Considering the author of this thread is making over 500 at the wheels with stock intake, you should be fine. Even if I had to give up 5hp I would keep it for the driveability.

 

I think some people are confusing "Vacuum" with the sucking motion of the turbo injesting air. This is not the case as the air entering the turbo is at 14.7 psi of pressure on a standard day. A TRUE vacuum is a lack of any air....

 

Don't need to. Blow across the top of a straw. It will suck up liquid due to the Bernoulli effect. You don't need "restriction" to generate vacuum.

I think someone is confusing density with pressure. In the same moving gas, pressure is very different when measured from different directions. Density is more or less constant. (As long as the mach number is low, etc.)

There should be a pressure drop with, or without, restriction. If a device does not measure any, it is not sensitive enough, not placed correctly, or not functioning.

 

Yeah, there has to be some. Just as current flows due to a potential difference, fluids flow due to a pressure difference. But the tests your friend did with his Viggen show that, at least up to some point, details of the intake just don't matter.

Dave

 

I mentioned ealier that the MAS was good to something 57-58 lbs/min. Just looked it up, and found logs of it reading cleanly at over 60 lbs/min, with estimates of it's capacity between 62 and 66 lbs/min. How much power you make with that 60 lbs/min is up to you (setup, fuel, and tuning), but the rule of thumb is 10 hp per pound, and wrung out on race gas that seems to always end up being accurate. But it is variable. I would definitely agree that is is safe to say it will support 450 whp though.

I'm glad I looked this up, it's encouraging news. I was hoping to stay on the stock MAS as long as possible.

 

Agreed

 

stop post whoring! someone delete this guy's clutter.

 

This is not a hard debate... it is a restriction... plain and simple.

Can you see anything inside the hole... yes (A large honeycomb). Is the turbo fluted straight to the atmosphere... no.

Now does it cause a series HP loss... most likely not at any level it can read accurately to.

I crushed mine from vacuum and my car is most likely in the 550 hp range.

If someone wants to send me a decent electronic sensor (Preferably 0-5 volts) that can measure in/mg accurately down to say 1/10 of 1 in/mg I would love to test the actual vacuum and post it up with and without the MAF. I will do so at boost starting at 20psi and do more and more tests up to 35psi of boost.

Also, for those that dont think a tiny restriction could matter, well it does. Mainly because you are compressing that air... minus a small amount in front = alot in back.. it gets multiplied. On top of that, it pushes the turbo farther into its effective range (RPM) because it needs to spin faster to hold the same amount of boost).

 

see... i have to beg the question, if it can crunch due to the flow... how the hell can it not pose a restriction???

 

just the mass amount of air passing by the hole in the intake will make a vacuum of some measurement. The valve cover breather line to the intake creates a little vac. every car that i have modified with the stock intake sucks oil into the intake and once i remove the line and replace it with a little K&N breather, oil stops coming out of the little breather what was moving the oil? the vacuum.

 

Some of us DSMlink users jack the evo mas for its higher metering (about 20% greater than a stock 2g mas). It has been logged at 62 lb/min of airflow with no signs of over run. They are pretty close to being maxed out at that level.