Turbobike Web Site www.Turborick.com

Re: [turbobike] carburation vs fuel injection

CRAIG S WALKER (CSW_CMT@prodigy.net)
Sun, 18 Apr 1999 19:35:02 -0000

I believe he is referring to the intake temperature drop.  N2O becomes a gas
at -127 deg F....quite an intercooler.  This fact alone is what led to
funnybike racers experimenting with the stuff in the late seventies - early
eighties.  In those days ,folks like Terry Kizer were running 3 stages of
nitrous w/30-35 psi of boost.

Speaking of which, I heard Terry Mr. Turbo Kizer has run in the sixes on his
push button start pro mod/funnybike ZX11.  Has anyone got the low down?

Craig S. Walker

----- Original Message -----
From: Bryan Goodwin <bgoodwin@iquest.net>
To: John C Williamson <john.williamson5@virgin.net>
Cc: Lorcan Parnell <lorcan@globalnet.co.uk>; <turbobike@natvideo.com>
Sent: Sunday, April 18, 1999 8:37 AM
Subject: Re: [turbobike] carburation vs fuel injection

N2O makes a great deal of cylinder pressure and heat. N2O often requires
retard and/or good fuel by itself. I do not believe you should add any boost
because of N2O.

John C Williamson wrote:

> >From a simple 'physics' standpoint a carb always has to restrict the air
> flow slightly, as this 'venturi' is the thing that actually draws fuel
> the floatbowl. The flow through carbs is pretty efficient on modern bikes
> though so the difference will be quite small.
> It is true that fuel injection will allow more accurate fueling in all
> conditions, if money / time allows so less flat spots and possible better
> throttle responce.
> On the other hand my 1100 GSX EF used a cheap stock Mr Turbo kit with a
> single draw through carb and this was fine! Idle was a little ragged, but
> kind of adds character! Unlike the short 'banana' drag style exhaust pipe
> that tries to turn your left leg to charcoal.
> Does anyone know how much extra boost is possible with N2O due to the
> cooling effect?
> ----- Original Message -----
> From: Lorcan Parnell <lorcan@globalnet.co.uk>
> To: <turbobike@natvideo.com>
> Sent: 18 April 1999 19:41
> Subject: Re: [turbobike] carburation vs fuel injection
> Christer,
> I have to disagree. It is not possible to match the performance of EFI
> 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
> 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