injectors

[travis]

Does anyone know if the fuel injectors are bigger on an Apex than on a Nytro ?? Do they have the same plug in for the wiring harness. Basically are they bigger and will they fit into a Nytro or do you need to go to an aftermarket injector. I'm only curious because my buddy just got his impulse turbo in and you need to change the injectors which are bigger, But you also have to solder on new caps for the wiring harness. It seems it would be easier to just install Apex injectors if they fit as they would need no wiring just plug in and you're done !!! Thanks for the input

 

[motorman]

apex- 39mm Mikuni® fuel injection
nitro- 41mm Mikuni® fuel injection

 

[ruffryder]

apex- 39mm Mikuni® fuel injection
nitro- 41mm Mikuni® fuel injection

That is the throttle body size, not injector size.. If you assume that the motors produce the same amount of power (I know they don't but..) with the Nytro having one less cylinder and therefore, one less injector, I would say the Nytro has larger injectors then the Apex.....

 

[travis]

Anyone else know for sure? I don't think just because the nytro has one less cylinder that automatically makes it have bigger injectors. I could be wrong but I don't think it works that way. Anyways someone out there knows the answer for sure. Also the injector holes could just be a little bigger and still fit in the fuel rail fine.???

 

[happyhour]

the part number is the same as the apex other than the first three digits. Yamaha is usually good about using the same parts just changing the first digits so they can charge you more. I would say that they are the same injector.


the first part number is for a 2006 apex the second is off a 2008 nytro

https://www.onlinemicrofiche.com/xtremepowersports/shoppingcart/CheckOut/Viewcart.asp

 

[ruffryder]

the part number is the same as the apex other than the first three digits. Yamaha is usually good about using the same parts just changing the first digits so they can charge you more. I would say that they are the same injector.

That would make sense too...

 

[Motleyone]

Nytro injectors ARE larger than the apex.

 

[MOB]

negative...Apex injectors flow more than the Nytro injectors. I don't recall the exact spec...but someone will post them shortly I'm sure.

Edit: 330 Nytro v. 380 Apex says my memory...could be off a bit

 

[08_Nasty_Nytro]

Injectors

Hey Guys the nytro injectors are longer that is the difference in the size. They with fit into the apex and vice versa but the apex injectors will be higher in the throttle body(On the Nytro and vice versa), As for CC's i am not sure on the #'s.

 

[MOB]

LOL...good point...didn't consider form factor...more than one way to be 'bigger'...

Travis: I haven't done it myself yet (Apex injectors sitting in my workbench)...but apparently the Apex injectors will fit fine in the Nytro rail AND are plug compatible with the harness. Was told there is a tab of some sort on the Nytro rail that must be removed, but they will fit.

It seems the latest verdict on larger injectors is that the Apex guys are drilling out the Apex injectors to flow 440..vs original 380. Waiting for testing to be completed on the Nytro and in go the Apex injectors...

 

[travis]

Thanks MOB!! This is very technical and very important as to how the sled performs, Which you seem to realize more than others. When you say drill out to flow more, are you talking to tiny 4 holes on the bottom of the injector? So simply installing the Apex injectors would not be efficient enough? Thanks for the input

 

[MOB]

I'm not sure WRT how they're drilling them out, but its obviously not as simple as honing it out with your favorite cordless drill. Once testing is completed I figure I can send the injectors out/swap for higher flow versions from a couple of possible sources. Plenty of folks looking into the same thing...bound to be a source or two.

WRT are the Apex injectors adequate, they're certainly better than Nytro injectors for flow, but for bigger boost/higher fuel rate requirements they may run out of duty cycle also.

Others have said they simply turn up the pressure to the rails via fuel regulators to increase flow rates, haven't tried that yet...I would think it's adequate for smaller deficiencies in fuel flow, however for larger deficiencies I'd prefer staying within efficient duty cycle of the injectors

I'm no expert, just what I've learned I guess...

 

[travis]

Thanks. Apex injectors seem like the better choce. let us know how your testing goes MOB. Thanks

 

[travis]

Your correct about turning up the fuel in the fuel rail thing. I was running hot with the stock fuel regulator on my s/c, then I changed out the stock regulator for a bigger and better one and now I have no heat troubles. Seems like the regulator and Apex injectors would go a long way to make a Nytro run better and cooler.

 

[happyhour]

stock injectors flows 330cc at 43 psi if you take that same injector at 60 psi it is now a 440cc injector get your self a 1:1 rising rate fuel regulator turn up the rail pressure I use the stock injectors at 22 lbs no problems. I have been told the stock injectors will go to 90 psi.

 

[MOB]

How is the idle at 60 lbs...?

 

[ruffryder]

Your correct about turning up the fuel in the fuel rail thing. I was running hot with the stock fuel regulator on my s/c, then I changed out the stock regulator for a bigger and better one and now I have no heat troubles. Seems like the regulator and Apex injectors would go a long way to make a Nytro run better and cooler.

Seems you are just using fuel as a cooling method..... You could also just increase the fuel map for the same effect..

How is the idle at 60 lbs...?

That be the issue with sizing injectors for peak power, especially when there is a very large spread in power output of the engine... ie boost.

Most of the car setups go to dual stage injectors... keeping the stock system for off boost and mild boost response, and then secondary injectors for peak boost, high hp.

Though, that gets a little more complicated... Does the RB3 have this capability?

Could always go motec... for like 4 grand and a lot of headaches! lol

 

[TBird]

That be the issue with sizing injectors for peak power, especially when there is a very large spread in power output of the engine... ie boost.

Most of the car setups go to dual stage injectors... keeping the stock system for off boost and mild boost response, and then secondary injectors for peak boost, high hp.

Though, that gets a little more complicated... Does the RB3 have this capability?

Could always go motec... for like 4 grand and a lot of headaches! lol

Or do as MCX and Yamaha MotoGP bikes!
MCX have extra injectors in the IC plenum, that adds extra fuel only when needed = @ boost!
Yamaha MotoGP bikes have extra injectors in the airbox, that delivers extra fuel when needed!

In sled films i watched i noticed several boosted Yamaha's run like crap on low rpm, they must fiddle with the throttle for a while before the engine begin to run clear again, like clearing the troat, and my guess is that they run rich on low rpm and only runs clean on load!

 

[ruffryder]

Or do as MCX and Yamaha MotoGP bikes!
MCX have extra injectors in the IC plenum, that adds extra fuel only when needed = @ boost!
Yamaha MotoGP bikes have extra injectors in the airbox, that delivers extra fuel when needed!

Stock CBR600 and 1000 do it too. They spray right above intake runners and call it dual stage injection. They run a total of 8 injectors though, 2 per cylinder.

MCX uses that too? Interesting....