fire exhast

ECUs, intakes, turbos, fluids, transmissions, exhausts etc.
Sparky
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Post by Sparky » 05 Jul 2006, 9:10 pm

I'd like one... i'd be a hit in BBQs with that thing. (Y)

preludeq82
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Post by preludeq82 » 05 Jul 2006, 11:06 pm

can some 1 bring the details how much it is in dubai or sharjah? the whole kit whats it rate these days well every 1 would apperciate if anybody can bring the details thanks

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Neo
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Post by Neo » 05 Jul 2006, 11:48 pm

Alrite, seems like the thread has gone sideways..

Somebody is talkin about flame thrower..
Somebody else is talkin about the real stuff, backfiring...

why dont u guys take the flame thrower to another thread in aerodynamics...
Instead of confusin it wit a genuine engine related thread...

Edited the post to add more stuff..

I was thinkin about this specific issue since its somthing real simple but tough to explain.
Again....

Happens most of the time on a high performance car during downshifts...
Maybe we gotta look at wat actually happens durin a downshift.

In a downshift unlike shiftin upwards... u need to sych the engine speed relative to ur car speed... which means when u deaccelerate quickly u need to shift down into a gear and to a spot where there is torque.

In shiftin up, u have a specific RPM at which u shift to the next gear. Simple...

Most of these high performance cars employes Dog shift gear boxes and racing clutches....

Lets say durin downshiftin , When the clutch is depressed for a sec or less to shift down, the engine becomes free, ie no load.
And it doesnt require all the charge to keep it runnin and hence the excess charge comes out of it burin....


Hope that clears everything... add the previous mentioned ideas to it... and it give a complete picture.. doesnt it..

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Post by mikeh » 06 Jul 2006, 10:05 am

Neo wrote:Lets say durin downshiftin , When the clutch is depressed for a sec or less to shift down, the engine becomes free, ie no load.
And it doesnt require all the charge to keep it runnin and hence the excess charge comes out of it burin....


Hope that clears everything... add the previous mentioned ideas to it... and it give a complete picture.. doesnt it..
Well, I'd think that these cars have sequential shifting actually...

Yeah, it has to be something that when shifting a certain load of charge goes in, and out of the cylinders without being burned.. (overlapping intake/exhaust cycle?) I'm just wondering.. why, on such expensive cars.. would there be a "mistake" with the ignition then?

The only reason I see it.. It might be that when the throttle closes, and at that engine speed (say 10k), you have much more fuel being injected, then air.. (although I'd hope the ecu would be fast enough to notice the amount of air in the manifold.. and inject approprately) which doesn't murn and get's pushed through...

So frankly, sometime a car's rev limiter is just an ignition cut.. so revving high and then falling back down, would give you "the bang" ? :D

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Accord98
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Post by Accord98 » 06 Jul 2006, 11:55 am

just a question - when i watched Initial D (dont ask..) - Takumi once raced with a Subaru? i think - and they kept saying he installed a "backerr - fire Shhh -ishhh - tem"

-- does it have any added benefits? performance wise?

PS - nice topic guys :)

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Jin
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Post by Jin » 06 Jul 2006, 3:36 pm

found this on net!!!!!
copy pasted but it does make some sense!!!!!

"Backfire in an automobile engine typically results from various malfunctions related to the air to fuel ratio. Usually, backfiring occurs in carbureted engines that are running lean where the air fuel mixture has insufficient fuel. ("Running lean" is typically a sign of mal-adjusted carburetors or fuel injection where there is not enough fuel for the amount of air). Afterfire, however, occurs in engines that have an exhaust leak or unburnt fuel in a decatted exhaust system. When a driver shifts up and lets off the gas, the engine has a moment of running rich or with insufficient oxygen. This causes an incomplete burn which causes the fumes to explode in the exhaust system. The leak itself is the most dangerous aspect. Without it, the mixture would cool enough not to explode. A fuel injected engine may backfire if an intake leak is present (causing the engine to run rich), or a fuel injection component such as an air-flow sensor is defective."

Jin :wink:

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Post by Jin » 06 Jul 2006, 3:41 pm

found some more!!!!!
hope it makes sense!!

"The basic idea is that unburned fuel and a spark (or heat, enough to cause combustion) are getting in the exhaust manifold at the same time. This could be caused by a carbuerator needing adjustment, the timing could be off or one of the cylinders isn't firing at all. Time for a tune up!"

"v-tec tends to have less back fire. Backfire occurs when you go from a very high rev to a very low rev (and vice versa) very quickly."

"Unburned fuel in the collecting in the catalitic convertor or the muffler is the cause. The reson for the excessive fuel in the exaust system varies usally carburator forcing to much fuel in or retarded ignition timing. I've also seen leaky exaust valves cause backfiring but that is very uncommin."

Jin :$

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Post by mikeh » 06 Jul 2006, 4:11 pm

Guys thank you all for your input. I'd like to see more topics like these..

Unburnt fuel in the exhaust manifold, i think that's the golden rule.. and one of the only ways I see it is for instance, if in the work cycle (piston giong down) not all fuel is burnt.. because of

- malfunctioning (but lets rule that out)
- speed.. fuel burns to slow

Which indeed might be I think when you downshift and peak your engine to 10.000 rpm, the amount of air going through. I guess is enough to "blow out" whatever is in your cylinder towards the exhaust..

