I'm getting a friend of mine to do this for me, the car has numerous extensive airflow mods(headwork-porting, lzm stg 2 cams, full mandrel 2.5" exhaust, wrapped header with 2.5" output, AEM CAI, ported tb, ported intake mani, etc.), I am putting in 310cc injectors, and getting him to reprogram using HPT. Now, unfortunately, we don't really have easy access to a dyno, or windeband o2. He has mostly tuned forced induction setups, and hasn't blown anything up yet. Anyways, he says he'll have no problems with reprogramming for the new injectors, lowering the PE rpm, and all the usual stuff.

However, what I am looking for, is a rough idea on what changes to the ignition curve would work well. Keep in mind, that the stock ecu is tuned for 87 octane, and I have no problems with running 91 octane if needed. Does anyone have any numbers for what should work(n/a ecotec engine)? I know datalogging is the proper way, yadda yadda, but has anyone done this on a similar setup, and can give me some numbers that should work?

on first read through I would have said don't let him touch your car.

but on the second time through.. umm, well, don't let him touch your car. Words like, no wideband, no dyno, hasn't blown anything up yet, and the word tune, don't belong in the same paragraph. You can not tune a car without a wideband as a minimum. Get a new friend.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Also when i was datalogging my car with 36lb injectors at 7k rpms i was at 60ish% duty cycle..... So idk if those are big enough injectors for a higher revving N/A car.

Tom, that was with the WRONG injectors for your ECM.....60% is not bad what so ever......Ge force.... how did people tune before wide band O2 sensors?....

looking at KR,(Knock Retard.) MV (milavolts) Fuel Trim, (OBD-1 Block Learn) CAN be used to "tune" a car, is it good? no, not with the tools of TODAY.

keep a watch-full eye on KR, narrow band MV, i would keep it higher than 700. but not 900. and maybe up your max KR to be safe.

its TEST and tune. data log it and see what works..................................

or pops a piston.


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

if the computer says 60% the injectors are open 60% duty cycle, irregardless of size. I'm not sure, how did they tune high horsepower turbocharged 4-cyl gas engines before wideband sensors??? last time I remember aftermarket boosting on 4-cyl applications has only become really big in the last couple years.. more like 7 to be more specific. and widebands were out way before then. You can tune without one, but I very highly doubt that your buddy has the knowledge to do it, I know I surely wouldn't trust my engine without one, you can, but you have been warned.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Taetsch Z24 wrote:Tom, that was with the WRONG injectors for your ECM.....60% is not bad what so ever......Ge force.... how did people tune before wide band O2 sensors?....

looking at KR,(Knock Retard.) MV (milavolts) Fuel Trim, (OBD-1 Block Learn) CAN be used to "tune" a car, is it good? no, not with the tools of TODAY.

keep a watch-full eye on KR, narrow band MV, i would keep it higher than 700. but not 900. and maybe up your max KR to be safe.

its TEST and tune. data log it and see what works..................................

or pops a piston.


Chris

BUT he said 310cc which are smaller then the 36lb injectors.... with as much air as his car "could" flow those will be too small... I understand the resistance was wrong but still they were open 60% of the time on a STOCK flowing LD9. If i had cams some headwork and a better flowing exhaust i could see those being maxed out or close to it.

7 grand? dang man I hope your engines built. I'm pretty sure once and injector gets over 70% open, it starts loosing its ability to effeciantly supply fuel. So If your injectors are reading low 60% numbers at 7 grand and WOT, as long as your not gunna run the rpms any higher than that (already over stock redline), you should be fine.

Weebel wrote:7 grand? dang man I hope your engines built. I'm pretty sure once and injector gets over 70% open, it starts loosing its ability to effeciantly supply fuel. So If your injectors are reading low 60% numbers at 7 grand and WOT, as long as your not gunna run the rpms any higher than that (already over stock redline), you should be fine.

80% is the "safe" limit for injectors.

And nope the engines NOT built... i upped it so i could stay in 3rd at the strip. Just so happens the ld9 falls on its face at 6500 with stock cams. 160k and going strong. This engine has seen 7500 on accident OOPS!

A built motor is in progress so im not really that worried about going into the higher rpms.

7 G on stock LD9's... who does that?! 80% is safe with boosted appts....... duty cycle is the computers way of THINKING it knows how much is going in. Like OBD-1's block learn, it can add more fuel to make the fuel trim correct. hell stock LSJ 2.0 SS cars are at 109 fuel trim, or 130% duty cycle stock. and we all know GM doesn’t know what the hell there doing.

Case at point, my Z24 had 310 in it, and lasted 120K, i think this eco with the same injectors will be safe.

