EFI forum

[shawn kloker]

I have started my efi project ,bought a megasquirt 1 v2.2 ,megaview and a set of throttlebodies off a cbr600rr and a in tank fuelpump with sender courtesy of a...............cbr600rr.So I've been researching every piece of info I can find .i have a spare motor that I can use as a template so to speak and the one thing I haven't really decided yet is whether to use the throttle bodies I already have or to go for the single big one .Either way it is going to be abitch making the manifold/s.And you do not need a cam / crank position sensor unless you are planning on doing the spark side of things.2 I don't think sequential is needed either since at high revs most efi's are running fulltime as in open and spraying continuously IMHO .This is going to be a very much a budget build as always but it should be an interesting thing to do.Any and all advice is welcome Cheers Kevman

Oh yah! Somebody had the balls to try this!Good Luck! Now CHOP-Chop!

 

[Birdoprey]

This is something that interests me ALOT! This is something that i would like to do, but i don't have the tools/skills/time for all the fab work. I usually spend alot of time figuring ways to not fab things! I was looking at the list of parts/prices on the link that was posted and i may be able to offer some cheaper options.

The fuel pump would be a biggie to me. I would not relish removing the tank/cutting the bottom and welding a flange(or whatever is needed) to make it work.
One can use a fuel pump assembly from a 99-00 Hayabusa. These use an EXTERNAL pump with a built-in regulator. Regulator pressure is set at 43psi which is perfect for this project. It uses a vacuum line to pull pressure down at idle like most all regulators do. It is semi-large and one would need to find a place to mount it.(I would mount mine where the rear coils are. I've converted to COP's and now have room here...) Once that was done, all one would need is to figure out the return line and your fueling issues are done. It even has a screen filter in the inlet of the pump(replaceable) AND a normal panel type filter between the actual pump and the regulator(replaceable). They can be had for $50-$125ish
Good thing about this is that the fuel is regulated BEFORE it hits the fuel rail, requiring only one line running to the rail(in this case one would need to T that line to feed each rail since the V-Max would use two banks)
If i were doing this, i would use a set of GSXR600 or 750 Throttlebodies. I don't recall exactally on the 600 TB's, but the 750 and 1000 TB's bolt together individually, as does the fuel rail(on the 00-03's that is). One of the outer ones has a Throttle posistion sensor already on it(0-5volt range like would be needed). The other outer has the throttle linkage. I've actually mocked up a set with just the two outers bolted together for a EFI DS650 ATV project. Never got to finish it as i got rooked on some motorwork i had done and then had to move across the state(Texas), parted the whole thing. There would be a few other little things to do to the TB's but they are simple and i would be happy to post if anyone was interested in knowing. They can be had for $50-150ish range
The GSXR TB's have low impedance injectors already mounted and would be enough to support over 200rwhp. The 600/750/1000 AND Busa's all used the same injectors.
Individual filters can be had easily. I'm sure one of the 600 or 750 TB's would be a close fit in the stk intake manifold boots. I used to have their respective ID/OD measurements. Dunno if i still do somewhere.
Pickup a air temp sensor and screw it into the top of one of the air filters(for the easy/simple way of doing it), and then all one needs is a map sensor(GM sensors are fairly cheap)
Its been awhile since i checked out the Megasquirts, and i believe they have newer/smaller versions. I don't relish studying all that again, but would if the other stuff were figured out.

 

[Shuriken]

The guys on the XS11 forum have worked out FI for the XS11 and it works very well. Easier, I suppose, to do on an inline 4. Nonetheless, this thread has a ton of good information (162 replies):
http://www.xs11.com/forum/showthread.php?s=&threadid=3289&highlight=fuel+injection

 

[kevman]

I have done a lot more research and I have found /thought of a way to use stock manifolds and airbox[maybe].Remove carbs and replace with aluminium tubes with fuel injector bungs epoxied/welded in place .Make a replacement cover for the airbox and fit a car throttle body to it and mount a ramair tube to it and an airfilter on the end.Any thoughts ,gentlemen?Kevman

 

[gleno]

Here are some thoughts.

