DIY Fuel Injection

[Corley]

I was wonderring if anyone here has thought about, or tried to build, their own super simple ECM for fuel injection. Something along the lines of a 555 timer with the output being tweeked by the CPS, TPS, MAP, TEMP, and OX2 sensors. I've been toying with the idea of using some motorcycle throttle bodies with this on an Olds 215ci engine that I have. I'd have to make the manifold, probably just mill the ports into a stock manifold and weld in stub pipes that the coupling hoses could attach to. The 4 cylinder motorcycle throttle bodies use a short hose clamped to the input side to attach to the head, so this makes an easy hookup. They also have an injector for each cylinder/throttle body, and there are a few different flow rates to select from from the different displacement bikes. They are pretty decent looking, and two rows of 4 would look great sticking straight up on the V8 engine.

Enrichment is the biggest issue to overcome with this setup. Some guys already use this simple 555 timer concept on airplanes (Subaru engines), where that is not such a problem. (Airplanes tend to stick to one RPM/loading.) If enrichment could be overcome to the point that the engine ran decent, then "perfect" and smog free operation would not have to be a goal, just driveability. No need to mess with the ignition, stock distributor would be OK. The whole ecm could fit in a very small space.....Hm....

My, how the mind wanders when locked in the house with icky weather...

Corley

 

[Northstar T]

I've been toying with the idea of using some motorcycle throttle bodies with this on an Olds 215ci engine that I have. I'd have to make the manifold, probably just mill the ports into a stock manifold and weld in stub pipes that the coupling hoses could attach to. The 4 cylinder motorcycle throttle bodies use a short hose clamped to the input side to attach to the head, so this makes an easy hookup. They also have an injector for each cylinder/throttle body, and there are a few different flow rates to select from from the different displacement bikes. They are pretty decent looking, and two rows of 4 would look great sticking straight up on the V8 engine.

Corley

Motorcycle throttle bodies on a car engine??? well that's just about the craziest ides I've ever hear of.:whisper:

The setup I build for the Northstar is a bit easier due to the manifold being "dry", for one thing, and because the manifold mounting surface is horizontal it's easier to get the injectors aimed correctly in the intake tubes. you could use a stock manifold I guess, but you'd of course need aluminum tubes to be tig welded into the aluminum manifold. injector aiming migh be the real challenge if you go that way. using a stock manifold would solve the water circulation issues however, so it's about an even trade I recon'. If you get serious about building one I'd be happy to share my experience in DIY ITB injection for the street. I really enjoyed my project. It's one of those deals that really makes the creative juices flow. Go for it!!!!
here is a pic of my manifold. it's pretty much like building an exhaust header flange.

also don't forget you'll need various vaccume sources for things like pvc, map sensor and fuel presure regulator + perhaps power brakes as well. the plumbing does get a bit more complex than you might think.

The ECM might be a bit more challenging. I'd stick to a OBD 1 factory unit like the 7730 GM or other well hacked unit. maybe a Mega squirt if you really want to do the diy thing in the electronics also.

Russ

 

[Corley]

Russ,
Turns out that the 215 Buick Olds is a "dry" intake except for a water passage to each head, and uses a separate valley cover. This makes it pretty easy to mill away everything except the water passage and the flanges, so I'd just need to weld in aluminum tubes. The Suzuki motorcycle injector throttle bodies that I have also contain the injectors, so I'd just need to get those pointed toward the valves as best possible. They also have some cute little vacuum plumbing in the form of rubber tubes and 'T's. Since this would be a low performance setup, perfection would not be required.

I agree something like the GM OBDI ECM would be simplist to use, and obviously work much better out of the box. I guess the 555 idea is more for the project than the end result. An old fart like me could learn a ton about FI I suspect! On the other hand, I suspect your idea would teach an old fart like me about all his mind can contain... You have a very cool setup, and that's something like I envisioned. (Maybe I'm not TOTALY senile just yet...)

