Ram air vs rejetting carb

[Wevil Knievel]

You are not well enough informed on this subject and therefore just don't get what is being said here, Neither the carb nor the engine suck in air/fuel, atmospheric pressure rushes in through the carb body when the port or reeds open due to the case pressure being lower than that of the atmospheric pressure outside of it, the outside air is not drawn away from the carb in a vortex or vacuum or ever air speed around it because it's NOT moving fast enough nor does it have the pressure to over come the atmospheric pressure so the only fight here is you beating a dead horse not understanding the facts! Your gains though small are very easily explained since you've unshrouded the carb of it stock cover the volume was slightly increased which is normal and to be expected, put a more restricted air filter on and you'll lose that volume gain it's really quite simple!

I do not doubt you sir. Obviously you are better versed in this than I. Maybe my anomaly is due to the shape and design of my bike and the way I ride. But I cant explain 6 mph difference with and without it. Maybe its over jetted and the air fuel mixture is giving me the extra speed?

It doesnt blow directly into it it catches the air and "scoops " it to it. Its not a closed sealed system . As you can see by my pictures it open at the carb because I figured that it wouldnt run correctly due to the low level vortex needed to sustain idle being my scoop being so large and long.

I think the confussion comes from my lack of proper description of what I was referring to.

A ram air system is closed from scoop to carb where as an air scoop merely aids in diverting air so as to be taken up by the carb as needed.

Correct?

 

[Wevil Knievel]

You did do this, Right???...lol...DAMIEN

Yes its just not shown.

 

[Street Ryderz]

I do not doubt you sir. Obviously you are better versed in this than I. Maybe my anomaly is due to the shape and design of my bike and the way I ride. But I cant explain 6 mph difference with and without it. Maybe its over jetted and the air fuel mixture is giving me the extra speed?

It doesnt blow directly into it it catches the air and "scoops " it to it. Its not a closed sealed system . As you can see by my pictures it open at the carb because I figured that it wouldnt run correctly due to the low level vortex needed to sustain idle being my scoop being so large and long.

I think the confussion comes from my lack of proper description of what I was referring to.

A ram air system is closed from scoop to carb where as an air scoop merely aids in diverting air so as to be taken up by the carb as needed.

Correct?

It just allows for the max volume to pass through the carb rather than being restricted by a cover and low flow filter, this is not uncommon to gain some power and speed with a proper tune and setup, I build stock engines that will do 50 or close to it quite often with some of those being back in 07-08 when there really was no aftermarket goodies to be had anyways LOL, I've still got a 50cc porting just cleaned up all stock (it's from 08) that out performs many of these later 66-69cc engines by far and does 50 stock gear and 26" wheel, faster when my son rode it being so light he accelerated and unloaded it faster than any of the 66's he ran against, that one also used a speed carb and 70 jet and all I used to do was drill 8-10mm holes on the face of the cover for more air flow, have a video of it on here somewhere climbing my test hill with no pedal chain attached to prove thte engine was gaining rpm on it's own climbing a very steep grade starting from the base of hill. I don't really get where this low level vortex you mention as that's not a thing at idle nor does the size of the scoop really matter, I currently used a 24mm carb on my modified 66 and many tried to tell me that that was way too big and it would have no velocity at and just off idle to about 1/4 throttle and then many would say my intake track is too long being almost 8" but no they just didn't understand that a tuned intake track and port's that actually all match that track not just hogged out or raised timing but actually all meant to flow the 24mm's volume work's perfectly as I turn a 26" wheel with it on a heavy bike and my 200lbs with 11/30 gearing so that I can cruise at 50 comfortably while still able to climb hills (as can be seen in my videos) and run sub 20 sec 1/4 mile times, so I'm a big believer in what all the decades of experience and dyno time the masters have passed down, and when we want the best results doing it right following these proven practices pay's off with big smiles, your enjoying the ride and that's the best part!

 

[Chop-chop]

U first need to understand how air flow behaves - it spirals into a port, in order to increase the velocity of the flow, u need to initiate it with a funnel shaped entry point ie 'velocity stack'. By doing this, as the rotation go from a large circle down to a smaller circle as it enters the port, the speed of the flow is accelerated.

 

[Street Ryderz]

U first need to understand how air flow behaves - it spirals into a port, in order to increase the velocity of the flow, u need to initiate it with a funnel shaped entry point ie 'velocity stack'. By doing this, as the rotation go from a large circle down to a smaller circle as it enters the port, the speed of the flow is accelerated.

Have you ever used or seen a flow bench used ? Ever seen a see through carb functioning which it's self is a venturi ? This whole topic is BS because the velocity and it's carried volume is metered by the body of the carb then the jet used, as it enters the case it's suspended/stalled not a constant flow into the cylinder, and not all that passes through the carb actually enters the case these are the facts backed by the physics so your ram air doesn't do what you think!

 

[Karl Snarl]

In a world of pure imagination, come with me and you will see, pure imagination............. Oh Wonka got his imagination going here on the forums. I love it. Lol

 

[DAMIEN1307]

In a world of pure imagination, come with me and you will see, pure imagination............. Oh Wonka got his imagination going here on the forums. I love it. Lol

It seems like this so-called "ram air" crap never dies...lol...It's just a motorised bike version of a glorified "Hood scoop" guys...lol...Thats all it is...DAMIEN

 

[Karl Snarl]

It seems like this so-called "ram air" crap never dies...lol...It's just a motorised bike version of a glorified "Hood scoop" guys...lol...Thats all it is...DAMIEN

You couldn't be more right. It's just like the hood scoop guys. Thinking their 200hp Camaro is making 250 hp now, all because they added a hood scoop.

 

[Chop-chop]

Have you ever used or seen a flow bench used ? Ever seen a see through carb functioning which it's self is a venturi ? This whole topic is BS because the velocity and it's carried volume is metered by the body of the carb then the jet used, as it enters the case it's suspended/stalled not a constant flow into the cylinder, and not all that passes through the carb actually enters the case these are the facts backed by the physics so your ram air doesn't do what you think!

No? I have experimented with different length and shaped velocity stacks mounted to the ends of my old twin Weber carbs and multi-throttlebodies, in these cases, different shaped funnels were the only variables AND they produced different torque curves on the dyno. I go by my 25+ years experience in blueprinting and tuning engines and the results speak for themselves. If you really want, I can provide you with university text references in this field to support what I'm saying.

 

[Karl Snarl]

I'm wondering if you are mistaking velocity stack, with ram air systems? A velocity stack works by increasing air speed by funneling the air into a smaller and smaller area. They come in styles ranging from a trumpet, to a little metal block with a cone shape hole.

A ram air system is used at high speeds, when you can actually get a slight increase. Nothing to write home about, unless you happen to have ram jet engines. Then you use the effect as the engines compressor, but you have to have an adjustable nozzle to slow the incoming air, or you just blow your engine apart and what was a plane just pummels down, down, into the ground.....