Until the government forces me to go to EFI, I'll stick with my carb's. More complexity translates to less reliability. All it takes is one component to fail in an EFI system, and you're getting towed back to camp.

 

My point exactly!! That's why I'll take my EFI over carbs anyday. Took me longer to get my wolverine carb cleaned out than it did to install an entire F.A.S.T. bank-to-bank system on a smallblock ford...

I thought it was Polaris or ??? that had a fuel injected sled somewhere in the 1989-91 years - who on here can confirm? I was in high school until 1991, and *swore* I remember "FICHT injected" sleds about the same time it came out for outboards! My understanding (which can easily be wrong :-) was that FI on a two stroke almost HAD to be direct injection? Maybe the guy who works on snowmobiles can set us straight - please do! I found links abuot sleds with Ficht injection but they're all newer - not older. please advise!

Regarding outboards - my family in FL have a 29' center console boat with a pair of EFI merc two strokes. I saw them with the covers off the engine; the electronics are all sealed up very well. At least with electronics and EFI it's even possible to seal from moisture - you can't do that with a carb - at some point atmosphere has to reach to float bowl. NOt the case with EFI.

and the saga continues!

 

Could somebody explain the differences between Fuel Injection, Semi-Direct Injection, & Direct Injection? I have a pretty good idea about what they are, but is one better for power and is one better for emissions or maybe better for tuneability, can Semi-Direct & Direct Injection be used on 4-strokes?

Thanks

 

I believe that Direct means that the Fuel is Sprayed directly into the compustion chamber and Indirect means that it is sprayed on the intake side of the head and pulled forward by the income air charge.

Smitty

Correct me if I'm wrong, cause it happens alot. LOL

 

TMK - direct injection puts the fuel injector directly in the combustion chamber. Benefits are fuel economy and power tuning, downsides are taht it requires very high pressure fuel system ($$$). It's been used in two strokes (recently) and in diesels for a long time. Semi-direct injection puts the injector in a "pre combustion chamber" - trades ultimate performance/economy for being able to use lower pressure fuel supply (less costly). Also been used on diesels for years, not sure abuot fuor strokes. Standard EFI puts the injector in an intake port, which requires much lower fuel pressure (and much less expensive injectors). This is the type that's most prevalent on four stroke engines.

 

For all the guys who dislike computers on quads are you going to slam the new yamaha because it is going to use a throttle position sensor with a computer to control the ignition timing curve. This provides a simple feedback feature for more power.
EFI reliabilty never even entered my mind because I thouhgt it was a given that it was more reliable. Im sure every one can argue examples either way on that subject.
As far as getting you back home if you are out in the sticks any EFI thats worth anything has a limp mode that can take over when one or more components fail. I dont know about the small engine EFI but every auto has this feature.
I work one the latest generation of diesels like the ford powerstrokes which can actually shut a complete bank of cyllinders down and contunue running the engine on the other 4 cylinders to get you home. They can also derate the engine if they start to overheat to keep the engine from melting down in the event of cooling system failure.

In my personal experience I can honestly say that over half of all EFI problems that I have encountered turned out to be a wiring failure. Seals missing on connectors letting water in,wires rubbing through on engine parts, connectors coming apart,pins not properly crimped from the factory , Most of these were a quality control problem and not a design flaw. The other half were component failures in which the engine usually made it back to the shop and were back on the road within a couple of hours after sensor replacement.

Hey guys I seem to remember Honda testing a efi 2stroke engine a few years back in a dirt bike. It supposedly had gobs of power and met epa emmisions. I think I saw it in a dirt wheels when I subscibed to that rumor mill.

 

DG, regular EFI was used on both polaris and arctic cat sleds, and even one year on a Ski-doo (Bomb. would like to forget that one). You're right, it doesn't seem to provide the advantages in a two stroke like DI or SDI for that matter. But they got it to work good enough to be an alternative to carbs. As rockrider points out, it hasn't taken the industry by storm. Wistech makes good point about limp mode on EFI's, if an O2 sensor fails on a GL1800 motorcycle, you really only know by the flashing FI light on the dash, you can't tell by the way it runs. However, certain things, like fuel pumps aren't normally backed up, so if it fails, you're walking or pushing.

 

As far as limp home mode, I'm not familier enough with recreational vehicle EFI systems to know whether the CPU can substitute a given value for a failed sensor. I recall General Motors EFI systems could keep the motor running with a number of failed sensors and that was pre OBD-II. I'd imagine the newer systems are even better at it.

Still, when you sit back and look at things, how complicated do people want their toys to become? A big part of owning an ATV, sled or bike is being able to work on it yourself. Very few people work on their own vehicles anymore, and it has become accepted. Do you guys think the same sort of future is in store for our toys? I hope not.

Somebody asked me about E-start versus kick. I'll take kick thank you. I'm a minimalist at heart and I'm not so old and lazy that I need the convience of e-start. I actually had the battery crack in a Wolverine I used to own because I slamming it through the whoops too hard. Freak failure? Yes. But another example of crap I don't need.

Then again, I'm not some retro grouch, I love the new technology that has come to mountain bikes in the form of full suspension. I'm willing to put up with the added maintenance and increased costs because the benefits outweigh the negitives.

Basically, I don't believe the benefits (real or perceived) from EFI are necessary for me or most to enjoy riding a quad. What we've got works great, why change it for sake of change? Again the EPA will decide that one.[img]i/expressions/face-icon-small-disgusted.gif[/img]