anti lag valve?

[peter1127]

hi guys, any ideas/opinions on a anti lag valve like this? It uses excess air when closing the throttle to flow into the headers, and in combination with retarded ignition this should keep the turbo running. Reviews/video's not really conclusive and none for bikes. If it works it would be nice, but its a bitch to get it installed on a bike. Its for a road bike, for dragracing there is no point.

 

  https://www.turbosmart.com/anti-lag-valves/

 

Edited August 11, 2023 by peter1127

[Gixer1460]

Never seen or heard of it being done that way and query its actual effectiveness! Reasoning - turbo spool relies on heat pressure ie, hotter exhaust with increased flow make turbine spool up - agreed? Adding (what will be cooled via intercooler) air, pre turbine will slow the process! Doesn't matter that it is 'boosted' / pressurised air, its pressure is insignificant compared to the exhausts back pressure its being added into. Plus, excessive retard used on 'closed' throttle will over heat the turbine blades in turn destroying them in short order. This is fine in competition and with large budgets that can afford new replacement turbos every event or even during but pretty un-economic for a street vehicle. And, why would you need high boost launch control on the street anyway - most things are traction limited in lower gears with restricted boost !

Turbosmart are smarter than me and a lot more experienced but i'm still struggling to make sense of this - in an everyday scenario!

[Duckndive]

In the early days of Turbo F1 cars "20 odd years ago" and the mad Group A rally cars back then they used a similar thing to keep the snail spinning with some success  "some of the rally teams had it down to a fine art" 

but they were all out racing applications so be interesting to see how it goes 

[peter1127]

In rallysport they indeed add fuel and ignite it before the turbine: spectaculair and effective, but it eats turbos. This is supposed to add air to burning gasses in exhaust caused by excessive retarded ignition. So it must have a very lean combustion which will indeed be very hot. But as opposed to the rally version I assume the amount is much lower, so it would be less damaging but also less functional.

On the road its main advantage would be reopening the throttle and have some boost already available or at least quicker available. I'm not looking for launch control.

Edited August 11, 2023 by peter1127

[Reinhoud]

On 8/11/2023 at 5:49 PM, peter1127 said:

hi guys, any ideas/opinions on a anti lag valve like this? It uses excess air when closing the throttle to flow into the headers, and in combination with retarded ignition this should keep the turbo running. Reviews/video's not really conclusive and none for bikes. If it works it would be nice, but its a bitch to get it installed on a bike. Its for a road bike, for dragracing there is no point.

 

  https://www.turbosmart.com/anti-lag-valves/

 

I know that the Mitsubishi Lancer Evolution has this system, Subaru WRX STI too if I'm correct..

 

In theorie it works, what it actuallydoes I don't know.

[Reinhoud]

If this is an issue, wouldn't a quick shifter be an easier / better solution?

[peter1127]

2 hours ago, Reinhoud said:

If this is an issue, wouldn't a quick shifter be an easier / better solution?

Well, shifts are not really an issue unless looking for the last tenth on the track. Its about normal driving on the road: closing the throttle before the corner,and opening it at the apex. Then there is a second of nothing followed by a power surge. I would like for that to be smoother, hence I'm looking for options like this anti lag valve.

[Gixer1460]

If you know there is lag - just roll into the throttle earlier! Problem solved with no added complications! All the early race / rally drivers adopted this approach and used to mash the throttle before the corner entry!

[peter1127]

I guess I shouldnt ask.

[DAZ]

I know it's not exactly what you're on about with the anti-lag tech, but I remember that @IhmeJanneFIN runs a couple of reed valves in his plenum that shut off under boost but allows the motor to breathe at sub boost levels would this help in your scenario ? Please tell me if I've got it wrong as I'm here to learn !

[Jdeac]

Is there not something about recirculating Bov's dumping the boost pressure straight back into the turbo air inlet. To keep the turbo spinning a little more on shifts.

