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Re: [turbobike] carburation vs fuel injection

Christer Johansson (christer.johansson@mbox383.swipnet.se)
Sun, 18 Apr 1999 21:47:10 +0200


Yes F1 cars use EFI ,but thats another world ,now Youīr talking
extremeīs. They make alterations all the time to compensate for
different circuits, weather ,etc etc etc.
Yes a state of the art EFI will be ahead when it comes to
managment and to be in control, but do You need it ?
When it comes to emissions and saving fuel ,EFI is definatly ahead,
but then again is that something that interests this crowd?
An EFI is able to operate much closer to being to lean then carbs are.
How come that bikes that are much more power oriented than cars
doesent use carbs to the same extent as the everyday cars?
The guys who orginally built My turbo system have built many turbo
bikes but has stopped making efi versions simply because the carb
versions runs just as well and the efi just adds to the costs.
What was wrong about My point regarding flow through the plenum?
When comparing proīs and conīs between efi and carbs at least I have
the costs in the back of the head, maybe You donīt?
Why should I spend thousands of $ on something that gives no additional
hp or increases drivability, and adds complexity?
I should say that My bike idles happily at 900 rpmīs
(if so desired) and pulls through the revs clean and crisp with no glitches
or bogging. I would rather spend that money on a efficient turbo and
setup, where the real power is.
What kind of bike do You have that needs 16 injectors?

regards / Christer

Lorcan Parnell skrev:

> Christer,
> I have to disagree. It is not possible to match the performance of EFI with
> carbs. If it was, the F1 teams would use carbs. Indycars would use carbs.
> They don't.  EFI will always be ahead and as technology improves more so.
> Your point about the variations in flow is simply wrong. Yes, you need 8
> injectors, possibly more (my bike has 16). Bikes of the future will all use
> EFI. The only reasons to use carburettors is because they are cheap, or
> because the rules (like in Pro Stock) don't allow EFI.
> Regards
> Lorcan
> -----Original Message-----
> From: Christer Johansson <christer.johansson@mbox383.swipnet.se>
> To: turbobike@natvideo.com <turbobike@natvideo.com>
> Date: 18 April 1999 16:52
> Subject: Re: [turbobike] carburation vs fuel injection
> I thought of going to EFI ,but I saw no reason to do it.
> Efi does have some advantages in that you can map the fuel
> and ignition curves more precisly. But itīs possible with carbs
> and a adjustable ignition module to.
> As long as the engine gets the right A/F ratio there is no advantage
> in EFI powerwise. To know what A/F ratio you have,you will
> need a lambda cell, also a EGT sensor would be nice.
> This goes for both Efi and carb setups.
> During the dial in period I will use a lambda cell and EGT sensors in
> all 4 exhaust pipes and the collector, on the new system.
> Also, blow through carbs could prove more "forgiving" to the design
> of the plenum etc than a EFI would be. If you get sligtly more flow
> through some carbs the injectors on a EFI system will still spray
> the same amount of fuel, on a carb system it will drag the fuel needed.
> Also if you run a high hp EFI system you will need 8 injectors on a
> 4 cylinder engine ,otherwise you could get trouble with idle as the
> injectors would be qite big.
> Carbs gives better fuel atomizing at low engine speeds.
> But a EFI setup looks cooler though....
> Christer