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Nitrous
Cars Modifications Aspects of car modifications (tuning, styling) (uk.rec.cars.modifications)
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#11
 
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Re: Nitrous -
05-10-2004
, 03:44 PM
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"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote in message news  LPnc.7434$7S2.3511 (AT) newsfe1-win (DOT) .."Johnny" <repro007 (AT) hotmail (DOT) com> wrote in message news:2g9bm8F4innU1 (AT) uni-berlin (DOT) de... snipped The other thing that I can't quite figure is how the rising engine rpm and subsequent increased air flow through this chamber which will affect the n20/extra fuel/air ratio, It doesnt. Its a fixed x value regardless of rpm. I'm nervous about arguing |
Don't be!
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but unless the n2o/extra fuel supply rises with the engines increasing RPM to match the increasing air flow being drawn through the plenum chamber by the cylinders then the ratio of n2o/extra fuel to air (in the chamber) must drop, it can't possibly be same can it? |
Exactly. It does drop.
This is why a constant power increase right across the range happens.
If you feed in 40bhp at idle, you get 40 EXTRA at idle...
If you feed the same 40bhp at 6000 rpm you still get 40 bhp, Extra...
What actually happens is that it fires many more smaller doses as the rpm
increases.
Like the string chopping machine.
If you feed string as constant rate, it chops BIG lumps at slow speed but
tiny nibbles 6 times smaller at 6000 chops per sec! But its doing it 6
times faster????
So extra torque decreases with rpm, extra power stays exactly the same, as
power is Torquie X rpm?
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The only constants are the internal dimensions of the chamber and the n2o/extra fuel supply when on. The speed and therefore volume of the air stream it's being injected and atomised into per unit time is constantly changing with engine rpm. |
Think, you are adding the correct chemical mixture of Nitrous (oxygen) and
fuel. Constantly. At all rpms?
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Much more air is being drawn through the chamber at higher RPM. |
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If the n2o/extrafuel supply doesn't increase to maintain the ratio then as engine rpm increases the nitrous ratio per unit volume of air passing through the plenum chamber will decrease. |
less nitrous more often...
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This is what i'm trying to understand and trying to say in my usual cryptic way. Unless the nitrous system is only ever on at a fixed engine rpm and thus fixed volume of air per unit time. can maintain the power increase with a fixed n2o/extra fuel supply (Is it a progressive delivery?) and vastly more air, wouldn't the n2o component be greatly reduced at higher rpm. Sorry if these are daft questions. Of course. Thats why it makes say 40 bhp at 2000 rpm and the same 40 extra at 6000 rpm Thanks for the reply, I think I'm getting there. :\ |
#12
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"Johnny" <repro007 (AT) hotmail (DOT) com> wrote in message news:2ga26cFec0vU1 (AT) uni-berlin (DOT) de... snipped I'm nervous about arguing Don't be! but unless the n2o/extra fuel supply rises with the engines increasing RPM to match the increasing air flow being drawn through the plenum chamber by the cylinders then the ratio of n2o/extra fuel to air (in the chamber) must drop, it can't possibly be same can it? Exactly. It does drop. This is why a constant power increase right across the range happens. If you feed in 40bhp at idle, you get 40 EXTRA at idle... If you feed the same 40bhp at 6000 rpm you still get 40 bhp, Extra... What actually happens is that it fires many more smaller doses as the rpm increases. ...the n2o is increasingly diluted as the airflow increases but the extra |
in smaller amounts more often per unit time... i'm getting there.
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Like the string chopping machine. If you feed string as constant rate, it chops BIG lumps at slow speed but tiny nibbles 6 times smaller at 6000 chops per sec! But its doing it 6 times faster???? And if the string was fed faster as the cutter sped up it would make a hole |
(burgerman holds his head)
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So extra torque decreases with rpm, extra power stays exactly the same, as power is Torquie X rpm? If the ratio of nitrous was maintained then a jet giving say an extra 40bhp |
at 6000rpm (or thereabouts) a very hot engine and a very nice torque curve.
My only concern now is how it will affect the existing fuel management
system and sensors if at all, which is what really started me on this
thread. I can't imagine how it couldn't but that's probably me being thick.
There has to be more exhaust gas leaving the cylinders which is one of the
monitored quantities i believe.
#13
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"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote in message news:iXQnc.129$xd2.79 (AT) newsfe1-gui (DOT) server.ntli.net... "Johnny" <repro007 (AT) hotmail (DOT) com> wrote in message news:2ga26cFec0vU1 (AT) uni-berlin (DOT) de... snipped I'm nervous about arguing Don't be! but unless the n2o/extra fuel supply rises with the engines increasing RPM to match the increasing air flow being drawn through the plenum chamber by the cylinders then the ratio of n2o/extra fuel to air (in the chamber) must drop, it can't possibly be same can it? Exactly. It does drop. This is why a constant power increase right across the range happens. If you feed in 40bhp at idle, you get 40 EXTRA at idle... If you feed the same 40bhp at 6000 rpm you still get 40 bhp, Extra... What actually happens is that it fires many more smaller doses as the rpm increases. ..the n2o is increasingly diluted as the airflow increases but the extra heat generating capacity of the n2o remains constant, it's just being used in smaller amounts more often per unit time... i'm getting there. Like the string chopping machine. If you feed string as constant rate, it chops BIG lumps at slow speed but tiny nibbles 6 times smaller at 6000 chops per sec! But its doing it 6 times faster???? And if the string was fed faster as the cutter sped up it would make a hole pile of big lumps in next to no time. The penny has finally dropped. (burgerman holds his head) So extra torque decreases with rpm, extra power stays exactly the same, as power is Torquie X rpm? If the ratio of nitrous was maintained then a jet giving say an extra 40bhp at 2000rpm would progressively result in an extra power increase of 120bhp at 6000rpm (or thereabouts) a very hot engine and a very nice torque curve. |
Yep. This is what an expensive rpm controlled nitrous pulse controller
achieves.
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My only concern now is how it will affect the existing fuel management system and sensors if at all, which is what really started me on this thread. |
The motor resorts to a slightly rich 4 to 5 percent C0, and a simple map.
Don't worry, its not important!
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I can't imagine how it couldn't but that's probably me being thick. There has to be more exhaust gas leaving the cylinders which is one of the monitored quantities i believe. |
be off its rich scale anyway... But this is NOT used at full throttle, just
cruise and idle.
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#14
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| "Johnny" <repro007 (AT) hotmail (DOT) com> wrote in message news:2ga6khFe3mqU1 (AT) uni-berlin (DOT) de... My only concern now is how it will affect the existing fuel management system and sensors if at all, which is what really started me on this thread. At FULL throttle, those sensors are unused. The motor resorts to a slightly rich 4 to 5 percent C0, and a simple map. Don't worry, its not important! I can't imagine how it couldn't but that's probably me being thick. There has to be more exhaust gas leaving the cylinders which is one of the monitored quantities i believe. No, exhaust gas free oxygen is measured, but to be cortrect on nitrous would be off its rich scale anyway... But this is NOT used at full throttle, just cruise and idle. SORTED, hats off to the burgerman. All I need to do now is figure out what |
)
#15
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"Burgerman" <burgerman (AT) ntlworld (DOT) com> wrote in message news:QCRnc.7467$7S2.3323 (AT) newsfe1-win (DOT) .. "Johnny" <repro007 (AT) hotmail (DOT) com> wrote in message news:2ga6khFe3mqU1 (AT) uni-berlin (DOT) de... My only concern now is how it will affect the existing fuel management system and sensors if at all, which is what really started me on this thread. At FULL throttle, those sensors are unused. The motor resorts to a slightly rich 4 to 5 percent C0, and a simple map. Don't worry, its not important! I can't imagine how it couldn't but that's probably me being thick. There has to be more exhaust gas leaving the cylinders which is one of the monitored quantities i believe. No, exhaust gas free oxygen is measured, but to be cortrect on nitrous would be off its rich scale anyway... But this is NOT used at full throttle, just cruise and idle. SORTED, hats off to the burgerman. All I need to do now is figure out what bits are best to buy and how I can get them in there. Easy ) |
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