kennebellgt

do i need 24lb injectors? My mods are in my signature, will i gain any power if i do need them?

mattdel

yup. that combo would do nicely with a set of 24's.

kennebellgt

Do you guys think i'll gain any h/p?

Genhero

+1 on 24lb injectors. H/C/I motor could use bigger injectors than the stock 19.

mattdel

maybe a bit. at this point its more of a precautionary measure, running lean is an engines worst enemy, but its greatest ally at the same time.
the leaner an engine is, the more power it produces, but at the same time, can also cause catostrophic failure. you need to find a middle ground, and going to 24's is a good way to start that.

kennebellgt

right on thanks, i think ill go take some out of a mark 8 at pick n pull.

nitrous_bob

no you don't NEED them, and no will absolutely not go faster on them

SHOULD you do them ?? sure... like stated b4 good insurance

but you don't have quite 300 rwhp yet, so you don't need them

i ran my '89 w/ 100 shot on it all day long and it ran 12.50's on 19 lb'ers and a 190pump, never close to lean

Genhero

Assuming you don't want to go over 80-85% duty cycle, I wouldn't use the stockers over 258hp.

How much power is your car putting out?

The formula is (Inj. Rating * Duty Cycle * Number of Inj.)/BSFC

with 19lb Injectors, (19 * .85 * 8)/0.50 = 258.4
with 24lb Injectors, (24 * .85 * 8)/0.50 = 326.4
with 30lb Injectors, (30 * .85 * 8)/0.50 = 408

This is a rough estimate because BSFC could be anywhere between .45-.50 on your NA motor, only way to know for sure is to check your duty cycle.

kennebellgt

how do i do that? with a moatesquarterhorse?

Genhero

QuarterHorse is just a piece of hardware(chip) that plugs into your J3 port, the software is what will determine what it does. I haven't used any of the software listed on Moates website but I don't see why it wouldn't.

If you type in 82139 in the sears website search bar, look for the sears multimeter for 30 bucks it can check your duty cycle also. If you don't have a multimeter already it might be worth it.

Did you have anyone tune your car after those mods?

Edit: I should also point out that I worded my last post a little weird, your duty cycle won't tell you what your BSFC is(I should have put a period not a comma). What it will tell you is whether your injectors are having to stay on for longer than they should because they are too small.

This is a nice calculator you can mess around with.
http://www.gtsparkplugs.com/InjectorSizeCalc.html