Exhaust pop

[oscar32]

Ok,

So, if you really want your car to shoot a flame out (like a few feet) here is one way I've been told. I've also been told not to use it on the street, which I'll explain in a sec. I wouldn't do it myself.

As you are flooring the car getting ready for a shift, you set up your management to continue fueling as you push the clutch in (and back off for that second) as you go through the gears. It also retards the ignition which keeps the turbo on boost, and shooting raw feul out the back (which will catch fire if the exhaust is hot enough). Runs great, and heaps of fire (think v8 supercars). Cat, no cat, its doesn't matter, as long as you have a resonable sized pipe.

The downside is if you are driving down a hill, backed off, the car will still be feuling - which means the turbo will get HOT. Apparently even coasting down a hill for 30 secs or so can make a turbo glow red and fail.

Another system is to shoot a flamable gas (nos?) out the exhaust from near the diff, using a spark plug to ignite (ah lah Fast and Furious).

not that i'd bother...

[Buddy Club R33]

Now my question is whether the pop is good or bad....

Is it just the car efficiently getting rid of unburnt fuel upon gear change or some kind of problem with the whole ECU set up.

[oscar32]

That description doesn't just make a pop, its a rather big bang.

I don't think its harmful for a little pop every now and then, most skylines I know seem to have always done it....

[adznight]

You do not need to pump other gas into the pipe to create a flame, I've seen kits that work on a coil pack and a spark plug. They simply spark in the exhaust tip and bang, you have flame. Don't forget boys and girls, those gassesfumes are flamable!

http://www.flamethrowers.com.au

Rice anyone? Ooooh yar, 2F2F....

[adznight]

Oh one more thing, that pop can have to do with turbulence in the pipe also I think, i get it on gear changes but unless you getting massive explosions I don't think it's an issue. It's kind like shooting a cap gun in a pipe.

[mjfawke]

I have no cat (sucked in everyone - not required on a pre-'72 car!) On occasion, I have made cars behind me disappear in a cloud of soot when it pops... Seems to be more of a problem on hot days.

[silver gts-t]

there something to be proud of

[Kaido_RR]

cars with a cat wont... some cars cats might be badly degraded (if its been on there for a few years etc) so you might get a flame.

Mine flames on the odd occasion... i think. Whether it makes it out the rear end or not i dunno. No-one's ever seen it.

You can tell the difference between a pop and a flame.

The sound is a tad different between the usual pop, and when the fuel catches.

not ture, i have a cat and i get flames (view the sauwa/silviawa cruise video) unless my abuses over the years has eaten it up

[HIPSI]

Apparently you get the pop out the exhuast more often when you have a external venting blow off valve. As for flames out the exhuast my R33 had a 3inch hiflow cat and after driving the car fairly hard (york cruise SAUWA!) would get flames on most gear changes.

[AzzurrA]

I have no cat (sucked in everyone - not required on a pre-'72 car!) On occasion, I have made cars behind me disappear in a cloud of soot when it pops... Seems to be more of a problem on hot days.

Pre-86 cars

[mjfawke]

Pre-86 cars

In NSW (and ACT, which uses the NSW rules), an engine conversion on a car built from 1972 onwards has to meet the emmissions requirements of the year the engine was built in. Cars built prior to 1972 only have to meet the emmissions of when the car was built.

So - if you were to take a 1985 car and put an RB engine in it, you would have to run an exhaust choke... sorry, "catalytic convertor". I think it was the CEO of Lukey mufflers who commented that the best flowing catalytic convertors flowed almost as well as the worst flowing mufflers...

In my case, I can run aftermarket injection, play with cams, turbo etc. etc., and as long as I meet the CO/HC limits for 1971, I don't have to worry about the EPA.