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Re: [turbobike] carburation vs fuel injection

sebastian (nxtlvlrcng@email.msn.com)
Sun, 18 Apr 1999 21:15:42 -0700

-----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
Date: Sunday, April 18, 1999 3:44 PM
Subject: Re: [turbobike] carburation vs fuel injection

Ah but nitrous acts as an intercooler while being injected dropping the
intake charge by 60-75 degrees,thus increasing hp. When the n20 molecule
breaks down the nitrogen acts as a buffer to calm the combustion process as
well. When using nitrous on a turbo it will eliminate turbo lag bringing the
turbo full boost rapidly.as with nitrous a turbo bike making good hp needs a
little ignition retard as well. Fuel wise it depends on what your
compression ratio is along with your static timing,etc,etc.I have run 75hp
nitrous systems on stock gsxr motors all using 92octane pump gas with stock
timing!!Never had a problem.

>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
>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