# Pops & Bangs / Shift Pops - How Do They Work?



## -SeanS (Apr 10, 2012)

I'm sure most of us have seen the videos on youtube of GTRs doing huge backfires and spitting flames all the time. I am currently at Stage 4.25 mapped by Litchfield and have the pops and bangs and shift pops. I'm not a chav but I do think the big backfires look pretty impressive and at my last visit to Litchfield I enquired as to why mine seem pretty tame in comparison to others I've seen (The Knight Racer ones seem particularly aggressive) and was told the aggressive pops and bangs maps aren't very good for your engine, well the words were "it destroys your engine". As Litchfield are experts in this field I'm happy to stay on a map that is safe for the car whilst still being able to make the odd bang here and there.

This got me thinking though, exactly how does the pops and bangs work, and the shift cuts? And how damaging is it to the various components in the car? I've heard crude explanations of unburnt fuel igniting etc, but is anyone able to offer a more in depth explanation as to how it works and how damaging it is to the car? I know many have had the KR650 conversions that have fairly aggressive maps, has anyone had any issues? One other thing I noticed is that Knight Racer seem to use a 'Racerom 5.2' version of Ecutek for their 4.25 conversions, does anyone know why?


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## dudersvr (May 7, 2003)

Call Ben Linney and ask, the KR maps come from him.


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## bobbie (Jan 3, 2013)

opcorn:

Bobby


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## Adamantium (Jun 24, 2002)

You run rich on overrun so that unburnt fuel goes straight into the exhaust and ignites at some point in the exhaust, typically close to the exhaust outlet where there is available oxygen.

It's similar to boost off the line except that boost off the line is produced with an open throttle so that unburnt fuel is ignited in the presence of excess oxygen but in the turbo rather than in the combustion chamber.

It's bad for the engine in more extreme cases because running excessively rich at any point in time can cause ignition in the turbo which reduces the life of the turbine blades, but also excessive fuel in the combustion chamber causes bore wash, where the excess fuel washes away the oil on the cylinder bores which lubricates the movement of the piston. This increases piston and cylinder wear. Mild pops and bangs won't come close to causing this.

Personally I hate the idea of them, the GT-R is not a rally car. Pops and bangs are a relic of antilag which is used in rallying. The GT-R never was and never will be a rally car. It doesn't need antilag, especially with the speed of its gearbox.

It's totally out of keeping with the nature of the GT-R.


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## WarrenA (Jun 2, 2016)

I'm with you on that Adam can't see the fascination with it and think it looks awful sitting there revving the nuts of it like a 18yr old with a flamer kit on his nova lol


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## Trev (Nov 1, 2003)

It's for chavs, end of.


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## 55chev (Mar 4, 2015)

To chav for me, don't see the fascination myself,must be getting old i recon


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## -SeanS (Apr 10, 2012)

Adamantium said:


> You run rich on overrun so that unburnt fuel goes straight into the exhaust and ignites at some point in the exhaust, typically close to the exhaust outlet where there is available oxygen.
> 
> It's similar to boost off the line except that boost off the line is produced with an open throttle so that unburnt fuel is ignited in the presence of excess oxygen but in the turbo rather than in the combustion chamber.
> 
> ...


Thanks Adam that's a good explanation. I'm assuming your point around bore wash is something that would generally occur over a long period of time rather than through the occasional use of more aggressive pops and bangs? i.e. if people were in that map every time they drive the car then that's where the issue becomes much more prevalent?

How about the shift pops is that the same principle?

To those saying it's for chavs I do agree and I rarely do it, but come on it's fun sometimes to release your inner chav and just make some extra noise :chuckle: A lot of cars at the minute have the shift pops built in, just look at Merc/Audi/BMW/Jaguar etc, I think I'm right in saying that all of their top models do a crack/pop when shifting or on the overrun, although have to admit sometimes it can sound pretty artificial.

The video I watched that made me think it was pretty impressive was this one: https://www.youtube.com/watch?v=vEhUVS2ey_M

That backfire in the tunnel is crazy!


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## borat52 (Jan 29, 2006)

I think the very aggressive pops are horrible, especially just sat stationary revving.

A few subtle burbles on over run can sound quite nice imho.

Obviously if you have cats, or decide to put them back in then they'll die very quickly with pops and bangs.


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## dudersvr (May 7, 2003)

borat52 said:


> I think the very aggressive pops are horrible, especially just sat stationary revving.
> 
> A few subtle burbles on over run can sound quite nice imho.
> 
> Obviously if you have cats, or decide to put them back in then they'll die very quickly with pops and bangs.