1) I like Kevman's idea of RAM forced induction. Finally get those scoops to do something.
2) It would be easier to get rid of the air box and fabricate your own so that it attaches to the rubber boots that the carbs sit in. So you retain V-boost. Connect it or not its up to you. Get rid of it and you have more space because the servo nad cable are gone.
3) Now the air box is gone, move all the crap under the scoops into the cavity that the old air box vacated (and that your front coils vacated if you go COP's) along with your EFI controller unit.
4) Super small budget would use a single throttle body on the new air box.
5) If you want a budget solution the Microsquirt unit is the way to go http://www.microsquirt.info/
6) A 'kit' approach would allow four injectors to be mounted into the exist lower manifold castings. Hell you can even have them sit up-side down and squirt up the inlets from below, (so you have a single rail instead of a split system) It'll make bugger all difference to the efficiency of the delivery. Drag racers do this.

...oh almost forgot. A 'kit' approach definitely has to have an external fuel pump that ideally sits where the existing one does. Heaps of these in the after-market.

...oh and another thing. The single throttle body lends itself to some simple turbo or supercharging mods.

 

[blvdblaster1200]

thats similiar to the route im going.ditch all the factory stuff -cdi,intakes to airbox.im going to fab up a plenum with runners and run a single throttle body.im going to use the microsquirt to run timing too.using a bosch four channell ignitor-as the squirt is only a two channell.just bridge the two channells together as inputs to the ignitor and presto you have four outputs to run some logic style cop coils.once i have all this sorted ill turbo it with two small turbos.getting the components together now.just found my coils and injectors off a 02 busa near where i live.ill post pics later and build info.later, mike

 

[Birdoprey]

I don't think anyone will be happy with all four intakes running to a single plenum with a single Throttle body. You will loose intake velocity and thus your low speed and even some midrange will go to pot. This is one reason the manufactures use individual carbs/throttle bodies.
I had a Mr. Turbo kit on a 99 ZX-9 with EFI conversion. Ran like a pig down low/midrange. Hard to even get bike moving from a dead stop. Had to rev it and slip the clutch. No throttle response when under a load. This setup used a single plenum with a single TB. I spoke at length with Terry Kizer(owner of Mr. Turbo) and he finally mentioned that it was more for dragracing than for a responsive street bike. I re-racked a set of GSXR750 TB's and had a small bread-box type plenum made to feed the TB's. No other changes to the bike and it ran/responded like stk off boost.

 

[maleko89]

Stupid question...what's a plenum?

 

[blvdblaster1200]

thats good to know.works great on cars but garbage on a scoot.did terry kizer comment on size of runners and plenum volume at all?or was it such a sacrifice that it couldnt be worked out?i have been priceing tb's from sport bikes and the only tough part is the linkage.will still use a plenum but with an intercooler just in front of the tb's.rather than an external one.thanks for the info saved me some time and headache no doubt.and mark -a plenum is nothing more than an air chamber sized for the engine it can be before or after the throttle bodies.

 

[Storloc]

If you've ever looked at an intake manifold with the carb removed it would be the area directly below where the carb bolts on that leads into the intake runners. Of course an EFI equipped vehicle differs a little in design but you get the idea.

 

[maleko89]

So it's an intake manifold? Or is the intake manifold the same as runners?

 

[Storloc]

Usually the intake manifold consists of the plenum and intake runners. Some setups use seperate pieces though. On a carb setup you usually see an order such as carb-plenum-intake runners-head. EFI is commonly air intake-plenum-injectors-intake runners-head.

 

[maleko89]

So a plenum is just an air source. Do the injectors inject into the plenum? I know Mike is using a throttle body to inject into and I'm guessing you're doing this because it's cheaper than multiport EFI? It allows you to re-use the air box and intake manifolds?

So, the Vmax doesn't really have a plenum or intake manifold...just carbs, runners, head.

