RX200013B

anybody seen those hilex thottle body spacers w/ like a threaded center? what if you took a housing and ported a swirl into the runner of the housing? would it hurt the flow, or help? my brain thinks about random stuff when at work.



thanks Scott

sen2two

although i have never tryed it....



im pretty sure it would seriously hurt flow.

RX200013B

THOSE spacers say that they help volicity and itomization, plus torque! i dont understand how it helps when under the throttlebody going into the intake, if it is "spinning" the air after the throttle, spining air in the intake chamber it still wont spin the air though the intake runners. but if "spinning" the air will help volocity and itomization, then "spinning" the air into chamber would most effective? would it come down to much restriction in the air flow to get the air to "spin", my thoery is to grind in small grooves in the side plates to imatate the swiral.







can anybody ask Ito, or Lynn to put me back in my place!

sen2two

theres a reason why people polish runners. smoother surface = better flow. piston or rotary, dosnt matter...



would you rather slide across ice, or a rocky path?



if you use one of those spaces that create a "swirl" it will swirl it all the way to the combustion chamber. if it infact does anything at all. there a cheap cheasy way to get people to spend there hard earned money. most of them just create unwanted turbulance and block air from getting to the engine.



dont worry about trying to "spin" the air. just try and get as much air and fuel into your engine as possible.

j9fd3s

i would say a side port rotary doesnt need much swirl, the turn into the chamber plus the rotor moving is gonna do that for you

Lynn E. Hanover

Well, causing the spin would cost you velocity, so you are trading energy from the flow speed for energy in the spin less the drag form the direction change. The centrufugal component would increase along the walls so surface drag that increases with

square of velocity would increase. The increased energy would help maintain atomization if that had been a problem.



In general the idea is to relieve you of your hard earned cash. If this worked, one of them would be installed on every car coming out of Detroit. They cannot pass up a cheap performance or mileage improvement.



The incresed drag would slow velocity at the port face and reduce the charge volume for each cycle. The first rotaries all had Pports to maintain the highest velocity at the port face. Even the side port engines pay a penalty for those 90 degree turns in their inlet tracts. As soon as there is an increase in the port face area, velocity slows (Bernulli) and the charge volume goes down. So, when you raise the closing line, and port down a bit, and out a bit to increase the open degrees, what are you also doing? Slowing the charge right where you would want the highest velocity, after the turn has removed energy from the flow.



So, the ideal inlet runner would start at the tuned distance for the RPM you want the help with, and there it starts with a handsom bell shape, like the end of a trumpet. A larger than avarage tube diameter to reduce velocity and resulting surface drag, away from the port. Then about the last 30% of the run would taper to the runner shape in the iron. So the runner length with the very highest velocity is as short as possible. The tubing would have a chrome like finish on the inside.

The high speed injector would be centered in the bell. The low speed in a shallow angle just outside the port, on top of the tube. The engine would be a Pport, modified for 10,000 RPM shifting. With a modest port size, it could be a smooth street engine. NA of course.



Everything between here and there is a compromise. Use as few as you can get away with.



Lynn E. Hanover



Its 11:00 PM. Where is your TDC?

Old Grey

Lee is right

Most of the big engine builders in the piston world check swirl to make sure they don't have too much, the energy required to swirl the air reduces the energy that could be used to fill the chamber. I think fuel injection has solved most atomising problems





Why taper?, a straight pipe will have the approximately the same velocity in as out eg 500ft/sec in, 500ft/sec out. A tapered pipe will have the air accelerating eg in 500ft/sec, 700ft/sec out. This extra energy has the possibility to ram(simplified explanation) more air in the engine. Open your tap at home and close it gently, the pipes only slightly rattle, now open the tap flat out and close quickly, the pipes rattle more, thats the energy of the greater velocity pressing on the tap seat.

j9fd3s

these days the injector is a higher speed unit; the newer ecu's can open and close the injector 5 times per cycle. these injectors use higher fuel pressure and are going right in the chamber. mazda, mercedes, and audi all have systems like this.



results are things like the 06 mercedes 320 diesel, which is rated at 37mpg (it'll nearly get 40), and is 2 tenths faster in the quarter than the gas v8. while being quiet and smell free

Kyrasis6

Turbulance in a port is going to decrease volume getting into the cylinder, like said Turbulance in the port is never a good thing. Once the air is in the cylinder though turbulance is very good as it promotes more efficient combustion although some thermal efficiency will be lost in the increased amount of air and fuel comming in contact with hot engine parts.

mazdaspeed7

For the sake of argument, lets consider this, even though its only applicable to piston engines.



A heavy swirl within the chamber in a piston engine will force the fuel towards the center of the chamber via centripital force. Doing so allows for a leaner overall mixture than normally allowable because you can have a pocket of easy to ignite rich mixture near the spark plug, while its surrounded by a much leaner mixture, especially closer to the walls of the chamber. That rich pocket near the plug is also why direct gas injection is taking off. It still allows reliable ignition of an overall lean mixture because the ignition point is leaner that the majority of the chamber.



Back to the swirl, honda is very fond of that. Most of their 4 cyl engines from the past 15 years have different lobe profiles between the 2 intake valves on each cylinder. By biasing flow to one of the valves, it creates a swirl in the chamber. Honda even went to the extent of using vtec to almost completely disable one of the 2 intake valves at low rpm on the mid 90's civic vx. That car was known to get exceptional gas mileage, close to 40 mpg. At low rpm, one of the valves was opened just enough to keep fuel from puddling in the runner. At higher rpm, when power was needed, both valves would be activated by their vtec system.