fire exhast

ECUs, intakes, turbos, fluids, transmissions, exhausts etc.
sara85
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Post by sara85 » 01 Jul 2006, 7:10 pm

hi all,,,,, how is it posible to get fire out of exhaus???? i dun mean da fake fire lik fast n furious , but da short *bam* .. how do u do it????? i see on many raceecars!!!!!
salam,,,,,,sara

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Post by preludeq82 » 01 Jul 2006, 7:40 pm

well i think u mean back fire it is a kit installe don ur exahsut and u can turn it on and when u give high RPM it gives out fire well the kit is known as back fire i hope i asnwered ur question lets wait for other people to reply also i wanted to know the priice in dubai also if anybody can help.
thanks
salam

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Post by mikeh » 03 Jul 2006, 8:49 am

I hope, sara, that are talking about the short *bang* with fire, out of an exhaust. Things like fast and furious are just flame throwers, and they are for wussies to be honest.

It’s an interesting question though, I guess is that when – on turbo’d cars – the wastegate is routed back into the exhaust… that in very high boost circumstances, this create a short fire. But I wouldn’t think that NA engines (the ones we have at least) have enough flow to get a flame through 3 meters of metal tubing.

Interestingly, I saw a video of a Honda F1 engine, whereby when the guys let go of the throttle (at like 17k RPM’s) , you had the same fire. Also GT cars (race cars, not your daily nissan) have this phenomenon.

Like to know more about it, Albertho?

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Post by mikeh » 03 Jul 2006, 9:01 am

I looked up and found a few things about this.. don’t know if they are right, can somebody confirm this?

In a turbo car (na car as well?), let go of the throttle quickly… although, from a physics point of view this would be strange. I’m still thinking how that would work, maybe because the boost would build up so quickly, that the dump valve would open up??

That, or put one of those lame flame thrower things… or even running rich with a sparkplug bolted into your exhaust pipe..

Or run nitromethane (devil emoticon)

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Post by Nismo » 03 Jul 2006, 4:42 pm

bak in days backfire system kits use to be for about 500 when i bought it ... but now u'll get bakfire kits systems everywhere for not more than 150 bucks even dats expensive ... there r many good onez out in market .. it works the same as with a spark plug and ignition coil.. but u should get it installed from a nice garage who knows about it ... not some shit shop who'll just fix spark plug in ur exhasut tip ... a nice garage would set ur fuel ratio . and the most important is to understand the positionin of spark plug .. trust me not everyone can do it .. i tried installin it myself i cudnt do it my wirin n everthing was perfect but i cudnt position the spark plug properly ... k the whole process works wid a button ... never ever try using ur bakfire of high rpm it will simpy screw ur engine ... cuz the momment u press ur button the car goes off for a sec .... i dunno wuts the logic behind this but its bad for ur engine if u dunno how to do it trust me ... how to get nice long flames ummmm u have to actually understand byt he sound of ur car ..rise ur rpm to max and then release when it drops down to 3 or 4 jus press the button ...it always works good on low rpm ... but i never tried to understand how the whole system works ..

mikeh
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Post by mikeh » 03 Jul 2006, 5:22 pm

Yeeeh, especially when she said
sara85 wrote:i dun mean da fake fire
, so nothing with flame thrower kits.

Still wondering how to do it though.

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Post by Nismo » 05 Jul 2006, 12:47 am

okay no fake onez then the best way is to get nice waste gate n enjoy the bams damns n wuteva ...and there r options in fake kits ... u can get than short bam as well .... it all depends how u use it ... but still she needs the original thingy .... i dunno how this thing works... but then it always comes when changin the gear ....it always comes when u release the preasure .. now it can be changin gear .. or dropin off from high rpm ... i'll search on this ..

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Post by mikeh » 05 Jul 2006, 8:37 am

I asked on another forum, and they said it’s when you shift to a higher gear, but don’t push it hard.. or when your tb closes, you’ll be running rich for a second.. fuel that doesn’t get burned in your block, but that explodes later... Strange how at professional races this happens almost every lap..

