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Need more fuel/ bigger fuel injectors?

9K views 15 replies 9 participants last post by  MMFB 
#1 · (Edited)
Ok well i did some homework and came up with an awesome tidbit of information for those of you who are looking to upgrade your fuel system for alot less money than the $600 speedstars. Face it, if you are going to upgrade to a stage4 speedstar kit (or of sorts) youll still need to get it tuned... why not save a few bucks.

As some of you know by looking in the FSM our stock injector is the nippon IMP-732, which is known in the more common world as the Denso CDH275.

factory specs:
flow @ 43.5psi/3bar is rated at 318 cc/min or 30 lb/h static (100% duty cycle)/ Typical: 310+/-5 cc/min @ 55psi
Impedance: High ("high-z") Saturated type and 15 ohms
Connector: Denso "top slot" style - note the slots are closest to the locking tab/notch
Color designator: Yellow (body)
Measurements: see the picture - note the injector is the red-orange cdh210

EDIT:
For clarification, the previously mentioned "common" DSM injectors do not fit, However - this does not apply to all of them. Not all injectors are the same as the CDH family injectors.

****Thanks to slinghang, he has found and installed some injectors from the Yamaha 150 and F255 outboard engines without a problem. His post is linked below.

http://www.rswarrior.com/forums/13-technical-discussion/196889-440cc-fuel-injectors.html

Regardless of future posts, the most common one will resemble the attached image, color may vary by manufacturer.... A simple search results can be quite vague, beware of the "fat body" style injectors - these are not for the aforementioned engines. See the link below for the website slinghang found his injectors.

http://www.tlfperformanceparts.com/category/Yamaha-Outboard-Fuel-Injectors.html

Concerning the fuel pressure regulator: FMU/ rising rate fuel pressure regulator and etc, read below. There are plenty of detailed explinations for reducing/increasing fuel pressure and rising rate regulators. GTS
 

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#3 · (Edited)
I knew i forgot something - i assume you are referring to an adjustable fpr or adjustable fmu (pressure sensitive) type? Sure that is also another way to get that extra but of flow from your injectors but you will eventually run into a wall when your fuel pump at its peak flow/pressure for whatever your injector allows.

The fuel system is rated at 3 bar, it is a reasonable assumption that it is rated at that pressure for a reason. Yes you can get a bit more volume and a better atomized spray if you bump up the pressure but you are also putting more of a strain on your fuel pump and injectors - electrically and mechanically. When pressure is increased, volume decreases; vise-versa.

on a personal note:
I have seen engines destroyed because an injector tip "exploded" into a cylinder due to running too high of a fuel pressure at a reasonable duty cycle, the internals just get beat to pieces!
Worse than that is when the tip wedges in your cylinder wall or better yet gets stuck in a valve on the way out and destroys everything in the combustion chamber, seen that too.. Call me paranoid but id rather not take that chance. Then again there are plenty of people who run cheap $30 FMUs and have no trouble. So dont let what ive seen deter anyone as i would be a hypocrite to say that i would never own one, because i do. I just choose not to run an FMU after considering the alternatives. larger injectors and a good tune in conjunction with the PCV analog input will do just the same... Theoretically you can say that without an FMU, thats one less critical component that can fail

chris
 
#4 ·
I mean after you upgrade the injectors you have to replace the stock FPR with something else, because as you said, "When pressure is increased, volume decreases; vise-versa."

What do you recommend? Because when you upgrade to the Speed* injector kit you get the new FPR also in the kit to allow the system to work properly together. You need a different regulator to lessen the fuel pressure for the new higher flowing injectors. ( I want to thank repsol61 for everything he has recently taught me about our bikes fuel system)

Redline, please do not get me wrong here as I am not pointing out anything bad or trying to make you look bad. I like this back and forth talk because I learned something in your first post and also in your second. This is great information for this forum and our members and want to make sure that between everyone here we get all the right stuff put in one place to help people :).
 