 

[Birdoprey]

Well, a plenum is basically an air SPACE or chamber from which the motor draws air from. It can be before or after the throttle that controls air flow. The size affects some of the motors characteristics. If its small, you have good air velocity(fast moving air mixes fuel very well promoting fast/even buring in cyl. This = more power, better efficiency). Draw back is that a small plenum has 4 cyl drawing from it very quickly which makes it hard to keep it "full of air". This will limit maximum hp so top end suffers. A large plenum has enough to keep cyls happy, but there is no air velocity to keep air/fuel mixed nicely at lower rpms. This hurts throttle response and low rpm power.
On most late model Trottle bodies on motorcycles, the injectors are mounted in each. This allows fuel to be directed directly into the fasted moving air(smallest ports right above the valves).
Motorcycles have relatively small motors covering a huge rpm range. They must be tuned to make power way up there so hp/tq down low suffers. A fix for this is having individual throttle blades(or carbs) on each port. This helps low rpm intake velocity with the benifits i mentioned above. A car motor on the other hand is much larger(bigger motors inherently make more tq), so they can afford some loss in velocity by using a single TB. They also do not cover the rpm range a small bike motor does and thus their air usage/needs do not have such a range.
Another example is Draw-through turbos vs blow-through turbos. Drawthroughs use small runners into a plenum with a single inlet fed by the turbo. Air is drawn in through a kinda large carb(single) and fuel is added and air/fuel flows through compressor and into plenum/runners then head. Ask any draw through turbo user and they will tell ya that low rpm/idle is'nt the greatest. Neither is off boost throttle response. You open the throttle and one big throttle opens. Air has to travel through the plenum(filling it) and then into the motor. Not very speedy is it? When on boost though, air is in more of a hurry...!
The blow through uses individual carbs or throttle bodies. There is a plenum ready to feed the cyl as soon as the throttles ask for it. Does'nt matter as much how large the plenum is, since the throttle blades are after it restricting flow(down low).Since the throttles are right above the head, response is rapid and velocity is high. The plenum needs to be large enough to supply air at maximum rpm.
I hope some of this makes since? Some times i get lost as to where i'm at when trying to explain more than one thing...

 

[Birdoprey]

thats good to know.works great on cars but garbage on a scoot.did terry kizer comment on size of runners and plenum volume at all?or was it such a sacrifice that it couldnt be worked out?i have been priceing tb's from sport bikes and the only tough part is the linkage.will still use a plenum but with an intercooler just in front of the tb's.rather than an external one.thanks for the info saved me some time and headache no doubt.and mark -a plenum is nothing more than an air chamber sized for the engine it can be before or after the throttle bodies.

Terry is a great guy and very knowledgeable. Most of the time he is willing to really help ya. He will go into detail on some things but all he mentioned to me was that for what i wanted, it might be best to run individual TB's and have a plenum made. Plenum size on a blow through turbo setup is not as important since the turbo will not allow it to be a restriction. There will always be more air available than the motor can naturally injest. It does need to be large enough to feed the cyl at low speed and thats about it.
Running naturally asperated, it would be more important. If using individual TB's AFTER the plenum, then the plenum size just needs to be large enough to feed the motor at higher rpms since the throttle bodies are keeping up the velocity.
Took me prolly 50 runs down the road and trying/changing everything Terry asked me to before he decided to tell me what the problem really was. He originally told me that the bike with his kit should run like a stk bike when off boost. After trying/adjusting many, many things, he says "well, my kit was really designed for dragracing, so low speed response would'nt be the greatest"...Thanks...

 

[kevman]

ok this is getting interesting ,the plenum on most cars that I have seen is basically a box with an airfilter in it.The vmax's is a box with an airfilter and trumpet inlets in it.These trumpets form part of the 9 1/2 inches that the bike needs for the inlet length which governs the power/torque delivery.So I read that inlets with trumpets on the end adds %19 1/2 or is it 19.5% more power throughout the rev range so when you make your plenum the bike would have more power if you make the inlets with trumpets on the ends .and I just bought a Mazda 323 throttlebody off ebay so it looks like I will be going that route since making linkages to suit individual tb's is going to be a major PITA for me cheers Kevman

 

