hello people..

just a querry on injectors and fuel system.
im currently getting my motor fully rebuild bottom end everything.. we are building it for about 250hp at the wheels (hopefully!) .. i have a autronic computer installed already as well..also the twin throttle bodies as well...
my question is what are the lbs of the standard injectors?? will they handle the power increase??
if not how big would be recomended??
what size fuel pump shoud i get??
do i need a rising fuel reg???

thanks

Stock injectors are 19lb but should be fine for that power level, plenty of I6 guys run around that power with the stock fuel system. Fuel pump too should be ok but if you want to be safe get an intank Bosch or Walbro 190l/hr pump. Rising fate fuel reg is for forcedinduction so it won't give you anything, I guess you are thinking about an adjustable reg which will allow you to push your stock fuel presure higher allowing you to get more power from your stock injectors.

yeah sorry i ment to say adjustable reg which will allow you to push your stock fuel presure higher allowing you to get more power from your stock injectors?? will i need this or should i have enough pressure anyways?? or will it make a diff anyways??

The stock 19's are good for approx 320hp(flywheel) on a V8. You should go for 24's straight up.
The stock pump is only rated at 88L/hr.
You can up the pressure to allow stock injectors to be retained but you end up with other problems like; dribbling injectors and more importantly the stock fuel pump will also reduce it's flow with an increase in pressure.
Something you just can't afford with such a low flow rate in the first place.
I believe Fuel miser now have a range of pumps available to fit in the stock location. You'll need one with at least 110L/hr up to about 160L/hr.
You can go for much larger pumps(like 255L/hr) but it also creates some problems like; excessive fuel heating via overcirculation of the fuel to engine and back. The disadvantages of this are obvious, plus you will get saturation of your charcoal canister which will mean you will breathe alot more vapours than you otherwise would have.

Cheers,
Pete.

so basicaly if i was to leave the stock injectors it should be fine but if i put 24lbs it would be better... but for sure change the fuel pump to at least a 110/hr or more i will be doin...

also sorry i forgot to mention i am sitting up a a direct nos injection setup
as well with about 75-100hp shot.. what about the injectors now?? do i need bigger to handle the increase???

Well no, 250rwhp means about 330flyhp so you'll be marginal with 19's. Go 24's straight up to be safe.
As for your nitrous; you'll need whatever extra fuel is required to burn with the nitrous added (usually a separate nitrous fuel supply is used with direct port).
Otherwise if you want to supply the extra fuel via your injectors you'll need to size them for your total power with the nitrous on. IE; 330+100=430hp. So you'd need at least 30's. Plus of course you'll need to up the size of your fuel pump to account for your total power with the nitrous on.

Pete.

Sorry Sly,

I just realised you were talking six cylinders. Obviously you'll now need larger injectors than you would with a V8 at the same power level.
You would need 30lb/hr for 360fwhp and therefore 42lb/hr if you want to supply enough fuel for a 100hp shot as well.

Regards,
Pete.

thanks for the info pete very helpful indeed!!