Depends what CATs you fit the ones AC fit are fine with pops and bangs.


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## Adamantium (Jun 24, 2002)

Occasional use is of course better.

The more aggressive and the more often, the more likely the damage.

Of course there's also damage to cats if you still have them.

Pops on gearchanges are more about noise than flames. I'd be surprised if a mainstream manufacturer released a car that spits flames.


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## 55chev (Mar 4, 2015)

REPHRASE= pops and bangs on upshift and downshift i like,
sitting in a carpark reving the tits of it NARRR!!!!


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## TAZZMAXX (Mar 9, 2010)

The only 'pops and bangs' that sound good are carburettor engined cars on overrun. Anti lag sounds shit. V6 engines trying to emulate either - even more shit. Each to their own and all that....


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## -SeanS (Apr 10, 2012)

55chev said:


> REPHRASE= pops and bangs on upshift and downshift i like,
> sitting in a carpark reving the tits of it NARRR!!!!


Agreed

Adam - Yes I was referring to the noise when shifting.


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## borat52 (Jan 29, 2006)

dudersvr said:


> Depends what CATs you fit the ones AC fit are fine with pops and bangs.


Really? Are they in the Downpipes or Y-pipe?


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## Stealth69 (Jan 6, 2005)

"Pops and bangs" on the gear shift is ****, it only really works over 5krpm and on WOT, anything less than those two factors the shift is bloody awful and the car detects DET so not only are you going slower because the gear change is shite it's also pulling timing, waste of time! 

Basically it leaves the injectors open and cuts the timing, same as pops and bangs in normal driving, total shit


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## Kieranrob (Apr 3, 2012)

I have only ever used the pop's and bangs map a hand full of times and that's when I had some pals in a car behind me. I feel it doesn't feel right for the car and am scared to turn my turbo's into turbo soup


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## Adamantium (Jun 24, 2002)

Stealth69 said:


> "Pops and bangs" on the gear shift is ****, it only really works over 5krpm and on WOT, anything less than those two factors the shift is bloody awful and the car detects DET so not only are you going slower because the gear change is shite it's also pulling timing, waste of time!
> 
> Basically it leaves the injectors open and cuts the timing, same as pops and bangs in normal driving, total shit


Why does the car detect det?

Too much fuel reduces chance of det as does leaving the timing late. It's basically taking too the extreme the changes you would make to reduce det.


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## terry lloyd (Feb 12, 2014)

I can see the knock sensors picking up false knock if the engine is making a lot of noise ....


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## Stealth69 (Jan 6, 2005)

Adamantium said:


> Why does the car detect det?
> 
> Too much fuel reduces chance of det as does leaving the timing late. It's basically taking too the extreme the changes you would make to reduce det.


Because under 5k the effect of the change are so shit and brutal the engine detects false det, use it, try it and find out...... its ****! The check engine light flashes it's nuts off

I didn't say it was detting, I said it detects det!


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## dudersvr (May 7, 2003)

And as if on Q here is another example of why not to sit for minutes on end with flames coming out of the exhaust, this GTR caught fire and seeing how it was treated I cant say im surprised or even sympathetic, only pre pubescent teens are impressed by this, a couple of seconds of anti-lag/launch can be funny but sitting for minutes on end shows zero mechanical sympathy and a certain mind set if you think this will impress anyone 






Even the bonnet is up and car covered in extinguisher remnants and as the other pics Ive seen on the net have the plate then good luck with an insurance claim


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## Adamantium (Jun 24, 2002)

I didn't say it was detting, I said why does it detect det?

I'm not entirely sure why the engine is any noisier.

knock sensors have a quite a high sensitivity to the specific frequencies of det, they aren't just wide spectrum microphones (for obvious reasons).

I could understand if they pick up the pops and bangs in the exhaust that travel into the block pretty much unattenuated, but I'm surprised that still registers as noise to the knock sensor.

Either way, seems we are in complete agreement that they are a stupid idea pretty much all round.

It's also embarrassing for the tuner. Cars like ours shouldn't pop and bang, it advertises bad mapping and it's not always obvious that it's intentional.