Like I said, watch it on the scanner and see what happens...

Or you’ll pop a piston.



after-markit on 4 cyl boosted appts has been around sence the chevy corvar, ford SVO's, DSM's, dodge "K" cars.......... think that it got "BIG" in the 80's with the K cars, dsm's and i know its not a 4 cyl, but its still like one in that it has a cyl head, pistions, rods, and a crakn shaft.... the turbo GM "G" cars.

dont think that tuning is ANYTHING new.

that said, people did blow there cars up more back then.

Chris



'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

arg, you can't read.

Do a search on this site. We are talking on this site. When did boosted applications become big.. .on this site. Thats right 7 years ago. Obviously boosted applications have been around longer than this site, but when did boost become a big thing.. on this site?? that was 7 years ago. It became even bigger when I first started selling ebay manifolds and put exploited out of business. and that friend was 2004. That year I sold just over 35 manifold for the J scene. So boosted 4-cyl apllications (on this site) became big 7 years ago.

I first boosted a J in 2002, and wideband o2's were out then, and I am sure they were out before that... how do you think factory's tune cars?? using a 0-1v signal or a 0-5v signal?? how long have heated wideband sensor's been around??? who the hell knows, but long enough to know if you are tuning via EGT, KR, and "listening for knock" on the highway in 4th around redline, you are an idiot.

The main reason that they have become more and more used are they are a linear output as opposed to the non-lineal output on the narrow-band, which changes from rich to lean as the temperature changes... narrowband oscilate so much the average.. "average" is 450mv with all it's movement. If it costs 250-300 on a good gauge to tune it right.. why "save" the money and risk your engine?? Answer that and I will go away.


another thing... fuel trim and Duty cycle are related, but a 109 fuel trim, won't give you a 130% duty cycle would net you a 100% duty cycle, you can not work an injector more than 100%


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

I bow down to THE MASTER! Because now we all know that duty cycle is not what GM SI says it is, or Mitchell, or all-data. It really is that it says open all the time.... not that it says open longer than the computer thinks it should to net "X" AF ratio. If the computer has it running at 130-160% that means its adding more than it THINKS it needs, this can stem from an improper tune, denser ambient air presser, burnt out muffler..... but you know all, so teach this person that asking, my car runs good, so i really don’t care.

Just because it’s not said on this all mighty web site, doesn’t mean there is not something to learn from it.

Chris



'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

I don't know all, but telling some kid tuning without a wideband is stupid at best.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

..... SO your the one that put brian ( not spider lover. AKA speed racer ) out of business?! Thank you, I DIDN’T LIKE that basted, since I saw his welds on bens turbo sunfire.

You’re right, sorry for coming across as being brash, but it can be done, but with the tools of today..........

It would be like getting in a fire fight, ( gun ) with a muzzle loader.

Chris



'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Yah, I have done many stupid things.. blown engines, chipped pistons, if I personally would have had a wideband it would not have happened... but in the long run we both want the same thing:

MORE BOOSTED J'S WITH GOOD SUCCESS.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

ive always just kept the rule of thumb, 900MV and higher is 11-1

120K on the Z24, still running.

its with NA, that it gets..... trickey, lean is meen.... but its also like a damn torch.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

also duty cycle is a mathematical equation based on RPM vs PW so its possible for it get over 100% but when you see over 100% i guarantee the injectors are clipping. but i saw it with my own 2 eyes an LSJ had a max of 150% duty cycle according to HPT. when new injectors were installed it dropped to 65-70%

ONLY IF THEY OVERHEAT. and over driving injectors can over heat them, but that system is a "dead head" so if anything’s to blame I would say it was the lack of fuel TO the injectors, an one who is big in to modding a car like that, IE srt-4's install a return system like the LD9s have stock....... I was running what...120-130, and that was with the LSJ injectors.... so what was it with the 310's?........

I agree, it is an issue, I just don’t think its as big as EVERY one thinks.



'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

100% duty cycle just means that the injectors are maxed out in potential to operate effiecently. some honda engines run the injectors to 100% all the time under WOT at redline, and for the design of the injector it is consider approriate.

Duty cycle, is like taetsch was saying, the appropriate ammount of time that you can use an item reliably without failure. 100% duty cycle means it is opened 100% of the time, there for a 310cc injector will flow exactly 310cc @ 100% duty cycle, if your computer sends a 130% duty cycle, you can still only get 100% which would still only be 310cc/min from that injector.

Quote:

Duty cycle indicates the proportion of time which a pulsed actuator is being excited for. Using an injector as an example, it shows what proportion of the time the injector is being held open. If the injectors in a modified car have a duty cycle of 100 per cent during full load measurement, then the max capability of the injectors has been reached - no more fuel can be supplied. 100 per cent duty cycle means that the injectors are constantly open.

