Another_User

I was reading up on kpa differences at different altitudes, and it seems that you lose 1% for every 100 meters above sea level, and that works out to be about 1 kpa. Would that mean that you would gain 1% more power (roughly) for every kpa you can free up in the intake by increasing it's efficiency to allow as close to sea level as possible in your manifold at WOT? And even more if you can raise intake pressures with ram air, etc?

conan

iTrader: (5)

About 3 years ago I graduated from the pittsburgh institute of aeronautics,we had about a week of talking about this. I dug out some of my old books"faa aproved" ,hope this helps... Standard atmospheric conditions:59degF, barometric pressure:29.92 inches of mercury. See leval air pressure 14.69psi. Now for 1000 feet, you lose 1in of mecury and temp falls about 3.5degF. Another example 18,000 feet ubove see level is 7.34 psi of air pressure. Trying to answer your question I dont think freeing up air restriction Will give you more manifold air pressure. You are limited by your elevation and air temps. Supercharging is the only way to over come The dencity of air going in to a n/a engine. I Live in utah now and i sill keep my camaro in pittsburgh. I have driven the car out here once and i feel about a 50hp loss here in the higher elevation. Pitts ele 900ft Park city ele 6500ft.Watching the scaner on hptuner map pressure is less in utah than in pittsburgh. I hope this is what you were looking for.

Another_User

I don't expect it to give me additional manifold pressure. But any restriction in the intake that causes a vacuum will decrease performance, right? Because that would mean the cylinders are going to fill less. So if I remove any restriction and allow the intake manifold air to come as close as possible to the outside atmospheric pressure, then wouldn't I get the same benefit as if I used ram air through a restrictive intake to try to do the same effect? I ask this mostly because I have seen a 3-5 kpa increase since I removed my MAF (definitely a restriction). So theoretically my intake should be more efficient (not considering air temperature in this example) than a ram air intake with the stock MAF in place, because you are merely pressurizing the air on the side of the MAF facing the airbox, and then coming a little closer to atmospheric pressure past the MAF. My point is, before I removed the MAF my intake kpa was about 4-6 lower than the outside pressure at most RPMs, but now my intake kpa is 100+ up to about 5000 rpms (where I believe the TB is becoming my restriction...unless it is the air filter, but that would be easy enough to check).

Now if I install a LS6 intake it should be able to flow more air and cause more of a vacuum at WOT in my intake manifold due to increased efficieny in airflow to the cylinders from the intake manifold.

conan

iTrader: (5)

I under stand you alittle better now. You will see more kpa with a more free flowing intake. I thought you ment by freeing up air restriction whould bring air pressure ubove what it is out side.