Don't know why a extra injector increases air density ? Air temp yea that would help air density. If you really wanting to increase air volume you would go direct injection. The fuels injected directly into combustion chamber not taking up volume.
@@2strokecarbtuningportingin187 The fuel pulls heat out of the air, and the air density goes up as the temp goes down (like you said). Adding fuel into the system earlier allows for more cooling effect from the fuel
There is also one more little aspect. The aircolumn get slightly heavier with an injector far back in the runner, and this makes slightly more ram effect at high rpm´s. Injector timing can make a great impact also, having a small amount of fuel squirted onto the closed intake valves makes the fuel vaporize, and suck up some heat. This often makes low rpm and response a little bit better.
@@Peter_Granfors we havent disclosed some of the dual squirt strategies on single (or dual) injection for youtube, but spot on. Injection timing is critical on single injectors located close - sucks up huge time to get that right plus fuel and ig curves
I would assume that injector angle, especially the injector closest to the intake valve has the biggest effect on the throttle response and should always be pointed directly at the valve for the sharpest response. Possibly a similar story with injector sizing as it seems you want the lower rpm and early throttle openings taken care of by the first injector. Since that first injector only now has to operate in lower throttle openings or lower RPM then it can be sized smaller than the second injector that is further away and can be used at higher rpm and larger throttle openings. If clubmx had a strategy like that implemented, then its crucial that both injectors work together, if you only had the first or second injector working then you'd have a huge hole in the power curve making it dangerous to ride the bike.
Very interesting. Cool engineering. That’s way above my pay grade. I wish I was a good enough rider to want more power. At my vet level of riding, I’d spend all my money on suspension. I never need a bike with more power, just need to be more comfortable to go faster.
Good Video Man, its hard to explain a Customer why 1hp is a lot of Stuff on this Engines! I recently worked on the 2025 sxf and it was a Nightmare to get more power out of this than Stock, with a must use HGS (Sponsors) and Stock Cams, without loosing Low End...This KTM Engines are insane IMO
Does the placement on the stock injectors on Ktm’s play along with the ktm’s liking higher rpms? It being vertical I imagine the gas stays slightly longer in the throttle body allowing it to vaporize more.
@@davidromo46 I would suggest there is no data metric to support ktm liking higher rpms vs lower. Only media feedback. The ktm makes the most power of all bikes low to top on our dyno and on all recent shootouts I saw as well. I do feel the ktm injector style influences throttle response which is “worse” than other bikes
@@HPRaceDevelopment with a couple different bikes coming with dual injectors now, do you think ktm would benefit from dual injectors? mostly curious for the 350.
@@fox13z400 We sell and offer dual injection kits for 250, 350, and 450 ktms The gains are as I said - about 1 hp. If we sold a lot more of them I would probably also sell a different forward injector to maximize the gains
Kind of. Imagine the standard jet of the carb the (rear) injector and the accelerator pump the front. The accelerator pump only injects fuel during throttle application to prevent lean bog because the standard jet always lags behind the engine "signal" The signal being the vacuum in the intake when intake valve open and piston on intake stroke.
@Roostfactor1 yea , haved see some video or picture passing fast , of injector places like that but didnt have realise its for a 2 injector setup and you can gain 2hp with that , good explanation vid
Im curious if direct injection is something their working on. Having direct injection AND the second injector (the far back one) would seem ideal for max power and timing control.
@@Roostfactor1 Imho from a performance standpoint DI is flat out worse. Its an emissions thing mostly - and in F1 they have a special form of DI that acts as the ignition system as well which allows amazing fuel economy not possible in spark throttle body injection. I might be wrong - but as of now I think DI would only hurt performance
@HPRaceDevelopment Well you're way beyond my level with moto engines so I'll take your word for it and yes I'm very familiar with F1's TJI system Merc started in 2014 when the "formula" changed from 2.4L v8's to 1.6L v6 with mguk and mguh. Imagine trying to tune one of those!?!
@@maxandreev27 It works the exact same. fun fact athena get brought dual injection into moto - with europe mxgp and pro circuit. Then kawasaki liked it so much they made it production. Kawasaki uses massive injector flow differences between close and far injector - optimizing their design as far as possible
Some bikes have dual inj stock, like 250 kawa and rmz 250 2019+ The 2e inj sits in airbox straitht spray fuel up. The kawa under angle. Do they also add 1 hp?
