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Model specific boards => Golf mk3 => Topic started by: gtiballs61 on 18 August 2012, 11:03

Title: Fire popping exhaust
Post by: gtiballs61 on 18 August 2012, 11:03
Since fitting my de-cat i have(other people behind) have told me that when i change gear(5000rpm +)
the exhaust spits out a flame. :cool:
What damage will this cause,if any?

I have a straight through exhaust with de-cat,pipercross panel air filter and have no engine mods.
I will try get a pic sorted of the popping flame.
It has been running like this for more than 8 months now.I have had no running problems apart from the maf sensor,which i sprayed with some sort of electric cleaner and has been fine since.
Oh and she does run a little rich
Title: Re: Fire popping exhaust
Post by: VW BUSH on 18 August 2012, 11:21
Over fuelling, damage will be done to valves and rings etc and not your exhaust.
You will be down on power and probably fail an emissions test
Can wreck a cat but this is not a problem for you :grin:

I have this going on at the moment, sounds like a V1 when engine breaking into a corner :grin:
kind of gone too far with a dremmel :lipsrsealed:
Title: Re: Fire popping exhaust
Post by: Khare on 18 August 2012, 11:43
Unless its massively overfuelling it's fine. All engines would spit flames, the thing that stops it is the cat and any silencers in the exhaust, and as you have none then you have flames. If it is overfuelling a lot with strong fuel smells and massive flames then it can wash out the bored and cause damage but that's in extreme cases.
Title: Re: Fire popping exhaust
Post by: gtiballs61 on 18 August 2012, 12:14
I don't think it is over fuelling massively.Im not getting any running issues or fuel problems.
Title: Re: Fire popping exhaust
Post by: Leroy on 18 August 2012, 13:00
I wish my Golf did that! must look cool!!!
Title: Re: Fire popping exhaust
Post by: sharki786 on 18 August 2012, 13:41
think mine does the same lol. quick rev to 2k and POP :smug:
bit chavy tho :embarrassed:
Title: Re: Fire popping exhaust
Post by: stainesy on 18 August 2012, 13:49
I don't think it is over fuelling massively.Im not getting any running issues or fuel problems.

If yours has no car or any silencers how bloody loud is it?
I removed the middle suitcase box on my black golf just leaving the cat as backbox and it was so boomy inside the car that it made my eyes shake and my vision go blury when driving. I had to change it back after half hour of doing it.
Title: Re: Fire popping exhaust
Post by: mush on 18 August 2012, 14:02
awesome my renault 5 turbo did this when the foot went down, found people tended to back off after that   :grin:
Title: Re: Fire popping exhaust
Post by: leigh_harty on 18 August 2012, 14:09
I don't think it is over fuelling massively.Im not getting any running issues or fuel problems.

If yours has no car or any silencers how bloody loud is it?


My vr is straight through  :lipsrsealed:

Although i cant see it, when i change at the redline it shoots flames out  :evil:
Title: Re: Fire popping exhaust
Post by: Gavv8 on 18 August 2012, 22:52
How can you see your exhaust tailpipe from the drivers seat?
Title: Re: Fire popping exhaust
Post by: forsh on 19 August 2012, 09:18
How can you see your exhaust tailpipe from the drivers seat?

rear view mirror ???
Title: Re: Fire popping exhaust
Post by: leigh_harty on 20 August 2012, 19:33
How can you see your exhaust tailpipe from the drivers seat?

rear view mirror ???

Mates behind me?  :grin:
Title: Re: Fire popping exhaust
Post by: ChowderV4 on 20 August 2012, 20:07
ive been told the same about my mk2, heel toeing on the downshifts and my mate said the exhaust was glowing orange inside from flames licking out.
(not glowing metal, just the glow from the flames haha)
Title: Re: Fire popping exhaust
Post by: gtiballs61 on 20 August 2012, 21:21
I think we need to see some pics :cool:
Title: Re: Fire popping exhaust
Post by: F17BAD on 20 August 2012, 21:28
we bought a VR6 for bens conversion last year

that was glowing orange too (i was behind it) then it spat out loads of bits of fire.. these later turned out  to be the innards of the CAT

Title: Re: Fire popping exhaust
Post by: Agreeable Slick on 20 August 2012, 21:51
Just putting this out there..... How many high performance (not including track tuned) cars do you see popping flames.

