0007 Posted December 28, 2014 Report Share Posted December 28, 2014 All EFI systems compensate but they don't know altitude They just need Baromatric pressure, engine temp and ambient air temp and throttle position as well as engine speed Motorcycle systems are pretty basic compared to automotive Quote Link to comment Share on other sites More sharing options...
copemech Posted December 28, 2014 Report Share Posted December 28, 2014 (edited) All EFI systems compensate but they don't know altitude They just need Baromatric pressure, engine temp and ambient air temp and throttle position as well as engine speed Motorcycle systems are pretty basic compared to automotive Point taken, yet baro = altitude as far as that is concerned..Add in your ambient temps then you have your density altitude. Baro will vary approx. 1hg per 1000 ft or so in elevation and with changes in atmo pressures, temps less of a concern, but still a factor. Google up density altitude calculators and plug in the numbers to see the differences. Sort of ironic, was a couple years back about this time of year I was going to take out the aircraft, would not run at takeoff power.Cut out badly. Took me a bit to figure out this issue as it did run ok with carb heat applied. Not an ignition issue. Baro was really high at near 31 or more, with temps low at -3. Calculated atmo density was near 3000 ft below sea level. Planes are not built to run there! Yet they normally do still. Come to find out this carb was set a bit lean from factory overhaul by about 10%, but it took a trip to the factory flow bench to prove it, and a concerned operator. Point being, density and temps do make a difference, regardless of true altitude as that had not changed. Edited December 28, 2014 by copemech Quote Link to comment Share on other sites More sharing options...
0007 Posted December 28, 2014 Report Share Posted December 28, 2014 Thanks Cope, Ya I hear you my point was that there is no such thing as an altitude sensor, engines and electronics don't know or care about altitude just barometric pressure It's a different way of answering the same question There are high BAR days at high altitude and vice versa This altitude and EFI thing is so ingrained in the snowmobile world and we have been doing altitude compensating turbo boost control since like 06 or so it really sounds weird to me to hear people questioning the potential of tech that is kind of old news but has just not made it to trials on a significant scale I think one of the problems is that much of EFI is tied up with patents and to use it manufacturers need to buy it or license it so it simply cuts into profit when riders willingly accept carbs Manufacturers only change when they need to and one day it will happen and carbs will fall by the wayside like points and mechanical ignition advance and so many other dinosaur systems Quote Link to comment Share on other sites More sharing options...
rob214 Posted December 29, 2014 Report Share Posted December 29, 2014 i don't have anything to add, but man i'm so sorry i read all the way to here. man i need a life...................lol if they build it. i like it, i think i want it, i'll buy. if it's a pig i'll stay away from it. brand doesn't matter. i've been riding dirt bikes since 1975 never owned a FI bike and if i live to ride long enough i may have to. i may even, oh this hurts, one day be forced to ride electric if i want to ride. maybe a meteor will strike earth and i can escape the electric part. i don't even care what color my bike is. i only care if it works properly whatever that means. FI or not if a bike works then to me the components or of no interest or value to me. if it doesn't then the company that makes them will hurt in the sales dept. when racing mx we used to be picky about jetting but after 20 years of trials riding i don't think i've ever messed with a carb except to adjust idle when summer turns winter here in the south the humidity and air density has an effect but no real big deal, yes an FI bike would do it on it's own but really it's not a big deal just a preference. i could probably ride any bike on the market right now and get the same amount of enjoyment out of it. the bike should not be so much of an influence they all work pretty darn good these days. i know this topic is about FI but................ rob 1 Quote Link to comment Share on other sites More sharing options...
axulsuv Posted December 29, 2014 Report Share Posted December 29, 2014 Don't any of the injected trials bike use a manifold absolute pressure sensor ? "cause that would deal with altitude/ density etc. as discussed above , wouldn't it ? Sorry , my brain tunes multiple carbs on the old stuff I work on , BUT I love Fuel injection !!! Quote Link to comment Share on other sites More sharing options...
axulsuv Posted December 29, 2014 Report Share Posted December 29, 2014 And I have a foggy recollection of reading about a industrial powerplant 2 stroke with direct injection that made serious torque and was very clean and long lived ... or was that a dream .... Quote Link to comment Share on other sites More sharing options...
billyt Posted December 30, 2014 Report Share Posted December 30, 2014 http://motocrossactionmag.com/home-page/homepage-new-products/mxa-team-tested-rd-racing-power-bowl-2 Open, scroll down to bullet point #3 Quote Link to comment Share on other sites More sharing options...
atomant Posted December 30, 2014 Report Share Posted December 30, 2014 This is the most painful thread to read I have ever read on Trials Central 2 Quote Link to comment Share on other sites More sharing options...