@@MrJacksmithFTW in what regard. Air velocity is a common talking point in performance engine building - and it plays a lot of roles including in fuel vaporization. But that said the fastest engine is the engine that balances flow and velocity correctly. A tiny port high velocity design becomes restrictive to flow
@@SLAYJUCE ktm tbi have 2 injectors - but not as described here. 2 strokes have a much different design - with the crank case having to fill up first so its a bit different.
no. 2 injectors will use roughly half the fuel of a single injector. otherwise your air fuel ratio would go stupid rich and it wouldn't run worth a crap.
@@TM22549 Good question but the answer is mostly no but sorta yes. Whenever you let off the throttle high rpm in decel - dual injection will be very slightly worse in economy for really complicated reasons. But otherwise its mostly the same economy
an injector pointed straight up will atomize fuel better than going with airflow (think of spraying water up and a fan blowing against it versus spraying water with the airflow. but i'd imagine spray pattern matters more than that. i'd be curious to know if the ignition timing can be pushed a little further with a cooler more dense air charge or something. so many variables that's why we rely on masterminds like derek who will put the work in to find out and then get that product out to the masses! one injector with more on time can supply the same fuel. so its not a volume thing. it has to be for air charge and maybe a more precise fuel volume. i'm thinking of the old dicks racing ktm intellijet thing that supposedly was awesome because it was able to get just a little more fuel at the right time. granted that's old 2 stroke carb theory.
what injectors cc's are you running in this crf ? main and second ? kxf 250 2012 I owned had so much power difference at the top comparing to the other bikes in that year... dual injection was game changer but nobody wanted to admit it because "it's not a ktm" 🫠😅 more fuel atomization = more power always
2 is always more fun right?
@@dustincarter83 top comment
Don't know why a extra injector increases air density ? Air temp yea that would help air density. If you really wanting to increase air volume you would go direct injection. The fuels injected directly into combustion chamber not taking up volume.
@@2strokecarbtuningportingin187 The fuel pulls heat out of the air, and the air density goes up as the temp goes down (like you said). Adding fuel into the system earlier allows for more cooling effect from the fuel
2 shoulders that work is awesome
BEST explanation I ever come across
There is also one more little aspect.
The aircolumn get slightly heavier with an injector far back in the runner, and this makes slightly more ram effect at high rpm´s.
Injector timing can make a great impact also, having a small amount of fuel squirted onto the closed intake valves makes the fuel vaporize, and suck up some heat.
This often makes low rpm and response a little bit better.
@@Peter_Granfors we havent disclosed some of the dual squirt strategies on single (or dual) injection for youtube, but spot on.
Injection timing is critical on single injectors located close - sucks up huge time to get that right plus fuel and ig curves
That good idea, which also straightens out your power curve that is noticed in your dyno chart and more likely don't feel it on the bike
I would assume that injector angle, especially the injector closest to the intake valve has the biggest effect on the throttle response and should always be pointed directly at the valve for the sharpest response. Possibly a similar story with injector sizing as it seems you want the lower rpm and early throttle openings taken care of by the first injector. Since that first injector only now has to operate in lower throttle openings or lower RPM then it can be sized smaller than the second injector that is further away and can be used at higher rpm and larger throttle openings.
If clubmx had a strategy like that implemented, then its crucial that both injectors work together, if you only had the first or second injector working then you'd have a huge hole in the power curve making it dangerous to ride the bike.
Stand off injectors are great for high rpm. My zx6r has them they spray from the airbox above the velocity stack. Formula 1 technology trickling down.
Very interesting. Cool engineering. That’s way above my pay grade. I wish I was a good enough rider to want more power. At my vet level of riding, I’d spend all my money on suspension. I never need a bike with more power, just need to be more comfortable to go faster.
Good Video Man, its hard to explain a Customer why 1hp is a lot of Stuff on this Engines! I recently worked on the 2025 sxf and it was a Nightmare to get more power out of this than Stock, with a must use HGS (Sponsors) and Stock Cams, without loosing Low End...This KTM Engines are insane IMO
@@hwperformance1409 our piston and head are quite good on that if you ever wanna try
Great vid and info as always! The man!
very interesting ,thank you Derek !
Love these videos!!
I love my 38mm pwk on my 380cc trx 250r...pretty bad ass tech tho
@@minibikemadman you probably need a 42 on that
Does the placement on the stock injectors on Ktm’s play along with the ktm’s liking higher rpms? It being vertical I imagine the gas stays slightly longer in the throttle body allowing it to vaporize more.
@@davidromo46 I would suggest there is no data metric to support ktm liking higher rpms vs lower. Only media feedback. The ktm makes the most power of all bikes low to top on our dyno and on all recent shootouts I saw as well. I do feel the ktm injector style influences throttle response which is “worse” than other bikes
@@HPRaceDevelopment with a couple different bikes coming with dual injectors now, do you think ktm would benefit from dual injectors? mostly curious for the 350.
