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Carby vs EFI - which is better?

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by rodgerdodger, Aug 22, 2005.

  1. Just wondering, this is mainly directed at glitch but I've noticed a few other comments, why do some people prefer carburetted bikes? From my minimal understanding fuel injection offers better fuel economy, more precise delivery etc? so why steer away from injected bikes? Just the servicing or do bikes regularly suffer faults with injection systems or something?

  2. I can onlly speak for myself, but for many of us I guess it's a money thing. Most injected bikes are going to be fairly new and therefore fairly expensive..
  3. EFI in bikes still has some way to go when comnpared with cars.
    In general, many EFI bikes have or have had at some stage of their model-cycle, a fairly "twitchy" throttle.
    Very small changes on the throttle translate into instant reaction of the bike as a whole. Coupled with the manufacturers settings to make the bikes pass various emission-laws in different parts of the world resulting in lean-settings, throttle action is often quite sudden and sorta jerky/ explosive....compared to the carbed bikes.
    EFI engines often "hunt", meaning they're just about impossible to run on even speed at steady throttle, they either want to accelerate or decelerate.
    Carbed bikes are "softer" on the throttle, easier to control (not as immediate in their reactions), don't "hunt" and can also be easily adjusted for lean/ rich settings without mega-bux electronic gizmos.
    Carbs don't have their "own life", but rather do exactly what's asked, when asked.
    All that doesn't make much difference on the straights, but rather counts through the twisties...more feel equals better control equals more fun equals , ultimately, safer riding.
    KTM with their soon-to-come 950 CARBED Vtwin Uber-motard know precisely why they didn't use EFI. The thing is made for carving twisties...

    EFI uses less fuel for the same given output?
    No. Long rides, side by side, of a dual-carb Pegaso 650 single and a later model of the same bike with EFI (with a 20kg lighter rider) have shown totally identical consumption, same top-speed, same hp, both getting hammered for hundreds of k's, with and without luggage.
    And still, the carbed one is a tad quicker out of bends as one can be more confident to roll-on the throttle earlier.
    The EFI never farts on over-run though ... :D
  4. How so?

    Which can also mean better responsiveness, and instant reaction. The bike does exactly what you want it to do, when you want it to. Without the split second lead time, or gasping for air when you high in the twisties.

    Yup, nothing wrong with that.

    Which is generally said for any bike, regardless of it's fuel delivery method.

    Experienced none of this on my '01 VFR EFI and in fact found it smoother and easier to control than my '03 VTR. The EFI VFR is instantly responsive and highly predictable based on throttle position. The carbed VTR responds differently based on air temperature and oxygen levels (and because I don't constantly ride in those conditions .. unpredicably). Yes, there is quite a difference between the V4 VFR and VTwin VTR, and I have allowed for that in my thoughts.

    Of which only a fully trained mechanic would have or need those gizmo's since the EFI will handle this, to a large extend, itself. You don't need to adjust the EFI for rich/lean settings, unless your EFI bike is sick.

    I wish .. as per above on air temperature and oxygen level. The EFI VFR was more precise and predictable.

    Metrics taken by the ECU of an EFI will always make an EFI smoother, especially through twisties. If this is not the case on a particular bike model, it's because the engineers didn't get the engine management working correctly, not because the EFI itself is less smoother than a carburettor. EFI fuel delivery will be based on engine speed, air temperature, oxygen levels, crankshaft position, throttle postion, etc. Without these metrics and the ECU guiding the EFI, you rely on the rider to decide that it's not the best idea to give the throttle a full twist and un-needlessly dump a throatful of fuel into the engine at low engine speed.

    When your behind the market and need to catch-up, eliminating EFI and all the sensors etc. that go with it, not to mention the R&D required to have it work correctly and efficiently, is a great way to vastly reduce your time to production/market and also costs. Removing EFI all helps you reduce weight, albeit slighty, which looks good to the paper spec's junkies. A carby on the 950 will also appeal better to the "track junkies" (the 950's main target audience) who like to tune and 'massage' every little component in search on the ever elusive extra HP on the dyno ... especially as they won't have the "mega-bux electronic gizmos" to fiddle with the EFI.

