I barely even got the turbo to warm up. Plus I'm using Mobil 1 15w-50. The best [email protected]#$% stuff on earth. Just kidding. I'm do for a turbo upgrade at some point. A GT28RS seems to be the one I'm going to be looking into. I want something that can boost 30lbs pretty easily. I looked in VNT turbos but nothing out there seems to fit the bill at this point.spg1 said:Allessence,
Oh, and after floging your turbo, you didn't wait one minut before shutting it off.:nono; :cheesy: hehe.
So, what's the next idea? I'm very curious. Maybe this should be patentened.ShadowWorks said:My boss found the data in the program I left running over night as it runs thousands of audio simulation which takes hours to process, anyway he was not happy with me but after I explained what I was doing to the exhaust system and he showed some interest at this point.
That is fantastic. Your boss showing some interest. Sounds like a person whom has vast knowledge and likes a treasure hunt.
I told him I was trying to make the exhaust ports flow better so more air could escape, he said "Well you want the ports to go sonic then" what?
I didn't even pretend to know what he was talking about this time like a normally do, he basically said I missed out lots of parameters but 3 important variables in the program for the results to be meaningful in the real world were.
1.Sonic pulse. The sonic pulse is the supersonic pre explosive sound wave that travels just as the explosive energy is released. It's like a prewave and has the highest energy of all the waves. It is also the wave used in tuning exhausts especially in 2 strokes but also in 4 strokes. The pulse can and does expand and contract to the inside diameter of the tube it is traveling in without loosing my of it's energy. It is also a reflective wave. It will bounce off objects in the exhaust system. If you add a plate to the middle of the exhaust head it will reflect the wave back and a person can change the Valve to valve timing as well as port to port. Basically out and back.
2.Thermal Pulse. Thermal pulse is the pulse that is generated when the explosive gases reach max Thermal force/expansion for the given volume of container and is what makes explosives work so to speak. *1Also the gases around heat/flame/explosive energy become super heated in a matter of Mseconds. this energy also creates positive and negitive pressure areas and is related to both thermal pulse and gas velocity. The thermal pulse also only creates a return pulse (low pressure area) but it's minimal and is short lived and is usally at the beginning of the flame kernal.
3 Gas velocity/expansion rate The gas velocity can be low but the Sonic pulse can be huge. The P&P of the head will have a very large influence on these two as well as the manifold. *2, On a tube header if you make a header. Start with medium size pipe and either work up or down if not gettng the results you want. In the pictures you took, the exhaust kernal was coming out not only with an arrow point flame front but also it pulses forwards with front narrow to wider to narrow behind the main flame kernal. (read *1 again)
The sonic pulse is the fastest wave in the exhaust system and its behavior is related but different from the thermal pulse and gas velocity, ie it can take corners without a reduction in speed and return to the valve seat faster then the thermal or gas velocity, this is why exhaust systems are long, so the sonic pulse comes back to a closed valve and not an open one,
OK I get it, thats what I hear and I'm trying to tune.
The thermal pulse is a wave in the system, the 4 piston chamber may have a 2 liter total capacity but the expanding or vented exhaust gas has more volume, what goes in comes out fatter, I guess the universe really is expanding, lol, ok I get that as well.
The thermal pulse will only last for as long as the heat remains at a steady state. As the temp falls so does the thermal pulse.Also the longer the air around the pulse get's more contact it is also expanding and creating a low and high pressure area in front of it if exposed to ambient air pressure. If you can keep the heat in it, it will do more work.
The velocity is critical for a fast turbo recycling or spool I was told, and to maximize the velocity I should make a delaval shape exhaust port, *2 3rd bold paragraph. On a turbo charged car we use the Sonic pulses to generate the largest hit to the turbine. The turbine is driven by, Sonic pulse, stays the same pretty much, Thermal pulse gets longer/ thinner as it goes into the turbine housing but with much less force than the Sonic pulse. and then lastly exhaust velocity to a lesser or greater extent. depending on back pressure within the exhaust manifold. The sonic pulse isn't influence as much by back pressure as much as velocity is.
I removed all the imperfections from the cast manifold and there were a lot to my surprise, its made of chrome alloy so it really did eat my grinding stones and took 7 hours, I did not mirror finish the manifold as the waters wetting and boundary affect would overrule any benefit of polishing it seems.