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## Adamantium (Jun 24, 2002)

dudersvr said:


> And as if on Q here is another example of why not to sit for minutes on end with flames coming out of the exhaust, this GTR caught fire and seeing how it was treated I cant say im surprised or even sympathetic, only pre pubescent teens are impressed by this, a couple of seconds of anti-lag/launch can be funny but sitting for minutes on end shows zero mechanical sympathy and a certain mind set if you think this will impress anyone
> 
> 
> 
> ...


battalion sticker on the back doesn't help their cause!


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## dudersvr (May 7, 2003)

Adamantium said:


> battalion sticker on the back doesn't help their cause!


I have a Battalion sticker on mine !!!!:thumbsup::clap::runaway::flame:


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## Stealth69 (Jan 6, 2005)

dudersvr said:


> I have a Battalion sticker on mine !!!!:thumbsup::clap::runaway::flame:


And yours broke aswell :running away:


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## dudersvr (May 7, 2003)

Stealth69 said:


> And yours broke aswell :running away:


Only a little bit though !!!! Still drove it out of Brands. Annoying thing is im waiting on a slot for the forged engine build at AC


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## Sam McGoo (Dec 30, 2015)

Good thread, and a question I was going to ask as well. 
I'm only stage 1, and obviously don't do flames etc but have very occasionally enjoyed a few pops on over run and up/downshift. 

The fact that some modern cars have this as standard and also the fact that on the Litchfield instructions it says "Map1 /95 - This mode is made for day to day driving" and "Driving the car with 99 fuel in the 95 mode will cause no damage" would suggest its harmless. 

It would be nice to get a tuners opinion in this! 

Obviously large flames and reving the nuts off a car at standstill isn't gonna be doing any good at all but a few pops on overrun/gearchange?


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## Adamantium (Jun 24, 2002)

What has driving in 95 map with 99 fuel got to do with this?

Modern cars do a slight pop on gear changes and only when accelerating. Nothing to do with overrun and no flames.


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## Stealth69 (Jan 6, 2005)

The modern cars do it by design from the factory, not forced as an after thought and gimmick.

As a day to day driving toy it will barely be active, the parameters of the gearshift is something like 85% throttle, on a day to day basis you won't be running 85% throttle very often, if at all. 

I had this on my car and messed around with it, it's really a crap feature without enough variables involved before it activates


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## Sam McGoo (Dec 30, 2015)

Adamantium said:


> What has driving in 95 map with 99 fuel got to do with this?
> 
> Modern cars do a slight pop on gear changes and only when accelerating. Nothing to do with overrun and no flames.


Just an illustration of the fact that on the lichfield paperwork everything is suggesting that using the 95 map will not cause any harm to your car. And its the 95 map that has the pops and bangs feature. 

I wasn't talking flames on modern cars, just pops and burbles. like on the M cars and the F-type etc


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## Sam McGoo (Dec 30, 2015)

Stealth69 said:


> The modern cars do it by design from the factory, not forced as an after thought and gimmick.


Which is why the question of how it works was asked. On our cars, as an "afterthought", is it done differently to those that do it as standard ? 
If so, why and what is the difference? If its done in the same way, why will it cause damage on our cars but not an M car or f-type for example?

As I said, I'm talking Stage1/2 cars not aggressively mapped fire-starters.


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## dudersvr (May 7, 2003)

Id be surprised if the 95 map has pops and bangs! All the 95 map is less timing and depending on map 3 less boost incase you get caught with no 99 octane


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## Stealth69 (Jan 6, 2005)

from what I understand the basic principles are the same but they are done properly from the off, by design, I don't know the ins and outs of it, but this is a stick on mod for a car that wasn't designed to do this. 

Irrespective of state of tune, the method and impact is the same


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## -SeanS (Apr 10, 2012)

dudersvr said:


> Id be surprised if the 95 map has pops and bangs! All the 95 map is less timing and depending on map 3 less boost incase you get caught with no 99 octane


He's right my 95 map was pops and bangs too (Although I only recently had shift pops activated which should have been there before). You can have it set so that it also goes off your suspension settings. I currently have to have it in 95 map with suspension in R mode, although I have noticed that it does it to a lesser extent in Comfort mode too. 

Just to clarify as I can see lots of people are jumping on the 'pops and bangs are sh*t/not in keeping with the GTR' bandwagon - I'm not saying they're great and should be used, my question was around exactly how they work, what damage they can potentially cause and if the technology is much different to other mainstream manufacturers. As has been said it's probably fair to say the shift pops are nowhere near as sophisticated in this application as the ones in AMG/RS models etc but I'd be interested to know why.


