Tech question

[dangerous]

I think the reason EFI has taken longer to get to bikes is because the bikes are more sensitive to incorrect fuelling because of their power to weight ratio. The early computers could not sample all the data required and map it to a fuel amount fast enough to produce smooth power.

I may be wrong but I believe that good systems sample the thottle postion, thottle movement, air density/velocity and map that to the ignition timing and fuel.

Someone correct me...

Yes and no..... the first sentence I would agree with, the second sentance I would not but that would depend on how 'early' you are talking eg: the GPZ11 was a bit dodgy however a mate has one and it runs just fine with a modded motor. My 82 CX 500tc was inj and one of the first to come out of Japan and it is as good a set up as inj today better than my 97 Guzzi 1100inj altough the number of senses has been lowered the CX had 11 were as now they are down as low as 5-7
As for the last sentance correct but you can also add engine temp (cyl head) and fuel flow.

[Lou Girardin]

Well,electronic engine control will keep the engine in tune for a hell of a long time compared to points and a carb,but if you want to modify then the carb is an easier option.Money no object,then a tuneable engine manement is the way to go.I was down at Possums a few years ago and they had a WRX on the 4x4 dyno they were tuning with the so called Possum Link - fuel and ign could be altered all the way,performance gains without touching anything else were huge - but you could buy another car for the cost of that sort of set up.

Motu, heard of Power Commanders? Much cheaper than a Link too.

[Motu]

Yeah,and there are systems you can get off the net and build your own.But this is one I saw in action,and anyway - I was talking to Possum about it,that's a good memory.

You can run fairly low on your inputs - say engine speed,MAP for air flow and TPS,then add more and more from there,the more inputs,the more outputs,the better it runs - simple as that.As I mentioned way back,bikes have nowhere as many control systems as a car,they are never going to be as good until they spend the money - it's all done,the modern car is very sophisticated,bikes are not a big money earner,they don't get the good stuff.

[menace]

I think the reason EFI has taken longer to get to bikes is because the bikes are more sensitive to incorrect fuelling because of their power to weight ratio. The early computers could not sample all the data required and map it to a fuel amount fast enough to produce smooth power.

I may be wrong but I believe that good systems sample the thottle postion, thottle movement, air density/velocity and map that to the ignition timing and fuel.

Someone correct me...

Thats all good but i think that the current microcontroles that are coming out have not problem calculating the inouts and otutig what is needed...

[Hoon]

A good carb tuner can make carbs do anything EFI can do. EFI is definately better for the average biker especially with all its sensors to adjust on the fly but performance wise for a given day at a given track - carbs can do just as well if not better so I've been told.

One area where carbs are still in the stone age tho is the accelerator pump which squirts raw fuel into the barrels when you twist the throttle to overcome the lag until the fuel reaches the cylinder. EFI is more precise hence better response, fuel economy and emissions.

While stripping my carbs in the weekend with my mechanic mate we were talking about EFI and he also agrees that carbs are all good. He also says that a lot of mechanics coming through these days don't know how to tune carbs...only EFI so he ends up doing most the carb work at his job.

[Dr Bob]

Yeah, its funny.

I can remember as a kid when my dad and I pulled apart and rebuilt the motor in mum's Herald 13/60 and he was trying to explain the difference in the motors between the car motor and the one in his GS550.

He was telling me how tehnology most often appeared in motor cycles first and told me how cars would one day commonly have things like electronic ignition and overhead camshafts.
.......

Fuel injection (at least for diesels) was commercial in 1927, the Merlin spitfire engine had overhead cams (not to mention nitrous injection), at the same time Messerschmitt used fuel injection and superchargers were old hat.