I doubt if they gonna put the effort and the weight of a “look at my f&f car” crappy product..

But don't sorry sara, i'm also looking into it.

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Post by mikeh » 05 Jul 2006, 3:08 pm

Food for thought:

By making the air-fuel ratio very rich (more fuel to air) and retarding spark plug firing timing heavily when the throttle goes to idle, the unburned fuel goes through the combustion chamber without being oxodized, and reaches the hot exhaust. It then causes a backfire(misfire) in the exhaust manifold and tubes, which builds up the pressure to drive the turbocharger, even when the accelerator is closed.

(from wikipedia)

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Post by Neo » 05 Jul 2006, 3:19 pm

Its the charge that comes out thru the exhaust... (charge = air fuel mixture)
To be precise happens during shifting , when therez sudden change in throttle position. Which mean change in Engine speed and Air fuel mixture....

As Certain amount of Charge escapes thru the exhaust while burnin... Funnyy.. and since the fire has no where to go it comes out thru the tail pipe....
It doesnt mean its burning at the exhaust tip... The flame cud have started from the cylinder and escaped thru the value and propogated thru the pipe.

Well not so fuel efficient.. But only happens in high power and tuning circumstances. Think about 800 or 1000 cc injectors and amount of fuel that is present....
Happens almost every shiftin during racing...

Also at times on cars witout rev limiters.. redlining the engine throws out unburned or burning charge thru the tailpipe...

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Post by mikeh » 05 Jul 2006, 3:54 pm

Yeah, but then you have to be at very high RPM’s with big displacement engines I guess..

I have pictures of races where this happens, and the flames come out of the tailpipe.

If unburned charge (a/f mix) would be pushed to the exhaust.. then why didn’t it burn in the ignition cycle? Mistimed, or maybe because it’s going “too fast”?

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Post by sara85 » 05 Jul 2006, 5:52 pm

tank you guyss!!!!!!!!! it make sens!!!!!! xxx

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Neo
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Post by Neo » 05 Jul 2006, 6:08 pm

mikeh wrote:Yeah, but then you have to be at very high RPM’s with big displacement engines I guess..

I have pictures of races where this happens, and the flames come out of the tailpipe.

If unburned charge (a/f mix) would be pushed to the exhaust.. then why didn’t it burn in the ignition cycle? Mistimed, or maybe because it’s going “too fast”?

Under normal circumstances it is mistimin... Which leads to burning of fuel in the valve chamber due to the high temperature... Happens in over-heated or badly tuned street cars.

But that is not the case for a highly tuned sports car on track..

These cars have engines runnin high rpm and the amount of power deilvered by the charge is comparitvity high. Which mean each power stroke delivers much more torque than a normal car.

If the charge which exists outta the cylinder, burns inside the cylinder instead... there wud be an uneven power delivery which will adversly affect the whole car. Hence its a neccessary evil.

Also I am not sure, but my theory wud be, they mite be keepin the valves open for this kinda stuff to happen. It can be open a few micro secs earlier... man this can get really complicated explain thru the forum.... Plus this cud be a dumb theory too... lol...

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Post by mikeh » 05 Jul 2006, 6:14 pm

Neo wrote:can get really complicated explain thru the forum.... Plus this cud be a dumb theory too... lol...
Let's sit together for this... interesting. Coffee in Abu Dhabi mall at 8pm? :)

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Post by Neo » 05 Jul 2006, 6:31 pm

mikeh wrote:
Neo wrote:can get really complicated explain thru the forum.... Plus this cud be a dumb theory too... lol...
Let's sit together for this... interesting. Coffee in Abu Dhabi mall at 8pm? :)
Are u serious mike...
If then lemme know... :D

I was going thru the new sticky...
I have been there before, and bookmarked the page...
But neve actually read it....

Edited: plus i am scared of long posts... LOL



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