It's NOT good for the engine, or exhaust.
Title: Re: Fire popping exhaust
Post by: ChowderV4 on 20 August 2012, 21:59
http://www.youtube.com/watch?v=GsJ4cnLE3uA (http://www.youtube.com/watch?v=GsJ4cnLE3uA)

 :smug:
Title: Re: Fire popping exhaust
Post by: Agreeable Slick on 20 August 2012, 22:03
Ah yes, TVR, the pinnacle of high performance.....
Title: Re: Fire popping exhaust
Post by: ChowderV4 on 20 August 2012, 22:08
Aventador, i'd say thats pretty pinnacle.
Title: Re: Fire popping exhaust
Post by: Agreeable Slick on 20 August 2012, 22:20
Maybe I should have been clearer.

A car should not spit flames when being driven, as it does and will damage the engine. Bore wash, injector lacquering etc. As cool as it may look, there is a reason these cars have auto timing advance/retard, fuel mapping etc.

It will give a flame when revved to a high rev range then cut off as the exhaust port will stay open to scavenge the charge out of the cylinder as it thinks it's going to require a lot of cleaner air. On most videos you will notice it takes a while for the car to pop a flame (if it does at all) because (as has already been mentioned) it's pumping non required fuel into the cylinder and doesn't have enough time to do a complete burn.

Roughly translated - when being a tool. :smiley:
Title: Re: Fire popping exhaust
Post by: F17BAD on 20 August 2012, 22:59
He is right...  flames = somethings not right
Title: Re: Fire popping exhaust
Post by: ChowderV4 on 21 August 2012, 16:42
oh i know, i wasnt arguing with that.   :smiley:

luckily mine only glows haha :grin:
Title: Re: Fire popping exhaust
Post by: paul herbert on 21 August 2012, 20:40
been told mine fires out flames on the strip but it is s charged and 100 shot of gas :grin:
Title: Re: Fire popping exhaust
Post by: sharki786 on 21 August 2012, 22:50
as said before: they only pop when there is no restriction (straight through pipe w/o any silencers or cats) i remember my mate had a straight through pipes (jap style on each side) for his rx7 and boy did that pop
mine pops aswell at 2k revs sounds like thunder (rumbling) :evil:
Title: Re: Fire popping exhaust
Post by: dom on 21 August 2012, 23:57
My Mk4 spits the odd flame when booting it, usually when lifting off after a sharp burst of acceleration. It only does this after I got rid of the cat and fitted a 3" turbo back :grin:
Title: Re: Fire popping exhaust
Post by: Khare on 22 August 2012, 09:42
Mine chucks out a small flame sometimes when I hit the limiter. Rumbles and pops at around 1800 if I'm coasting and when I change gear fast.

As said before, too many flames are not good for an engine. It's normal if it's a non restrictive system and it chucks out a small flame when giving it an absolute thrashing.
Title: Re: Fire popping exhaust
Post by: Rmachines on 22 August 2012, 17:11
The ECU/Engines mission is to achieve stoichiometric combustion at all RPM and load ranges, We all know thats not 100% possible, i don't think it should quite be spitting flames though.   However, its normal to throw fuel down the pipe when on the limiter, as it cuts the spark not the fuel.  But, realistically, it doesn't take much of an over fuel to cause a backfire, and were not talking about "new" lean burn engines here..... so i think to see flames, is kind of "normal" considering the straight through pipe
Title: Re: Fire popping exhaust
Post by: sharki786 on 22 August 2012, 23:14
The ECU/Engines mission is to achieve stoichiometric combustion at all RPM and load ranges, We all know thats not 100% possible, i don't think it should quite be spitting flames though.   However, its normal to throw fuel down the pipe when on the limiter, as it cuts the spark not the fuel.  But, realistically, it doesn't take much of an over fuel to cause a backfire, and were not talking about "new" lean burn engines here..... so i think to see flames, is kind of "normal" considering the straight through pipe

 :cool: