redline06

Exactly!

03Screamer

iTrader: (2)

5th grade logic FTW

2004Black350z

iTrader: (37)

Well still going to test I guess. Doing my valve covers now. New plenum back on then off to retune. Then tb comparison then 4" Intake test.

Epstein

iTrader: (5)

Actually, you will be able to suck more through the straw as long as you're not operating at choke flow, which in the case of intake components, we're not anywhere near. It's the same reasoning why you'll see a difference between 2 straws of the same diameter, one is 2 inches long, the other is 200 inches. Your analogy also implies that no one will ever make any additional power if they have a stock MAF housing and stock rear exhaust section, and they only change the headers, cats, cams, etc. There is a pretty ridiculous imbalance of old wive's tales to engineering theory on these boards.

3hree5ive0ero

iTrader: (95)

Your example of 2 straws of same diameter but different length doesn't apply here. Nobody's changing length.

As for stock MAF housing and stock rear section with aftermarket whatever in between is a complicated comparison. In that example, you're not only changing the diameter but flow characteristics with different header lengths, less restrictions through use of HFCs or test pipes, changing duration with different cams, etc.

I may have oversimplified things (Bernoulli's principle) but my comparison makes more sense than yours. I could be wrong so feel free to correct me.

03Screamer

iTrader: (2)

From a physics standpoint that is true, but the actual real world gains by reducing this ~ 1" length of restriction (when the inner plenum elbow is 4" in length at least) is going to be minimal.

And your analogy works in an entirely different manner for the most part. Of course removing cats will make power, but what about removing just one-foruth length of cat? It would seem like a waste of time to me. Cams regulate the amount/timing of air pumping through the motor...which is again a bit different. Headers have a large effect on scavenging, which again is quite differnet to discussing flow capacity of a pipe.

waldo36

iTrader: (2)

Just a few more posts and I think I could ace an engineering exam.

Patty

iTrader: (2)

Hagen-Poiseuille law : http://en.wikipedia.org/wiki/Hagen–Poiseuille_equation

as you can see, the radius of the pipe affects the volumetric flow rate exponentiated by 4. Taking this into account with our throttle body and leaving every other dimension const. - you come to the following conclusion :

(75mm/70mm)^4 = 1,318 what equates an increase of 31,8% in volumetric flow.

just a little bit of straight forward engineering

1cockyZ

iTrader: (46)

That law does not apply for these reasons: air is compressible, the throttle body has a larger diameter than length as well as not being uniform, there is a throttle blade in the way affecting laminar flow. More like straight forward misapplication. Find me flow bench data that supports this law for the application of an automotive throttle body.


closer to reality.http://www.lxforums.com/board/f88/th...ulator-194536/

Patty

iTrader: (2)

funny to follow the reaction.
Of course the equation I brought in has limits for applying it. However it will give you an useful idea 1st about the changes without beeing that far away like comparisons of surging through a straw. The calculation you refer to is much more homework going in addition with a lot more accounts you can just as little prove that it fits the situation better than hagen-poiseuille law.

..trying to keep things as simple as possible but accurate as necessary.

str8dum1

iTrader: (11)

you guys are arguing theory when there has been a dyno posted showing no gains. WTF

johnnyzcar

So where are the NWP people in all of this. I would think they would not want to mislead people and become known for selling snake oil.In other words someone should send them a link to this thread to get their reaction.

KingBaby

iTrader: (3)

^^^
that join date and post

Well what I found being out of touch as I am...if it's not on instagram or facebook...folks don't know how to google or use a forum...

If I were them I'd be looking into making a larger than aftermarket pipe

nitish21

This is odd.. The gains are not reported at the peak point but after 5200rpm when oem tb drops heavily

onevq35de

Old thread, no ****, but I've gotta add something here for the next guy who wants to stay n/a on a vq, just to set the record straight. I think I know where this went wrong.
There is no way, imo, to install the 75mm t.b. directly onto the v-plenum correctly. I was hoping to do so based upon this thread, but it's impossible, assuming one desires to keep the opening on the t.b. lined up with the opening on the v-plenum. It's not about the existing holes not lining up with the those of the 75mm but instead, the new holes will have nothing to bite into UNLESS you shift the t.b. and in doing so, it will not line up with the neck's entrance. Shame too because I was hoping to bypass the adapter plate, not to save $ but less ********. Even if one could get this to work, the v-plenum and most likely oem and other aftermarket plenums have a smaller opening than the t.b. which, with a larger t.b. would exacerbate the mis-matched issue causing increased turbulence.
After finding out the 75mm is a no-go fit, I ordered a nwp adapter plate and looked over the stock t.b.. The stocker is considerably larger than the opening on the v-plenum which is something I never considered to look at when I initially installed it. Sonofabitch. I've dremeled the opening to match the stock t.b. gasket until I get the adapter plate, at which point I'll match it to the lager t.b.. I also opened up the neck and will do more when the plate comes in. Will probably un-taper the tapered end of the plate which is tapered to match the oem neck opening.

drozzy

According to this Motordyne G35 guy, this mod makes the top 7 for a VQ - no manifold mod mentioned otherwise. He does mention the fact that he's getting a custom intake down the road but still puts it on the list at #5.



Is this a wrapped Injen CAI hooked up to the 75 mm TB? (7:04)

I think I see a 5/16" spacer as well. Can anybody tell if he had fitment issues?

Not getting it if it indeed made only a few horses on a fully built motor.....

onevq35de

https://www.infinitiscene.com/thread....230572/page-6
My main thread. Just look for the appropriate photos.