Fast 46lb fuel injectors for LS2
10-04-2015, 12:07 PM
#21
Race Director
Member Since: May 2004
Location: Raleigh, NC
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St. Jude Donor '15
My only point is you can't say things couldn't be better, even if the only thing that could be better is fuel economy
Only fuel vapor burns.. liquid does not. Smaller droplets vaporize more quickly/easily so they can then be burned
I would suspect with poor atomization you can still inject some extra fuel and still get enough of it to vaporize to achieve whatever AFR you want, and thus still make a good amount of power.. but I still think it could be wasting fuel
Can I say that for 100% sure? Honestly, no, I can't. I don't have a way to test it and tons of people are running around on drilled out injectors and are getting by. I do have to say the difference I saw in mine when I went from deka 60's to ID1000's was pretty impressive. Better fuel economy, smoother idle, and fuel trim values were almost exactly the same between bank 1 and 2, all with LARGER injectors. This is on a stock displacement/cam'd engine too. With the 60's I would see 6-8% difference between banks, so there's no telling what the actual difference was cylinder to cylinder. And the ID1000's are good for around 1000rwhp.
Anyways.. enough butt loving on ID.
Only fuel vapor burns.. liquid does not. Smaller droplets vaporize more quickly/easily so they can then be burned
I would suspect with poor atomization you can still inject some extra fuel and still get enough of it to vaporize to achieve whatever AFR you want, and thus still make a good amount of power.. but I still think it could be wasting fuel
Can I say that for 100% sure? Honestly, no, I can't. I don't have a way to test it and tons of people are running around on drilled out injectors and are getting by. I do have to say the difference I saw in mine when I went from deka 60's to ID1000's was pretty impressive. Better fuel economy, smoother idle, and fuel trim values were almost exactly the same between bank 1 and 2, all with LARGER injectors. This is on a stock displacement/cam'd engine too. With the 60's I would see 6-8% difference between banks, so there's no telling what the actual difference was cylinder to cylinder. And the ID1000's are good for around 1000rwhp.
Anyways.. enough butt loving on ID.
Last edited by schpenxel; 10-04-2015 at 12:10 PM.
10-04-2015, 12:46 PM
#22
Tech Contributor
Greg Banish has some great posts on fuel injector design and atomization, he does it for the OEM's for a living. Any time you change the injectors, size, fuel pressure, orifice, it's changing the fluid dynamics.
Now the truth is, our computers can compensate for a slightly mis-adjusted injector - heck they ran fine for 100 years using a carburetor, let's not forget. Our feedback system does a great job in closed loop even if the injectors aren't perfect. Both Fuel economy and performance will be fine if you get the injectors pretty close, and the spreadsheet that's out there does a pretty fine job at that.
At some point they will be too small to flow the fuel the airflow of the engine demands. I think I'm at the ragged edge at 475 RWHP, Dennis is wise to upgrade his as his car goes a full second faster than mine. Since I scan every run with a wideband I know exactly what my AFR is, if I didn't, I would have upgraded my injectors to give more head room on a cold day.
Now the truth is, our computers can compensate for a slightly mis-adjusted injector - heck they ran fine for 100 years using a carburetor, let's not forget. Our feedback system does a great job in closed loop even if the injectors aren't perfect. Both Fuel economy and performance will be fine if you get the injectors pretty close, and the spreadsheet that's out there does a pretty fine job at that.
At some point they will be too small to flow the fuel the airflow of the engine demands. I think I'm at the ragged edge at 475 RWHP, Dennis is wise to upgrade his as his car goes a full second faster than mine. Since I scan every run with a wideband I know exactly what my AFR is, if I didn't, I would have upgraded my injectors to give more head room on a cold day.
10-04-2015, 01:11 PM
#23
Tech Contributor
I am always eager to learn
so you are telling me that new injector over resized would make more power and go faster? because according to the AFR a very expensive one on Carteks dyno its tuned perfect, idles perfect no surging and shifts at 7200 rpm, with just the dyno tuning, no tuning at the track or street tuning, runs perfect runs cool and uses no oil between oil changes
so you are telling me that new injector over resized would make more power and go faster? because according to the AFR a very expensive one on Carteks dyno its tuned perfect, idles perfect no surging and shifts at 7200 rpm, with just the dyno tuning, no tuning at the track or street tuning, runs perfect runs cool and uses no oil between oil changesIf you put in too much injector, the duty cycle is so short that physics can't open and close it in that short of a time and too much fuel comes out... it'll run poorly and way too rich. So it's important to make your injectors perfect for Goldilocks....not too big and not too small. Within that range, the computer can do the rest with its feedback 02 system.
Last edited by Joe_G; 10-04-2015 at 02:18 PM.
10-04-2015, 09:42 PM
#24
Race Director
No Dennis, you're not going to go any faster on bigger injectors. I know yours are only like 60% duty cycle, plenty of headroom for cold days. Mine are 95%, about maxed out.
If you put in too much injector, the duty cycle is so short that physics can't open and close it in that short of a time and too much fuel comes out... it'll run poorly and way too rich. So it's important to make your injectors perfect for Goldilocks....not too big and not too small. Within that range, the computer can do the rest with its feedback 02 system.
If you put in too much injector, the duty cycle is so short that physics can't open and close it in that short of a time and too much fuel comes out... it'll run poorly and way too rich. So it's important to make your injectors perfect for Goldilocks....not too big and not too small. Within that range, the computer can do the rest with its feedback 02 system.
and for the record my car gets 25mpg at 30 40 50 and 60 mph thats with all my mods and 373 gears and the 3800PA yank converter which couples very quickly at part throttle now if I bring the fans on later it will run a 190 temp and get 27 but at a 165-181 it gets 25 now at 158-160 it get 23
10-05-2015, 10:38 AM
#25
Melting Slicks
it may go faster on a smaller injector Depnding on how it has been tuned with the larger injector. There is some good discussion on injector timing over @ HPT. Some solid HP gains changing injector timing with a large injector, a trade off to drivability. Best power was made @ 80% & higher IDC was the consensus, then you could work on injector timing in the low speed area's.A good injector will go past the 100% IDC which is just a mathematical calculation. I've been thru a box of injector's trying to get the IDC in the 90% range. At one point I had ID1000's thinking I might SC my LS3 stroker, I've since determined I'm in enough trouble with the NA configuration. When I was fighting my driveability concerns I swapped the ID1000's out for LS2 injectors with no noticeable difference in driveability.
I've also tried LS3/7 & LS9 injectors, I'm currently running Deatschwerks 43lb injectors. They work well & come with good data including flow numbers.