It seems logical in that when boost is off, the intercooler acts as a hindrance to free flowing air. I figure that a butterfly valve set up could divert the air around the intercooler through a hollow pipe regulated by a thermostat. Considering most driving is done 'not on boost' this free flowing engine would surely give better mileage and would increase the motors lower rev torque......whatdya think?:unsure:
Most driving done off boost???? really?? wow, if I had a TT, it would see boost quite often.. How can you drive around without hitting boost at least once??? Dont the turbo's start spooling at something like 2500-3000 rpms?? That rev range is easily reached when driving very very sedately, let alone if you need to overtake someone or need a bit more accleration. I'm not a turbo expert, but it sounds like a bad idea to me. Cheers
Jedi I knew this one would escape you.. The idea is that it runs through the intercooler when it NEEDS to..dork
ease up buddy.... no need to call me a dork. I'm no expert and am the first to admit it. I still dont fully understand how your little setup would work with its butterfly valve and thermostat and am genuinely interested in how it would work and if you could explain it to me.
Boost doesn't rely on your rev range as much as your foot on the pedal. If I really wanted to I could drive to work and barely ever see the positve boost (but that would be no fun) :zlove: Once i've hit the speed limit, its happy sitting around -16psi so long as the road aint uphill
Doesn't sound like a good idea to me! Even when not making boost, the air is still going through the intercooler - therefore still being cooled which is more optimum than a little bit of hindrance. Unless you're running a truck core or are using pipe the size of a garden hose, piping and the ic shouldnt hinder flow that much - not enough to warrant trying to rig something up IMHO.
Its self explanatory old mate..... The air only needs to travel through the intercooler when the air coming out of the turbo is supercharged and extremely hot. When the turbo is not supersonic the air passing through it is relatively cool and doesnt need to be cooled down any further thus it can bypass the restrictiveness of the intercooler and get straight to the intake plenum. When the motor hits any boost level the air is diverted through the intercooler but when not on boost it can flow freely to the motor.....
Throttle lag is directly related to the intercoolers.... of course theyre restrictive AND they create loads of turbulence further reducing the free flow of air to the motor.
Your idea has some merit but...... the complexity of such a system would probably far outweigh any possible gains. The intercoolers also cool "non boost air" as it passes through. Any mechanical device in the pipes is a probable hindrance to flow as well as a possibility of failure. What would be the purpose of the thermostat device in your bypass pipe ?
The bypass pipe runs in the same direction as the intercooler ducts straight through the 'up' pipe to the lower intake plenum. The thermostat would trigger the flap valve to redirect the air through a fork in the piping leading to the ic or the bypass
I can see Merit BUT how does the Air Flow Meter (AFM) work with this ?? I actually think I have an Air leak somewhere in the turbo/intercooler system..... I get a flutter in the (aftermarket) Boost guage...when gently boosting and when I floor pedal it the boos goes to almost 1 bar then drops back...... if you start bypassing the intercoolers it could REALLY play with flows and Mixture....
I'n no expert either but if you got the diverter v/v setup, the air in the pipework and IC would stop moving. So when you wanted to go on boost again, once the diverter v/v opened all that stationary air would have to start moving again. wouldn't this increase the amount of lag. Another thing that I just thought of is this. the stationary air in the IC would be cooled to a lower temp than when it is flowing through the IC normally. How is this variation in air temps going to effect the running of the engine. I don't know if the ECU is setup to control this sort of fluctuation correctly when everything else would be running at normal temps. I have no idea what sort of temp difference there would be. would it have an effect from a thermal shock point of view on the engine internals. Any gurus out there. regards bollie7
imagine that little metal flap on a truck exhaust... it has only one movement. open or closed. A flap valve flicks in an instant from open to close or in this case from one side of the fork or the other...the air does not stop it just changes direction. As to air temp fluctuations the Ecu's lambda (closed loop) would sample the air temp and adjust itself accordingly
One major fault in this theory, no thermostat that I know of> would be able to react quick enough to changes in temperature, and therefore your little flap/door would be opening and closing way out of synch with the throttle/air temperature changes. If your thermostat was located inside the pipework, it would cause massive turbulence, if it is located outside the pipework, then there would be a need for a shaft of some kind, for the flap to be attached to, this shaft would be one more place for a boost/air leak IMHO.
One last problem... is if somehow your flapper gets stuck or malfunctions and your running boost with no passage through an intercooler then bang goes your engine.
The only time i've seen a butterfly type setup in an aspirated car is on a super/turbo charged car, used to switch off supercharger (reducing load) once the turbo is making sufficient boost, even in this case it might not work as well as it sounds. To make such a setup just to bypass the intercooler would be a waste of time. You mentioned the intercooler causing turbulence, what makes you think your t piece where your flap is joining the bypass system will not cause lots more turbulence then what a intercooler could cause. When it is shut and going through the intercooler path the compressed air flow suddenly reaches a section where it is trying to go two seperate directions but is blocked off from one so goes to the other. Im no expert in air flow but its quite obvious that the original straight pipe would cause far less turbulence. If the difference between pressed and mandrel bends are that big imagine this t piece join of yours. If you really are that concerned about 'lag', consider water to air intercooler. They dont need to be large and will only require less the 1m of intercooler piping, it should have next to no lag because your the travel from turbo to throttle is so close. Cooling should be very good provided you do an appropriate setup.
Humbug?...You're the one advocating the invention of "Flubber", not me. Show me where my suggestions are wrong, Einstein!:LOL:
