OK who's making these?

[npaulseth]

Originally Posted by ecoli

Why would velocity stacks be more beneficial in an NA environment, besides the fact that NA guys are often trying to squeak out every last HP.

In every document I have read, they did not have seperate sections for FI and NA intake manifolds. I have done a bit of research on the subject, and basically have read that velocity stacks are good for NA and FI manifolds all the same. I have given JET the same reading material for his design on KA24DE manifolds that he was thinking about making a while back on NABR. I'll post up the link when I get home to the PDF I am siting.

[npaulseth]

Originally Posted by ecoli

In AMS's actual dyno testing they found more than a small amount of taper ended up hurting the power. They did use some taper though.

2-5% taper is a general rule of thumb for runners.

[niterydr]

Originally Posted by Jakey

Explain please.

Prove to me for once that it isn't a marketing gimmic.
Thats right, I want YOU to prove to ME something for once. I've done my research, my opinion stands.
Until that is done, I am saying that 99% of the time, it is a term that is thrown around and used to describe a poorly designed transition for a runner inlet.
Maybe I'll back to back test them on our flow bench (once its done). Heck I'd even donate some dyno time if someone wanted to test them.* Until then it's just a theory. I know of manifolds for different applications that use and don't use velocity stacks. The majority of the time, on a forced induction setup, it is a wash. Where in a NA environment, you usually see the gains with a velocity stack or a "bell" inlet for intake runners.

*But I would want the EXACT same manifold with and without velocity stacks. If its on the dyno, same car, same mods, same day.

I've done all the research on this I can. If I truely want to know, we'll design a intake manifold with both and test it. Until then, I am tired of reading about it and coming up with inconclusive data. (as far as velocity stacks on a forced induction setup is concerned)

[Shane@DBPerformance]

If they make power on an NA application, shouldn't they make power on a boosted application? Do they add power on an NA application?

[niterydr]

Originally Posted by ecoli

If they make power on an NA application, shouldn't they make power on a boosted application? Do they add power on an NA application?

I am thinking they are acting as a restriction on the turbo applications.
All I know, is all the digging I've done, I have yet to find concrete proof as far as a turbo'd application is concerned. Alot of the intake manifold design has been taken from N/A applications. In N/A applications, they have been proven to open up the rpm range and add power in some instances. I haven't seen anyone do back to back research on a FI setup.
To me, someone saying that you MUST have velocity stacks on a intake manifold (on a turbo car) just annoys the piss out of me.

[Jakey]

Originally Posted by niterydr

Prove to me for once that it isn't a marketing gimmic.
Thats right, I want YOU to prove to ME something for once. I've done my research, my opinion stands.
Until that is done, I am saying that 99% of the time, it is a term that is thrown around and used to describe a poorly designed transition for a runner inlet.
Maybe I'll back to back test them on our flow bench (once its done). Heck I'd even donate some dyno time if someone wanted to test them.* Until then it's just a theory. I know of manifolds for different applications that use and don't use velocity stacks. The majority of the time, on a forced induction setup, it is a wash. Where in a NA environment, you usually see the gains with a velocity stack or a "bell" inlet for intake runners.

*But I would want the EXACT same manifold with and without velocity stacks. If its on the dyno, same car, same mods, same day.

I've done all the research on this I can. If I truely want to know, we'll design a intake manifold with both and test it. Until then, I am tired of reading about it and coming up with inconclusive data. (as far as velocity stacks on a forced induction setup is concerned)

You've done your research but yet you have proven nothing. Everything I have said I can go grab my Fluid Mechanics textbook and site exact pages that I used to make any technical comments in this thread. You keep talking about the research you've done, let's see some documents. I'm not questioning what you're saying but I'm questioning how you're presenting your information. Too many of you all have been around the DSM far longer than me to start questioning any of what you're saying, which is why I'm asking for documentation of your claims. Any SAE papers?

Originally Posted by niterydr

I am thinking they are acting as a restriction on the turbo applications.
All I know, is all the digging I've done, I have yet to find concrete proof as far as a turbo'd application is concerned. Alot of the intake manifold design has been taken from N/A applications. In N/A applications, they have been proven to open up the rpm range and add power in some instances. I haven't seen anyone do back to back research on a FI setup.
To me, someone saying that you MUST have velocity stacks on a intake manifold (on a turbo car) just annoys the piss out of me.

Where did anyone in this thread say that velocity stacks are a MUST?

Time for reading:
http://www.webpages.uidaho.edu/~racing/05FFL-188.pdf
http://www.grapeaperacing.com/GrapeA...ionsystems.pdf
http://www.lesoft.co.uk/ (Go to papers)

[97GSXAWD]

Heck I'd even donate some dyno time if someone wanted to test them.*

I am more than game if you want to do some testing on my car once it is running. It would be nice to see actual results from a dyno.

[niterydr]

Originally Posted by Jakey

You've done your research but yet you have proven nothing. Everything I have said I can go grab my Fluid Mechanics textbook and site exact pages that I used to make any technical comments in this thread. You keep talking about the research you've done, let's see some documents. I'm not questioning what you're saying but I'm questioning how you're presenting your information. Too many of you all have been around the DSM far longer than me to start questioning any of what you're saying, which is why I'm asking for documentation of your claims. Any SAE papers?


Where did anyone in this thread say that velocity stacks are a MUST?

Time for reading:
http://www.webpages.uidaho.edu/~racing/05FFL-188.pdf
http://www.grapeaperacing.com/GrapeA...ionsystems.pdf
http://www.lesoft.co.uk/ (Go to papers)

I know where you are coming from.
Onefast99gsx is who I thought said you needed them, but upon re-reading his post I stand corrected.
Great links, lets try for less Mechanical Engineer, and more actually doing something....
My "documents" are the real world experiences I've seen. The applications I've seen some. Some of the forums I frequent (*edit* is one of them) touch on the subject, but most of it is a "I'd sure love to see a back to back test for once".
Im done with this thread, and I get tired of spoon feeding this forum.
*Hint, its about flow, not harmonics in a FI setup.

[Shane@DBPerformance]

Originally Posted by niterydr

I am thinking they are acting as a restriction on the turbo applications.
All I know, is all the digging I've done, I have yet to find concrete proof as far as a turbo'd application is concerned. Alot of the intake manifold design has been taken from N/A applications. In N/A applications, they have been proven to open up the rpm range and add power in some instances. I haven't seen anyone do back to back research on a FI setup.

It shouldn't matter too much if it's FI versus NA. At WOT in an NA application, you aren't at a perfect vacuum, you are really usually at ~14.7psi absolute. Just because we as humans don't feel the pressure, doesn't mean it isn't there. So, I don't see why at 30psi or whatever absolute pressure, it should be any different.

Velocity stacks are definately not necessary. You can make just about any design for a sheetmetal intake on a DSM and see significant gains in the upper RPMs.

[Jakey]

Originally Posted by niterydr

Im done with this thread, and I get tired of spoon feeding this forum.

Spoon feeding what?

[AJ]

Can we just stick to the discussion and have some people stop trying to get under others skin over and over? The answer to this thread was solved on page one. And several other valid points where made otherwise. If someone want to continue the discussion, make a tech thread for that reason. If someone doesn't want to take part in that discussion then feel free to ignore it.