When companies say that 80% is the maximum recommend "duty cycle" the reason they say that is to allow the injector (at 8000rpm) approx 4 milliseconds to recharge or repressurize with fuel before opening for the remaining 16milliseconds in that cycle. but it is impossible to operate for 22 mil. in 20mil, that would be 110% duty cycle which can not be done. I hope that makes sense.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

What do the terms “static” and “duty cycle” mean?

Quote:


An injector in an engine turns on and off very quickly to control the amount of fuel delivered. The amount of time an injector is turned on and delivering fuel is known as the duty cycle. This is measured as a percent, so 50% duty cycle indicates that the injector is held open and held closed for an equal amount of time. When the engine needs more fuel, the time that the injector stays on (its duty cycle) increases so that more fuel can flow into the engine. If an injector stays on all the time, it is said to be static (wide open, or 100% duty cycle). INJECTORS SHOULD NOT GO STATIC IN A RUNNING ENGINE! If an injector is static in a running engine (open 100% of the time), that injector is no longer able to control fuel delivery. It is just “along for the ride”. This could be an indication that the injector is too small for the needs of the engine. Injector duty cycle should usually not exceed 80% in a running engine at any time.

What is an injector’s static flow rate?

Quote:


Manufacturers rate fuel injectors by the maximum amount of fuel that they can flow in a given amount of time. This measurement is taken with the injector on 100% of the time (100% duty cycle, or wide open) and with the fuel at a given pressure (usually 43.5 psi). For example, a 19 pound per hour (Lb./Hr.) injector flow 19 pounds of fuel in one hour at 100% duty cycle and 43.5 psi of fuel pressure. Injectors in imported vehicles are often rated in cubic centimeters per minute (cc/min) instead of pounds per hour. This is also done at 100% duty cycle.

If injectors should not exceed 80% duty cycle under operating conditions, why do manufacturers rate them at 100% duty cycle?

Quote:

A test at 100% duty cycle is used to determine the maximum amount of fuel that will flow through an injector in a given time. This test is useful for determining whether an injector’s internal fuel passages were machined properly, but it does NOT check an injector’s ability to cycle on or off. It is usually NOT recommended to run an injector at more than 80% duty cycle under actual driving conditions. This 80% duty cycle operating limit is taken into account to make sure the injector will be large enough to feed the engine under ACTUAL OPERATING CONDITIONS and will not starve the engine for fuel.

oh, 20ms is 100% @ 6000, 15ms is 100% @ 8000 rpm, you will notice as rpm go up, the time to fire goes down.. which is why higher reving high horsepower engines start needing huge ass injectors.


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Quote:

Weebel
Today 2:49 AM
7 grand? dang man I hope your engines built.

I've seen 8100 on mine more than a few times with the stock crank pistons rods and balance shafts.

ecos love revving. especially the stock ones

now the valvetrain.. thats another story lol

Thanks Ge Force for the good read

and PJ this is a LD9 not a ecotec

, what and LD9's cant rev.... OHHH i forgot, the 2.4 has TORQE ie long strok, my LGO can rev....lol just playing.

i was always taught that at 100 percent it was rated at "X" but when your above that, IE the injector is staying open longer than the computer has calculated it should, it sill will flow more, because its plus with is longer. But then we do get into the realm of over heating them and ultimately, clipping. (From lack of fuel, {what I think is the LSJ problem.} or over working\heating)

But, what it all comes down to is.

Is the AFR correct?

IS there any KR, this can stem from over worked injectors not spraying a good "mist" or over heating.


There are a lot of factors, lots of math.... because it does take X amount of fuel to make X amount of power, weather it’s NA, boosted or spray.


So, can it be done as you want to, with out dyno time, and a wide band, yes, that’s how myself and Tom did it with my Z24.

BUT is it safe? No.

Chris



'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

by any chance did your AFR go from rich in the mid rpm to leaning out slightly in the higher RPM??


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

no, stayed at 947MV, 0-3 KR, 3000-7200 and 960MV 0-1 KR with watter injection on. (just watter, no mix.)


stock pulley, with anything but stock timing. i took shifted's tune and "messed" with it, and i have 36# LSJ injectors.


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Taetsch Z24 wrote: no, stayed at 947MV, ... 960MV...


Chris

OMG! that sounds awfully narrow band to me.


Oh and for the record, most of my cars have or do run the injectors static at some point in the RPM band.
I am fine with that.
My customers are fine with that.
My engines also seem to be fine with that.

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