Carb Vs. EFI on Atv's (Very Informative Read)

[Seed]

Found this and I found it very very informative. Hope you guys enjoy it. Answered alot of questions that people have.

http://www.venomperformance.net/pages/articleFuelInjection.cfm

[TNT]

Yes informative, I’m not sure I agree with it all.

EFI IS reliable, not only in the sense of maintenance but for the proper mixture, a Stochi metric of 14.5: 1 or close to it at 100% throttle range as it comes. EFI has been around for years in autos and reliable, the system components themselves.

“Same power potential” hmmmm? Different power, better peak power in many cases, and in a closed loop system especially much better throttle response.

Dyno tuning is easier on EFI and more accurate sorry.

What are they talking about, the EFI systems on quads; our can-ams DO adjust for air density, altitude, temp, etc. That’s why we have a MAP and Ambient Air Pressure & Temp Sensor(AAPTS). The technology has evolved with the PC5 to ‘automatically” adjust the MAP based on Throttle position on the track; so this article is wrong! The O2 sensor feeds the info back to the PC5 to make the constant adjustment, there is no “10% bulk map” .

Guy that wrote this article did a good job and brings out the worse in EFI, sounds like an old school carb guy. I can identify, been there, but the future is in the EFI for quads, the technology on quads is just getting started making the carb obsolete. Sorry carb guy!
:p

[Seed]

Though Terry the guy is right in the fact that the technology of EFI is not quite there yet in the atv side. Yes the new atvs do have the sensnors but the computer is not advanced nearly enough to get a perfect fuel mixture on its own it needs to be told. Hes right that a quad has to be almost remapped everytime you do change something such as an exhaust, intake and what not. Remember it is EFI not a full induction system. Meaning you still have to comepletely retune the quad after every mod done to the motor. Yes you get a better throttle response and the power is smoother. Im sorry but when it comes to reliabilty a a carb is more reliable because you dont have to comepletely rely on computer. all you need is fuel, air, and spark for a carb. EFI you have alot more going on thus making more stuff that can burn up or fail. Though Im all for EFI, very good system. But we cant argue with the reliability of carbs and EFI because a carb will win.

[coryatver]

That is shocking that even with one of them programmer boxes. you can still only adjust 10% of the base curve. Great article.

I wish everyone would stop asking Honda for EFI:mad:

[TNT]

I agree the EFI technology on quads has a ways to go. The whole concept of injecting fuel other than directly into the cylinder is ancient automotive. Having a MAP sensor that’s not in the manifold and in a “throttle body” is weird!!...It’s not functioning as a MAP sensor there, I think it is being used to calculate pressure differentials w/the AAPTS in the air box. If you look at the formula for air density a “delta p” is needed(between ambient/barometric and the manifold). I believe it was the easiest most cost effective way the quad industry could adapt the system to the carb configuration without a major redesign of the motors head, so in that respect the current quad EFI technology is not far removed from the carb yet. But for this article to compare the current technology and not consider it’s potential is wrong. Look at the automotive industry mainly EFI and for a good reason. The carb technology on quads has peaked whereas the EFI is just getting started. Big down fall of the EFI systems imo is the battery power required to charge the fuel system for starting, the fuel pump and its electrical circuit reliability. If they can figure out a way to remove it and simplify the electrical system that would help.

The two most expensive components are the ECU $600 and the AAPTS around $230 and they have proven to be reliable, the rest of the sensors are cheap. To add an open system to a carb motor around $1,500 closed $2,000. The EFI fuel economy will be better and save $ over time.

I got 10:1 Honda adds EFI in 2010. KTM will be next. Maybe one will take it to the next level, single point.

That’s the way I see it anyhoo……

:D

[k4f5x0r]

KTM with the current economy is already dropping production of alot of their bikes including the two quads.

On the dirtbike forum(thumpertalk) a little birdy has let us know thats KTM will NOT be going to FI for 2010. possibly in 2011 or 2012 depending on the state of the economy.

[LTR450_#67]

Originally posted by TNT
Big down fall of the EFI systems imo is the battery power required to charge the fuel system for starting, the fuel pump and its electrical circuit reliability. If they can figure out a way to remove it and simplify the electrical system that would help.
:D

The LTR has that capability with the kicker kit from Yoshimura, no battery needed......is that not good enough? I think it's funny that Kawasaki KFX450 has to have battery for the kicker setup on them....What were they thinking. Only the factory racers have no battery.....My bet is Honda will have FI on their new 450R...the CRF450 has it..so why not. I don't have anything against a carb. it's simple and it works. You can't make on the fly adjustments but jets are cheaper thant fuel controllers.

my .02

[1Rockey1]

I didn't see any mention as to which one atomizes the fuel better. If I was a betting man my money would be EFI

[RosquistRacer39]

I was under the impression that the aftermarket has already come out with a closed loop system for the current group of efi bikes. Doesn't the power commander V with the autotuner automatically tune the bike while riding? Or is that all hype?

[TNT]

Carb vs. EFI intake atomizing is approached differently and is dependant on the port. With EFI the intake port is made rough to mix(atomize) with the pressurized fuel, carb port is smooth to mix with the jetted delivery. What’s equally important to the EFI system and what gives it an advantage over the carb are the atoms out the exhaust and maintaining two oxygen molecules per one carbon, or CO2. That’s where the O2 sensor comes in; it sends the info back to the control unit for proper fuel delivery based on the exhaust gas.

Problem with today’s quad EFI is the tuning is based on 10% throttle positions, not continuous MAP. The ECU reads from an analog table of values stored in its brain, like 800 pre-calculated values based on algorithms, so there is a 10% bulk rate that is in-determinant in the stock ECU/PC3. The PC5 02 sensor w/ 5% tuning however compensated for this deficiency by keeping the MAP tuned at all times.

Once the industry installs the MAP sensor in the manifold and tunes to continuous real time MAP, then we will see a drastic improvement in the performance of EFI. PC5 is a step in the right direction but not a means to an end.