fuel injection

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
That's been on here before and looks like a cool set up. But, no dyno info to justify the cost. I'm thinking the injector holders would be restrictive on this throttle body type. Good ingenuity though.
I'm hoping for more info on the FI system posted up not long ago. Most multi-port systems like it, seem to die out when it's software configure time. The Vmax engine timing events are a bit complicated, more so than automotive engines.
 
I'm going to head down the EFI route, but I'm going to use throttle bodies (the kind that are easily seperatable will work best - I grabbed GSX 750 TB's fairly cheap), fab up some TB to manifold connectors (this will be fun...got some SS tube and will attempt to create some reducers to connect TB to stock manifold), and will most certainly go down the batch injection route (all the reading I've done suggests that getting the Vmax to a multi-port state requires adding sensors and other headaches - not worth it to me for the marginal performance gain). So the hardware isn't terribly difficult, but the mapping will be challenging. I know a mechanic that dables in EFI so I'll be relying on his expertise to get it kinda running decent. Carbs are ok, but EFI will be slick if it can be done reasonably...
 
The Vmax world has come A LONG WAY over the last 15 years. If there were a practical, affordable , USER FRIENDLY way to do it it would have been done.

THERE IS NOT. But I wish you good luck
 
Sequential fuel injection means that you have crank triggers and or cam triggers so you inject fuel exactly at the right moment when the intake valve starts to open. More sensors, more work, more money.
crank triggers
Pulse generator... it is what tells the ignition system when to fire. Can someone explain to me WHY the FI timing could not be run off of the pulse generator on the crank? Everyone says cam position sensor, but the cam position is solidly fixed to the crank position.
 
Pulse generator... it is what tells the ignition system when to fire. Can someone explain to me WHY the FI timing could not be run off of the pulse generator on the crank? Everyone says cam position sensor, but the cam position is solidly fixed to the crank position.

Not an expert in this subject but my best guess is because the cam turns at half engine speed and the injection pulse would be triggered on the inlet stroke.
If mounted on the crank then you would get a pulse every rotation and would have to filter out alternate pulses.

For the ignition it doesn't matter if there is a spark on the exhaust stroke.

Could be wrong though...
embarassed.gif
 
The Vmax world has come A LONG WAY over the last 15 years. If there were a practical, affordable , USER FRIENDLY way to do it it would have been done.

THERE IS NOT. But I wish you good luck

Rick is talking from experience. He ran a well known unit for a while. I'd only see some benefit from a multi-port set up. All those sensors would keep an engine running well, most likely better, no matter the elevation, temp, throttle position or riding style. We have come a long way in understanding the vmax carbs too. Stage 7 and the Morley kit have both been dialed in by many tuners and made most info. available here on the forum. Even getting good mid range torque and millage from the stage 7. I also wish you the best with your project Frank. Innovation on the Gen 1 will always be welcome and admired.
 
I'd love to see a system with the stock carbs gutted and smoothed out in the bores, and injectors located right in the manifolds.Right where the v-boost connect the manifolds, as not to restrict air flow. A fuel rail where the v-boost used to be. No hint of the system visible.The sticking point is always the software. Not my strong point to put it mildly. When I started wrenching magnetos, ignition retards, points, dinosaurs walking around, good gas,one piece bathing suits.... There are more here like me. OLDER TOO
biglaugh.gif
 
Yeah...the software will be fun, but batch is definately the way to go...batch (or intake wetting) has been around since the 60's...timed sequential came about as a necesity for cleaner emmisions...I have no desire to snych the timing of the intake valve opening with the injection cycle, given the rediculous amount of effort/cost required, especially when it's not detrimental to the fuel system as a whole. It runs good with the carbs, the objective would be to get it to run good, not great, with EFI...

I just got it running decent with Sean's kit, but that requires pulling things apart...the beauty of EFI is that a laptop is all that's needed to make adjustments.

I'm not delusional, as I know several have tried to get this working, but it's definately the final frontier for the Gen 1 and I can't help but try...
 
I'm not delusional, as I know several have tried to get this working, but it's definately the final frontier for the Gen 1 and I can't help but try...

Please do....I had people tell me that i shouldnt run the Factory Pro needles, instead of the stage 7's, and they wouldnt work. Sometimes you have to go against the grain, and find out things for yourself.