[blvdblaster1200]

all you need to make the linkages is some aluminum bar stock,a good tap set,some threaded rod and end peices which you can usually make.i was going to go the single tb route but since im switching to turbos shortly after i get the injection up and running ill probably just stick with the stock gixxer 42 mm tb's and make up linkage.it will give me more intake velocity when im naturally aspirated and will still work fine when i boost it.i had a gpz 750 turbo that was set up like this.plus ill use the plenum to house a water to air intercooler in the intake stream instead of have it hanging off the bike someplace looking like a growth of some sort.should help clean up things a little.i still think a single tb will work ok but you need to size it accordingly to keep up velocity at slow speeds to not make the engine lazy ,but then you have to get more air through those smaller holes and build power up high which is where the problem lies.two different schools of thought naturally and supernaturally.

 

[blvdblaster1200]

So a plenum is just an air source. Do the injectors inject into the plenum? I know Mike is using a throttle body to inject into and I'm guessing you're doing this because it's cheaper than multiport EFI? It allows you to re-use the air box and intake manifolds?

So, the Vmax doesn't really have a plenum or intake manifold...just carbs, runners, head.

typically injectors shoot into the airstream just up from the valve but on some engines you do have injectors that fire into the plenum they are secondary injectors meant to supply additional fuel.a rx-7 mazda is one example of this.i was going to use a single tb for air only and build a fuel rail and weld injector bungs to the runners close to the head.but because the set up im using is destined to be boosted ill go the individual route.i was trying to cut a corner by not dealing with the individual tbs and simplify things. some times it works and some times not.the runners are in essence the intake manifolds.some times an intake contains a plenum of significant size and other times its merely the internal size of the runners.

 

[maleko89]

Mike, so are you going to use the p/u coils as your crank positions sensor? Are you going to run one O2 sensor? You probably could use the temp gage unit as your coolant temperature sensor. Anything else needed besides a manifold air pressure sensor?

 

[blvdblaster1200]

Terry is a great guy and very knowledgeable. Most of the time he is willing to really help ya. He will go into detail on some things but all he mentioned to me was that for what i wanted, it might be best to run individual TB's and have a plenum made. Plenum size on a blow through turbo setup is not as important since the turbo will not allow it to be a restriction. There will always be more air available than the motor can naturally injest. It does need to be large enough to feed the cyl at low speed and thats about it.
Running naturally asperated, it would be more important. If using individual TB's AFTER the plenum, then the plenum size just needs to be large enough to feed the motor at higher rpms since the throttle bodies are keeping up the velocity.
Took me prolly 50 runs down the road and trying/changing everything Terry asked me to before he decided to tell me what the problem really was. He originally told me that the bike with his kit should run like a stk bike when off boost. After trying/adjusting many, many things, he says "well, my kit was really designed for dragracing, so low speed response would'nt be the greatest"...Thanks...

you got me thinking,im a auto driveability mechanic and messed with a bunch of tuner cars over the years.i think you could run a small log style plenum-1 per bank and one small tb per bank.that would keep the air speed up during low engine speed to keep the motor from being lazy.then build a primary air chamber for high speed operation.basically the turbos would boost into the primary and the engine would run off boost from the secondary or log style chambers.in theory it would give you the best of both worlds.i helped set up a 406 inch twin turbo vette like this once.it made over 1200 rear wheel hp.it had accel dfi,a accell super ram and an air chamber both turbos fed into then into the tb and plenum.and it had crisp throttle response like a normally aspirated engine in spite of the lessened comp ratio and cam profile.that f-in thing was sick.ill have to see if i can dig up any pics of it.but this is doable and at this stage its only r and d anyway so what do i have to lose other than a little time and aluminum.right?that sucks mr kizer didnt do more research before he marketed a kit like that.if he sold a kit for a street bike he had to know people will pick it apart as its ridden on the road.i just got rid of my zx-7r.but i was going to stick an h-2 engine in that chassis -would have been alot of fun.thanks for letting me pick your brain.you have given me a direction i probably wouldnt have gone till i saw it wouldnt work that way.later mike