general fuel injection musings. anyone with experience/opinions, please participate.

as i begin a fuel injection project, i have a few assumptions that i want to either blow away, or have confirmed. i figured that just starting a fuel injection thread as catch-all topic might bring together some of the minds on here on this.

i know there are quite a few people here with experience doing this, as far as starting from scratch goes, as well as modding up some existing injected bikes.

i have a pretty good knowledge of injection, i would say. the various subsystems and functions are fairly well known to me, but i am a little weak on some of the specifics, as far as they are concerned with injecting a 30 year old air cooled machine.

a couple questions to begin.

1) it appears the general concensus is to use existing throttle body/fuel rails/throttle linkages. is this for ease of application, or is it absolutely better than going with a fabricated manifold with a single t/b?

2) ignition, control with with the ecu, or just run a dyna?

3) fuel systems solutions. internal pumps vs. external?

feel free to throw in more questions, these are just a few that i have bouncing around in my head, that i figured would get things going.

i look forward to some interesting input.

--r

solomrus wrote:

a couple questions to begin.

1) it appears the general concensus is to use existing throttle body/fuel rails/throttle linkages. is this for ease of application, or is it absolutely better than going with a fabricated manifold with a single t/b?

It's for ease of application along with a general consenses the ITB's make more power.

2) ignition, control with with the ecu, or just run a dyna?

You have to learn to crawl before you can walk, let alone run
Ignition control with the ECU is great, but do fuel first then add in ignition later if desired.

3) fuel systems solutions. internal pumps vs. external?

Got room to mount a fuel pump in your tank, and a fuel tank you don't mind cutting on? Or room for a smaller surge tank with a internal pump? If not then external pump is the answer. 87-90 Ford F150's (and others) used an external pump that will work quite nicely (and they are cheap at most boneyards).

1) In absolute power terms there is no difference, but there is scope for poor distribution in a custom manifold so existing TBs are a safe bet.

2) Control with the ECU. Not only does it keep all the electronics in one box but if you turn the power up and need a stronger spark most ECUs already have coil drivers to kill an elephant. An exception would be Motec, which uses an external driver pack to keep electrical noise down.

3) External unless the tank you are using already has an internal pump. Internal pumps are not built as ruggedly and need to be immersed in fuel to keep cool. That's why they are cheaper. And I just don't like the idea of electricity and fuel in the same place...

solomrus wrote:

as i begin a fuel injection project, i have a few assumptions that i want to either blow away, or have confirmed. i figured that just starting a fuel injection thread as catch-all topic might bring together some of the minds on here on this.

i know there are quite a few people here with experience doing this, as far as starting from scratch goes, as well as modding up some existing injected bikes.

i have a pretty good knowledge of injection, i would say. the various subsystems and functions are fairly well known to me, but i am a little weak on some of the specifics, as far as they are concerned with injecting a 30 year old air cooled machine.

a couple questions to begin.

1) it appears the general concensus is to use existing throttle body/fuel rails/throttle linkages. is this for ease of application, or is it absolutely better than going with a fabricated manifold with a single t/b?

2) ignition, control with with the ecu, or just run a dyna?

3) fuel systems solutions. internal pumps vs. external?

feel free to throw in more questions, these are just a few that i have bouncing around in my head, that i figured would get things going.

i look forward to some interesting input.

--r

looks like this is where i start spending money :evil: one of the systems he is engineering is going on my 1385 turbo,so all of you turbo/fuel injection geniuses feel free to jump in here.its also gonna have a nitrous bottle plumbed in there so we need to figure out how much extra fuel we need when the button gets pushed.now we just need to find a volunteer to ride the turbocharged uni-cycle when its done,dont know if the pacemaker can take the hit!:evil: hahaha

i'd read a while ago that ITB's were great as far as better throttle response goes, and that was about as far as that article went.

that's kind of what i was thinking lorcan. that overall, you'll see similar power between the two. this setup will eventually be boosted, which will override the distribution somewhat, but maybe not entirely, if the manifold is poorly thought out.

just for reference, here's what i have in mind. this is all high-level, making some assumptions no proof of concept yet.

custom manifold, more like custom injector blocks with a manifold for good measure. use the blocks to locate injectors, fuel rails, fpr, and lines. the initial thought process is that the injectors will be angled to fire into the ports, possibly on to the back of the intake valves. this is my first thought, however i have other ideas for that as well.

