RazMan
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| posted on 7/12/07 at 08:51 AM |
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Jet engine powered turbo?
I had an interesting conversation yesterday about a hillclimb car builder who has a novel way of boosting his Cossie engine, and I thought I might
start some more discussion here.
Apparently he has strapped a helicopter starter motor to a conventional turbo and force fed his engine with great success - 2 bar of boost can be bery
handy off the start line in hillclimb!
The helicopter starter is apparently a small jet engine which is in turn fired up with a conventional electric motor (might be 24v though) He drives
up to the start line queue and waits his turn, then at the last minute his swmbo appears to start the little jet engine to get the turbo up to
pressure and whooooosh!
Anyone heard of this before? I think he might have something there 
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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brycheiniog
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| posted on 7/12/07 at 09:00 AM |
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Have a google for the Mannic beattie...
Jonathan
[Edited on 7/12/07 by brycheiniog]
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BenB
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| posted on 7/12/07 at 09:04 AM |
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Doesn't that sort of miss the fact that the advantage of a turbo is that it is driven by the exhaust gases of the engine it supercharges? The
setup used means you have a 2nd engine (with all its weight, fuel tanks, ECU etc) to provide the boost... The only advantage I can see is that you
could have high boost levels without turbo lag (because you dissociated the turbo with the engine). However, unless you vary the turbines rpm (which
typically takes quite a long time, some small turbines have spool-up and spool-down times taking many seconds) you'll get constant boost
regardless of engine rpm...  Scary...
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Minicooper@work
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| posted on 7/12/07 at 09:10 AM |
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Yes ,
I have seen this car before at Gurston Down, I forget his name but he used to have a turbo V8 Minor as well that used to do very well.
It's certainly very quick but what a faff on to get the thing going, I have a few starts on my camcorder, if I can figure a way of getting them
posted I will
Cheers
David
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Ivan
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| posted on 7/12/07 at 09:18 AM |
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A simpler and more common way of achieving a similar result is to overfuel your motor at a high idle speed and greatly retard ignition so that some
combustion occurs in the exhaust - this also causes early high boost but sounds terrible but you get realy cool (hot) flames out of the exhaust as
well.
All you need is a manual switch tied in to the clutch pedal to do this.
[Edited on 7/12/07 by Ivan]
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joetait
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| posted on 7/12/07 at 09:21 AM |
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Manic Beattie
That was John Beattie's evil contraption (www.RaceEngineDesign.biz) - he did the ITB's and initial mapping for my S2000 Dax Rush.
I guess you could make it work with a monster waste gate but you would need to supply the turbo with a higher pressure oil feed as spooling up full
boost at idle wouldnt provide enough oil pressure for lubing or cooling the turbo.
http://www.raceenginedesign.biz/Manic-Beattie.htm
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zilspeed
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| posted on 7/12/07 at 09:24 AM |
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Nick Mann's Mannic Beattie is a very specialised car though.
It has 4wd and hillclimb slicks so needs low down grunt to get it moving. Low down grunt usually means a big engine, which would be really heavy and
not actually fit his car. Then there would be the impact on the car's handling etc.
In his case the instant boost coupled with a lightweight engine - It's a BDG canted over to keep the C of G nice and low suits better.
It's a great answer for his problem, but not for everyone.
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martyn_16v
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| posted on 7/12/07 at 09:59 AM |
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quote:
Originally posted by Ivan
A simpler and more common way of achieving a similar result is to overfuel your motor at a high idle speed and greatly retard ignition so that some
combustion occurs in the exhaust - this also causes early high boost but sounds terrible but you get realy cool (hot) flames out of the exhaust as
well.
All you need is a manual switch tied in to the clutch pedal to do this.
...and a new exhaust manifold every couple of hundred miles  Isn't that exactly how the bang bang anti-lag works on rally cars?
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kikiturbo
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| posted on 7/12/07 at 10:33 AM |
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WRC cars, when they shut the throttle off, use the air from the intake manifold which is under pressure, run it trough a valve (similar to an EGT
vlave) and dump it directly into the exhaust manifold, along with some fuel, bypassing the engine alltogeather.. that whay they have boost all the
time.... when you look at the system, it is quite similar to an jet engine.. 
[Edited on 7/12/07 by kikiturbo]
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jono_misfit
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| posted on 7/12/07 at 10:57 AM |
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There was a full feature on it in race tech mag i think (might have been racecar engineering).
I thought it was a BDT engine though canted over almost on its side. The car has AWD.
Doesnt the starter burn diesel?
Id try digging the article out, but their at my dads place.
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ned
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| posted on 7/12/07 at 11:38 AM |
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there was a thread on this car some time ago on this site...
ps here:
http://www.locostbuilders.co.uk/viewthread.php?tid=58466
[Edited on 7/12/07 by ned]
beware, I've got yellow skin
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brycheiniog
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| posted on 7/12/07 at 02:02 PM |
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There is a very good video of the Mannic Beattie running at Gurston Down here:
http://www.brayspeed.co.uk/assets/films%20for%20web/nick%20mann.wmv
Jonathan
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RazMan
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| posted on 7/12/07 at 03:22 PM |
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Out of interest, what is the (I presume) compressed gas that is pumped in to spin up the jet engine?
Cheers,
Raz
When thinking outside the box doesn't work any more, it's time to build a new box
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Confused but excited.
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| posted on 7/12/07 at 04:54 PM |
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That will probably be the exhaust from a small rocket.
Tell them about the bent treacle edges!
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