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Re: [turbobike] carburation vs fuel injection

Jeff Churchill (jcperformance@juno.com)
Wed, 21 Apr 1999 13:08:45 edt

Dear motorheads,
    Everybody is right and makes excellent points,...but some food for
thought.  Carbs require a somewhat restrictive venturi and work best with
higher intake velocities.  EFI systems can be sized for max flow
throughout,..and the fuel atomization problem is solved by the
injectors,...even at low port velocity.   Of course throttle bodies and
carbs of similar sizes should make similar maximum power,....all other
things being equal.

Jeff Churchill

J.C. Performance    617-06  Bicycle Path   Port Jefferson Station   NY  
11776    USA
tech:  516-928-6679  or  516-928-9863
website:     http://www.jcperformance.com/

On Wed, 21 Apr 1999 17:29:36 +0200 Christer Johansson
<christer.johansson@mbox383.swipnet.se> writes:
>Yes Iīm enjoying this to, but iīm a bit frustrated to see that You
>wont accept the facts...hehe
>Why didnīt You answer to all my statements in the last mail?
>I was talking about modern days bike carbs ,besides fuel injection
>has been around equally long.
>Well I think I have proven My point over and over again, thereīs not
>much more I can do about it...
>Not all EFIīs can be adjusted individually.
>I just knew You would mention Terry Kizers bike!
>But is his bike also a GSXR 1127 with the same turbo setup,
>just with EFI instead ? No it aint , You cant compare
>apples and peerīs ,now can You?
>Please explain to Me  why it is that an EFI will make more power
>than a carb setup that works right!
>Well I already now the answer to that ,IT WONT.
>regards / Christer
>Lorcan Parnell skrev:
>> Hi Christer, I hope you are enjoying this as much as I am! hehe...
>> >To make full use of a EFI setup you would really need to know what 
>You are
>> doing
>> and use all types of sensors, otherwise it will be more primitive 
>than any
>> carb
>> setup.
>> and carbs aren't primitive? Only been around 100 years...
>> >I know what a MAP sensor is ,I work with dynoing engines at a 
>> research
>> center.
>> Then you should have kicked my ass on this discussion by now - I'm 
>> amateur!
>> >Yes some sofisticated EFIīs can adjust for different flows but then 
>> would
>> need
>> a map sensor in every inlet rubber, on a carb setup the stronger 
>signal will
>> just pull
>> more fuel in that carb, nothing of major concern but nevertheless.
>> No, you could just adjust the fueling/ignition on each cylinder 
>against a
>> brake dyno.
>> >Yes Your van have EFI (to clear emission laws) but a Yamaha R1
>> (who makes 150hp/litre) doesent , understand My point?
>> Yes, now I do.
>> >You may be able to buy an ECU for Ģ650 and injectors for Ģ15 ,but I 
>> that John Doe can walk into an speed shop and get a nice EFI setup 
>for that
>> amount.
>> I AM that John Doe! No, I didn't walk into a speed shop, i just 
>> around.
>> >Besides you need alot more than ECU and injectors, throttle bodies 
>and a
>> box
>> full of
>> sensors ,wires ,not the cheapest stuff around. The carbs are already 
>on the
>> bike
>> True, but you are coming back to cost, the one point I concede.
>> >How fast do I wanna go? well the old setup easily made 200mph and 
>the new
>> one
>> is more powerful. As I said in an earlier mail Mark Moisan out of 
>texas made
>> 429hp
>> ...and Terry Kizer made 494 on his EFI ZX11...
>> Cheers
>> Lorcan