Fuel Injected XJ750 *UPDATE*

So I'm on to my assembly now with all my parts ordered. Here's what I've gotten so far.

-Megasquirt II
-Megasquirt Relay Board
-01-03 GSXR600 Intake setup
-01-03 GSXR600 Injector Harness
-Ford EDIS 4 Digital Ignition Setup
-3" 36-1 Trigger Wheel
-New Battery
-Building a new dash/rewiring
-Bosch Universal O2 Sensor
-Hayg Fuel Pump (eBay Special) similar to Bosch 070 - puts out a constant 43 psi so I'm hoping to not need a regulator or return line

I'll be taking pics and post them as soon as all the parts arrive and we start the main assembly.

Originally I was going to build an intake manifold, but found that it was easier (and cheaper) to buy something that was complete and close to ready to go on the bike)

I've got the MSII system all assembled and I've started to test it on my laptop with the stim. Additionally I'm extrapolating my ignition maps from the manuals that I have and will be putting those in as soon as they are completed.

So far the main issue I had was when building the board, I had to install the MSII main board for testing and broke a pin upon removal. I contacted DIY Autotune and they gave me a part number through digikey and I was able to replace the pin without any issues. The assembly of the MSII unit went together a lot easier that I had initially thought and I was very surprised to have it working on my first try.

Tonight I will be installing a bung for the O2 sensor into my 4-1 exhaust system and should be able to get some pics up of the bike as it is right now and the installation of the bung.


I'm fuel injecting and possibly turbocharging a 750 seca for my senior design project at school. im planning on using the megasquirt system with it and i had a few questions.

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What am i going to need to make the bike work with the mega squirt system aside from injectors and all that. i'm more referring to ignition modification etc.

I'm having trouble trying to find out how much volume i need for my intake manifold, i am doing a sign throttle body, log type, but i cant find any information that directly tells me how much volume i need.

I have been doing fabrication for most of my life and i know this is a big project to get into but i was wondering if anyone may have any other input that may help me with this project.

Thanks in advance.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Member "SQLguy" built a system that worked well in it's second configuration. Seemed like a lot of work. He hand made a "tone wheel" mounted where the ignition is on the crank that took some trial and error.
Search for it, and good luck !

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

I hope this is it.
http://xjbikes.com/Forums/viewtopic/t=1 ... ction.html

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

That's the one... too bad all the pictures evaporated.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

too bad the guy evaporated

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

The megasquirt system will work well, but you should get a custom made disc to trigger the ignition. You can also run many different coil types including later higher energy ones, as the dwell is now programmable.

Are you designing a manifold with a plenum and single throttle, or 4 individual throttle plates?

Also current draw needs to be looked at as the fuel pump will draw around 6 amps on its own.

I am in the process of fitting microsquirt to a XJ750 engine thats getting rebuilt.
I will be using Yamaha R6 injectors some other interesting ideas.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Read through this :
http://users.hal-pc.org/~dhutch/

A fuel injected XJ1100, similar to what you want to do to your 750. Step by step and a bill of materials for the project. Some day I would like to try it on mine.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need H

I am using a single throttle body and a log type intake manifold, which is where im stuck because i dont know how much volume i need to make the manifold

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

I still have a Turbo 650 intake plenum with the reed valves, the knock sensor, and various bits and tubes, if you are building a stock type system.
PM sent.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need H

The volume will change significantly if you turbo charge it BUT

I would think you can do some simple calcs to come up with a close guess.

Logically, if you have a 750cc engine....it displaces 750cc, but it only moves air every other stroke (you lose a stroke to compress and fire).
SO, if you redline at 9500 rpm, you should be able to take
375(cc/rev) x 9500 (rev/min)=3,562,500 cc/min maximum...or 3,562.5 L/min
Or ~ 125.8 CFM

This would give you an average velocity through the (4) 32mm carbs of approx 110,774 cm/min or 50mph...which seems a bit slow to me

The metric system makes so much more sense!

I'm not an engine or carb designer so I'm not sure if the relationships are nearly that simple, but it should give you a starting point.
Air velocity is a critical factor to your design. I would GUESS that combining all four into one intake, you may be able to assume that you need to approximate the same intake area as the four combined 32mm carbs which would put you about 57mm throttle body to give you the same approximate velocity as the existing carbs...but again, just an educated guess.
A single body will be much easier to incorporate, but you will need to have as close to symetrical intake as possible.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Seasons will change, children will be born before completing this project. That's quite a mod, I am impressed.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Thanks for the support haha

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Infamous, if you go forced induction, does the IM volume matter as much (as compared to naturally aspirated)? Wouldn't incoming air volume be dependent on what the turbo provides? Obviously design would be key as far as optimal flow rate, etc...

For design, are you thinking along the lines of a sheetmetal race manifold, ala:


That being said, there may be a magic ratio out there of intake runner volume to total plenum volume. If you made a prototype, maybe try adjustable runner lengths? As far as the plenum size, plumbing space/configuration may make the decision for you...

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

I found a few things about runner length that related that to harmonics, and having a runner length for the power band that is wanted. And i've done the math for that. at this point since i have to have it finished by may, that i may just build the manifold to the naturally aspirated cfm i found and just try it that way, im honestly not sure if im going to get time to get a turbo on it before i graduate. id like to get it running first without the turbo, because it would make tuning a bunch easier.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

Dont get too caught up in the dynamics of intake design. I have taken carb manifolds off cars and put on manifolds with a plenum with no big issues. Sure you can slightly change the torque curve with different lengths, but it will still run great and still have power all through the rev range regardless. Make a neat manifold, try hard to make the airflow equal to all cylinders and all will end well.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

^what darkfibre said...equal airflow to each cylinder. Infamous, are you planning on using the stock airbox? That would likely be the easiest, as it already, to some degree, helps equalize air you intorduce to the equation.

However, this would be awesome, albeit on a motorcycle, a little difficult to get even airflow :

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

sorta, im building a log manifold with 4 runners and direct port injection

 

Re: Fuel Injecting a Seca for Senior Design Project - Need H

I think that, since this is a senior design project, I would disagree with what has been said above MOSTLY due to complexity.

Any senior design project you don't want to just cut/weld or reuse pre-existing items like Stan's XJ1100 project that was linked. What Stan did was awesome, but really he's just reapplying existing technologies with very minor fabrication.

I assume that the requirements of your senior design project involve you having to write a technical report. Make sure you have enough information to put in there. I'd do as much fabrication work on this as possible.

I agree strongly with "keep it simple, stupid" but this task will be too easy if you don't go all the way.

THEREFORE I wouldn't go with a log manifold, they're low HP intake manis because cfm is not evenly spread, equal length runners will be difficult but at least then you'll have a SolidWorks model you can show off.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

That was the goal with a log manifold, i wanted to do it as simple as possible, and on a budget, the goal of this project is not so much to make a super performance bike, but to modernize an older fuel system on a budget. with a slight increase in performance, if possible. If i was going to do a super performance bike, which is my next project, i would be doing it with a chain or belt drive, just because i dont like the weird torque from a shaft drive, and i dont like stressing a drive shaft on a bike that much.

 

Re: Fuel Injecting a Seca for Senior Design Project - Need Help!

I got the log manifold mocked up in cardboard, it looks like everything is going to fit pretty nicely in there with some decent volume