

Originally Posted by Red2.4SS

When I had my turbo tuned, my tuning guy talked about that 5D table, but said he didn't have to deal with it because we did a MAF tune not a speed density one. The MAF functions are more standard and easier to deal with.

It will be interesting to see what if any gains are made by changing the VVT operations.

Originally Posted by Pully Police

Yeah....I dont know these newer ECU's (I have an LSJ) - I do this type of math though. I dont blame your tuner for not wanting to touch it - I would imagine that there would be a timing mess to contend with as well. So by the sounds of it, the MAF just ensured the desired AFR and PE would force the cams to phase for max power, so that would be easy to tune as well. The timing for PE would also be easy since you are only dealing with only the "max power" cam phase. Since the VVT functions are mostly beneficial at part throttle, you can probably leave them alone. YOu could probably change when the max power phase kicks in by changing your PE engagement settings.

Originally Posted by Red2.4SS

Yeah, he had to change the PE onset to keep the AFR safe for the turbo. It was a bit tricky to get it all dialed in. Some of the stuff was not suported on HPTuners. Its running very well now.

Originally Posted by Pully Police

Good to hear!

VVT was intended more for fuel economy in the first place. It could be used to generate max torque / HP if you stomp on the throttle at a low RPM - but that is alot of friggin tuning when all you had to do was downshift

Originally Posted by Red2.4SS

Yeah, I don't think I would be brave enough to mess with the VVT even if it could be done. I have no problems with it now, why create them?

Originally Posted by Turbo06Sedan

Basicly, think of "VVT" as GM's version of VTEC.

Only big difference is, is ours is on the majority of the time, vs a honda's xxxx rpm.

Honda's is just noticeable due to its "on and off" switch functions...

Ours is simple...it puts the car into "vtec" mode when we get on it, even from a dig...

I guess you can say our VVT would be the equivalent to a VTEC thats set to engage at 1500 rpm.

Originally Posted by Pully Police

Not quite. The VVT does not have an "Engagement point" the engine is always adjusting the cam phasing while you drive. When you stomp on it, the engine goes into PE and the cam phases to its "max power" setting. While you are cruising, the PCM is always hunting for the best economy and running conditions and ajusting the cam phasing to deliver the commanded conditions.

Originally Posted by Turbo06Sedan

Correct. I was just trying to explain its similarities.


As stated "its on the majority of the time"...as opposed to VTEC's "on and off" switch.

Originally Posted by Turbo06Sedan

Correct. I was just trying to explain its similarities.


As stated "its on the majority of the time"...as opposed to VTEC's "on and off" switch.

Originally Posted by IonNinja

doesn't VTEC only engage at full throttle though or at a set RPM regardless of throttle position?

with all the reference to VE it sounds like VVT is only used during partial throttle.

so you guys aren't able to adjust VE at all or you just don't have access to all the tables? I would think it would be hard to get PE dialed in without any adjustments to VE?

Originally Posted by riko540

No VTEC engages a certain rpm I think on the 07 honda civic si its like 6500. I only know this cause a buddy of mine has one.

Originally Posted by Zdeuce4

yup its a certain rpm... my friends 02 rsx-s is at about the same iirc. integra gsr's are like 4900... withhondata they can lower it. i wonder y we cant do something similar...

Originally Posted by Cloudio

Haven t seen anyone throw this out yet so iam going to go ahead and ask ........ everyone is talking about how hard it is , but whats the pay off ??? I mean off the top of your head what is plausible power gain from vvt tuning ??





................ and VTEC has nothing to do with throttle position its based on rpm anyone whos drivin an s2000 can tell you all about it

pros and cons of VTEC TO VVT
VTEC = HORRIBLE LOW END -GREAT TOP END

VVT = AVERAGE LOW END-AVERAGE TOP END = MUCH SMOOTHER POWER AND MORE USABLE