sparky300

quick question,


over the last week i have had a jap cat back system and a dump valve fitted the car is running 11-12psi its a my93

every time a put my foot down to here the turbo going, on change of gear there is a little pop from the exhaust, should i get worried about this?

PS it does not do it all the time just if i am driving it hard.

frayz

iTrader: (7)

Its pretty common for that to happen when you have a vta dumpvalve and a full decat mate.

The vta vents air to atmosphere that has already been read by the MAF. This in turn results in the ecu supplying fuel whan the air that was meant to use it has been dumped from the system.

This creates a momentary rich condition, its this excess fuel that ignites in the downpipe thus resulting in the pop you hear.

Its a basic view but hope thats helps

[Davey]

As above same thing happens on the other halfs WRX, the dump valve creates a rich mixture as you come off the throttle.

sparky300

but in not a de-cat, just a cat back, is there one or two cats on a my93 import?

sparky300

thanks peps

gaz c

if you time it right you can get a pop and bang on every gear change.

and the od flame.

Criss

GazTheHat

Go on then, explain how you do it?

I've tried feathering the throttle on overrun & stabbing the throttle on overrun. Whilst it pops and rarely bangs, i can't do it on command.

deanwoodward

me to i want to no how to do that

rossyboy

iTrader: (8)

Only one cat, in the down-pipe.

You dont need to have it removed to get pops. Mine did it with just the VTA before I removed the cat. With the cat removed they became more frequent and louder.

If you get your car properly mapped, it'll hardly do any at all.

GazTheHat

That probably explains why i dont.

rossyboy

iTrader: (8)

Ditto, I only get little pops on over-run now. Nothing at all between gear changes. Better for the engine though

gaz c

i will try to explain? my car is 95 wrx.

ive got a cat back system. a clinic BOV. and no remap! i run it on opitmax and millers octane boost.

i can get mine to pop and bang in 1st 2nd and 3rd and sometimes 4th.

what i do is as follows.

in 1st gear i increase speed gradualy to around 4000 to 4500 rpm and do a quick change of gear to 2nd and so on. 8 times out of 10 it will bang sometimes loader than other times.

to make it pop i simply coast it down a hill in any gear and i get pop pop pop bang?

ive had a word with the clinic and they say its normal and not to worry.

hope this helps.

sparky300

so is this popping bad for my engine (ps it does not do it all the time, only in hard gear changes)

GazTheHat

Isn't it to do with running rich? unburnt fuel is getting through and exploding when hitting the hot exhaust, therefore, when mapped it is less likely as the fueling is correct.

sparky300

must be cus of the cat back and the vta, but will this at the moment (till its mapped) damaged my engine, it there any drawbacks, will this cause power loss?

chrisola

my pops when coasting sometimes, just little ones.

just got a cat back Ninja exhaust (on a MY00)

scottish_jim

I have an STi7 PPP Turbosmart DV and TSL Typhoon BB and it pops and bangs like a good un. Love it. Can almost do it on demand. think it sounds great.

rossyboy

iTrader: (8)

Do a search on dump valves

sparky300

done a search mate, yes it seems like a common issue, cus of the mods its running rich, what i want to know is can running rich like this damage the car in anyway (although as said i do like the sound lol)

GazTheHat

if it's over fuelling it can cause bore wash, which is not good. Do a search on that.

MaDaSS

Same for me on an MY03 WRX. Ninja BB. Coasting always gives me little pops and that. Especially the long downhill roads, LOL.

sparky300

i get little pops, but sometimes (not often) a bang (not like a backfire, more like a loud pop)

its only got a cat back and vta, no de-cat

g3m xr

i get it sometimes on 1st to 2nd change !

SUBTYPER

Mine pops and bangs all the time, Oh hang on I got a GEMS ECU ith anti Lag lol

Big-G

Mine pops on overrun.

Scooby World decat centre pipe with TSL Typhoon back box.
Awesome sound on full throttle but low deep rumble driving past the neighbours

pnbond007

iTrader: (1)

pop-in / bang-in & flammer kits

Surely this is for the chav brigade....

If you want meaningful stuff like this going on just fit anti-lag & do it properly

alex_00s

iTrader: (18)

You gotta love the popping!

I have mine fully de catted with a vta bov and when the car gets really hot on long hard runs she pops like a flatulant bull bog that just eaten half a kilo of baked beans!

A nice trick I like to pull off is when I'm slowing down thru the gears, as you dip the clutch to select the next lower gear, select the gear and just as you come up on the clutch if you catch the revs just right, blip the accelerator a tad and it chucks a bit of fuel out and you get a lovely bang front your *** end! Give it a go!

pnbond007

iTrader: (1)

[QUOTE=alex_00s]You gotta love the popping!

Oh I do,
but ***** footing along so grandad can hear your exhaust ain't driving the car in-it...

alex_00s

iTrader: (18)

***** footing??

To get the bangs, or explosions as some ppl like to call them, you simply cant be "***** footing".

To get these noises you have to be absolutely ragging the daddy f*** out of it and timing these bangs on deceleration thru the gears is when revs are up near the red line.

I'm talking hard driving ppl - sorry for any confusion, this is not a trick you do while poddling along, or "***** footing".