fuel injection?

[humhead]

but your home built system will not be equal to the one in my car. In power, driveability or emissions.

I love it when someone says " It can't be done" Makes me work harder to prove them wrong. As I said before, I have a second bike for experimental use. I plan on getting everything else right first, then and only then add fuel injection. The megasquirt is currently based on an 8 bit motorola cpu. This is similar to mid to late 80's auto FI systems. By the time I'm ready to install, a 16 bit system will be available. Besides I'm not comparing whatever system I install to the one in your car. My bike has mikuni roundslides, not modern auto FI. It's a lot easier to improve on 25 year old carbs that require regular attention & still have shortcomings in all 3 areas. I have some experience tuning late eighties FWD Mopars.
They have a similar system. If I can match that, it will be an improvment in all 3 areas. Best of all, I enjoy working on challenges like this.

Terry

[Anonymous]

8 bit

The kawa gpz's were 8 bit cpu's too. I cant see fuel map step resolution being uber critical enough to matter. Poster who said about the o2 sensor at cruise and correction only isnt quite right, the megasquirt can be placed in full closed loop operation if so desired.
The kawa system doesnt even run a o2 sensor though, they just have the maps on a rom (but including a secret race mode which when activated has a alternative fuel maps set up for a higher state of tune.)

You'll never match a modern auto FI system for emissions, but only because they tune for emissions at the expense of driveability and power because they HAVE to. They use the o2 sensor to run the motor lean to achieve this, not at stoich as you'd think. Thus to these ends, their hands are tied in a way that a amateur tuner's arent. My bike certainly wont have to pass any sort of emissions testing to be legal on the road (it has to pass a "smoke" test, that is if it doesnt make too much blue smoke visually its ok) , so I can tune for rideability and power. This goes way back too, the gpz turbo fi system was made over lean for the us market to pass the emissions legislation there (and we're talking 1985 here), and tweaking them to run more fuel pressure and a couple of mods to get round the changes results in a sweeter running and idling and better behaved bike more akin to the euro version bikes with actually a net gain in road manners and power (and less likely to blow the back out the surge tank in extreme conditions).
Manufacturers can be improved upon in respect of the specific areas you are interested in, despite the odds because although they have these huge R&D budgets and expertise, they also have a whole bunch of compromises foisted on them by budget constraints, legaslatitive, market perception and other factors.

Besides, im hoping its not going to stay at one throttle opening long enough to worry about anything but hanging on :twisted:

[Anonymous]

I love it when someone says " It can't be done" Makes me work harder to prove them wrong.

Go to it. I would be very interested to see your results. It's a very cool project, just a HUGE very cool project.

If I can match that, it will be an improvment in all 3 areas. Best of all, I enjoy working on challenges like this.

If you enjoy the work and tinkering, it will not matter if it is totally successful, because you had a good time getting there anyway.

The kawa gpz's were 8 bit cpu's too. I cant see fuel map step resolution being uber critical enough to matter. Poster who said about the o2 sensor at cruise and correction only isnt quite right, the megasquirt can be placed in full closed loop operation if so desired.

The map resolution can be critical to driveability issues. Otherwise, it is not that important. For your turbo set up, you could probably map it every 500rpm in the high torque area and it would be fine.

Even full closed loop operation only uses the O2 sensor for small corrections, the sensors do not respond fast enough to have them correct for throttle opening changes. Full closed loop systems still run from a map for fuel settings and then the O2 sensor will tweak it a bit if it sees lean or rich at steady cruise.

True enough about the tuning of our bikes compared to OEM autos. The OEM's are hamstrung with regs from the govenrment, but my comments about emissions were based on the original post that said emissions were an issue. As I mentioned previously, a full race FI system can be done much more easily than a fully refined street engine version. But just don't expect to match a well set up set of flatslides for power, or driveability in a street vehicle with a home-brewed injection system. It's all of the light-load, part throttle stuff that can be a bitch to get right. The full throttle settings are usually easy.

There is a reason why Yamaha ran carbs the first season of MotoGP - because they couldn't get the same smooth response from FI as well tuned carbs.

I expect Terry will get a system to run OK if he sticks with it, but it's the final refinement and polishing that is so hard. I know we got a turbo'd 600 Ninja engine to run on the Formula SAE car when I was in university and we ballparked the initial FI settings from calculated airflows, with no bench testing at all. It never ran completely right while I saw it, but it DID run OK with a bit of tuning on a dyno. I expect that is where this will end up.

Good luck with it, it should be a fun, educational project.

Mark

[humhead]

Mark
I do appreciate your words of caution. It sounds like you've done this sort of thing more than once. I like to challenge myself. Exercise for the brain. Even if I'm not completely successful, I'll learn a lot.
[/quote]but it DID run OK with a bit of tuning on a dyno[quote]
This is encouraging....... There's a motorcycle shop with a dynojet less than ten miles from home.
My benchmark isn't a late model auto. If I can match a mid to late eighties FI system, that will be a big improvment. Remember, I'm starting with 25 year old roundslides (ugh!)

[Pete's GS]

EFI works well in cars because it has had a lot of R & D under the pressure of the EPA regs, which I'm all for. Motorcycle manufacturers seem to have taken longer to get EFI dialed in, though. There were complaints of "digital" feel and dead spots. It appears to be getting better throughout the industry now but when you think an engineer has to make EFI work from 0-15,000 rpm in all sorts of weather and air densities and engine loads, you have to be impressed. It's still hard to beat a good set of CV carbs though.