A couple of questions come to mind: First, what injector bodies did you use, second, how did your CFM come out and is it a decent match for your engine? Those bike engine really rev, and they MUST flow a lot of air/fuel at those speeds! Because of that, I'm thinking that the Aluminum 215CI Olds may only need one row of throttle bodies, each being shared by two cylinders.?.?. Maybe a motorcycle ECM??? Nah...

Corley

 

[ellis8500]

Airplane engines do tend to run at a set RPM. As such, the carb/fuel injection system is very simple compared to an auto setup that has to operate properly with almost continuously varying throttle settings and engine load conditions. Airplanes also have a seperate,manual mixture control. A 555 timer has it's function set by an RC circuit. It does not have the capabilty to use the sensors you mentioned to vary it's timing pulses. To do that you will need a microprocessor and a program. Now if you can figure out how to use a 555 timer to operate a fuel injection system in an auto setup; be sure to properly document all of what you do with witnesses signing all of you design documents. Get it patented and you'll make a fortune.

 

[Northstar T]

Russ,
Turns out that the 215 Buick Olds is a "dry" intake except for a water passage to each head, and uses a separate valley cover. This makes it pretty easy to mill away everything except the water passage and the flanges, so I'd just need to weld in aluminum tubes. The Suzuki motorcycle injector throttle bodies that I have also contain the injectors, so I'd just need to get those pointed toward the valves as best possible. They also have some cute little vacuum plumbing in the form of rubber tubes and 'T's. Since this would be a low performance setup, perfection would not be required.

I agree something like the GM OBDI ECM would be simplist to use, and obviously work much better out of the box. I guess the 555 idea is more for the project than the end result. An old fart like me could learn a ton about FI I suspect! On the other hand, I suspect your idea would teach an old fart like me about all his mind can contain... You have a very cool setup, and that's something like I envisioned. (Maybe I'm not TOTALY senile just yet...)

A couple of questions come to mind: First, what injector bodies did you use, second, how did your CFM come out and is it a decent match for your engine? Those bike engine really rev, and they MUST flow a lot of air/fuel at those speeds! Because of that, I'm thinking that the Aluminum 215CI Olds may only need one row of throttle bodies, each being shared by two cylinders.?.?. Maybe a motorcycle ECM??? Nah...

Corley

I guess you could keep the section of manifold intact that contains the thermostat as well, so using the stock manifold would certainly work. I've never tried the bike injectors myself. I guess most any injector that sprays a mist of fuel in the proper amount for your engine would work, most bikes use a smaller base injector that automotive, so you might as well give it a try, if they flow enough for the 215. there again, my engine was already made for injection so I used the stock Caddy injectors and fuel rails. I knew they would work .
For the Northstar I like the 97 Susuki GSXR600 throttle bodies. they're new enough bikes to be easy to get with very low miles off flee-bay ($75.oo each average). they require quite a bit of modification, but they work real well for me. they're just shy of 40MM at the base, which might be a tad big for your 215, but ITB injection isn't like building a carb setup. injectors do the atomizing, not a venturi, so a little big is actually better than too small, but you have a wide range in an case.
you mention you already have some TBs? what are they from? earlier 90s Susuki bikes used individual TBs (mine are cast in pairs) that would be easier to mount the way you diescribe.
"Maybe a motorcycle ECM??? Nah..." Naw is right!