lotus54 Posted December 30, 2014 Report Share Posted December 30, 2014 I have a 2014 OSSA Explorer (same bike as the TR with some more junk added on) FI has been wonderful, much less hassle than the carbs on my other bikes I've had/had. I did have to reset the TPS at around 100 hours- took about 5 mintues. Still trying to get the aftermarket cables (I have the software)- the factory ones are way too much $$$. I borrowed the dealers cables to reset it. I have around 150 hours on it, it always runs great, freezing, 90f, sea level to about 8k feet. It starts very well (unless you touch the throttle, it doesn't like that) and I like the way it wokrs better with a one step hotter sparking plug. On the OSSA, the injector goes directly into the crankcase- points right at the rod bearing. (So some call it 'semi-direct'). Mine is street legal and works just fine on the road, quite smooth actually. Not much fun with 3psi in to be tyres and sitting- but for connectors and getting to the local trails I like it. I don't know how much the fuel pump costs, I've had no issues and I believe the importer has not sold any. Pain to get to it though. I know they has issues with some of the earlier bikes- but the map I have is quite nice. I've never has issues with my FI street bike (2005 Ducati Multi), or my cars since way back I the 70's. (My Lotus is due for new injectors, I have the ira box) I ran the APT Smart Carb on it 300 KTM, it took some fettling (I had a rather earlier one) but once sorted it worked really well (better mileage also). I think they have a 27mm also. The OSSA is very, very linear in power- I don't know how much the injection has to do with it. I'm quite happy with it. Mark 1 Quote Link to comment Share on other sites More sharing options...
dadof2 Posted January 1, 2015 Author Report Share Posted January 1, 2015 Atomant #87 - why bother to read it and post if its painful? Fuel density, because fuel is pretty incompressible then is should follow that its density can't be changed that much. And that is correct when you are talking about mass per unit volume as the measure of density. However when you are talking about weight per unit volume the effective density varies with gravity because weight varies with gravity. That is how a centrifuge works, by increasing the g force and increasing the effective density of the materials in the centrifuge, causing them to separate. To make EFI work Honda /mont has to use quite a complex system of capacitors, Ossa had had to fit a battery and now it seems Vertigo are to do the same. Perhaps its time to ditch the troublesome fine wire ignition source coils (that date back to at least the 1960s) and have homogeneous thick wire coils in the alternator (ACG), a decent rectifier / regulator and a proper 1 or 2 Ah battery. This would give the fan and electronics a far easier time and give reserve capacity so bike could keep running for some time even if ACG failed. Quote Link to comment Share on other sites More sharing options...
0007 Posted January 1, 2015 Report Share Posted January 1, 2015 Sir Issac Newton where are you now Mass does not change when an object is accelerated or decelerated Again, go drop your jerry can, it won't get bigger as it falls and shrink when it stops It's not gravity that changes just accel and decel so mass is identical but kinetic energy is stored then released when the fluid stops Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted January 1, 2015 Report Share Posted January 1, 2015 Atomant #87 - why bother to read it and post if its painful? he is entitled to post his opinion even if doesnt agree with your view, and i think hes right to make a comment, just as anyone who wants to discuss it is too? are you the forum police now as well? Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted January 1, 2015 Report Share Posted January 1, 2015 I would love to have a fuel injected bike that ran like my FI cars. However the current FI bikes don't appear to offer any advantages over the carburated versions. The Montesa has a ridiculously high idle, which would stop me buying the bike, and the Ossa certainly from what I have seen doesn't start any easier, make any more power and most people seem to get them remapped? At the World round we went to two years ago we arrived at the practice area on the Thursday as the first riders started to practice. All the two stroke bikes were ridden untouched by minders or mechanics [Raga changed a clutch] however the hondas of Bou and Fuji were continually hooked up to a laptop, sent off to ride for a couple of minutes and back to the laptop and technicians again. This went on for some period of time, meantime all the carburated two strokes,GasGas ,Beta, Sherco, performed without incident. I did not see the Ossa of Oliveras at this session so cant comment on his bike. Quote Link to comment Share on other sites More sharing options...
the addict Posted January 2, 2015 Report Share Posted January 2, 2015 Sherpa325, the 4rt idle might be high but you soon get used to it and I don't notice it at all anymore, loading the motor slightly drops it anyway and its free to run everything when it doesn't matter that its high. 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted January 2, 2015 Report Share Posted January 2, 2015 I would love to have a fuel injected bike that ran like my FI cars. However the current FI bikes don't appear to offer any advantages over the carburated versions. The Montesa has a ridiculously high idle, which would stop me buying the bike, and the Ossa certainly from what I have seen doesn't start any easier, make any more power and most people seem to get them remapped? At the World round we went to two years ago we arrived at the practice area on the Thursday as the first riders started to practice. All the two stroke bikes were ridden untouched by minders or mechanics [Raga changed a clutch] however the hondas of Bou and Fuji were continually hooked up to a laptop, sent off to ride for a couple of minutes and back to the laptop and technicians again. This went on for some period of time, meantime all the carburated two strokes,GasGas ,Beta, Sherco, performed without incident. I did not see the Ossa of Oliveras at this session so cant comment on his bike. This is why they don't compete in the SSDT ? They would need a minder with a laptop and sat phone ! Quote Link to comment Share on other sites More sharing options...
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