Rover 3.9 Injector CC's

Post by **Coops** » Fri Dec 08, 2006 2:22 pm

any one know the cc's of the 3.9 hotwire injectors???
want to make sure i have the required fuel set correctly on the ecu, but need to know the cc's of the injectors..188 rings a bell for some reason

Post by **katanaman** » Fri Dec 08, 2006 2:36 pm

I posted the specs of all the rover injectors on the old forum if you want a search. If you cant find them I will post them again when I get home from work.

Post by **Coops** » Fri Dec 08, 2006 2:41 pm

cheers mate ill go look

Post by **Coops** » Fri Dec 08, 2006 2:52 pm

it don't seem to find it mate,
comes up page unavailable

Post by **katanaman** » Fri Dec 08, 2006 3:06 pm

I dont know and you were the expert on the old system too

depending on age of injection system

standard fuel pressure 36psi

88-89 = 167cc min - 16lb hr
90 on = 195cc min - 18.6lb hr nearest injector size 19lb hr

43.5 psi fuel pressure (you will need an adjustable fuel pressure regulator)

185cc min - 17.6lb hr around 250 hp max
214cc min - 20.4lb hr around 275 hp max

for information the 3.5 injectors flow the same as the 88-89 ones

from this http://www.v-8.org.uk/snitzforum/topic. ... IC_ID=2603

Post by **Coops** » Fri Dec 08, 2006 3:29 pm

not sure what year mine is

think mines the 185cc's

Wotland · Post by **Wotland** » Fri Dec 08, 2006 3:41 pm

Hi

A very helpfull web link to identify your injectors with their reference : http://users.erols.com/srweiss/tableifc.htm

Cheer.

Post by **Coops** » Fri Dec 08, 2006 3:49 pm

looks like i need to find my numbers off the injectors again then

Post by **katanaman** » Fri Dec 08, 2006 4:28 pm

if their the hotwire ones their the larger ones. Basically there are 2 flow rates which are flapper injectors and hotwire injectors. Cant comment on the thor system but their probably the same.

Post by **Coops** » Fri Dec 08, 2006 4:38 pm

so you are saying mine are the 195cc then mate???
if so if i have done this right the required fuel is 16.42 m/s
we have it set at 13.0 m/s

i know it dont sound much but want to try and get every thing as close to spot on as possible,

Basic req_fuel calculation:

req_fuel = 6.49 * (D / N / I)
I injector flowrate (cc/min)
D engine displacement (cc)
N number of injectors

ihatesissycars · Post by **ihatesissycars** » Fri Dec 08, 2006 4:52 pm

I found this on Phils Cobra site a little while ago about injectors.

I needed to find out the flow rate from the 4.6 injectors, I'd had the original set from my engine (3.5 Flapper) cleaned and tested last year, and it's not cheap, £140. So I decided to make up a test bed and do it myself. I also got my hands on a ultrasonic cleaning bath. This was filled with fuel injector cleaner and then the injectors were placed inside before testing their flow rates. Basically, the test bed is an old fuel pump and regulator from a scrap yard, piped up with a pressure gauge. The injectors were connected up and a measuring jug was placed underneath them. In order not to drive the injectors at 100% and risk damaging them, I knocked up a quick circuit that pulsed the injectors on for 333mS and off for 666mS. The test revealed that the 4.6 injectors were exactly the same flow as my original 3.5's (180cc/Min @ 43psi). Just incase anyone's interested, a mate sent me some 3.9 (hotwire) injectors to be tested and they came out at 210cc/Min at 43.3psi

Post by **katanaman** » Fri Dec 08, 2006 6:16 pm

That's interesting as the 4.6 injectors are supposed to be the same as the 3.9 accept like I said dont know about the thor system unless those 4.6 ones were thor system. No reason to query the results as the other figures are near as damn it to the factory figures. I guess anybody buying 4.6 injectors are wasting their money really.

Tony yes you have the bigger injectors but I am not sure if the req_fuel figure should be at your actual fuel pressure or the standard test pressure of 3 bar. Course if your pressure is 3 bar then it isnt a problem. Apart from that req-fuel makes no odds at the end of the day, its just a baseline that the ecu works from. if the figure is low your maps will just be lower if its high your maps will be high, or is it the other way round lol. Either way its only a problem if your maps run out of scope as in if say you cant make them high enough, your req-fuel is way off. You would then have to reset the req-fuel and re-map.

r2d2hp · Post by **r2d2hp** » Fri Dec 08, 2006 6:31 pm

I have it written down as 188cc/min @ 36.25 PSI. I did have mine cleaned and flow tested so will see if I still have the details that came back with them.

Clasic Injector with Green Band is D1830GA

The Later Injector as found on the Thor manifold is
Part Number lbs/hr cc/min grams/min PSI BARS
0-280-155-787 16.75 176.0 126.6 43.5 3.00

jwriyadh · Post by **jwriyadh** » Fri Dec 08, 2006 8:47 pm

Land Rover quote green band injectors for 3.9 hotwire as 180-195cc/min at 36.25 psi

jw

Additionally, courtesy of Megasquirt,

new flow rate=old flow rate * sq. root(new pressure/old pressure)

kokkolanpoika · Post by **kokkolanpoika** » Fri Dec 08, 2006 9:09 pm

My 3,9 hotwire injectors (part nro D1830GA) all give 250cc/min @ 3bar when they cleaned ultrasound wash machine and flow tested.. Before cleaning about 246-249cc/min @ 3bar..