Here is the latest video.

https://www.youtube.com/watch?v=FMg79-a_Ago
 
I will do my best to take lots of pics and post progress...I don't mind trying & failing...as failing is learning. I'm fortunate to have good local resources and $$$ at my disposal. However the objective is to do this affordably (otherwise I'd just go & buy a Gen2). I got real nice TBs cheap ($100) that can easily be configured into the current carb arrangement...that led me to wanting to use the stock runners...I have both boost & non-boost versions...(I paid like $45 for a set of non-boost runners)...would love to get it working with vboost, but if not I'm covered (making a custom set was doable, but not practicle). Making the connectors will be the fun part as I couldn't find a workable alternative. My TB's came with a TPS...not sure if rollover is in there as well...lots of inline fuel pumps push 45psi...so that shouldn't be hard either. The hard stuff (electronics) I'll hand to my mechanic buddy...this will be a winter project...don't want to rush it...
 
Not an expert in this subject but my best guess is because the cam turns at half engine speed and the injection pulse would be triggered on the inlet stroke.
If mounted on the crank then you would get a pulse every rotation and would have to filter out alternate pulses.

For the ignition it doesn't matter if there is a spark on the exhaust stroke.

Could be wrong though...
embarassed.gif

I believe that would be the difference between single and dual fire ignitions. If they can get an ignition to fire only on the compression stroke...

I, for one, would be VERY interested in getting all of this to work, and to have it all work with the V-boost even would be an added benny XD
 
Among others, I believe H-D's us a 'waste' spark where the plug also fires on the exhaust stroke. It might even help to limit unburnt hydrocarbons in the exhaust flow.

It may only be a matter of terminology, but I believe the spark propagation across the combustion chamber occurs on the 'power' stroke, and yes, I know there is something known as 'advance.' The thinner the size and the smaller the volume of the combustion chamber 'envelope,' the more advance you have to run.

I believe that would be the difference between single and dual fire ignitions. If they can get an ignition to fire only on the compression stroke...

I, for one, would be VERY interested in getting all of this to work, and to have it all work with the V-boost even would be an added benny XD
 
Among others, I believe H-D's us a 'waste' spark where the plug also fires on the exhaust stroke. It might even help to limit unburnt hydrocarbons in the exhaust flow.

It may only be a matter of terminology, but I believe the spark propagation across the combustion chamber occurs on the 'power' stroke, and yes, I know there is something known as 'advance.' The thinner the size and the smaller the volume of the combustion chamber 'envelope,' the more advance you have to run.

I believe that is them finding a use for the dual-fire setup. Simpler to just let the trigger fire the plugs on the exhaust stroke as well, so might as well make it so it helps with emissions.
 
I'm going to head down the EFI route, but I'm going to use throttle bodies (the kind that are easily seperatable will work best - I grabbed GSX 750 TB's fairly cheap), fab up some TB to manifold connectors (this will be fun...got some SS tube and will attempt to create some reducers to connect TB to stock manifold), and will most certainly go down the batch injection route (all the reading I've done suggests that getting the Vmax to a multi-port state requires adding sensors and other headaches - not worth it to me for the marginal performance gain). So the hardware isn't terribly difficult, but the mapping will be challenging. I know a mechanic that dables in EFI so I'll be relying on his expertise to get it kinda running decent. Carbs are ok, but EFI will be slick if it can be done reasonably...
Did you get around to finishing this up?
 
I'm going to head down the EFI route, but I'm going to use throttle bodies (the kind that are easily seperatable will work best - I grabbed GSX 750 TB's fairly cheap), fab up some TB to manifold connectors (this will be fun...got some SS tube and will attempt to create some reducers to connect TB to stock manifold), and will most certainly go down the batch injection route (all the reading I've done suggests that getting the Vmax to a multi-port state requires adding sensors and other headaches - not worth it to me for the marginal performance gain). So the hardware isn't terribly difficult, but the mapping will be challenging. I know a mechanic that dables in EFI so I'll be relying on his expertise to get it kinda running decent. Carbs are ok, but EFI will be slick if it can be done reasonably...
What type of ecu box will you be running
 

Latest posts

Back
Top