    "a later model" being the key. Too many other factors being contributory determinants than just the carb vs. EFI

    Carb .. dump a throatful of fuel into the manifold, with little air speed to assist the balance of air/fuel mix and your more likely to get a short 'bog down' out of engine followed by a sudden burst - the sudden burst giving a feeling of being quicker/punchier out of the bend. Have an EFI constraining fuel delivery to match environmental factors and metrics and you have a better performing engine. It may (and will), on some bikes/engines, feel either more like an 'instant punch', or a delayed reaction depending upon gearing and engine speed. But this is an EFI doing what it is supposed to do, and how well or seamless/efficient it does it is the design of the management unit and fuel mapping etc.

    Less R&D on your bike's fuel delivery and usage patterns at design stage, and yes a carb will be better than an EFI .. but that is because of the bikes design and modelling not because a carb, as a generalistion and all other factors being equal, is better than an EFI. Almost impossible to have a carb give the most efficient fuel delivery across teh entire rev range. Add in different environmental and operating conditions and an EFI will certainly be better.

    Simply, if a carb was better than EFI our beloved MotoGP rockets would be using them and not EFI. I don't believe a single MotoGP or WSB bike (even teh Ducati's) still uses a carb, or has done so for teh last 3-5 years. Enuff from me :)
  5. EFI because of what Mouth wrote.

    I bet we could come up with a list of EFI;s advantages over Carbys that is 6 times as long as the one glitch posted.

    I think alot comes down to what you want from your bike. I'd choose EFI without a second thought.

    If it's not running perfectly, it's just not tuned right.
  6. Some people just don't want to come in, out from the cold :shock: :p :p :p

    Glitch its true some of the older model bikes were a bit snappy on the throttle but most bikes now have a pretty smooth delivery IMHO. New technology is always going to bring with it a few a teething problems, but they get worked out in the long run.

    Cheers 8)
  7. In 20 years, I expect to still be able to get relacement carbs and carb parts for my bike, which will by then be over 45 years old. Any parts not available new will be able to be built by any competent machinist. Try getting replacement or repair of EFI electronics that far down the track..
    Of course this is all of no consequence unless you plan on keeping a bike long-term, or you are into restoring older bikes.
  8. The major reason road bikes have adapted EFI is to meet increasingly stringent emmisions laws, with which carbies struggle. No doubt EFI will be refined and perfected in bikes as it was first in cars. Any bike under 10 years old really needs an experienced or competent mechanic to tune it or service it, so whether you've got EFI or carbies, you're probably going to have to pay for tuning anyway.
    ABS is next!
  9. Simply by the fact that a 1500kg EFI Falcodore masks EFI-jerkiness and glitches by it's sheer weight, different on a bike.

    Erratic responsiveness is rather like it. The bike rather does something that might've been wanted, but in a manner that wasn't wanted.
    Sure is ...in a set of rough twisties where controlling the bike through the bars the lumps and bumps of the road translate into over-responsive throttlechanges.

    But something that's near-impossible to "fix" on EFI without Power-Commanders etc with some bikes (even brands of bikes, since they don't provide adjustment-leeways ). Add laptops and a stack of maps at hand to "tune" things properly and things become quite expensive, quite regularly without guarantees that glitches are sorted without introducing new ones.

    All bikes are different, different characters, different base-sets, different weights. What works well with one is no good on the other. The much touted Yamaha R1-brakes are not instantly transferrable throughout the whole Yamaha range just because they are the duck's guts on one model.

    And there lies the problem. Quite a few bikes (often the first batch of a breed) are sick. Things aren't balanced. Settings were calculated for one market, implemented, then found to be no-good after things had to be "adjusted" to comply to another market.
    EFI is often quite limited in self-adjusting.

    I wish .. as per above on air temperature and oxygen level. The EFI VFR was more precise and predictable.
    That's the theory...

    As if KTM would have a lack of either finances or expertise...
    There are plenty of parts-bin off-the-shelf EFI systems available, the time and cost for setting up either system should be roughly equal.

    "later model" isn't the key. Apart from the change from USD to conventional forks the later model is totally identical.

    The bog-down-and-jerk are the EFI-related probs(if it's not set up properly). If there's not enough air-speed with the carbs....you ain't going quick enough :D

    Agreed to the former... to the latter...better? in which way?

