Exahusted fire.

[MrKipling]

No, that p*ss taking was justified. The idea that you can get 3-5bhp from a flamer kit is stupid. And wrong.

I have seen flames spat from a standard road car: the 360CS has dragon-like tendencies when it is being driven in the exhaust bypass zone.

[hightower99]

well nobody has asked why I think that a properly set up flame system can make horsepower...

when you are accerating and exaust is being pumped into the exaust system if you have a really hot flame system that ignites and helps pull the exaust out then it puts a negative pressure behind all the exaust valves before they open taking away most of the pumping losses for the exaust phase.

is that too hard to believe?

[Matra et Alpine]

well nobody has asked why I think that a properly set up flame system can make horsepower...

when you are accerating and exaust is being pumped into the exaust system if you have a really hot flame system that ignites and helps pull the exaust out then it puts a negative pressure behind all the exaust valves before they open taking away most of the pumping losses for the exaust phase.

is that too hard to believe?

yes

Pulse propogation in an exhaust system is not that simple
Surroinding every low prsesure "pulse" is an area of high pressure
For some revs in fact that pusle MAY hit the exhaust manifold at precisely the moment the exhaust valves open and REDUCE the gas outflow.


Anyone SELLING these crappy exhaust injectors is telling porkies to con fosks into buying them. Some will believe it.
The same kind of folks usually who bought those turbo "things" that are just a bent bit of metal in the inlets to supposedly make the air spin and increase performance !!

The world is full of snake oil salesmen and gullible customers
Don't be taken in by the veneer of believability !!!!

[hightower99]

yes

Pulse propogation in an exhaust system is not that simple
Surroinding every low prsesure "pulse" is an area of high pressure
For some revs in fact that pusle MAY hit the exhaust manifold at precisely the moment the exhaust valves open and REDUCE the gas outflow.


Anyone SELLING these crappy exhaust injectors is telling porkies to con fosks into buying them. Some will believe it.
The same kind of folks usually who bought those turbo "things" that are just a bent bit of metal in the inlets to supposedly make the air spin and increase performance !!

The world is full of snake oil salesmen and gullible customers
Don't be taken in by the veneer of believability !!!!

the only systems that work the way I am talking about are not commercially available.
oh and adding a spin if done correctly will help performance...

the system does not create a pulse it simply increases the velocity of the flow and pulls all the exaust away from the exaust valves. (you would think that that would make a very high amount of negative pressure but there is almost always exaust valves open to feed the flow!

[Matra et Alpine]

the only systems that work the way I am talking about are not commercially available.
oh and adding a spin if done correctly will help performance...

oooh thre's a surprise.
Sorry, ht, you dont seem to know what you are talking about
If this upsets you then please give an explanatino of the physics of how either of these ADD power to a designed system already optimnised for gas flow ??

the system does not create a pulse it simply increases the velocity of the flow and pulls all the exaust away from the exaust valves. (you would think that that would make a very high amount of negative pressure but there is almost always exaust valves open to feed the flow!

Please, if you wish to LEARN then ask questions.
If you want to be criticised make statements like that.

EXhaust is and always will be pulsed.
That's why so much effort is taking by manufacturers and even more by tuners to "tune" the exhaust.
It's purpose is to optimise the timing and pressures of those exhaust pulses to assist in drawing the exhaust usually either at peak power or at another point where flow is causing engine loss of power.
SO there ARE pulses.
You now add on top of that a flame ... now this flame if usign injected gasses is burnign and to do so MUST draw oxygen. WHere does the oxygen come from ? Usualy the exhuast tip -- guess what THAT is now flow OPPOSITE of the direction. Now lets assume it's a much more complex setup and is injecting atomised fule and air mixter, well it receives additional gasses from teh exhaust pulses coming down the pipe. These will alter combustion at the injector tip. These variatiosn cause different fuel burn wavefront at the inject tip. Some of which will induce BACK pressure and then alter the free flow and planned flow of the exhaust gasses.
So with a little bit of effort I can show you how sometime ( probably MOST ) burning fuel at the exhaust is WORSE performance Race cars do it when they dont' need/want power, so they dont worry about it

SO it does NOT "increase velocity" because in reality it is drawing in Oxygen in the opposite direction and creating a backflow at the tip. It does NOT "increase velocity" as it equally alters the back pressure - back pressure SLOWS down exhaust flow.

