Fire-spitting tailpipes!!
#1
Instructor
Thread Starter
![Question](https://rennlist.com/forums/images/icons/icon5.gif)
A friend of mine with C4S w/after market turbo charger (Lotec) was in front of me driving at a fast pace on Sunday. I saw fire coming out of his tail pipes a few times.
I think it happens when he was slowing down, and changing gear. It looked pretty cool, but I am wondering whether his engine or exhaust might be damaged because of it.
We got off the highway, switched cars and I tried to repeat the phenomenon by downshifting from 3rd to 2nd @ 4,000 rpm. But I couldn't do it. I heard that it may be due to unburnt gas in the exhaust coming thru the hot tailpipe and got re-ignited again.
Does anyone know why this might happen?
I think it happens when he was slowing down, and changing gear. It looked pretty cool, but I am wondering whether his engine or exhaust might be damaged because of it.
We got off the highway, switched cars and I tried to repeat the phenomenon by downshifting from 3rd to 2nd @ 4,000 rpm. But I couldn't do it. I heard that it may be due to unburnt gas in the exhaust coming thru the hot tailpipe and got re-ignited again.
Does anyone know why this might happen?
#7
Three Wheelin'
Join Date: Jun 2001
Location: SF Bay Area
Posts: 1,276
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Nope - a turbo Porsche running without cats will do this when the turbo is hot. It usually occurs on downshifting as exhaust gasses with unburned fuel are forced out past a red hot turbo and ignite. My 930 does this - it is very cool to see and is normal. It generally does not damage the car.
Trending Topics
#8
Addict
Rennlist Member
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Unfortunately it wasn't me driving, this pic is off of my mini DV camera - it was at a trackday at Donnington where we shared the track with a couple of Porsche Racing teams.
The 'Pink Gazelle' ended up in the gravel soon after...!
The 'Pink Gazelle' ended up in the gravel soon after...!
![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
![Cheers](https://rennlist.com/forums/images/smilies/beerchug.gif)
#10
Three Wheelin'
Join Date: Jun 2001
Location: SF Bay Area
Posts: 1,276
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Well it better be a bit rich when you are under boost or watch out - in any event, ask any turbo tuner out there ahd they will tell you this is normal for a turbo running without cats.
#11
Instructor
Thread Starter
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
Thanks for informative comments.
So, this means my friend's turbo-charged C4S maybe running without catalytic converters?
If his car has cats then there shouldn't be any fire coming out of the tailpipes?
So, this means my friend's turbo-charged C4S maybe running without catalytic converters?
If his car has cats then there shouldn't be any fire coming out of the tailpipes?
#12
Rennlist Member
![Default](https://rennlist.com/forums/images/icons/icon1.gif)
And without cats you can use the leaded gasoline say octane 118 : ). Great on the track with better mid-high rpm but kinda loud for the street and smellls like the dickens. Regards. Mike