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## Adamantium (Jun 24, 2002)

Sam McGoo said:


> Just an illustration of the fact that on the lichfield paperwork everything is suggesting that using the 95 map will not cause any harm to your car. And its the 95 map that has the pops and bangs feature.
> 
> I wasn't talking flames on modern cars, just pops and burbles. like on the M cars and the F-type etc


Didn't realise that 95 was the pops and bangs map.


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## -SeanS (Apr 10, 2012)

Adamantium said:


> battalion sticker on the back doesn't help their cause!


Had to laugh as it's also a Knight Racer conversion as you can see from the back :flame:

To be fair it looks like that car either has a flamer kit installed or an extremely aggressive tune outside of usual pops/bangs to be making those flames (which the owner has clearly requested at his own peril). Those videos are cringey as hell though


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## Hackett88 (Dec 27, 2016)

has a Kream Developments flame kit from what ive been told hence the PBR stickers


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## dudersvr (May 7, 2003)

More and more cropping up, a flamer kit works from a spark plug in the exhaust the black car and ones in this vid are doing it of a map setting, the cars are on the limiter, look at the blue car its exhaust at the tips is glowing orange

https://www.youtube.com/watch?v=NcP9K9f0QvA&index=5&list=FL54gwmJcqsFuS88p6yfiLww&t=1s

You dont need a flamer kit for pops and bangs, this is proper antilag, made a bar of boost in neutral.


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## Tin (Aug 15, 2010)

Pops & Bangs was an addon to the 95 map, by owner request - as far as I'm aware. Not a default mapping setup from Litchfields. For those who specifically asked for pops & bangs, Iain put it on the 95map.


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## Adamantium (Jun 24, 2002)

I think the OEM pops are handled by a dedicated map that accesses an entirely different table purely for the purposes of making the little blip noise on gearchanges when in certain aggressive driving modes. They are not universally applied.

The fudge factor of the tuner remap is to create lift off overfuelling. It is created by intentionally putting what would otherwise appear to be an error into a conventional map.

That means it will happen whenever that map is selected rather than only when asked for. I assume thats why Iain at least puts it in the 95 map, which is really only a get you home map when proper fuel isn't available, rather than a map that should be used for any length of time. As a result of all the available maps, it's the best one to "waste" on pops and bangs.

OEMs will have a dedicated facility purely to generate the noise and it will be done in a controlled manner that doesn't sound like a backfire and doesn't result in an unpredictable pop or bang. This reduces the changes of being sued for causing heart attacks, and at a guess, doesn't use anything like enough fuel to be capable of causing damage the expensive internals of a precious metal exhaust after treatment device.

From my experience of my sister's TTS, I'd say the effect is really poor, and almost as dumb as the pops and bangs map on the GT-R. It produces a blip on queue, whereas the pops or bangs sound accidentally and sporadic.


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## Tinyflier (Jun 13, 2012)

dudersvr said:


> Annoying thing is im waiting on a slot for the forged engine build at AC


Haha - got in before you! Mine is with Andy from March 4th! :clap:

In some ways I feel a little sad that the work of the master engine builder in Japan will all now be undone - I always thought it a little cool that mine came out of a dedicated engine build room as opposed to being built up from bits along a robotic line. BUT post re-build it will be one of an even smaller group!

David


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## Evo9lution (Aug 24, 2013)

I wonder if anyone has paid any attention to their oil temperature when running Pops & Bangs aggressively?

I have anti-lag on my Evo which I've used for less than 30 seconds in the six years I've had the car (one run during a 30-130 event) and the oil temperature increased extremely quickly compared to not having the anti-lag selected (10 degrees above the comparable runs) and that was at high speed with a huge amount of air being forced through the engine bay.


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## dudersvr (May 7, 2003)

Evo9lution said:


> I wonder if anyone has paid any attention to their oil temperature when running Pops & Bangs aggressively?
> 
> I have anti-lag on my Evo which I've used for less than 30 seconds in the six years I've had the car (one run during a 30-130 event) and the oil temperature increased extremely quickly compared to not having the anti-lag selected (10 degrees above the comparable runs) and that was at high speed with a huge amount of air being forced through the engine bay.


I dont think they even watch the rev counter !!!!


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## Evo9lution (Aug 24, 2013)

dudersvr said:


> I dont think they even watch the rev counter !!!!


Exactly ...


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## dudersvr (May 7, 2003)

Evo9lution said:


> Exactly ...


Too busy looking to see if any 14 year olds knickers have fallen off.


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