Not quite what your asking. But surely there is some benefit to this

[colinworth79]

The current rally x  cars use this system but I believe it works in combination with retarding the ignition ect but less aggressive.  They found aggressive anti lag would be driving the car  , making it harder to turn and stop . Having a turbo bike on the road for the last 13 - 14 years I think a certain amount of lag is helpful , I wouldn't want to be mid corner and as I open the throttle have the engine produce 7 - 10 psi of boost pressure . 

[Gixer1460]

Wuss!  

[Reinhoud]

9 hours ago, peter1127 said:

Well, shifts are not really an issue unless looking for the last tenth on the track. Its about normal driving on the road: closing the throttle before the corner,and opening it at the apex. Then there is a second of nothing followed by a power surge. I would like for that to be smoother, hence I'm looking for options like this anti lag valve.

In that case I don't think a lag valve will do anything, to much time in between.

[IhmeJanneFIN]

12 hours ago, DAZ said:

I know it's not exactly what you're on about with the anti-lag tech, but I remember that @IhmeJanneFIN runs a couple of reed valves in his plenum that shut off under boost but allows the motor to breathe at sub boost levels would this help in your scenario ? Please tell me if I've got it wrong as I'm here to learn !

Yeah, I run two reed valves from a 2 stroke moped on my plenum design. Might be ok with just one as they are quite big, but the location kind of asked for two for the sake of more even airfow.

On my first engine, which was stock 750 short stroke, it started to build boost around 1000 rpm earlier with the reeds and also felt considerable more happy to respond to throttle inputs on off boost situations.

As that engine was stock and with stock valvetiming it "came alive" at 7000 rpm, but the turbo started to build boost around 5000 rpm without reeds, and around 4000 rpm with the reeds.

My current 988cc Frankenstein starts boosting around 3000 rpm with the same turbo. We'll see how it will behave with the reeds on 1216cc and different turbo, once I get to build it.

[Reinhoud]

3 minutes ago, IhmeJanneFIN said:

Yeah, I run two reed valves from a 2 stroke moped on my plenum design. Might be ok with just one as they are quite big, but the location kind of asked for two for the sake of more even airfow.

On my first engine, which was stock 750 short stroke, it started to build boost around 1000 rpm earlier with the reeds and also felt considerable more happy to respond to throttle inputs on off boost situations.

As that engine was stock and with stock valvetiming it "came alive" at 7000 rpm, but the turbo started to build boost around 5000 rpm without reeds, and around 4000 rpm with the reeds.

My current 988cc Frankenstein starts boosting around 3000 rpm with the same turbo. We'll see how it will behave with the reeds on 1216cc and different turbo, once I get to build it.

Interesting..

Do you have a diagram or photo's of this set up?

[IhmeJanneFIN]

26 minutes ago, Reinhoud said:

Interesting..

Do you have a diagram or photo's of this set up?

Tried to check through my photos on my phone, but could not find one. Will continue to check, as I cannot take a great photo of those as the bike has fairings on blocking the view.

In the meantime, they can be seen on my short youtube video. Were we allowed to put up youtube links?

Anyhow, it can be found on youtube with searchterm "Suzuki GSX 750 F Turbo (Ka**na), little garage run". The word is cencored here, becuse of the rules and is meant for clickbait for the people on the US and A.

Edited August 13, 2023 by IhmeJanneFIN
Removed text about the reeds to be seen in my insta, as they cannot be seen there but on my youtube as the video is longer there.

[IhmeJanneFIN]

Found one pic, which I could crop so one of the reeds is visible. Cannot find better pics from my current phone, as have changed phone, so they are at the old phone and on my laptop.

Ps. Plenum is made out of mild steel as I don't have ac/dc tig yet

Edited August 13, 2023 by IhmeJanneFIN
typos

[peter1127]

Reed valve interesting thought

[Reinhoud]

On 8/13/2023 at 3:44 PM, IhmeJanneFIN said:

Found one pic, which I could crop so one of the reeds is visible. Cannot find better pics from my current phone, as have changed phone, so they are at the old phone and on my laptop.

Ps. Plenum is made out of mild steel as I don't have ac/dc tig yet

So, it just sucks air from outside into the plenum?

[Gixer1460]

On 8/13/2023 at 6:44 AM, IhmeJanneFIN said:

Found one pic, which I could crop so one of the reeds is visible. Cannot find better pics from my current phone, as have changed phone, so they are at the old phone and on my laptop.

