yeah, consult someone..i'm not a good source for turbo tuning info..haha..your talking to the guy who rocks a fastArest DX.
What causes exhaust flames?
- Thread starter Matthew
- Start date
Installshield 2
Gothenburg Superiority
It is not necessarily just a rich mixture...You can do it regardless of richness (a lean mixture can literally melt a rear valence)...
Most of it depends on valve timing...A few years ago WRC cars would use this trick to keep big high revving turbo's spooled between shifts...The exhaust valve timing would be advanced enough to allow the expanding mixture to escape into the exhaust system and hellishly fling the turbine...The timing would be set to respond to immediate throttle lifts..meaning electronic s*** would open it when the driver would lift the throttle between the shifts...It made some of the coolest flames this world has ever seen...But popped a lot of turbos...
This is not what is happening in your case Matt, in which it most likely is residual hydrocarbons in the exhuast can ignite from heat and huge pressure changes...like mentioned...just wanted to point out that in purpose built race cars throwin' flames, its not just a rich mixture usually...
Most of it depends on valve timing...A few years ago WRC cars would use this trick to keep big high revving turbo's spooled between shifts...The exhaust valve timing would be advanced enough to allow the expanding mixture to escape into the exhaust system and hellishly fling the turbine...The timing would be set to respond to immediate throttle lifts..meaning electronic s*** would open it when the driver would lift the throttle between the shifts...It made some of the coolest flames this world has ever seen...But popped a lot of turbos...
This is not what is happening in your case Matt, in which it most likely is residual hydrocarbons in the exhuast can ignite from heat and huge pressure changes...like mentioned...just wanted to point out that in purpose built race cars throwin' flames, its not just a rich mixture usually...
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- MP5T / 944
Bling Bling.
I don't know if I would want my car to do that. I think it looks cool and all, but so far the cops leave me completely alone because the car is dead quiet untill the gas is hammered. Having a flame shoot out of a 4 inch exaust would probably give them much greef. Most of the Civics and J-Bodies around here have resonatior fat can muflers and like to run them at WOT. ****** Domestic Rice!!
I don't know if I would want my car to do that. I think it looks cool and all, but so far the cops leave me completely alone because the car is dead quiet untill the gas is hammered. Having a flame shoot out of a 4 inch exaust would probably give them much greef. Most of the Civics and J-Bodies around here have resonatior fat can muflers and like to run them at WOT. ****** Domestic Rice!!
i dont care if it happens or not, i race so far away from civilization they probably dont have cops in that area, and i never hit 8psi on the local roads or anything. i dont want to adjust it until i get w/b though.You won't get flames when at full throttle. It normally happens when you let off the gas FROM WOT. During the transition from WOT to part or no throttle, there are unburnt gases escaping. Hot spots in your exhaust, or even the cat can ignite those gases, hence the flame, and why it happens during shifting while racing, or at high rpm lift throttle conditions.
You're not going to shoot flames if you're driving conservatively.
You're not going to shoot flames if you're driving conservatively.
MP3skaterNC
JDM *****.
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- slotege mp3
shooting flames is just part of the open exhaust/ turbo car fun. my car used to spit foot long flames at 10psi w/ the emanage. lol.
being rich is alot better than being lean. that narrow band isnt that great either, so just stay where your at, and be happy until you get a real tuning device.
being rich is alot better than being lean. that narrow band isnt that great either, so just stay where your at, and be happy until you get a real tuning device.
Installshield 2
Gothenburg Superiority
True...instant lift throttle at WOT results in a dead rich mixture (your cutting the air off) for a couple of engine cycles....which gets sent out into the hot ass exhaust pipe...and through the hot ass cat...and ignites...Gen1GT said:
Striker187
Member
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- 2008 MS3 GT
isn't 13:1 a little on the lean side? i thought 12:1 was the ideal ratio for turbo cars? or maybe i'm just losing it 
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- MP5T / 944
14.5 On Paper is a Good Clean Burn!! 
Installshield 2
Gothenburg Superiority
yeah 14.7:1 is ideal stiochiometric...Not sure who tries to run leaner than that but it isn't best for anything but a grenade...Most modern engines can barely tolerate 14.7:1 at idle without overheating...As load increases more fuel is required to keep detonation at bay...which is exactly why our stock ECU's are running on two loop modes...Open for emissions at low load levels...and closed when load increases...Open keeps the mixture as close to stoichiometric as possible, and closed dumps fuel big time...
Every engine behaves differently with different mixtures...leaner mixtures can be run with more retarded timing (ignition wise), but 13:1 does sound lean with a turbo...
Every engine behaves differently with different mixtures...leaner mixtures can be run with more retarded timing (ignition wise), but 13:1 does sound lean with a turbo...
MP3skaterNC
JDM *****.
- :
- slotege mp3
that is true, over time if your stupidly rich, you can wash the rings out. gas in the oil is a sign of this. matthew shouldn't be that rich at all though. Alto of stock turbo cars will shoot flames when they have full turbo backs. its really not that big of a deal.Bigg Tim said:
like i said before. id raither run 11.5 and be safe, than gain 10whp, and the chance of detionation if you get some crappy gas.
rustychops41
Member
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- 2007 Mazda 3s HB
Reminds me of just before we were teenagers first getting into cars and such. I had a friend who SWORE that lighting farts taught you all about how the internal combustion engine works. He said it displayed, "Compression, ignition, combustion, exhaust." Well, sorta.
Striker187
Member
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- 2008 MS3 GT
i thought it was the other way around? the lower the ratio, the richer you are. hmmm....time to run a search for some answers.
im pretty sure its not. 12:1 FMU pushes more fuel because its 12 parts fuel to one part air. like if im at 64psi of fuel at 8psi of boost divide and you get 8:1...lean as hell...now im at 96psi of fuel and 8psi of boost its 12:1...
thats why less fuel is more susceptible to going boom! because say 8:1 is only 8 parts fuel to one part air, meaning there is a lot more air which is highly combustable in the fuel...where at 13:1 you only have one part air for every 13 parts of fuel.
thats why less fuel is more susceptible to going boom! because say 8:1 is only 8 parts fuel to one part air, meaning there is a lot more air which is highly combustable in the fuel...where at 13:1 you only have one part air for every 13 parts of fuel.
Striker187
Member
- :
- 2008 MS3 GT
see that's what i thought originally too. but i'm looking at the msp dyno in turbo magazine.....the a/f ratio starts around 13:1, goes to about 14.5:1 around 3.5k rpm, then drops to 10:1 and stays there from about 4k rpm on. and the msp is known for runnning notoriously rich 