All it does is lets chavs ( well here in teh UK anayway ) have somethign else to boast about along with the stikkaz and scoops and bulges and not forgetting the hi-fi which all add power to teh car

[Coventrysucks]

Could this happen in a street car equipped with catalytic converter? Not a chav-mobile but an untampered with car.

Evo make several references to the Gallardo SE spitting blue flame out the back.

IIRC all new cars have to be fitted with a cat, and I don't think that Lambo would be putting aftermarket exhausts on their press cars

[charged]

Race cars do it when they dont' need/want power, so they dont worry about it

I have only seen it on closed throttle applications, never on WOT applications, except for Nitro cars

[hightower99]

Ok I know exaust traveling in the system is always going to have a pulse what I said was that the flame system doesn't add a new pulse what it does is make the out flowing pulse stronger and the backwards back pressure causing pulse to be weaker

why... well think about it with a high temperature flame expanding at high speed out of the exaust tip will facilitate the outgoing flow by speeding it up but as certain conditions change and the backwards pulse starts it has to work against the powerfull flame making it slower and less powerfull!

the flame is close to the tip of the exaust and a small opening is made through the exaust allowing air to mix with the exaust prior to passing the flame. the flames heat sucks the air from the hole behind it and out the tip creating a strong one way flow.

[Matra et Alpine]

no paint picture needed.

I've been over this with guys at track when we've told them to disconnect it as scrutineers dont' allow it in case it drops fuel !!!

Think about what you said. You open a hole to introduce the air. So WHERE do you think it is sucking air from now ?
Now, On WHAT basis do you think an open exhaust pipe acts like a rocket engine nozzle ?

Now lets even assume it IS workign do you think this pressure equalises up the lenght of the exhaust pipe ? You are looking at similar calulations exhaust tuners do to decide where to put an expansion box What hey do is SPREAD a pulse. It's the physics of gas flow.

Sorry, ht, but I think you have read some stuff SELLIGN these POS and lack the backgroudn to question it. "flames heat sucsk air" ? Heat does not "suck" I've already given half a dozen reasons these are BS. When you can produce the gas flow analysis propersly calculated I'll come back to engage.

The REAL WORLD facst are given. They do NOT work as sold by the POS manufacturers. They are for SHOW, no GO !

[PBB]

Could this happen in a street car equipped with catalytic converter? Not a chav-mobile but an untampered with car.

Yes, but only after a huge hole was burned through the cat. Modified turbo cars with no/bad tuning running rich can wreck a stock cat in literally, a matter of minutes. There are metallic high-flow performance cats which can handle the additional heat/unburned fuel but not all will be emissions legal even with proper tuning, thus defeating the purpose of buying one.

[Matra et Alpine]

I'm not goign to explain all the obvious errors in yoru assumptions, th, as you're clearly touchy about it.

So provide the properly exlpained CFD on teh gas flows and pressures and we might believe it. ( hint, you need to think more about gas flows at the tip of the exhaust and flame-front pressures )

[syko]

During V8 supercar races you only see it when there going around corners or in braking zones.

[MrKipling]

That's because it happens on over-run - when the engine is being driven by the wheels.

The Lambo and Ferrari CS manage it thanks to cat-bypass valves.

[KnifeEdge_2K1]

putting a flame in to suck air from the exhaust ... WHAT !?!?!?

where are you getting the air from ?? and what's to stop the flame from traveling back up the exhaust pipe creating more pressure ??

and if this actually does work why not just add a fan at the end to suck out all the exhuast gas ??

[derekthetree]

That's because it happens on over-run - when the engine is being driven by the wheels.

The Lambo and Ferrari CS manage it thanks to cat-bypass valves.

do they kick in when the engine revs up? they are closed on the drive past for the noise regs and then open the rest of the time?