Sidepipe flames

[NorCal Cobra]

I was on the freeway last night and abruptly lifted the accelerator after hard acceleration in 4th gear. I was surprised to see the reflection of blue and yellow flames coming from the sidepipes off of the concrete center divide.

I proceded to do it numerous times with the same result.

Too cool!!!!

Anyone have similiar experiences? Anything to be alarmed about?????

427 Stroker motor 560/560

[svtcobra]

Assuming that you have carburettors rather than fuel injection, this is nothing much to worry about. During hard acceleration and at high revs., the carbs. allowed as much fuel and air as possible into the engine; when you lifted off suddenly, the engine continued sucking lots of fuel in, which didn't burn in the engine (because the butterfly valves in the carbs. were closed by the throttle so didn't allow any air to mix with this fuel), which then got blown through and exited down the exhaust manifold. When these hot, fuel-rich unburnt waste gases met the oxygen in the silencer / muffler chamber and outside the tailpipe, the fuel ignited and caused the flames.

My BRA 289 (Rover 4.6 litre V8 with Holley carbs. on Offenhauser manifold) does this above 5500 rpm, and it is a great way of getting a tailgater off my @rse on the German autobahns .... I love watching the front of the car behind dip down as it brakes hard to avoid being set alight by the flames from my twin rear-exit pipes !!

Another way of provoking such fireworks is to switch off your ignition for about 2 seconds at high revs., then turn it back on again (assuming that you have a separate ignition switch, not one integrated into the steering lock ) - this usually produces a much louder bang and larger flame !!

The only risk that I know of is that the explosion of unburnt fuel may blow out the baffle plates in your silencers / mufflers, unless they are good quality units (I destroyed a pair of Dynopack Glasspack mufflers within 1 year) .

[BDR561]

My 1st BDR with its 408 stroker would throw flames... Really cool at night...

[CBattaglia]

When I shut my car off I get a flash from each side with a cool flame noise.

[rdorman]

Better bang is to shut it off, give a couple of quick pumps and then turn the ignition back on. POW!

[CBattaglia]

Is it safe? Not for me, for the car

[MaSnaka]

When I was 18 I always thought it was cool when my friend's cars would make that big bang. It would usually scare the pants off anybody nearby. So...I tried it when I got a car and blew my muffler clean off. The car was a 66 Buick Station wagon. That was back when the $100.00 repair bill really hurt the wallet. I haven't tried it since, but you all go right ahead. hehe

John

[rdorman]

MaSnaka.... reminds me of a story... back in the mid 80's I was at the run-offs at Road Atlanta with a few guys from Ireland that where competing. The night of the banquet was a Sunday night and the area was dry. This of course would not stop a bunch of irishmen from drinking. So with a fully loaded cooler we proceed to slip a couple of cases through the door over the course of the evening and managed to tie on on fairly well. We left them in a large pyramid of empties on the table right in the banquet. Many around us wanted a cold one as well.

Any ways, for the back fires. John was driving and decided to give the locals a little thrill as we passed them by. The classic dive over the bushes or pull over looking for the flat tire that just exploded has us, in our condition, rolling from laughter. John could make that van explode loudly! Well I guess the locals where not impressed because the police got calls that a bunch of guys where shooting off shot guns from a van meeting our description. I don't know what the problem was, I thought that was the norm for a sunday night in the Atlanta area

A short time later we are at a four way stop waiting for a light when all of a sudden we are surrounded by about 5 or 6 police cars coming from all directions. They leap out of their cars guns drawn and order us to put our hands up! They approach, spot lights, guns and dogs toward our van... very cautiously. Quickly they realize that we are there racing, they explain about the calls and the shotgun, and of course, let us go... with out so much as looking around inside the van! They even joked around with us... nice guys! We may not have had a shot gun, but they did have the right guys! Ah youth

[svtcobra]

I used to work for BFBS (British Forces Broadcasting Services is the equivalent of AFN, except that it is a private company employing civilians and partially financed by the military for whom we were providing a radio and television service). The favourite company vehicle was a Land Rover V8 which would backfire and spit flames whenever the clutch was dropped and the throttle was blipped up to 5000+ rpm.

This did not go down well whenever we did this whilst driving through the garrison after dark during red alerts (caused by the IRA terrorist attacks). But the sight of grown men in uniform throwing themselves flat onto the ground as we drove past will remain a fond memory for many years to come !!

I'd like to blame this on our youth, but we were all in our late 20s then ....

[wtm442]

Originally Posted by CBattaglia

Is it safe? Not for me, for the car

Absolutely safe. What's a small explosion inside of a side pipe. Absolutely safe until you blow off the side pipe. Gee, I wonder if exploding steel can go thru fiberglass?

Why don't you just throw some M80 firecrackers up the side pipe and see what happens.

Friend of mine did the "turn key off and back on" when we were teenagers in his straight 8 Buick. Blew the entire exhaust off, ran over the mess which punctured a tire causing the car to swerve hitting a big curb and bending the rim. We fixed the problems and a week later threw a rod right thru the block! Ah, those were the days.

[NorCal Cobra]

Thanks for the detailed explanation SVTCOBRA. I assumed it was just the unburnt fuel in the sidepipes igniting (just like when you see Nascar cars as they slow for a turn).

How cool would it be to install those exhaust tip spark plug igniters on a Cobra!!! (I know they are highly illegal)

Although, you would probably melt your rear fenders after a while.

[MaSnaka]

Hey rdorman, I notice your in Columbus OH. I have many family ties to Columbus, Grove City and Upper Arlington. I use to spend time there during the summers visiting my Grandparents...a long time ago. I was there in 69 when the astronauts walked on the moon for thr first time. Johnny Bench and Hank Aaron were hitting the long balls. Brings back memories.

John

[svtcobra]

Originally Posted by wtm442

Absolutely safe. What's a small explosion inside of a side pipe. Absolutely safe until you blow off the side pipe. Gee, I wonder if exploding steel can go thru fiberglass?

I'm OK, because I have rear exit pipes .... so I would only get exploding steel going through the 32 gallon gas tank located under the trunk floor and directly above the exhaust mufflers

Originally Posted by wtm442

Why don't you just throw some M80 firecrackers up the side pipe and see what happens.

Now that would be childish .... wait a minute, where did I put those firecrackers left over from last New Year's Eve ??? ....

Originally Posted by wtm442

Friend of mine did the "turn key off and back on" when we were teenagers in his straight 8 Buick. Blew the entire exhaust off, ran over the mess which punctured a tire causing the car to swerve hitting a big curb and bending the rim. We fixed the problems and a week later threw a rod right thru the block! Ah, those were the days.

Oooppppssss - maybe I should consider going back to edit my "comparatively harmless" post

[rdorman]

Originally Posted by MaSnaka

Hey rdorman, I notice your in Columbus OH. I have many family ties to Columbus, Grove City and Upper Arlington. I use to spend time there during the summers visiting my Grandparents...a long time ago. I was there in 69 when the astronauts walked on the moon for thr first time. Johnny Bench and Hank Aaron were hitting the long balls. Brings back memories.

John

I am just across the river from UA. Been here all my life and I remember well watching those first steps on the moon. I used to know a number of people from Thousand Oaks as well. Grueter's, Shilington's, etc. We used to host a party here during an OSU football weekend called California Invasion and every year about a dozen guys would fly in from Thousand Oaks CA.

[MaSnaka]

rdorman, I remember watching boat races on that river (Scioto?) shooting their rooster tails of water up to bottom of the bridge. I forget the street name. My dad and uncle are both OSU alumn. The world is getting smaller everyday.

John