If I'm not going to gain overall from having vvt, I don't want it. Maybe pat g or ed Curtis could chime in here.

 

A few years back I performance built a VVT engine and we were not happy. After I was schooled on how it works we built another engine and gained about 200 rwhp.

This was in a street car.

 

What is the RPM range? Yes you can extend it with VVT, but at a cost.
Say 3000 to 6000 or 6500. You will have a stall converter then and you gain nothing or very little on the low end.

I don't know everything about this by far, but what I have learned was the hard way.

 

Did you mean 200 rwhp or 20. Lol. I see where you are coming from on the converter deal tho. On my reference to the l99 vs ls3, the l99 peaks at 5900, same as the ls3. The l99 peaks tq about 300 rpm sooner though at 4300 vs 4600 for the ls3.

I think the more tame the setup the more vvt can be a benifit. The more radical setups are built to run in such a narrow power band I can see where vvt may not be as beneficial.

 

Let's say you have an aftermarket cam that has a range of 2500-6200 rpms hypothetical. Let's also say the cam is ground straight up with no advance or retard. When put in a non VVT engine, the cam would make a specific peak torque/hp number at a specific rpm. But in a VVT engine you could advance and retard the camshaft at will, thus shifting the peak torque/hp rpm around in the rpm range.

So if you constantly varied the camshaft angle would not that vehicle perform better do to a broader torque curve? Provided the tune was good, would not the VVT car be faster than the non VVT car with the same cam? If so, how could it be said that the VVT would give no performance gain? Maybe it wouldn't show on the dyno, but in reality, the dyno doesn't matter. Performance when driven matters.

 

Stock or built motor...principle is the same
Stock converter or higher stall...doesn't matter...I'm talking about engine power here, not track times, so converter talk is irrelevant.

To make more power, you don't necessarily have to extract more BTU's from the fuel...you could just burn more of it...Changing the cam phasing CAN allow the engine to breath better at a given RPM, which would allow more fuel to be burned.

I would definitely agree. My posts above were in reference to a mild street motor. I wouldn't bother with it on a max effort track setup.

Yes, if you tuned it properly, the car with VVT active would make more average power than the one with it turned off, given the same cam.

 

Most of the stuff he is saying is accurate info. Seems that you are the one who's poorly educated in this case...

 

Converter in this case is irrelevent. VVT controls ICL angle of the cam. Idk what is considered to be a VVT cam, but to me a "VVT cam" would be one with no advance or retard ground into it.

Bottom line is, the VVT system does not make more peak power. It allows you to make more average power by varying the rpm at which peak power is made. So in that case, when you get to talking converter, you don't need to choose converter with a VVT system the same way that you choose a converter for a non VVT car.

Take, for instance, my cam from above. Say in a non VVT car it makes peak torque at 4200 rpms with 4 degrees of advance ground in. So you would need somewhere in the vicinity of a 4000 stall. But, with a VVT system, you could grind that same cam straight up and vary the ICL. So you could advance it at lower rpms and bring the peak torque down to, 3000 rpms or 3500. Then you would need around a 3000 stall, which would be much more street friendly.

Then you could retard the cam as rpms rise and move the peak torque up, while gaining some peak power and extending your rpm range. So saying that you will not make more average or overall power is a weak argument. Plus, throwing stall out to support it doesn't work either IMHO.

 

I am looking for a dyno sheet. When I find it I am hoping it will shed some light on how it works.

This camshaft position actuator has 60 degrees of crankshaft authority. This camshaft position actuator is in the home position when the actuator is fully advanced. This camshaft position actuator has 17 crank degrees of advance and 43 crank degrees of retard.

 

Do you have access to any engine simulation software? If you do, plug in a given cam, then advance it 4-8* from striaght up and note the power, then retard it 4-8* and note the power....There will be a decent difference...that is exactly what the VVT system could be used to do. While I don't put a ton of weight in exactly what sim software says, it gives you an idea of what the outcome would actually be.

I am actually very surprised that more vendors haven't done dynos with different VVT tables on their cam, and shown the differences.