Am I out of injector?
A wide band O2 sensor would make it easier.
That's about as good as I can do with no car information.
Al 95 Z28
That's a pretty big cam in there with pretty good overlap. I would hazard to guess that you're probably fine with what you have in there. And remember most folks tell you that you should always go to only 80% duty cycle on the injectors while I quoted 90%. The reason I went that high is due to the fact that I've been there and have run at 90% without issues for years.
Now I assume you had the car dyno tuned? If so get the graph and look at your RWHP. It should also have a A/F ratio number in there also. If you don't have dyno information then I recommend you get a dyno reading. Reading the plugs will work but when I've seen it done it's fresh set of plugs, make a run, shut it off right after the lights, coast to a stop after the turn off and have it towed back to the paddock to pull the plugs and read them.
For $190 bucks you can buy a wideband but you'll have to get a bung welded on to your exhaust. For 100 bucks you should be able to get a dyno graph done on your car with ther WB data on it from a full service speed shop.
That's a pretty big cam in there with pretty good overlap. I would hazard to guess that you're probably fine with what you have in there. And remember most folks tell you that you should always go to only 80% duty cycle on the injectors while I quoted 90%. The reason I went that high is due to the fact that I've been there and have run at 90% without issues for years.
Now I assume you had the car dyno tuned? If so get the graph and look at your RWHP. It should also have a A/F ratio number in there also. If you don't have dyno information then I recommend you get a dyno reading. Reading the plugs will work but when I've seen it done it's fresh set of plugs, make a run, shut it off right after the lights, coast to a stop after the turn off and have it towed back to the paddock to pull the plugs and read them.
For $190 bucks you can buy a wideband but you'll have to get a bung welded on to your exhaust. For 100 bucks you should be able to get a dyno graph done on your car with ther WB data on it from a full service speed shop.
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from your mods list, I would have to bet you are beyond 80%.... 42# is likely overkill for your setup...maybe 36# would be fine
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heads cam cars - what heads?... it always depends
sure, a ls1 car swapped to a custom cam and ls6 heads, yeh that will work fine.
If you are going to start doing mods and you know you will be doing more, why not provide enough fuel for at least 15% future power, as the injectors and the fuel sizing won't care and the tune in the car won't care. You can run 42# injectors on a stock car with absolutely no idle problems or any problems of the sort.
I know you are likely just noting a point about it being doable, and there is such a thing as overkill or going overboard, but c'mon we can go around and around about this. In general, if you are looking at modifications its always good to keep things in perspective and know where you are with regards to fuel consumption and your engine.
take 26# per hour and convert it to liters per hour
your fuel pump is rated liters per hour
BAM. solution
take 36# per hour and convert to liters per hour
find a fuel pump that is above this rating
BAM. solution
heads cam cars - what heads?... it always depends
sure, a ls1 car swapped to a custom cam and ls6 heads, yeh that will work fine.
If you are going to start doing mods and you know you will be doing more, why not provide enough fuel for at least 15% future power, as the injectors and the fuel sizing won't care and the tune in the car won't care. You can run 42# injectors on a stock car with absolutely no idle problems or any problems of the sort.
I know you are likely just noting a point about it being doable, and there is such a thing as overkill or going overboard, but c'mon we can go around and around about this. In general, if you are looking at modifications its always good to keep things in perspective and know where you are with regards to fuel consumption and your engine.
take 26# per hour and convert it to liters per hour
your fuel pump is rated liters per hour
BAM. solution
take 36# per hour and convert to liters per hour
find a fuel pump that is above this rating
BAM. solution
Download UConeer conversion program.
1 Liter IS 0.2642 gallons
so 1 Liter per hour is 0.2642 gallons per hour
A Fuel pump rated 300 Liters Per Hour can handle:
300 LPH
79.26 GPH
1 gallon of gas is 6.07LB OR
1 liter of gas is 1.604LB
300 Liter ......... 1.604 LB ...... 481.2 LB
1 hr ........... x 1 liter .......... = 1 hr
(* cross multiplication, liters cancel; you are left with LB/hr)
Divide by 8 injectors
481.2/8 = 60.15 LB/hr injectors at a single 300 LPH pump
also keep in mind everything is NOT perfect and won't give you exactly what these numbers say, I'm in no way responsible if you hook this up and it doesn't keep your fuel supplied, hahaha.
it is also good to see or know the fuel pump curve for each fuel pump you use, this tells the story.
Last edited by mikh338; Mar 9, 2012 at 09:16 PM.
our fuel pressure is 58psi (4 bar)
Sqrt(58/43.5) = 1.1547% larger value
multiply the 30LB * 1.1547 and that is your new injector value at our 58psi
which is: 34.64 LB / Hr
check out www.rceng.com and their Technical Sizing link at the left, then scroll all the way down to the bottom 520 engine HP makes it about 35LB/hr injector...so at the wheels about 490 or so
check out www.rceng.com and their Technical Sizing link at the left, then scroll all the way down to the bottom 520 engine HP makes it about 35LB/hr injector...so at the wheels about 490 or so







