Would Venom Vents void Mercury warranty?

[zyphyon]

No cowl test for those that asked on a 300R. I will be testing this summer using the same cowl run on my 450R on a 300R. This modification performed as shown on my 450R. As I mention in the video, the super charger sound was worth it alone. I own two cowls, so can swap as needed. I ran this cowl all summer. I really liked the sound and the looks of it. The boat was fast enough, it didn't really need to be faster. I keep the plugs in the boat for towing in the rain if I get caught out, but I run the stock cowl if rain is in the forecast. I'm making my own ram air center hatch cover scoop to test this summer. I'm curious about how the performance of that design differs.

[QUOTE= I'm making my own ram air center hatch cover scoop to test this summer. I'm curious about how the performance of that design differs. [/QUOTE]

Rockbottom Designs here in Texas has a replacement door assembly scoop. I believe the owners name is Jimmy, has some pretty good data on running them on the 450r and 300r.

[mactlman]

love the color above! a wrap I am guessing?

[fishnfireman]

love the color above! a wrap I am guessing?

If you're asking about the blue on gray Allison its not a wrap.

[rocketmanjp]

If you're asking about the blue on gray Allison its not a wrap.

I think he’s commenting on the gray & black Merc 300 ProXS!

[mactlman]

I think he’s commenting on the gray & black Merc 300 ProXS!

yes, the merc colors

[kllr bee]

Angleiron, If you're straw was pulling air through a smaller straw it would be the volume that the smaller straw would handle. If a motor runs better with more air it means it is designed to handle it. You're trying to sound technical but missing the mark.
Richard aka Kllr Bee

[Tim Powell]

I can tell you that we have removed the service door and gained 1 mph and 100 RPM on back to back passes with a 300R.

We ran a stock cowl and a cowl with venom vents back to back. The boat ran 96.5 mph at 6150 with the stock cowl and 97.5 @ 6250 with the vented cowl.


I run the venom vent cowl on my 450R and the supercharger enjoys the extra air.

[lpugh]

The computer is designed to take the air intake and match with fuel output and be efficient. More air and more fuel makes more fun efficiently. Look the product up and watch the video. Those intakes make a big difference.
Richard aka Kllr Bee

Only on systems that use air flow sensors, as far as I know, mercury does not on any application as they are speed density systems. Also motors with o2 sensors do no use its input for high load conditions, another words the computer operates in open loop mode ignoring the o2 sensor.
Be very careful when improving air flow on any speed density system, as fuel mapping must be modified to compensate for more air.
Not sure about Verardos or the new 4 strokes.

[yam911]

Does a speed density system use manifold pressure and air temperature to determine the quantity of air?

I would think more air flow would result in a higher manifold pressure.

[zyphyon]

Does a speed density system use manifold pressure and air temperature to determine the quantity of air?

I would think more air flow would result in a higher manifold pressure.

The down and dirty of it is, Speed density systems work first by measuring the temperature of the inlet air and then the manifold pressure via a manifold air pressure sensor, or MAP sensor. They then calculate a density of air with which the ECU can calculate how much fuel it needs.

[lpugh]

Does a speed density system use manifold pressure and air temperature to determine the quantity of air?

I would think more air flow would result in a higher manifold pressure.

Barometric air pressure, intake air temp, manifold absolute pressure, RPM, coolant temp and throttle position

[lpugh]

Does a speed density system use manifold pressure and air temperature to determine the quantity of air?

I would think more air flow would result in a higher manifold pressure.

Look at this way, air flow is determined Soley by the difference in pressure between the surrounding atmosphere and manifold pressure! air pushed by the differential difference, not sucked in. This why we work with absolute pressures instead std pressure gauge readings which are set to read when the absolute pressure at sea level is 14.7 psi. The throttle valve controls the difference as well as a lot of other things that effect flow rate which is another subject.
.

[yam911]

Assume the throttle is wide open. Cowling on. Cowling somewhat restricting the flow due to the size of the air inlets.

Atmospheric pressure is 30" Hg. Due to the cowling being on and other normal intake pressure losses the manifold pressure is 29 "Hg.

If removal of the cowling removed the restriction to air flow, such that the manifold pressure increased to say 29.5" Hg, should the motor make more power?

[lpugh]

Assume the throttle is wide open. Cowling on. Cowling somewhat restricting the flow due to the size of the air inlets.

Atmospheric pressure is 30" Hg. Due to the cowling being on and other normal intake pressure losses the manifold pressure is 29 "Hg.

If removal of the cowling removed the restriction to air flow, such that the manifold pressure increased to say 29.5" Hg, should the motor make more power?

If additional fuel is added, yes. if not could result in a blown motor due to lean run.
Slightly lean can make more power due to faster burn rates, butt can cause damage because of that fact. Can lead to preignition and or detonation.
Motors with air flow systems would compensate within the limits of the fuel mapping table, speed density calculate air flow based on known values, The pcm does not have any way of knowing there was an increase in air flow.

[yam911]

My thought was the added air flow would result in increased manifold pressure. PCM knows the pressure via the pressure sensor. PCM would increase the injector on time to add the right amount of gasoline.

[lpugh]

My thought was the added air flow would result in increased manifold pressure. PCM knows the pressure via the pressure sensor. PCM would increase the injector on time to add the right amount of gasoline.

It will be based on pressure only, It does not know about the increased volume which determines the air fuel ratio. Pressure is no indication of CFM though it does have some an effect on it.

[kllr bee]

Howbout we put it this way, would a motor run better at sea-level or in say a mountain lake at 10,000 feet elevation? ��
Richard aka Kllr Bee

[lpugh]

Better with one Bar of forced induction if on the lake instead of in it

[yam911]

Howbout we put it this way, would a motor run better at sea-level or in say a mountain lake at 10,000 feet elevation? ��
Richard aka Kllr Bee

Sea level means better performance. Manifold pressure will be higher. Normally aspirated motor.

Higher manifold pressure equals more air equals power. With the appropriate amount of gasoline of course.

[lpugh]

keep in mind volumetric efficiency ( VE ) which is just one of the tables for mapping fuel curve, at 125% ve you can very well have the same pressure as at 100% ve, needs more fuel at 125%. Porting, air restrictions, exhaust tuning all effect ve which have to be accounted for. This is one of the most important mapping tables in the program, VE skyrockets with forced induction.

If ve is increased it does not mean pressure will up, it can actually go down a little, pressure and volume are related but not absolutely in a linear way.