I'm curious if anyone has ever done any dyno testing - or hopefully even a back to back comparison - of an 00VI with it open the entire run (or removed entirely) and with it working as it should. I want to compare the torque loss between the two because I've been kicking around the idea of removing the powervalve or forcing it to be open all the time - simply to avoid the possibility of it screwing up and sticking closed which is all too common.

Tilley did it, ask him. Probably more top end and less low end, which is perfect for you. And it's always a relief to have a completely empty intake manifold, with no moving parts inside that could potentially screw up the engine.

i believe sloppymax did one with the power valve removed also

Cool thanks guys.

check with blackbirdvq also

mine is out and will not go back in under any forseeable situation. let me scrounge up the dynos. my actual comparison would be a non working vias which it was not opening up as opposed to being stuck open versus having it removed. off the top of my head, it was around 30whp.

sloppymax, I think I have your dynos (under the name Nathan's run files)

If you don't mind, I can email them to nealoc if you can't find them

do you mean the difference in top end was 30whp higher with the 00vi stuck open, or that the difference in the midrange was that it was 30whp lower with it stuck open. what i'm actually interested in is how much lower it is in the midrange with it stuck open (or removed) - but it sounds like your dynos will illustrate this just fine since one was open and one was closed.

id love to get those run files also. email: maxgordon7@hotmail.com Good stuff id say....

you can email those but those are nathans unless SR put mine in the same file. he (nathan) actually has a 5spd so it might be more relavent. mine are most likely at work that i will access to on monday.

a quick comparison

nathan vs. me (both in 4th gear). Power valve removal vs. working DE-K
unknown mods for nathan
Me: y-pipe, TS ecu, Stillen intake, and 18" Axis wheels



around a 10-20 ft/tq difference in the mid range with working DE-K
around a 10whp difference on the top end with power valve removal

looks nice, id like to see the same car back to back tho.

thats what SAE correction is for. Geez, we can't all be dynoing back to back modifications all the time just for the sake of the org

That is a very nice comparo, thanks. Anyone else know nathans mods? (who's nathan i can just email or pm him and ask him)

you can ask Sr20den. He's the one that gave me the files

ok cool thanks. thanks for posting them too.

I have an MEVI dyno comparison with what your wanting. Both of my car on the same day. If you want to see them I can post them when I get back in town.

pretty sure he only had a y pipe, catback and some brand of cai. his tb restrictor was most likely removed along with bypassing coolant lines into the tb. also was on stock 16" wheels iirc.

I've got one of those of my own Thanks though.

so what's the conclusion on this? it looks like from the dyno that midrange is sacrificed but top end is better. it may be better to remove the power valve?

Well my application is a boosted one so my conclusion may well be different than that of an NA max.

Check the results in my thread...
http://forums.maxima.org/showthread.php?t=444516

here is mine. i can email the files if you want. this is a 2nd gear pull. 1st run is with bad vias and 2nd is with power valve removed and moderate fuel tuning. i know alot of people tend to make excuses if they hit lower numbers but i was having fuel issues. my fuel pump would not hold pressure after 6k rpms. i was running 4 bar of fuel and backing it out with the vafc2 but it was dipping to just below 3.5bar after 6k.

Can you post the torque curves?

Yes, the torque crossover point is the determining parameter for when you want the power valve to open.

And concerning post #20, I'm not exactly sure what the reference was to, but I doubt that you can make more top end power with the power valve removed than you would if it was installed and opened as/when it should. From that opening RPM point on up, the two ought to be pretty darn close to earh other.

waaahhh?? Did you miss post #11 with the dyno graph? Removing the power valve gives a nice horsepower gain because the car makes peak torque later in the rpm range. However it comes at the price of low-mid range loss.

Post #11 is of 2 different engines. A more valid comparison would be of a single engine, one run with the power valve closed throughout the run, and one run with it tied open throughout the run.

And NmexMAX, if you have ever taken one of those 00VI's apart and studied how it actually works, you'd have seen that the power valve doesn't open up a secondary intake passageway, but opens up what is essentially a closed "sonic chamber" that provides a dynamic ram effect. If there is any gain at all in the upper RPM range by having removed the power valve, it would only be because the sonic waves can pass thru unobstructed by an open power valve, not because it's allowing more air to pass past the missing power valve.

It creates a shorter route in order to accomplish dynamic supercharging more effeciently as RPMs increase.

I've taken both a MEVI(not much) and 00VI apart, and they are very similar.

There is a small increase in volume, though I did not ever say that it was the sole reason why the rodless DEK VI creates more power up top.

I do see your point of using the open/closed method in order to find the optimal switchover point.

This is why it creates more power IMO.

They are both DE-Ks and the charts are SAE corrected. Under your reasoning no mods or engine dynos in the world would be comparable between two vehicles because they are not done back to back on the same engine. Our engine build tolerances are close enough to have a minimal variance in power levels.

No one is arguing with you on how the power valve works and most know the construction of the DE-k manifold. We simply said it makes more top end power which can clearly be seen in the dyno curves at the upper rpm, regardless of engine differences. The car is making the peak torque later in the rpm band, meaning that it has the ability to make a higher hp number

just to back up the point of making peak torque at a higher rpm and holding it higher to redline.

This is the graph I was hoping to see. This sloppymax plot confirms that the torque crossover point (and where the RPM switch should be set) is right around 4900-5000.
Just to clear up what seems to have been some confusion here, my point was that there is no logical or rational reason I can think of why a DE-K with a fully functioning power valve ought to generate better power/torque in the upper RPM range (i.e., above the point that the power valve opens) by the simple, complete removal of the power valve. If someone can provide such an explanation to support a contrary position on that, I'm open to listening to it.

The power valve restricts airflow while open vs. no power valve, however I believe the PV could be "shaved" to still provide a seal while closed, yet minimize the restriction while open.

Also, your "4900-5000" switchover is based on a broken PV vs. no PV not a working closed PV vs. working open PV torque curve, which isn't valid IMO for someone trying to maximize their torque area under the curve via a working VIAS. Plus, that dyno is a 2nd gear dyno, which IMO is the wrong gear to be data collecting in.

In short, my opinion from seeing typical bolt-on mods, ie I/Y/E, a DEK w/working VIAS switchover should be set around 4600rpm to actually switchover by 4700rpm due to the ~100rpm delay.

Here's my dyno from last year with a working PV. For me 5000 right on the nose was the best point.

impressive numbers, what gear is that in? What mods do you have? Thats the first working PV with such a smooth dyno curve and it doesn't dip too much in the upper rpms either

could you set the smoothing factor to 5 and see what the hp/tq is again?

Jeez that's a nice dyno...what mods do you have again?

Can you zoom in on the switchover area or send me the two files?

Also, why such different gear ratios?

Haha.. looks like some people haven't ventured into the dyno forum in a while... that post was on the first page for months..

The link NmexMax provided has most of the mod info and the run file downloads as well.

Come spring I'll be dynoing again with some improvements in several areas and some more tuning. I expect to be able to up those numbers another 5-10 hp or so and improve the slope of the upper end of the curves but we'll see. I will post results at that time of course.

i'm just amazed at how the curve looks like at the top end. Almost as if the power valve is removed

In case you didn't check out my thread, here's a comparison of opening the VI at 5200 vs 5000. As you can see, opening it at 4800 might even be better, if only my AF ratio wasn't tweaking during that RPM section....


Larrio- I have a question for you. You said that
"They are both DE-Ks and the charts are SAE corrected. Under your reasoning no mods or engine dynos in the world would be comparable between two vehicles because they are not done back to back on the same engine. Our engine build tolerances are close enough to have a minimal variance in power levels."

Can you help explain why my car, with very similar mods to DandyMax, put down some 30 hp/tq less than his car? If we were both on Dynojet 248's, and dynoing in the same gear, there really shouldn't be such a large difference in our numbers. My AF ratio isn't perfect, and his aren't posted, but that can't account for the huge difference, can it?

You have a full DEK right? Dandy only has the DEK IM. He's tuning with wideband o2 and EMU. It might be the 'little things' in this case



DandyMax VS 95maxrider