1987RX7guy

iTrader: (3)

I have been looking at some mechanical boost guages for now to see if I can make a Ram Air scoop for the filter. Are mechanical good or bad?


This is going to be used for a second add-on product for our intake.


Santiago

dr0x

Mechanical are fine, the only advantage that electrical have is they use less vacuum line (vac source -> sensor, instead of vac source -> cabin -> gauge).

Cory Simpson

Ram air is a load, and is only working at very high speeds!!! And I dought it would push enough air to even register on a boost gauge.

RETed

Ram air systems barely make over 4psi of positive pressure.&nbsp Go find a pressure gauge that will read up to 5psi or 10psi MAX.&nbsp You're wasting your money buying a typical boost gauge that will usually go up to 15psi or more.


-Ted

J-Rat

iTrader: (2)

I cant see a Ram Air system causing too much positive pressure in the intake path, but whatever. I prefer the mechanical boost gauge.

Jarrett

1987RX7guy

iTrader: (3)

Thanks guys!


REted-when is your site comming back up?
If you need funds let me know. I will try and help you. I loved your site man.

RETed

The bank fucked up, and they can't bypass their policies.&nbsp I had to change my address, and they told me I need to wait 30 days before I can ask for another CC issue.&nbsp So right now, it's another 5 more weeks.



-Ted

Evil Aviator

http://www.vararam.com/reality_of_ram_air01.html

Turblown

iTrader: (12)

I am suprised it can make that much,wow. No wonder people say Ram-Air is forced induction....
But is this with a huge headsup ram air scoop or what?

Cory Simpson

Did you not read the link that evil aviator posted??? If you didn'y I will sum the amount of boost that it gives you. It said at 100 MPH that it gives you .176 PSI of boost. And I am thinking that would equal about 1/10th of a HP. And there is no way in hell that will register on a boost gauge.

1987RX7guy

iTrader: (3)

Corry you seem to not get what the point of ram air is. The article goes on to explain some advantages of ram air and how it helps the intake be more efficient:


Psi, Air Density, Flow Rate and Horsepower
All of these effect one another, however, all do not have to be present to make Hp (Psi is not required). First, let's go over what you will need to use to measure manifold pressure. You will need a boost gauge that reads below 1 Psi. Some use a millibar gauge. Others use a laboratory grade electronic manometer that reads as low as .001 Psi. Some of these devices can be configured to read in both values. The reason is simple. You need to be able to measure as low as .001 Psi accurately because you are looking for .10+ changes in manifold pressure and a typical boost gauge will not indicate this for you. A typical boost gauge won't even move unless there are changes of up to 1 Psi, positive or negative.

In any engine as you go to wide open throttle (WOT) pressure is created in your intake manifold. The general assumption is that the motor is breathing or developing 1 atmosphere or 14.696 Psi. The motor, if efficient, will build to 1 atmosphere however this rarely occurs in any motor. What normally occurs is that the motor builds to a given pressure, somewhere below or equal to 1 atmosphere, and then begins to loose pressure under increased load. This loss of pressure is somewhere below 14.696 Psi. These losses of intake PSI are dependent on intake manifold design, camshaft profile, cylinder head design, compression ratio, the Rpm you are turning and the overall heat and frictional losses that occur. Usually on a stock motored 2001 LS1 the pressure loss is about -.75 Psi and it's costing you Hp. A totally stock C5 can be below 1.1 Psi at WOT depending on the year. A Ram Air system is designed to draw or pack that pressure back in to the manifold. Well you say, what's -.75-1.10 Psi really worth? In order to give you this explanation, we will keep it simple but we will have to set up some control parameters. This is for Psi only; we will cover CFM and Air density later.

To factor your gain if using a ram air system, test your car with whatever intake system; stock or modified. Monitor the intake pressure on the dyno to give you your Hp/Psi formula. You may then proceed to road test monitoring the pressure increases if any to determine the true power and overall efficiency of your system.

The day: a textbook 14.696 Psi or 1 atmosphere.
The car: a showroom stock car, no modifications at all.

I will give you an example: a totally stock 2001 6-speed Corvette and a textbook 14.696 PSI day. These are rare but will suffice for this explanation. There will also be some variation from car to car as there are casting irregularities, deviation in cam lobes and overall build differences. This is why some guys get the ringer car and others well...fall a little short. This deviation will show up in the manifold pressures at WOT. So basically use this as a reference. The best way to see how well your intake system works is to dyno your own car whether stock or modified and measure the manifold pressure at peak and then the drop at higher Rpm. This will give you a good base to use these formulas. You must remember that the on-road losses will be greater than the losses on the dyno. Automatic cars will lose more than 6-speed cars due to increased loading in each gear.

WOT=13.946 Psi, that's -.75 Psi, car dynos at 310 Hp at the rear wheels. In other words, your car is losing this pressure under load and it will lose more under actual road and track loads. (For our explanation this will suffice)

The equation is simple. 310 Hp divided by 13.946 = 22.23 Hp/Psi. Remember that the car is -.75 Psi at WOT. So the equation is: 22.23 Hp x .75 = +16.67 Hp increase. Now at this point you are not into positive boost yet. You are only at 1 atmosphere (14.696 Psi). If you have an aftermarket intake system you would simply add the gains that you saw on the dyno to this figure for your total power at that speed and Rpm.

Now let's try a 99 6-speed C5 with its more restrictive factory intake system using the same control for the test.
WOT=13.45 Psi, that is -1.25 Psi, car dynos at 301 rear wheel Hp.
301 Hp divided by 13.45 Psi equals 22.38 Hp/Psi.
22.38 Hp x 1.25 Psi equals 27.98 Hp increase at 1 atmosphere.

fastrotaries

what a pitot tube, like the ones found on aircraft?