funguy

I know this is an odd ball question. I'm tossing around the concept of using a 127mm electronic ducted RC fan system made by XPS and mount it to the exhaust inlet of the turbine housing of a medium sized "real" turbo and mount this to my gt mustang. the thought is to use 30 + lbs of thrust to spool the turbo instead of using exhaust from the car to spool the turbo

This 127mm XPS fan can produced well over 30lbs of thrust, I have been in contact with the engineers who developed this setup and they claim unofficially 40+ lbs of thrust, all depends on the power source /amps. For this topic nevermind the power source , it will be a car battery setup in the trunk with a trickle charge back system to keep all 4 of the deep cycle batteries charged.
http://www.xtremepowersystems.net/pr.../newmotor1.jpg
Here is a pic of the EDF unit, I want to experiment on mounted this to the exhaust inlet of a medium size turbo and run some test to see if the compressor side can produce PSI.
MY goals in this experiment would be to..

1: mount a "real" turbo closest possible to the intake of my 07 gt mustang with the shortest compressor piping possible.
2: build a electronic components to have the EDF unit blowing air at a constant rate all the time untill i step on the gas at which point the electronic system will fully engage the fan at full thrust of 40+lbs and spool the turbo.
3: or... I would consider having the turbo spooled full time and rely on a boost controller and a waste gate combo to controll boost.

I just wanted to get engineers opinions on the exhaust turbine, what type of energy is required to spool a turbo powerful enough to create boost?
before you

oh ya,, item 4.

I was thinking about just mounting the 127mm EDF unit on the intake by itself,, but not sure if it will create psi

here is a vid from utube about the 127mm motor fast forward to 10
http://www.youtube.com/user/billyd44...91/tCRat-GVPUs

thanks

busa4

Exhaust gasses near the cylinder head travel at a speed of ~700 ft/sec. A turbo can spin at an astonishing 100-200k rpm. To get a blower to replicate this maybe impossible or very expensive.

funguy

i experimented with an 2003 evo turbo i picked up for 80$ on craigslist. nothing special it has journal bearings and it twin scroll. my i first test was to spin the turbo using a shop vac with the thrust hose mounted to the exhaust inlet. this next to produced nothing.
I then put the shop vac back to its original configuration as a vacuum and connected the hose the the exhaust exit side of the turbo and turned the shop vac on that really spun things into motion. The compressor wheel started blow lots of air.. So i connected the compressor wheel to 1 foot pvc pipe and hooked up a boost gauge and I was surprised I was getting 1 psi with the shop vac sucking air out the exhaust turbine. Im now rethinking the whole concept and I'm considering using 2 high amp shop vacs and connect the suction pipes via a "Y" pipe and see if I can increase the vacuum on the turbo.

busa4

of course its going to produce pressure.... theres nothing on the compressor side using the air your putting through it. with it connected to an engine, the the vacuum pump is not going to spin the turbine enough to generate the cfm needed to create boost. you need to exceed the engines naturally aspirated cfm in order to create boost. the most power your going to make is maybe 10-15hp which is a waste of time and money for the work performed. you can get that kind of power increase from a header and/or k&n filter.

funguy

i drilled a 1/4 in hole at the end of the pvc pipe cap to simulate usage. the important thing to me is the air was warm which indicates to me some level of compression

valkyie

You are wrong about how the turbo makes boost. The output of the turbo does not need to exceed the engines cfm requirements to make boost. A turbo is an internal compression device because it makes its own pressure. When the air is drawn into the turbo it is slammed into the inner walls of the compressor housing squeezing the air together thus pressurizing the air.

More cfm means that the turbo can deliver pressurized air throughtout the rpm range. I have also been working on a similar project. I am using a custom blower that puts out 6lbs of thrust at 12V. More thruts you have the faster the impeller will turn. Most likely I willl have to go to 24V for a faster speed. I am using a centrifugal blower because puts out more kenetic energy at less power requirements then a axial fan ( EDF ).

funguy

oh wow very cool can you post pics?
I have now changed up my design. I bought small twin turbos and I will be doing a twin remote turbo on my mustang. I will be replacing the muflers with the turbos and mount them in their place. I have 2 electric fans and will be building an electronic assisted remote twin turbo system. the fans will help pre-spool the turbos before i step on the gas. Hopefully i wont need the electronic assist and the twins will do just fine.

busa4

LOL! completely wrong. yes the turbo creates the pressure but without a restriction (the engine) there is no pressure made by the turbo. it will just push air with no pressure. you sir, must have failed physics. pressure is the direct result of volume. if more air volume is trying to enter the engine than the engine can use, pressure is created. good luck on your theory. im sure many colleges will jump at the chance to grab you.

valkyie

Yes you are right but at the same time wrong. Yes a turbo does make a slight pressure differenial when more cfm produced by the turbo exceeds the cfm requirement of an engine. That most likely happens at peak compressor speed because at low speed the turbo is not putting out enough air. But the turbo by itself alone produces pressure. Look at a turbo compressor map it proves that a turbo puts out so much pressure at a given air flow rate. A turbo draws in air and converts high speed low pressure air into low speed high pressure air. So the turbo is the main force behind making the pressure in an engine and the additional pressure that is created from the cfm build up is just a byproduct.

Maybe you are thinking about how a root supercharger works. Research the term Dynamic Compression to get a better understanding how a turbo works.

busa4

just like the turbo, the engine also produces different cfm at different rpms. compressor maps are designed to allow you to pick the correct turbo for you engine application. each engine is different and the main calculation on a compressor map is pressure ratio. this pressure ratio is a calculation of a specific engines airflow.

yes. the turbo compressor makes the pressure but it cant make pressure unless there is a restriction. your saying reguardless off the engines cfm usage, the turbo makes pressure? if this was true, you would be able to disconnect the boost line from the turbo compressor and the turbo would still be able to make boost.

the pressure created from the turbo is not a byproduct. the heat created by the pressure is a byproduct. the pressure is needed to exceed the engines cfm usages. if you dont exceed the engines naturally aspirated cfm usage, then all you have is a naturally aspirated engine.
by pressurizing the engines intake you are essentially adding more air(cfm) than the engine can suck in from natural aspiration.
this is what creates the pressure because its a restriction. the volume of airflow(cfm) the turbo is pushing is larger than the engine can use. the turbo continues to push the air even though the engine cant take in anymore. once this happens the turbo is no longer pushing air, it is now compressing it, making pressure. this pressure now forces more air into the cylinders than before. and this process keeps going on and on until the pressure increases to the wastegates psi spring limit or until the throttle is closed and the pressure is vented/recirculated.