All the people out there with larger upgraded turbo's and hitting around the 400 bhp mark, what size injectors are you using.
injector sizes
- Thread starter stevepudney
- Start date
A
Anonymous
Guest
no of injectors x flow of injectors divided by 7 = power @ 85% duty.stevepudney said:
4 X 720 =2880 div 7 = 411bhp.
Nad
Active Member
Or this can be calculated the other way around:
Choosing The Correct Fuel Injector For Your Application:
Fuel requirement in cc/min = ((Max HP x BSFC) / (number of injectors x duty cycle) x 60) / 6.177
where: BSFC or brake-specific fuel consumption is the amount of fuel consumed per unit of power produced is equal to:
Engine type..................................Petrol
High compression......................0.45 to 0.55
Low compression.......................0.50 to 0.60
Super/Turbocharged..................0.55 to 0.65
To be on the safe side always calculate with a slighty richer mixture i.e .60 upwards.
When an injector is open 100% of that time, the injector is in what is called a static condition. For road-racing engines that are at maximum power for extended periods of time, the desired maximum safe duty cycle is 0.85. This ensures that the injector is closed a sufficient time to keep it from overheating. Take your pick, if u are on the road a lot and dont hit max power i.e. 100% DC then u can use a higher DC rating, but 85% is the safe limit if max power is hit often.
Therefore: ((400 x 0.63)/(4 x 0.85) x 60) / 6.177 = 720cc (3sf)
Bloody complicated but good if u know how much power u want.
Nad
Choosing The Correct Fuel Injector For Your Application:
Fuel requirement in cc/min = ((Max HP x BSFC) / (number of injectors x duty cycle) x 60) / 6.177
where: BSFC or brake-specific fuel consumption is the amount of fuel consumed per unit of power produced is equal to:
Engine type..................................Petrol
High compression......................0.45 to 0.55
Low compression.......................0.50 to 0.60
Super/Turbocharged..................0.55 to 0.65
To be on the safe side always calculate with a slighty richer mixture i.e .60 upwards.
When an injector is open 100% of that time, the injector is in what is called a static condition. For road-racing engines that are at maximum power for extended periods of time, the desired maximum safe duty cycle is 0.85. This ensures that the injector is closed a sufficient time to keep it from overheating. Take your pick, if u are on the road a lot and dont hit max power i.e. 100% DC then u can use a higher DC rating, but 85% is the safe limit if max power is hit often.
Therefore: ((400 x 0.63)/(4 x 0.85) x 60) / 6.177 = 720cc (3sf)
Bloody complicated but good if u know how much power u want.
Nad
S
Sirnixalot
Guest
bad Paul! no instegation allowed *tisk tisk*
L
Little Erve
Guest
Heh, this is interesting..
Bosch motorsport state their injector flows in g/min of N-Heptane (specific gravity of ~0.697 ) and the reason they give is:
Fuel flow specifications are given in grams per minute [g/min]. This is an internationally accepted standard at vehicle manufacturing
level. As development engineers deal with the weight or mass of air inducted by an engine not its expected power rating, the
weight of fuel that an injector can provide is the pivotal measurement. Bosch does not rate fuel injectors related to expected
engine power outcomes.
It seems like PULP over here is anywhere between 0.7 and .77 SG.
just 2c worth..
Bosch motorsport state their injector flows in g/min of N-Heptane (specific gravity of ~0.697 ) and the reason they give is:
Fuel flow specifications are given in grams per minute [g/min]. This is an internationally accepted standard at vehicle manufacturing
level. As development engineers deal with the weight or mass of air inducted by an engine not its expected power rating, the
weight of fuel that an injector can provide is the pivotal measurement. Bosch does not rate fuel injectors related to expected
engine power outcomes.
It seems like PULP over here is anywhere between 0.7 and .77 SG.
just 2c worth..
A
Anonymous
Guest
don`t get used to it,it doesn`t happen oftenGINGA said:Omg their agreeing on something:lol:
Nad
Active Member
Does anyone :?:, if so got a link :?: U could possibly rate a single injector by bhp but then what about duty cycle, fuel pressure etc and the type of fuel. The two calculations above are only rough guides which is good enough for most people.Little Erve said:
As stated before a set of 4 700cc injectors ( some are 720's but diff companies state diff flows) can run from 330 up to 550crank bhp at diff duty cycles and fuel pressures so there is never normally a need to be 100% accurate.
Nad
A
Anonymous
Guest
it`s also good to leave yourself with a bit in reserve as well,just in case you get a particular good turbo that produces more than what the manufacturers say it does.as a rule the manufacturers tend to quote 3-5% low.
my turbo is supposed to be good for 550bhp but the injectors are good for 570bhp @ 85% duty.
my turbo is supposed to be good for 550bhp but the injectors are good for 570bhp @ 85% duty.