A solid clear polish will keep the Sonic wave moving at a smoother pace than an area with roughness. The idea about water wetters, boundry effect has to due with fluid dynamics and eddy effects. As air/water passes over an object the area in contact grabs the air/water and creates a shear layer. This is where the outside layer starts to curl around on itself because of the friction generated. This has to do with gas velocity, more than sonic pulse. The more pressure fed thru the tube the greater the shear and the consequence of the eddy getting larger and as some point will start to interfer with flow toward the center of the tube. This speed is usually at the speed of sound. The sonic wave /pulse can actully clean the eddy's off the sides(not exactly) and create a smoother flow pattern. So, if the tube is absolutely smooth and once put into use will do 2 things to remove problems which can hurt performance. It will help to keep carbon from building up on the inside of the manifold and it will keep the pulse moving along instead of getting caught on reflective ripples. Also as the manifold gets used it wil get some carbon build up and create the small eddy/slip effect I beilieve you after.
The inside of exhaust tubes, 2 stroke expansion pipes must be kept burr, ding, and weld puddle free.
This is the kind of crap my head is full of. I should have gone to school to become and engineer.
I did sample your exhaust and Jennifer and it has very defined sound pressure wave, what size is your exhaust system? Thanks for the sampling. very neat. Will you be keeping these for future experiments?
This is your idle, it very, very consistent indeed.
This graph above was your acceleration phase, it has lots of amplitude which means high pressure and once again is very consistent, it looks like the sound energy is very even across your rpm range.
Is the highest point the initial firing phase and then the rest the end pulses? going form left to right? Not forwards to backwards.
Your camera was using a AGC with adjust the signal to the microphone so dont be surprised that its not off the chart in terms of db.
I have no idea what the rasping sound was to be honest, it could have been a wind noise effect or just the vortexs from your exhaust tip
Were is your peak power on a dyno graph 3200rpms? 4000rpms is max power and is where the exhaust sound changes into the air leaking sound.
I have a newer mad idea for the manifold but I need to see if its even realistic first, you will like this being a nut.
Hi spg1, He is really a she,Or I should say Allesence is a female, Jennifer is my name. I had thought my sign on name would have given the hint, but I guess I was wrong.spg1 said:Allessence said about his turbo that it has a crack in it may be what I have and what you hear. What do you think?
You need a recirc dump valve which is connected to the ex man, so when the throttle plate shuts the excess boost is dumped through the turbine.The EGR is perfectly place for an injector at the end of the manifold branches, the thermal pulses could ignite the extra fuel making a huge shock wave and thermal pulse that would smash the turbo giving instant boost, what do you think? I know I'm mad.
I am not sure how much oxygen is in the exhaust gas but I could in theory take a small diameter pipe off the turbos compressor side and use this to flush the manifold with air around the injected fuel?
I thought to test my theory I would use a surgical need with 5cc of fuel and just squirt it in.
Don't all laugh at once
Thanks man I just did after you posted the links, I thought I was just being silly:lol: So I don't need fuel, I just need air, this should be very easy to do?philb said:You should read up on anti lag systems
A mechanic rescently suggested introducing the ceramic core of my cat to a broom handle, he recond the testers would'nt be able to tell the difference.Over here in MA we have cats on any car produced after 1983 (84my) and are driven on the street.
http://paultan.org/archives/2006/06/28/what-is-an-anti-lag-or-misfiring-system/Rally cars use a different way of introducing petrol into the exhaust manifold. There are separate injectors that introduce fuel directly into the exhaust manifold. Some of this mixture will continue burning in the turbine and down the exhaust system, resulting in the flames and explosions you hear coming out of the exhaust muffler.
It's not to reduce boost. It's to keep the engine rpms in a range that keeps boost avalible at an instant. The greater the load the more boost the turbo will produce. This is why if you are just idling the car and romp on the gas the boost doesn't really go anywhere once it reaches ambient.philb said:As for left foot braking - its a skill well worth developing, its used more to adjust the handling of the car, theres not much need to use it to reduce boost, though I have tried this once.
Si you can get a fake CATSi said:A mechanic rescently suggested introducing the ceramic core of my cat to a broom handle, he recond the testers would'nt be able to tell the difference.
Sha, rather than using a stock recirc. you need an external WG, you just swap the nipple to the back of the diafram so it opens when a vacuum is applied to it, stick it on your inlet with it venting to the exhaust manifold.