flames??

[jono172sport]

hi all have a 172 sport got a stainless manifold and straight through exhaust no cat or centre box the system is 3.5 inch all the way through but it wont pop flames is there any reason why? does any one elses?

 

[Aluco]

Because it for getting exhaust gasses out of your engine, not setting things on fire

 

[jono172sport]

yeh i no that but most 16v cars i no with no cat or silencer pop flames on the over run or when you change gear

 

[sideways danny]

hope you mean 2.5 inches !!!! pops, bangs and flames are down to getting the exhaust hot (high exhaust gas temps) and rapid variations in ignition timing on over-run. dificult to manipulate without being able to alter the map. Some setups will run the exhaust hotter so be more likely to flame

 

[jono172sport]

and ive seen a few vids on the net with clio's poping flames so why wont mine do it

 

[*Danny*]

lol fair point, dont know how the flames acour but if you have no cat or centre box i cant see y you arnt getting flames, take you back box off then try it (joke's)

 

[jono172sport]

no its 3 and half inch why? that bad it came like that

 

[sideways danny]

and ive seen a few vids on the net with clio's poping flames so why wont mine do it

you might have seen some that have been mapped specifically to pop and flame. It's just some simple map trickery but if you know what you're doing you can fine tune how much it happens quite accurately

 

[sideways danny]

no its 3 and half inch why? that bad it came like that

JESUS CHRIST, that's big enough for about 500 horsepower lol. Too big for an NA 2 litre clio and it's highly unlikely to ever get hot

 

[*Danny*]

search f0xy on here, standard engine no fancy maps just got a de-cat and side exit but with a middle box and that pop's bang's and flames like crazy

 

[jono172sport]

you might have seen some that have been mapped specifically to pop and flame. It's just some simple map trickery but if you know what you're doing you can fine tune how much it happens quite accurately

how do you fine tune it then? so basically your saying it needs a re-map to spit flames? and my exhaust is 3.5 inch all the way through seems to fit good to the manifold and back box is this bad that its that big? i dont no what make manifold it is as it came on the car but its fookin huge lol

 

[jono172sport]

JESUS CHRIST, that's big enough for about 500 horsepower lol. Too big for an NA 2 litre clio and it's highly unlikely to ever get hot

ahh maybe il look into changing it then lol what is a good size to go for? also would i gain any more power by doing this?

 

[Aluco]

Far as I'm aware for there to be flames the backbox of the exhaust needs to be pretty hot ? and you need to have strange timing on overrun for the car to
spit out a small bit of unburned fuel or vapour.

Having a 3.5" exhaust tip probably means cooler tempratures,
you could always just buy a flamer kit off ebay if you that desperate to impress your mates though ! :rasp:

 

[Aluco]

ahh maybe il look into changing it then lol what is a good size to go for? also would i gain any more power by doing this?

Might aid compression, will deffs sound and look better too.

2" / 2.5" maximum imo!

 

[jono172sport]

its a scorpion cat back system with a decat pipe and manifold the system from manifold back is 3.5 inch not sure what size the exhaust tip is looks about 3 inch but dont quote me. each branch on the manifold is huge aswell

 

[sideways danny]

how do you fine tune it then? so basically your saying it needs a re-map to spit flames? and my exhaust is 3.5 inch all the way through seems to fit good to the manifold and back box is this bad that its that big? i dont no what make manifold it is as it came on the car but its fookin huge lol

not really what i was saying, it's not really why you re-map, but it's something fun you can throw in if you know how and where to adjust while doing the map.

Exhaust size I can see being open to a lot of debate. F4Rs do like a fairly large exhaust, but IMO 3.5 is way too big

 

[Tucker]

compression???

you mean back pressure

you are most likely losing alot of power with a 3.5'' system

both inlet and exhaust systems rely on airflow pressure.

your car will probably be alot faster over 130mph though, not sure how useful that is to you

 

[jono172sport]

compression???
your car will probably be alot faster over 130mph though, not sure how useful that is to you

well thats quite interesting because my car does seem to be a bit slugish once it gets to say 100-110 mph reckon that could be why or are all 172's like this?

 

[Dave..]

surely if your exhaust is spitting flames thats bad...

unburnt fuel in the exhaust = inefficient combustion in cylinders

 

[jono172sport]

the correct term for spittin flames is valve overlap. you get this when 2 valves inlet and outlet are open at the same time were talkin splt seconds if that. this causes unburnt fuel vapors to go down the exhaust obviously a hot exhaust ignites them and bang flames

 

[Dave..]

again, I bring you to my point

unburnt fuel in the exhaust = inefficient combustion in cylinders

I want all my fuel vapour igniting in the cylinders please

 

[sideways danny]

again, I bring you to my point

unburnt fuel in the exhaust = inefficient combustion in cylinders

I want all my fuel vapour igniting in the cylinders please

the point you've missed is that it's on over-run. If the AFR is too rich you're cooling the EGTs so you wont get flames you'll just get a puff of black smoke. leaning out fuel and retarding the ignition on over-run is basically how it's done

 

[jono172sport]

hmm interesting so basically its the luck of the draw som cars do some dont? depending on modifications?

 

[sideways danny]

hmm interesting so basically its the luck of the draw som cars do some dont? depending on modifications?

without specific mapping yes


just noticed you said it's a scorpion. I think it will be 2.5 inch with a 3.5 inch tailpipe in that case

 

[jono172sport]

lol i guess it is sorry for beeing such a noob thanks for your help

 

[Fletcher]

Why would you want flames anyway, pointless imo.

 

[Adey.]

what sidways danny says is correct, flames dont mean ure cars running rich and they are created by changing the ignition values on overrun. im still not convinced on exhaust sizes yet tho, my car makes very good power and im still on a 2inch system, would be worth trying to see if theres a difference by stepping up a size tho

http://www.youtube.com/watch?v=OCYhPAmSPgw

here you go for the flame lovers