ok, so the injectors are located. enclose the intake side of these blocks with a sheetmetal manifold. probably aluminum. find a suitable throttle body with TPS, idle air control, and of an appropriate size. something between 40 and 60mm is my thinking. probably on the smaller side of that. maybe a ford tb, as i am familiar with those, and they are easy to get a hold of.

now, for distribution, i am thinking that the tb should be located in a similar orientation to as stock set of carbs. air will come in from the rear, and go directly into the ports. it'd be an upside-down triangle, with the point oriented at the tb and the long side oriented at the head.

the other way, could be that the manifold takes more of a transverse orientation, with the tb on either side, most likely the left side. this would require considerable fabrication to make a plenum suitable for this, especially where distribution is concerned.

just the ideas bouncing thru my head on this.

--r

Post edited by: solomrus, at: 2006/08/09 10:22

on the 1385 the turbo is gonna be located down low in front of motor like on lorcans 750.Lorcan ,if you get a chance can you post those pictures of your bike when you were mocking it up without the bodywork again so me and solomrus and the engine bulder can get some ideas where to locate some parts?thanks! i dont think ill have room for intercooler,but i still think it will look cool with the turbo and a stubby banana pipe poking out one side and throttle body and k&n sticking out other side.:evil:

I did the single TB thing years ago on my dragbike (not to be confused with my streetbike, although they are both 750 turbos), but the butterfly was on the turbo inlet. The injectors were mounted in blocks between the plenum and the head - they looked similar to throttle bodies, but they were empty, no need for individual butterflies. Worked great on a dragbike as there was no need for immediate throttle response (just hold it wide open on the stutter box and dump the clutch), but even so, the throttle response was acceptable. I'll dig out some pics. One advantage of having the butterfly between the turbo and the plenum though would be that the turbo would not need to be carbon sealed. That can be a pain, especially with a modern ball bearing turbo. The single butterfly I used was 60-65mm, I can't remember exactly but I've still got it somewhere...

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What the...? This is an accident waiting to happen. The proof is in the picture! :lol:

Lorcan wrote:

I did the single TB thing years ago on my dragbike (not to be confused with my streetbike, although they are both 750 turbos), but the butterfly was on the turbo inlet. The injectors were mounted in blocks between the plenum and the head - they looked similar to throttle bodies, but they were empty, no need for individual butterflies. Worked great on a dragbike as there was no need for immediate throttle response (just hold it wide open on the stutter box and dump the clutch), but even so, the throttle response was acceptable. I'll dig out some pics. One advantage of having the butterfly between the turbo and the plenum though would be that the turbo would not need to be carbon sealed. That can be a pain, especially with a modern ball bearing turbo. The single butterfly I used was 60-65mm, I can't remember exactly but I've still got it somewhere...

that's it. save for the tb in front of the compressor inlet. that's an interesting draw-thru system that way. i'd think closing the throttle with that thing still spinning would eat seals...

my thinking is that this will be very similar to an automotive setup. if your pre-compressor tb had good throttle response, this should be fine. i have no doubt it will take a lot of tuning, but should work out ok. 60/65mm ought to be easy to find. pretty sure a stock ford mustang (pushrod at least) tb is between 55/60mm.

it's going to be a necessity to have a good BOV on there too... but that is easy enough. HKS SSQ baby, only way to whistle while you work. 8^)

wire, i doubt we'll be able to intercool this thing on the first go-round. might be that the design changes enough to make it happen, but not sure so early. also, i think that getting a system up and running on an NA engine is gonna help your turbo project overall. at least it will cut the top off the learning curve.

wastegates... TiAL or turbonetics? this one concerns me too, as i want to upgrade my ATP setup to something better. the old block/valve wastegate... well, leaves something to be desired.

--r

skippr76KZ wrote:

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What the...? This is an accident waiting to happen. The proof is in the picture! :lol:[/quote]they wont let me put a motor in it,solomrus says im gonna hurt myself!:evil:

I'm going to go out on a limb here and disagree with my hero Lorcan

When you install a brand new EFI system on a previosly carburated bike and you have to create a whole fuel map from scratch, do you really want to have to deal with the ignition as well? My opinion is that it's better to use the ignition system that's already working and get the fuel right first, then add in the ignition later. I'd rather just deal with one problem at a time

Just an idea on fuel enrichment when using NOX. Just put a Bosch elect fuel injector in the intake manifold/plenum. Then wire it to the trigger so it richens up the mixture when only on the bottle. It would have to be plumbed into the fuel presure scorce of course, but shouldn't be a problem.