Injector Calcs.

Post by **Coops** » Sat Dec 15, 2007 9:14 pm

I have found these cals which may be of use to some of us,

500cc per minute is approximately equal to 49lbs per hour which is

equal to approximately 100hp.

lbs/hour = cc per minute / 10.2

lbs per hour = HP / 2.04

cc per minute = lbs per hour x 10.2

cc per minute = HP x 5

HP = cc per minute / 5

HP = lbs per hour x 2.04

psi X .0689 = bar

bar = psi / .0689

So if you have a 280 bhp engine.
you need:

280bhp x 5 = 1400cc do you have to divide this by the amount of cylinders?
if so this works out at 175cc's per injector yeah?

Post by **katanaman** » Sat Dec 15, 2007 9:56 pm

I tried several calculators and none of them came up with the same figures as you have

This gives the maths http://www.rceng.com/technical.aspx and http://www.rceng.com/technical.aspx#Fue ... Worksheet_ is a calculator which works it out to 22lb or 231cc at 3 bar/43psi. They all come up with the same figures.

Post by **Coops** » Sat Dec 15, 2007 10:17 pm

ta mate.
I have saved that page,
the figures i post i found here mate:

http://members.shaw.ca/s15/Fuel%20Injector%20List.htm

badger · Post by **badger** » Sun Dec 16, 2007 10:23 am

I was always led to believe that a good figure to work to when using the green-band 3.9 injectors was 190cc/min, and that they were good for 300bhp, so that pretty much ties in with the conversions given, if that's anything to give comfort?

Post by **katanaman** » Sun Dec 16, 2007 2:54 pm

badger wrote:I was always led to believe that a good figure to work to when using the green-band 3.9 injectors was 190cc/min, and that they were good for 300bhp, so that pretty much ties in with the conversions given, if that's anything to give comfort?

Standard injectors wont do 300bhp unless you up the fuel pressure a fair bit. If your looking to buy new injectors anyway then your as well to get ones that flow enough without giving the fuel pump a harder time.

Post by **Coops** » Wed Jan 30, 2008 11:15 pm

katanaman wrote:
badger wrote:I was always led to believe that a good figure to work to when using the green-band 3.9 injectors was 190cc/min, and that they were good for 300bhp, so that pretty much ties in with the conversions given, if that's anything to give comfort?
Standard injectors wont do 300bhp unless you up the fuel pressure a fair bit. If your looking to buy new injectors anyway then your as well to get ones that flow enough without giving the fuel pump a harder time.

Im waiting on dnb's verdict on my injectors,
BUT it looks like im defo maxing mine now,
i have been looking around for injectors and they are so damn expensive,
Anybody used bosch style injectors from other cars for higher output v8 rovers and had good results?
Ian Stew uses BMW i think, but i can't remember what engine size or year.

So i will have possibly a set of cleaned (July 07) 3.9 injectors going soon

Post by **katanaman** » Wed Jan 30, 2008 11:37 pm

There is a link on the old forum somewhere with a big list of injectors what they are used in and what they flow. Unless your looking to pull them out cars in the scrapies (could be iffy) I doubt you will beat getting them from Summit or the states in general, specially with the exchange rate just now.

Post by **Coops** » Wed Jan 30, 2008 11:45 pm

i agree mate,
looks like im gona have to wait for a bit, theres a few on ebay i have been looking at,

Post by **katanaman** » Wed Jan 30, 2008 11:46 pm

just looking there now lol but cant see much that would be any use yet.

5000SE · Post by **5000SE** » Wed Jan 30, 2008 11:46 pm

My twin-flapper 4.6 made around 310/367 with series 3 Jaguar injectors and a rising rate regulator, but it wasn't cranked up to silly pressure.
That setup was a popular one with V8 Dev

Post by **Coops** » Wed Jan 30, 2008 11:48 pm

what you like marki,
was hoping to get something sorted before March 9th,
but paying back the good ole xmas expence, anyone want two kids going cheap, but expensive at christmas and birthdays

5000se im using hotwire style injectors mate, i had a set of them jag ones, but went to hotwire in the end,

stevieturbo · Post by **stevieturbo** » Thu Jan 31, 2008 12:17 am

I still say get the 42lb Bosch ones....

They really arent expensive !!!! Arent some places selling 8 new ones for about $300 ??

If you really wanted a budget upgrade. You are using an 044 arent you ?

Ramp it up to about 60-70psi base pressure.

That should give you a good bit of extra flow over what you currently have. According to RCEng...going from 45psi to 70psi, will be about 25% increase.

Its a bandaid, but might get you some more fuel for now, for nothing. Just make sure all fuel lines etc can handle the extra pressure.

FWIW, I did a flow test on my setup the other day. In short. Both pumps, at 13.1 volts, ending up into the jug via a single -6 line, flowed approx 486lph at 66psi test pressure.

So a single pump would probably be 243lph at 66psi at 13.1volts.

These pumps do maintain excellent flow to about 8 bar, which is over 100psi.

dnb · Post by **dnb** » Thu Jan 31, 2008 1:34 am

thev8kid wrote: Im waiting on dnb's verdict on my injectors,
BUT it looks like im defo maxing mine now

You are indeed maxing your current injectors. I saw an average duty cycle of 85% in the "hot" areas of the datalog you sent me.

You were running the car a bit rich, but this won't save you much.

I tend to agree with Stevieturbo on injectors - VEMS can control the big injectors well enough for them to be silly sized if you run them sequentially.

Post by **Coops** » Thu Jan 31, 2008 7:18 pm

dnb wrote:
thev8kid wrote: Im waiting on dnb's verdict on my injectors,
BUT it looks like im defo maxing mine now
You are indeed maxing your current injectors. I saw an average duty cycle of 85% in the "hot" areas of the datalog you sent me.

You were running the car a bit rich, but this won't save you much.

I tend to agree with Stevieturbo on injectors - VEMS can control the big injectors well enough for them to be silly sized if you run them sequentially.

here we go again, i reached the limit of something else now,
injectors are the next important thing to get now then

cheers,
im just uploading a cold start datalog to the other post for you dnb

,

Post by **Coops** » Sat Feb 02, 2008 10:02 pm

anyone heard or tried these?
http://cgi.ebay.com/ebaymotors/Venom-30 ... enameZWDVW