Injector Calcs.

Post by **Coops** » Mon Feb 04, 2008 10:21 pm

once paypal sorts its self out and excepts my payment i'll order the bosch green 42lb ones from fiveomotorsport

Post by **Coops** » Tue Feb 05, 2008 8:18 pm

They are now ordered :racing

just hope they are the right ones now

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0003703098

stevieturbo · Post by **stevieturbo** » Tue Feb 05, 2008 8:40 pm

Post by **Coops** » Tue Feb 05, 2008 8:42 pm

cheers stevie,
mmmm whats next to do now

done the pump, now the injectors, changed ecu, anything else?

Post by **katanaman** » Tue Feb 05, 2008 8:53 pm

Chevy LSx?

Post by **Coops** » Tue Feb 05, 2008 8:56 pm

katanaman wrote:Chevy LSx?

ooooooooooooo marki i wish mate

stevieturbo · Post by **stevieturbo** » Tue Feb 05, 2008 8:57 pm

fuel lines, map sensor, boost pipes, turbo...ummmmmm gearbox, clutch lol

Post by **Coops** » Tue Feb 05, 2008 8:59 pm

stevieturbo wrote:fuel lines, map sensor, boost pipes, turbo...ummmmmm gearbox, clutch lol

@stevie
BUT forced is my next route,

Post by **Coops** » Thu Feb 07, 2008 1:57 am

just to make sure i got this right,

my req fuel will be this yeah?

I injector flowrate (cc/min) ( 440 )
D engine displacement (cc) ( 3947 )
N number of injectors (piece, eg. 4 for a 4 cyl port injection) ( 8 )

Simplified equation is: req_fuel = 6.49 * D / N / I

so 6.49*3947/8/440 =7.277 (7.3)

i have got that right aint i

stevieturbo · Post by **stevieturbo** » Thu Feb 07, 2008 6:29 pm

Where have you got the equation from ?

using the online stuff on RCeng's site is easier. Takes less thinking

r2d2hp · Post by **r2d2hp** » Thu Feb 07, 2008 6:44 pm

Using the RCEng guide based on 300bhp it works out that you need 23Ib injectors. I assume this is based on the injectors being able to meet all the demands on the engine supplying max power continuously

I also read that running injector that are too large can effect tick over and slow running, is that correct.

Post by **Coops** » Thu Feb 07, 2008 6:51 pm

stevieturbo wrote:Where have you got the equation from ?

using the online stuff on RCeng's site is easier. Takes less thinking

here mate:
http://www.vems-group.org/wiki/index.ph ... torOpening

stevieturbo · Post by **stevieturbo** » Thu Feb 07, 2008 7:10 pm

But what is the equation trying to do ?

Whats it trying to prove ? Is it something specific to the needs of the VEMS ? or a general equation ?

Dont forget, that equation ...

Assume

* fuel density=0.755 g/cc
* AFR=14.7 at stoich
* intake air density = 0.0012 g/cc (at MAP=100 kPa, which might be a cheat from the real 101..104kPa ?)
* (alternate+1)*divider = N (see N below)

It isnt calculating a general injector sizing question.

dnb · Post by **dnb** » Thu Feb 07, 2008 7:17 pm

stevieturbo wrote:Where have you got the equation from ?

It's just to set the base pulsewidth for the ECU. Probably best to use the equation as-is

BTW Tony - are you going to wire the injectors in batches of 2 now they're bigger (instead of the batches of 4)

Post by **Coops** » Thu Feb 07, 2008 7:32 pm

not sure Dave,
what would you recomend?
does it need to be done that way now then???????
and is there a diagram of it mate???