#6 ·
Redline, please do not get me wrong here as I am not pointing out anything bad or trying to make you look bad. I like this back and forth talk because I learned something in your first post and also in your second. This is great information for this forum and our members and want to make sure that between everyone here we get all the right stuff put in one place to help people .
Thats part of what this place is for and why were here, no? We will work on it :).. hopefully when were done here we can get this info up on the popular mods and repairs page. :D
 
#5 · (Edited)
hey man no disrespect taken, i like questions! First of all, overthinking things has always been my deal, lol.. but i like to make sure little is missed and precautions are at least considered. As far as replacing the stock FPR, its safe to say the situation dictates per your mods. You may consider a quality aftermarket for reliability concerns, for example Fuelab.com, expensive but reliable fuel system parts! Then again you also need to be careful w/ ebay china regs too.. Do your homework and find what fits your application and wallet within a means of reliability.
With any engine project, its not a bad idea to at the very least to have a pressure gauge. The last thing you want is a bad FPR screwing up your engine.

To make short of what i said about the volume vs. pressure, if youre cranking up the pressure youre creating more work, generating more heat and wear and at the same time theres less flow to carry away that heat. In reality all if that may never cause a problem on our bike then again the harder you push something beyond its designed limits, the quicker its going to wear out or malfunction.
Suppose you can call it my 2 cents... cant say ive read that any warriors have "max out" flow or cooked a fuel pump but thats not to say it has not/cannot happen.

As far as the speedstar injector regulator is concerned - ill be honest to say i dont know, youd have to ask whoever designed the system.
-There are many guesses to why the pressure is dropped.. Mine being that they dropped the pressure to compensate for the unneeded flow at 3 bar~ to back that it may have been the most "cost effective" manner to supply adequate fuel flow without reprogramming the stage4 ecu ~ who knows.

AZwarrior made a good point a few years ago that it is doubtful yamaha designed an injector specifically for the warrior... which would also add to yamaha using already available flow rates or maybe leave room for error when you do more upgrades...

chris
 
#7 ·
AZwarrior made a good point a few years ago that it is doubtful yamaha designed an injector specifically for the warrior... which would also add to yamaha using already available flow rates or maybe leave room for error when you do more upgrades...
Very true. They took an already on the market injector, flow tested it versus their static calculations and started testing what was available in the injector market. They then settled on the ones we have in our bikes. The proof is in the fact you can buy the same injector for a Mitsubishi car and it is plug-n-play on our bikes (as you stated in your first post) and has been known to us "frequent" users for some time. Your post, however, is the best summary of proper information in one place yet to date. That is why I jumped at the chance to fill in some gaps and put the information we have in this thread and available to our members.

I went to college for Motorsports Technology and learned a great deal about fuel management (carbs, alcohol injection, FI...) on race cars. Our bikes equipped with end of line regulators was new to me and only learned about them in the past 2 months. I'm better at straight engine building than the electric and FI systems in cars and bikes. Used to build 360ci Sprint Car motors at school for a local race team and never had one pop:D.

I love learning about new stuff everyday on here and I try and contribute back when I can. Thanks for taking the time to post up this good info!
 
#8 ·
Well now that its all sorted out, its out there for everyone else. Honestly ive looked many, many times for an aftermarket injector on the forums but the closest thing i could find was the denso cross reference, which yielded alot of good info and bad info just the same, and someone who posted they can get aftermarket injectors for about $300 a set - which is still not very useful considerignwhat little you might learn from just shelling out a couple hundred dollars. If anyone else has anything to add, please let me know and ill stick it on there!
 
#10 ·
I dont know where I read this, could have been on the ih8mud forum (land Cruiser)

I have a '94 80 Series Toyota Land Cruiser and I was told or read that they use similar or same Fuel Injectors as the Warrior.

Sorry, cant back this up, just threw it out there, it might help someone.:D
 
#15 ·
hey mmfb, the thread is 3 or so years old and the post you quoted is a year old , but good luck on a reply . redline.... started the thread and never got his bike fully turboed and went back to just pipes on the side, but the search is your friend, btk572
 
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