Here's a couple links you might want to check out to calculate what size injectors you'll need:http://www.witchhunter.com/injectorcalc1.php4 and what size TBs will work best for you (and lots more good info here)http://www.jenvey-dynamics.com/~Mansyss.htm Russ

 

[Differen T]

I guess you could keep the section of manifold intact that contains the thermostat as well, so using the stock manifold would certainly work. I've never tried the bike injectors myself. I guess most any injector that sprays a mist of fuel in the proper amount for your engine would work, most bikes use a smaller base injector that automotive, so you might as well give it a try, if they flow enough for the 215. there again, my engine was already made for injection so I used the stock Caddy injectors and fuel rails. I knew they would work .
For the Northstar I like the 97 Susuki GSXR600 throttle bodies. they're new enough bikes to be easy to get with very low miles off flee-bay ($75.oo each average). they require quite a bit of modification, but they work real well for me. they're just shy of 40MM at the base, which might be a tad big for your 215, but ITB injection isn't like building a carb setup. injectors do the atomizing, not a venturi, so a little big is actually better than too small, but you have a wide range in an case.
you mention you already have some TBs? what are they from? earlier 90s Susuki bikes used individual TBs (mine are cast in pairs) that would be easier to mount the way you diescribe.
"Maybe a motorcycle ECM??? Nah..." Naw is right!


Here's a couple links you might want to check out to calculate what size injectors you'll need:http://www.witchhunt...ectorcalc1.php4 and what size TBs will work best for you (and lots more good info here)http://www.jenvey-dy...om/~Mansyss.htm Russ

Maybe this is a starting point for your project. www.dynamicefi.com/ I use one of their older models in my 90 k2500. The new model is a tune as you drive setup based on an OBD1 GM TBI . Bob is very knowledgeable on DIY FI. The wiring is based on a GM TBI which is readily available at the bone yard at a reasonable.

Al

 

[Corley]

Bill,
If you take a look at the ckt diagram I posted, you'll notice that the RC network that controls the 555 timers output pulse width is modified by the engines sensors, thereby changing the pulse width of the output. This is the same way the guys using this in the airplanes do their fine tuning in flight. In addtion, the 555 timer has an extender input pin, which can also be used by a sensor to vary the output pulse width. There is no problem in getting as many different ouput pulse widths (injector on time) as you'd like, by varying these inputs, no processor required. Additionally, a variable pressure fuel pressure regulator (using engine vacuum) will also provide feedback on the engines loading, providing a higher pressure when more fuel is needed.

The biggest problem in getting it to run well with a 555 timer is not controlling the mixure at a fixed RPM/loading, it's adding the needed enrichment at the proper time. (IE, you almost would like the mixture enrichened as the throttle is pressed down, not after the engine has responded.) Then, if you want to really make it a "clean" engine, you need to do a lot more sophisticated stuff, and you really do need a processor. I thought perhaps that is not needed in a bucket... Patentable, not in this life!

-----------------

Bob,

My current throttle bodies are off of a 2001/02 Suzuki GSXR1000 motorcycle, and they are 4 individual throttle bodies connected together in a row, each with it's own injector. I've done the GM OBDI ECM conversion on a couple rigs already (using a stock TBI throttle body), and that's just a matter of hanging parts, and either matching a factory prom to the engine or tuning to create your own prom. It works well, and is fairly easy to do. Your conversion, using a mix of parts was a bit more complicated, and required a lot more research and knowledge to get the fuel flow correct. What I was thinking of is a little different, in that it is a $2 ECM. Practical, NO! Fun learning project, Yeah... I probably won't actually do this project, but we learn by considerring what would and would not work, and what it might take to make it work, and having retired as an electrical/firmware engineer my mind wanders in that direction... As I said, crappy weather does make the mind wander!

Corley

PS I see on eBay that the Rover 3500 (Basically the same engine) used an intake that would be very easy to adapt as it already has 8 port stacks pointed up, and they are cheap to buy. Much easeir starting point...

 

[Gerry]

Bill,
If you take a look at the ckt diagram I posted, you'll notice that the RC network that controls the 555 timers output pulse width is modified by the engines sensors, thereby changing the pulse width of the output. This is the same way the guys using this in the airplanes do their fine tuning in flight. In addtion, the 555 timer has an extender input pin, which can also be used by a sensor to vary the output pulse width. There is no problem in getting as many different ouput pulse widths (injector on time) as you'd like, by varying these inputs, no processor required. Additionally, a variable pressure fuel pressure regulator (using engine vacuum) will also provide feedback on the engines loading, providing a higher pressure when more fuel is needed.