    ...simply, because ALL F1 cars use HUGE, FAT tyres...do I need them/ are they of any benefit on the family- people mover?
    When will the CT110 come with carbon-discs (the shithot item on racebikes some years back)?
    Horses-for-courses still stands, near all dirtbikes are still carbed (exception: Aprilia 450 twin, AFAIK), EFI is NOT better by simply being the "done-thing". Practical implications often get in the way of "technology".
    Multi-cyl engines seem to have proven easier to EFI than twins/ singles.
    Power-Commanders/ Yoshi box et al seem to have replaced the screwdriver for not much gain.
    Gotta give one thing though....EFI is more environmentally friendly, pollution-values are quite simply lower due to the fact that things don't change, even with bad servicing. Carbs needed way more fiddling/ adjusting/ checking to get, and keep, things right.

    ....and enuff from me :)
  10. pete, that might well be the longest post in Netrider history (lol)
    we take EFI for granted in cars because we can get in, fire it up and drive away without a choke, etc. That same benefit comes on an EFI bike, but is the comlexity, etc, of THAT MUCH VALUE, when it imposes higher servicing costs, etc? No personal axe to grind here, it's just that a couple of extra ponies in already (arguably) over-powered street bikes (and under-powered riders!!) seems like complication for technical smart-aleckery, not real gain.
  11. ...and the other way around....
    Just because it's the "done thing"? How come that many VFR800 owners of the pre-Vtec models wouldn't touch the V-tecs then...are they all wrong?

    I rather try both and then make up my own mind....

    which applies to BOTH systems
  12. Agreed :)
    Some EFI bikes are certainly pretty close to "the feel' of a carbed one, my own Strom a good example. Some brands also seem to be better than others with their EFI stuff.
    But there's never ever one gizmo/ method to cover everything.
    Just because carbs are 'out' it doesn't mean that they were/ are inferior overall.
  13. ...and linked brakes....and the BMW-single-wire- sytem...and brake-servos (that BMW has got HUUUGE problems with...and WTF is wrong with conventional wiring, an extra kilo of weight? who gives)
    Too much tech-for-tech sake which comes at huge cost and bruhaha and provides absolutely marginal improvements.
  14. EFI for bikes are still being sorted out.

    For cars their great. Their generally closed loop and ther's only a couple of different types out there. On a car there is no way I would go back to a carby

    Bikes are different. Some I would others I wouldn't

    5 years ago I would have gone carbies every time. In 5 years time I can see EFI being the only way.

    At the moment I would be very selective about which sytem was on my bike, before I said yes.

    Ask a car EFI mechanic whether he would touvh an efi system from the mid-80's. Thats where some of the bike systems are at at the moment.

    Carbies are pretty forgiving on the rider. The sudden responce of EFI was trivialised a bit earlier, but it's very important when you hit a bump mid corner and your throttle hand moves. EFI caused some big highsides in WSB.

    Plus the bike carbies, even the OEM ones are as good as they get. Even out of tune they can be ridden. The same can't always be said for an open loop EFI system.

    Like I said. It depens on the EFI
  15. Bullseye!!
    Education doesn't come with T-shirts/ stubby-holders or glossy ads in bike-mags though...and it's impossible to replace with carbon-parts :LOL: :LOL:
  16. Jeez, you make it look so easy....that is what I should've said... :LOL: :LOL:
  17. Tell me about it... I need a bit of tuning on the R6. It can cruise below 6000rpm ok, but at certain spots in the midrange it wants to accelerate or decelerate, and jerks horribly if you try and cruise.
  18. Ha!
    Serves you right dan for trying to 'cruise' on a flash R6!
    Daz. :wink:
  19. I would never go back to carbies, Efi is better by far! I have never had trouble with the throttle jerking, mabey you gus are holding the bar to tight! The extra responsiveness is a blessing, it allows you to move out of idiots way, quickly. It's also great for going around the twisties as you can use the engine braking and then be hard on the gas within an instant. Also gotta love the sound! Thats my ten cents.
  20. So Yamaha haven't got it sorted, but Kawasaki has?

    I also heard the Webber type ones on BM and Guzzis are pretty ordinary at low revs. Anyone?