@@fox13z400 We sell and offer dual injection kits for 250, 350, and 450 ktms
The gains are as I said - about 1 hp.
If we sold a lot more of them I would probably also sell a different forward injector to maximize the gains
I liked this video, thankfully we can leave our bikes to you .
Great vid m8 but ur riding style is so stylish it probably adds 3 hp
does that mean puting a carb with the acceletor jet did the job of 2 injector
Kind of. Imagine the standard jet of the carb the (rear) injector and the accelerator pump the front. The accelerator pump only injects fuel during throttle application to prevent lean bog because the standard jet always lags behind the engine "signal" The signal being the vacuum in the intake when intake valve open and piston on intake stroke.
@Roostfactor1 yea , haved see some video or picture passing fast , of injector places like that but didnt have realise its for a 2 injector setup and you can gain 2hp with that , good explanation vid
Im curious if direct injection is something their working on. Having direct injection AND the second injector (the far back one) would seem ideal for max power and timing control.
@@Roostfactor1 Imho from a performance standpoint DI is flat out worse. Its an emissions thing mostly - and in F1 they have a special form of DI that acts as the ignition system as well which allows amazing fuel economy not possible in spark throttle body injection.
I might be wrong - but as of now I think DI would only hurt performance
@HPRaceDevelopment Well you're way beyond my level with moto engines so I'll take your word for it and yes I'm very familiar with F1's TJI system Merc started in 2014 when the "formula" changed from 2.4L v8's to 1.6L v6 with mguk and mguh.
Imagine trying to tune one of those!?!
What about dual injection on kawasaki in comparison with working strategy in this video?
@@maxandreev27 It works the exact same. fun fact athena get brought dual injection into moto - with europe mxgp and pro circuit. Then kawasaki liked it so much they made it production. Kawasaki uses massive injector flow differences between close and far injector - optimizing their design as far as possible
Some bikes have dual inj stock, like 250 kawa and rmz 250 2019+
The 2e inj sits in airbox straitht spray fuel up.
The kawa under angle.
Do they also add 1 hp?
@@bernardvanderveen7656 you think kawasaki wants to add an injector for no reason!?
@@HPRaceDevelopment honda did with twin pipes lol publicity stunt. jk.
What has been the results of going to 2 injectors on any 450?
@@The_Snowbike_Channel similar as deccribed
Could be wrong but didnt duel injection come from F1?
no they ran the far away injector type concept
motogp and superbikes were likely first
is air velocity a factor?
@@MrJacksmithFTW in what regard. Air velocity is a common talking point in performance engine building - and it plays a lot of roles including in fuel vaporization. But that said the fastest engine is the engine that balances flow and velocity correctly. A tiny port high velocity design becomes restrictive to flow
On a two stroke ?
@@SLAYJUCE ktm tbi have 2 injectors - but not as described here. 2 strokes have a much different design - with the crank case having to fill up first so its a bit different.
Stupid question alert: Does dual injector make the fuel consumption way worse?
1:39
no. 2 injectors will use roughly half the fuel of a single injector. otherwise your air fuel ratio would go stupid rich and it wouldn't run worth a crap.
@@TM22549 Good question but the answer is mostly no but sorta yes. Whenever you let off the throttle high rpm in decel - dual injection will be very slightly worse in economy for really complicated reasons. But otherwise its mostly the same economy
an injector pointed straight up will atomize fuel better than going with airflow (think of spraying water up and a fan blowing against it versus spraying water with the airflow. but i'd imagine spray pattern matters more than that. i'd be curious to know if the ignition timing can be pushed a little further with a cooler more dense air charge or something. so many variables that's why we rely on masterminds like derek who will put the work in to find out and then get that product out to the masses! one injector with more on time can supply the same fuel. so its not a volume thing. it has to be for air charge and maybe a more precise fuel volume. i'm thinking of the old dicks racing ktm intellijet thing that supposedly was awesome because it was able to get just a little more fuel at the right time. granted that's old 2 stroke carb theory.
Kawasaki and KTM power. Both in 1. Snap or a kawai with pull of a KTM.
Good video.But can you please not talk with the bubble gum bouncing around in your mouth 🤮
@@johnlastname2895 extra gum
for next time just for you
what injectors cc's are you running in this crf ? main and second ? kxf 250 2012 I owned had so much power difference at the top comparing to the other bikes in that year... dual injection was game changer but nobody wanted to admit it because "it's not a ktm" 🫠😅 more fuel atomization = more power always