The biggest problem in getting it to run well with a 555 timer is not controlling the mixure at a fixed RPM/loading, it's adding the needed enrichment at the proper time. (IE, you almost would like the mixture enrichened as the throttle is pressed down, not after the engine has responded.) Then, if you want to really make it a "clean" engine, you need to do a lot more sophisticated stuff, and you really do need a processor. I thought perhaps that is not needed in a bucket... Patentable, not in this life!

-----------------

Bob,

My current throttle bodies are off of a 2001/02 Suzuki GSXR1000 motorcycle, and they are 4 individual throttle bodies connected together in a row, each with it's own injector. I've done the GM OBDI ECM conversion on a couple rigs already (using a stock TBI throttle body), and that's just a matter of hanging parts, and either matching a factory prom to the engine or tuning to create your own prom. It works well, and is fairly easy to do. Your conversion, using a mix of parts was a bit more complicated, and required a lot more research and knowledge to get the fuel flow correct. What I was thinking of is a little different, in that it is a $2 ECM. Practical, NO! Fun learning project, Yeah... I probably won't actually do this project, but we learn by considerring what would and would not work, and what it might take to make it work, and having retired as an electrical/firmware engineer my mind wanders in that direction... As I said, crappy weather does make the mind wander!

Corley

PS I see on eBay that the Rover 3500 (Basically the same engine) used an intake that would be very easy to adapt as it already has 8 port stacks pointed up, and they are cheap to buy. Much easeir starting point...

Yep
That was called a Rover Vitess and they were EFI. Like gold dust over here. Not a brilliant system, but I tried to get one many years a go and failed. I can look into it but if you search for Rover V8s and look at the UK sites there are a few specialist that have developed and offer all sorts of set ups for this engine. They are popular here for Rods and Drags and the BHP they can get it out of this world. We used to stick to the SUs and occasionally Webers. Course you can always supercharge them. Lots do. By the way it is a CUTE little engine and all alloy to boot. I put one in my VW based kit car. Fun Fun Fun
Gerry

 

[GT63]

I'm running an Injector plate between the bug catcher and blower that's controlled by an Accel DFI Gen 7 ECU. It's fairly easy to configure and control with a laptop.

 

[Screaming Metal]

I was wonderring if anyone here has thought about, or tried to build, their own super simple ECM for fuel injection. Something along the lines of a 555 timer with the output being tweeked by the CPS, TPS, MAP, TEMP, and OX2 sensors. I've been toying with the idea of using some motorcycle throttle bodies with this on an Olds 215ci engine that I have. I'd have to make the manifold, probably just mill the ports into a stock manifold and weld in stub pipes that the coupling hoses could attach to. The 4 cylinder motorcycle throttle bodies use a short hose clamped to the input side to attach to the head, so this makes an easy hookup. They also have an injector for each cylinder/throttle body, and there are a few different flow rates to select from from the different displacement bikes. They are pretty decent looking, and two rows of 4 would look great sticking straight up on the V8 engine.

Enrichment is the biggest issue to overcome with this setup. Some guys already use this simple 555 timer concept on airplanes (Subaru engines), where that is not such a problem. (Airplanes tend to stick to one RPM/loading.) If enrichment could be overcome to the point that the engine ran decent, then "perfect" and smog free operation would not have to be a goal, just driveability. No need to mess with the ignition, stock distributor would be OK. The whole ecm could fit in a very small space.....Hm....

My, how the mind wanders when locked in the house with icky weather...

