StickyMicky

a mate has an evo which has been mapped on a motec ecu to give pops and bangs on overrun and when the throttle is lifted

what exactly happens when this os in effect?
i belive the timeing is altered to help?

do the pops and bangs happen in the cylinders or actually in the exhaust?
this might seam like a daft post, but im having a total brain freeze and i dont really have a clue whats happening today

if they happen in the exhaust, i cant see how timing would change it?
if its cylinders, does this have an antilag effect?

Floyd

iTrader: (9)

I thought it was just unburnt fuel igniting in a hot exhaust. The map would be very rich at a guess.

F

StickyMicky

the mapper told him that sumthing was changed in the map to promote it, i could have sworn he said "retarded" which is why i thought timeing was involved?

or it could have just been evo-scooby banter and he was calling me a numpty
lol

Tidgy

from what i remember pat saying was its something to do with exhaust timing (may be wrong on that) but it def is mapped into the cars cpu

TonyFlow

IIRC, if you retard the timing @ certain rev/load levels (i..e on overrun you will have relatively high revs @ little or no load), you will get unburnt fuel delivered into the exhaust due to then fuel not being able to complete its combustion process in the engine, this will hit a hot exhaust and create the pops and bangs.

StickyMicky

so it is in fact both the ecu and the hot exhaust

BlackWrxScooby

i have a MY93 with upgraded ECU and full de-cat. it pops and bangs through the gears, half sound like an Anti-lag system. it sounds amazing!!

StickyMicky

the car i was in was not just a pop every other gear change, its was multiple bangs, as soon as the throttle was released

it was pretty impressive to be honest

TonyFlow

I think it is also to do with hitting oxygen in the exhaust which creates a combustable atmosphere (oxygen is needed for a flame), causing the fuel to ignite

fitzscoob

so if a car's exhause pops and bangs, does this mean then that given the right circumstances, hot exhaust etc that flames will be naturally occuring?

TonyFlow

My car does spit flames occasionally with no flamer kit.

white knight

My car previously had a Motec ECU fitted to it (unfortunately, the previous owner took it off when he sold it ), and he'd had pops and bangs programmed into the map on the over-run.

Even with the standard ECU, mine used to pop and bang like a good 'un (after I'd changed from the Jetex backbox to a 5" Cobra one anyway!), but unfortunately, after Andy F had supplied, fitted and mapped my Apexi PFC, these pops disappeared

All is not lost though, as after heat-wrapping the downpipe, mine now pops mid-gearchange rather nicely if I take my time with upshifts and the exhaust is hot enough - after it's been sitting in traffic for a minute or two is usually the best time! And I've been told it occasionally spits out small flames as well - cool!

RR

The pops and bangs are mapped in, i have the same. Its the Evo a little to quick for you now Micky.

DaveW

White Knight,

You could always speak to AndyF as he mapped my PFC with 'simulated' anti lag

Dave.

StickyMicky

not sure exactly what you mean, i dont have my car at the moment.
i have not driven it for a few weeks

its away getting a few mods done

GBruce

Hi,

My car used to pop and bang on overrun with big flames coming out the exhaust. TBH it was nice for a couple of days then it got really annoying so we sorted out the fuel so it cut on ovverrun down to about 1300rpm and it has completely dissapeared. And now getting much better MPG too :-) not throwing in loads of fuel when it's not needed.

George

69WRX

You guys that have a commander with your PFC, check this out

http://bbs.scoobynet.co.uk/showthrea...hlight=overrun

white knight

I had tried this a few times, but without much in the way of results, but might give it a go again tonight for our Ipswich Scoobycity meet