[Diy_efi] This turbo assist stuff, suggestions

[Matt Porritt]

You my friend have 
a) got too much time
b) smoked too many drugs in your youth
c) are a smart cookie ;)

Why not use a properly sized exh housing with a BB core and a modern
compressor design?

Modern GT turbos can spool as low as 7psi @ 2200rpm on a 2l and produce over
400hp.
Quire frankly I don't like boost that low so I'd go bigger, and nothing is
simpler that a quick wiff of nitrous setup on pressure switches to get a
massively oversized turbo up and away ;)
-- 
Matt Porritt
RC Race Cars and Supplies
ICQ #22776813


On 31/12/02 5:36 PM Mike wrote

> In reference to all this stuff about assisting the spool up of turbos,
> presumably for fast takeoffs and gadget value, what do people think of
> this dual approach (a=motor, b=boost):-
> 
> a.    The "Motor" part,
> Engineer the compressor plate to make it the rotor of a brushless
> (induction) motor - by placing polyphase windings behind it and
> driven by a 2 - 5 Kw motor driver, which could work as follows:-
> 
> 1.    The compresor plate is your classic induction motor rotor
> 2.    In 'normal' mode, the motor is off and the compressor
> plate at idle would spin as per normal and accelerate as
> per normal when foot placed on pedal. Eg. I observed my
> little T3 spinning at 300 rpm when engine at idle.
> 3.    In 'power' mode, brushless motor keeps the compressor
> running at a higher speed in readiness for planting the
> foot - such as a 10,000 rpm - but not for long as the comp.
> housing will get 'warm' and the windings likewise. In this
> mode induction motor at say 20% of rated and exhaust pumping
> away nicely.
> 4.    When pedal to floor (during 3 above), full power to induction
> motor windings! So the comp is boosted as fast a possible
> by the induction motor and exhaust gas.
> 
> *and*
> 
> b.    The "Boost" part,
> Compressed air is injected tangentially to compressor plate to
> also aid in spinning up with an extra injector to add the correct
> amount of fuel (slightly) rich to match the air injected. Some
> issues are:-
> 
> 1.    Compressed air feed via PWM injector to ensure control and
> of course to prevent over-spinning that poor turbine.
> 2.    Motor control and Boost control would work best if integrated
> to the same controller with feedback on turbine speed, this
> could also datalog the operation quite effectively.
> 3.    If there is enough power from (a) above and the compresor
> air injection is also 'optimum' - I would expect the turbo
> would act much like a one-way valve such that large amounts
> of additional compressed air and fuel could be added without
> the need for nitrous or special fuels.
> 4.    Having a tank with compressed air would be helpful which matches
> the 'boost spurt' people are looking for at launch, with a water
> trap and cooling so the compressed air can be cool enough to
> resist the detonation point - ie. It chills as it expands.
> 5.    A cheap way to get compressed air is to use one of those
> scuba tanks that hold 5000psi or so (need a regulator) from
> a scuba outlet - costs $5 to refill.
> 
> Comments ?
> 
> rgds
> 
> mike
> 
> 
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