Specd_out

Maybe I am missing something but whats the point of a velocity stack. Being N/A the engine can only suck what it needs at that time. I dont see how having a larger filter can make power. Its not like its a ram air setup.

Grand_hustle17

iTrader: (22)

can i be honest... i dont even know what a velocity stack is to be honest... never even cared to look into it, maybe one of these days

MoncefA33

iTrader: (6)

Makes airflow more laminar, reduces turbulence.

Grand_hustle17

iTrader: (22)

Post a pic... I think I know what it is, not sure

MoncefA33

iTrader: (6)

Bottom piece.

Unklejoe

iTrader: (6)

Having a larger filter is always better. In any case.

Reduces resistance to flow and lasts longer.

CMax03

iTrader: (3)

Bellmouths are used on turbine engines as well to ensure straight non turbulant airflow......before entering the compressor section to prevent compressor stalls! Here's a shot looking into my bellmouth and trying not to get any body parts ingested in the intake (F.O.D.) or small kids.....LOL

knight_yyz

iTrader: (40)

a 3" coupler will fit on the TB

Grand_hustle17

iTrader: (22)

Thank you sir

SoonerFan

iTrader: (5)

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

jeff5347

Just wanted to throw this in since i read the entire post. i believe the vc to hose should be looped back in as intended. The emissions thing does have valor but also it helps in creating the positive crankcase pressure.
An engine for the most part is an engine. Whether a Nissan , ford, chevy or hyundai. The hose from vc to intake helps take out the pressure that builds up in the crankcase that would lead to excessive blowby in the piston rings had the line been removed. Ive seen guys with drag cars that attach the line to the VC and then have a bung mounted in the headers ading in the suction of the gases.
http://www.streetperformance.com/par...844-25900.html

This also helps the rings to seat tighter in the bore gaining the car more HP. That would be overkill in a street engine even making 260whp but the oem line from vc to intake would be better than not attaching it...if anything it helps the engine live longer ; read:rings

Grand_hustle17

iTrader: (22)

nice link but that is rediculous i couldnt even read it...... thanks for the info though

SoonerFan

iTrader: (5)

improves airflow...probably minimal impact with our engines

Grand_hustle17

iTrader: (22)

pardon my noobness, but i dont get what you are talking about

SoonerFan

iTrader: (5)

i have no idea what he is talking about

Grand_hustle17

iTrader: (22)

agreed

Rochester

iTrader: (3)

Does Wikipedia offer a language conversion to jive? Maybe that would help.

Yo.

Grand_hustle17

iTrader: (22)

.................... I'm gonna let you slide as idk what "jive" is, must be a software term, I do need translation with that thank you...






Yo!

MoncefA33

iTrader: (6)

AY! Word em up.

Z-Powered

Leave the PCV hose connected to the midpipe...

Chris Gregg

iTrader: (59)

Re-iterated my point made in Post #20.....thank you. But I believe your statement should read "it helps in creating the NEGATIVE crankcase pressure." Pulling out the gases works to create a vacuum - ie: lower than atmospheric pressure. Remember, at higher rpms, the PCV valve is closed.

As far as the Wiki post, I think only the top part is really relevant to what we are discussing. But, I'll try to simplify and make more relatable. Imagin air particles are like cars. The intake of the engine is like a freeway. Well, when there are cars traveling down the free way, if there were several side streets meeting the freeway with cars trying to enter, things would get very congested and force cars already on the freeway to move over, ultimately slowing things down. However, freeways as we know them have onramps and merging lanes....these are the equivilent of a velocity stack. As cars move onto the interstate with many other cars already traveling, they get to maintain a higher rate of speed. The vehicles already on the interstate get to maintain there velocity/speed as well and further allow the merging cars to find their place into the flow of traffic. This allows the overall speed/flow of traffic to remain high for ALL vehicles while also allowing more vehicles on the freeway and the transition for everyone is much smoother. Therfore, increased flow/velocity down the freeway (intake).

Crude translation, but hopefully that helps for the common people.

Interesting though, even 3rd gen Maxima's have a velocity stack built into their stock air box.

Grand_hustle17

iTrader: (22)

^^^ I don't find the last statement interesting, unless you look at it from the POV where the 3rd gen have a velocity stack but when removed for a regular intake it makes more power.... interesting I guess

Chris Gregg

iTrader: (59)

Just interesting to me 3rd gen had a VS stock... at least upon the initial thought.....some hours later......uhm, not so much.

NmexMAX

iTrader: (22)

I like Jeff & Chris.




So, in essence of this thread, I'd like to show the Helmholtz vs straight tube:

Helmholtz:



Straight pipe:

Chris Gregg

iTrader: (59)

Great - untuned engine airflow BATMAN.. 0.89 horsepower LOST by using the Helmholtz.

LOL "I see what you did there!"

For those that might need some translation of the above graphs, I believe the point being made is not the actual figure...0.89 hp could be chopped up to a lot of variables.

However, what I believe NmexMax is clearly pointing out, is that when air flow is smooth (tuned if you will), then the power band of the engine is significantly changed for the BETTER that when USING the HELMHOLTZ power comes up much more smooth, seeing less fluctuations through the rpm band.

You could almost draw a smooth near bell curve off the first one. The bottom one with straight pipe looks more like the stock market!

CMax03

iTrader: (3)

Should've used the same graph, one's by 10's and the other is by 5's.......to keep it apple too apple the entire way......But with my fully understand what Nmex is saying that's what I was feeling with my butt dyno smoother power delivery using my Oem Helmholtz....it just seems to pull more consistently.

NmexMAX

iTrader: (22)

All these were done on an untuned engine on the same day. Only difference was the intake.

I can post it on whatever scale you guys would like. I actually ask for my runfiles

It just looks horribly scrambled eggs style when all four are on there same graph. What I plan on doing is a comp between 2 and 2. The low 2 (Helmholtz and not) and the higher 2, et al.

Z-Powered

Two questions:

1. Does a smoother power curve necessarily equal faster times if all other variables are equal?

2. If the answer to number 1 is yes, does adding a velocity stack smooth out the power curve as much as keeping the stock Helmholtz resonator?

Grand_hustle17

iTrader: (22)

Don't matter....

NmexMAX

iTrader: (22)

Really, it doesn't matter. Area under the curve = FTW ..

CMax03

iTrader: (3)

Edumication time?

Grand_hustle17

iTrader: (22)

Please

NmexMAX

iTrader: (22)

Area under the curve you mean? Most hp over the entire scale.


This is completely stock airbox, both with the holtz and w/o.




This is with the GAB, both with and without said Holtz:

Chris Gregg

iTrader: (59)

Question: NmexMax - With the Helmholtz removed, did you leave the recirculation system open to air (just put a filter to the front/left side valve cover)? Or, did you reconnect the stock rubber tube off the front valve cover back into the intake somehow?

I ask only because I wonder how much of the HP difference is the helmholtz itself versus the vacuum pulled on the crank case through keeping the recirculation system connected and functioning properly.

Also, could you edit the above graph to better clarify which trace is which (Red vs Blue) in each graph.

NmexMAX

iTrader: (22)

The higher peak values are with the Berk midpipe, no box with that said, I was using said mid-pipe, so everything was as it was supposed to (PCV connected).