Ps. Plenum is made out of mild steel as I don't have ac/dc tig yet

How does this work as physics says air inside the plenum and outside it will be at atmospheric pressure - vacuum / lower pressure only occurs engine side of throttle blades. In a two stroke, the whole of the crankcase is the vacuum chamber as piston rises causing the reeds to open and draw AF mixture in. I've seen 'Priority valves' like this but they were connected to engine side of carbs / TB's. 

[IhmeJanneFIN]

On 8/14/2023 at 11:44 AM, Reinhoud said:

So, it just sucks air from outside into the plenum?

Yes. They are before carbs.

[IhmeJanneFIN]

On 8/14/2023 at 12:26 PM, Gixer1460 said:

How does this work as physics says air inside the plenum and outside it will be at atmospheric pressure - vacuum / lower pressure only occurs engine side of throttle blades. In a two stroke, the whole of the crankcase is the vacuum chamber as piston rises causing the reeds to open and draw AF mixture in. I've seen 'Priority valves' like this but they were connected to engine side of carbs / TB's. 

I saw some forum/internet post somewhere, where this thing was called "primary breather valve", but I think they didn't use 2 stroke reed valves, it had some more complex type of membrane valve

Anyhow, there is small "vacuum" or "air movement towards cylinders" inside the plenum when the engine is running at off boost situations and these valves just reroute the air stream to be shorter, so rather than pulling the air through turbo and charge piping, it is drawn much shorter distance through the reeds. So better throttle response at off boost situations, and because there is better response from the engine, there is smaller turbolag? I don't, it just works.

Atleast on my case they work very well, because before turbo starts building boost, it draws air through these reeds, as I can hear the induction sound from the reeds, but it stops as soon as there is movement on the boost needle. I still need to fabricate some sort of air filter for those reeds by the way. Without these reeds in my case atleast, it's much more sluggish from idle to around 3000-4000 rpm before the turbo starts to spool up.

 

[Reinhoud]

32 minutes ago, IhmeJanneFIN said:

I saw some forum/internet post somewhere, where this thing was called "primary breather valve", but I think they didn't use 2 stroke reed valves, it had some more complex type of membrane valve

Anyhow, there is small "vacuum" or "air movement towards cylinders" inside the plenum when the engine is running at off boost situations and these valves just reroute the air stream to be shorter, so rather than pulling the air through turbo and charge piping, it is drawn much shorter distance through the reeds. So better throttle response at off boost situations, and because there is better response from the engine, there is smaller turbolag? I don't, it just works.

Atleast on my case they work very well, because before turbo starts building boost, it draws air through these reeds, as I can hear the induction sound from the reeds, but it stops as soon as there is movement on the boost needle. I still need to fabricate some sort of air filter for those reeds by the way. Without these reeds in my case atleast, it's much more sluggish from idle to around 3000-4000 rpm before the turbo starts to spool up.

 

Thanks for your explaination!

I'm about to make a new plenum, see if I can think of something. The reed valves is easy, but the air filter is going to be a challenge.

[Reinhoud]

41 minutes ago, IhmeJanneFIN said:

I saw some forum/internet post somewhere, where this thing was called "primary breather valve", but I think they didn't use 2 stroke reed valves, it had some more complex type of membrane valve

Anyhow, there is small "vacuum" or "air movement towards cylinders" inside the plenum when the engine is running at off boost situations and these valves just reroute the air stream to be shorter, so rather than pulling the air through turbo and charge piping, it is drawn much shorter distance through the reeds. So better throttle response at off boost situations, and because there is better response from the engine, there is smaller turbolag? I don't, it just works.

Atleast on my case they work very well, because before turbo starts building boost, it draws air through these reeds, as I can hear the induction sound from the reeds, but it stops as soon as there is movement on the boost needle. I still need to fabricate some sort of air filter for those reeds by the way. Without these reeds in my case atleast, it's much more sluggish from idle to around 3000-4000 rpm before the turbo starts to spool up.

 

Isn't your plenum too small?