The strange thoung somehow would be that why wouldn't the sparks be able to keep up? They can keep up if you accelerate...

I made a picture where this is shown..
Image (yeah, my r/t is too slow i think.. :lol: )

Edit: Neo, coffee would be nice, i'd like to meet up with you to talk about engines and projects.. I can come to abu dhabi, no worry at all. Maybe we can even have a unofficial meet in abu dhabi one of these weekends (just for a new place for pictures)

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Post by Neo » 07 Jul 2006, 3:54 am

Tat car in the pic definitely wud have a dogbox mike...
I guess street legal cars like Evo,skyline and other imports racing for JGTC etc wud be around 500BHP and using dog box, i have been watching lot of videos lately. The box is very evident, from shift forward or backward of the stick to increase or decrease the gears, plus the gear hum or whining which is very obvious.
I guess u where thinkin about supercars... i know they got all these hi tech gear boxes, quite similar to auto, wit names like steptronic, tiptronic...my @$$tronic.... some times i get lost wit all these names...

:?



PS... Sure mike, I wud definitely be looking forward to that.... And I was in dubai until 1:00am today. Been checking out cars and then accessories, gotta know the price and stuff available for here to hav the knowledge of the current market.

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Crush
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Post by Crush » 24 Jul 2006, 8:43 am

1-just get a dirct pipe from your engine

2- put a small silancer in the end

3- install the apxi fuel controler

4- incress the fuel in the axpi a bit

finaly give gas and release and enjoy .( you can enjoy with reveres gearing to or what ppl call engin break).


cool and easy no need for all kits that after weeks the wires will be burned

note: this basic mod will increase HP too

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Neo
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Post by Neo » 24 Jul 2006, 11:16 am

Crush wrote:1-just get a dirct pipe from your engine

2- put a small silancer in the end

3- install the apxi fuel controler

4- incress the fuel in the axpi a bit

finaly give gas and release and enjoy .( you can enjoy with reveres gearing to or what ppl call engin break).


cool and easy no need for all kits that after weeks the wires will be burned

note: this basic mod will increase HP too

Wat r u talkin abt???

:|

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Post by mikeh » 24 Jul 2006, 12:21 pm

Crush wrote:note: this basic mod will increase HP too
It might increase torque, because you are running rich, yet nothing too "wow"-ish.

So, any NA car with a small silencer that's running rich will backfire?

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Neo
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Post by Neo » 25 Jul 2006, 12:47 am

mikeh wrote:
Crush wrote:note: this basic mod will increase HP too
It might increase torque, because you are running rich, yet nothing too "wow"-ish.

So, any NA car with a small silencer that's running rich will backfire?
Weird!!!

And if ur stock car is made to backfire like that... it wont even run 75Km...
Ur exhaust header and system will burn in hell due to the added heat.

The miss firing system system on a WRC is car is based on a retarded ignition timing.
Happens why they lift from the accelerator.
During then
By the time the sparkplug fires, the exhaust port is open and the charge is on the way to the exhaust pipe, it starts burning then and gets pushed out thru the exhaust outlet.
Period!

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Post by blackie » 25 Jul 2006, 8:38 am

This works especially on nissans patrols ( if its a brand new car that has not done more than a thousand kilometers) drive like you stole it hit top speed and continue doing this for the next 15 minutes, and yes i know that you that you are killing your engine, but you will get immediate back fires %#%$ a result of this.

This next step is for any one that has a land crusier gxr ( 2000 to 2002 models) leave your car in nuetral, make your rpms hit 4 or 5, then what yo9u need to do is rev your car all the way even if its hits the red line and switch the car back on, ( remember that your car should not be moving) by turning the key to the right again and holding it for a 5 to 10 seconds, it will immediatley back fire and it will sound like an ak47.

this is the easiest way to do it for all cars the next time you have to take your car for its service, ask the service advisor to increase the fuel flow into the engine, so if its a 4 litre car, it can be made to perform like a 4.6 litre car, after that when you get your car back take it for a spin rev it up all the way and you will immediatly get a back fire, the main problem in doing this is your milage is killed but you get power that you never thought you had, this works for all cars .

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Post by mikeh » 25 Jul 2006, 8:45 am

blackie wrote:...but you will get immediate back fires %#%$ a result of this.

This next step is for any one that has a land crusier gxr ( 2000 to 2002 models) leave your car in nuetral, make your rpms hit 4 or 5, then what yo9u need to do is rev your car all the way even if its hits the red line and switch the car back on, ( remember that your car should not be moving) by turning the key to the right again and holding it for a 5 to 10 seconds, it will immediatley back fire and it will sound like an ak47.

this is the easiest way to do it for all cars the next time you have to take your car for its service, ask the service advisor to increase the fuel flow into the engine, so if its a 4 litre car, it can be made to perform like a 4.6 litre car, after that when you get your car back take it for a spin rev it up all the way and you will immediatly get a back fire, the main problem in doing this is your milage is killed but you get power that you never thought you had, this works for all cars .

Erm... stock Nissan patrols have catalytic converters... even if you drive it at redline all the time... i don't think you'd get flames. Not with the stock exhaust system that they have.

Increasing the fuel will only work to win some torque back.. but now way you can make your 4.0L perform like a 4.6L.

Starting your engine when it is running already is just plain wrong for a car.. it will damage your starter motor and i highly doubt you will get flames... unless from your electrical system.



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