Corley

I'm amazed at all you guys building your own systems! :thumb: I play with the old mechanical systems all the time....and have messed with the megasqirt quite a bit....check this out....


http://www.teglerizer.com/fi/megasquirt/index.html

 

[Screaming Metal]

Well, I couldn't add the extra link to my origional post, so I had to add this....
After you read about the MegaSquirt EFI....you can add what you want and/or need, as far as sensors, they're fully adjustable and can be setup from 1 cyl to v16's if wanted and have every possible option included in the base unit....
After you check on the unit on the 1st link....go to this next link for additional info....

http://www.diyautotune.com/catalog/megasquirt-complete-c-25.html

:wacky: :hi:

 

[Corley]

Gerry,

Those Rover engine parts are all over the place over here, and for very resonable prices. Lot's of Land Rovers and Discoveries in the yards I guess. Certainly lot's of stuff on eBay... I also have installed that aluminum engine behind a VW transaxle, once in a sand rail, and once in a Baja Bug. The VW bug transmissions held the power just fine, but the differentials tended to loose teeth fairly often. Now days there are all sorts of beef up parts to make that combo work well I suppose. Quite a few made there way into home built aircraft too...

As you said, great little engine, really light, and can really put out the power. BL did a lot with it after GM dumped it, (and then wished they hadn't). I always liked the Olds version best because it had a little better head design, but BL used the Buick design heads and did a lot with them in later versions. Did you guys ever put a decent automatic behind it? This one has the little SlimJim (Roto Hydramatic model 5), which leaves a lot to be desired... Or, maybe there is a way to make it into a good one?

Corley

 

[PotvinGuy]

I'm amazed at all of us thinking the same things. I've been sketching 555-based EFI circuits for a long time. I think it is doable. The Megasquirt site has lots of good EFI info. My present crappy Haltech ECU has a shorted driver and I'm gonna tear into it while we are snowed in here in MN.

If by enrichment you mean the accelerator pump function, that's easy to do in the circuit. That is basically all the TPS does; run it thru a capacitor to increase the pulse width momentarily when you punch the throttle. Play with the time constant to get the best response. The MAP will take care of the mixture after that.

 

[PotvinGuy]

I'm amazed at all of us thinking the same things. I've been sketching 555-based EFI circuits for a long time. I think it is doable. The Megasquirt site has lots of good EFI info. My present crappy Haltech ECU has a shorted driver and I'm gonna tear into it while we are snowed in here in MN.

If by enrichment you mean the accelerator pump function, that's easy to do in the circuit. That is basically all the TPS does; run it thru a capacitor to increase the pulse width momentarily when you punch the throttle. Play with the time constant to get the best response. The MAP will take care of the mixture after that.

 

[PotvinGuy]

...nothing new under the sun. Check this out: http://www.rotaryeng.net/simple-cheap-555.html

Still looks like a fun project.

 

[Corley]

PotvinGuy, (do you have a name?)

The site that you cite is where I got a lot of my ideas and thoughts on the 555 injection, and I'm pretty convinced that it would "work", and be a fun project. It's probably not a "worthwhile" project, since it's sort of re-inventing the wheel, but I'd sure like to give it a try... Maybe someday, huh? Glad to hear someone has looked at the idea and validates the concept, if not the implimentation. HA! Go for it and I will cheer you on!

Corley

 

[PotvinGuy]

PotvinGuy, (do you have a name?)

The site that you cite is where I got a lot of my ideas and thoughts on the 555 injection, and I'm pretty convinced that it would "work", and be a fun project. It's probably not a "worthwhile" project, since it's sort of re-inventing the wheel, but I'd sure like to give it a try... Maybe someday, huh? Glad to hear someone has looked at the idea and validates the concept, if not the implimentation. HA! Go for it and I will cheer you on!

Corley

If this crummy Haltech bites the dust, I just might try it. And the Multisquirt looks like a great learning experience, too.

I'm Kerry Smith, just moved from Dallas to the Twin Cities in MN. The bucket is snowed in for some months to come, but looking forward to the Back to the 50's show, and meeting a bunch of new bucket nuts here.