Injector Timing? Reference Periods? refereencing what?

[Wnts2Go10O]

My long way home involved a half hour out of the way to a friends house to help him with Wiring on his project Car...3rd gen camaro with an High Boost LT1 engine, running an LS1 PCM.
I made some gauges and stuff work tonight...
then I drove a half hour home

what I noticed is that the Fueling went richer now that I'm not blowing so much out the exhaust...
part throttle definitely feels better.
I actually tried to roll race a buddy of mine in his LS3 GTO, but I blew the tires off my car in 2nd and 3rd gear on the highway at 65mph in 2nd and 75mph in 3rd...
but I dont know if that was my crappy tires or an increase from injector timing... I would guess at shitty tires.. I have problems with this rubber on these rims.

i dont see why a better fuel timing wouldnt gain power. even if its just a little. i would think the biggest changes would be throttle response, drivability, and fuel mileage.

[S2H]

I agree with that a lot...
definitely not a blanket thing...
but its a starting point for testing..

I may be able to put my own car on the dyno next week.... have a buddy that wants to see how my car reacts on his dyno before I put this "cock of Thor" cam in it(yeah.. its really going to be that big) and we may play around with the EIOT on the dyno as well

[LSxpwrdZ]

If it's a loaded dyno I would play around with this at partial throttle and monitor HP/Torque at light loads under 3000rpm. That would be a good indicator on getting the injector timing pan'd out.

In your test drive did your setup run smoother at lower RPM's 1500-2300rpm? That is where mine really woke up and smoothed out.

[S2H]

If it's a loaded dyno I would play around with this at partial throttle and monitor HP/Torque at light loads under 3000rpm. That would be a good indicator on getting the injector timing pan'd out.

In your test drive did your setup run smoother at lower RPM's 1500-2300rpm? That is where mine really woke up and smoothed out.

I would say noticeably better at low rpm and part throttle stuff

and yeah.. its a loaded dyno... Dyno Dynamics..and it reads really low compared to any other dyno I have been on... but its extremely consistent

[LSxpwrdZ]

Yeah DynoDynamic's US headquarters are based about 30min's up the road from me haha. If/When I can afford the payment on one I'll be purchasing one from them! Dang good Dyno's. Keep us updated on what ya find! Also curious on the power numbers you make compared to the dynojet numbers!

[S2H]

Yeah DynoDynamic's US headquarters are based about 30min's up the road from me haha. If/When I can afford the payment on one I'll be purchasing one from them! Dang good Dyno's. Keep us updated on what ya find! Also curious on the power numbers you make compared to the dynojet numbers!

my current #'s are on a dynocom that reads just slightly higher than most mustang dyno's

[WS6FirebirdTA00]

I don't think I am going too deep in to this. I believe you have to so one can have a complete understanding of the change in events and what would be "ideal".

Good point LSx. Finishing the injection some point earlier could mean entering the chamber a bit later. The LS7 finishes, at low engine speeds, around 370*IIRC. Just throwing some numbers out there I figured by 0.020" the scavenging would be to a minimum so I was using that for a starting point. 0.050" numbers may be better to use when you account for the transfer delay of the fuel to the cylinder. Of course this will vary a bit and as you said there are a lot of other variables that may change this car to car.

[WS6FirebirdTA00]

Also, digging back to my days of balancing chemical equations, I believe the AFR reading on a WB is based on the values from combustion itself. Unburnt fuel going through the exhaust is not read as it was not part of combustion. Better mixing means more fuel in the chamber for combustion, giving a richer reading. This has also been an area I would like to research more. As your cam overlap increases and scavenging gets better, you have the potential to pump more fresh air through the exhaust thus giving a "leaner" reading. My thoughts/questions at least. I've noticed the larger my car the "leaner" the AFR on the top end it can stand and make gains in power. Not sure if there is any truth to this or if this pumping of fresh air is negligible. On the positive side it just means most cars may be rich (if it holds true).

I may be wrong here, it has been several years since thermo 1 and 2

[Google]

when testing 02's you can pass propane over the wb sensor and it will show rich.. with that you could take a can / jar and poor gas in it, cut a hole in the lid and put the wb sensor in and test if the raw fuel fumes change the afr readings.. as the wb messures 02, I would say it does change..

[WS6FirebirdTA00]

But now we are in a system that little oxygen is present. If you run a motor at 5000 RPM (by driving it with another motor) and simply inject fuel but do not burn it, I would imagine it show oxygen as a percentage rather than AFR because it would be high. I think the added vapor that is unburnt will still show up lean.

[MikeGyver]

when testing 02's you can pass propane over the wb sensor and it will show rich.. with that you could take a can / jar and poor gas in it, cut a hole in the lid and put the wb sensor in and test if the raw fuel fumes change the afr readings.. as the wb messures 02, I would say it does change..

I am pretty sure that the same thing would happen if you used any gas. The oxygen sensors measure oxygen, and there is no free oxygen in propane. If you used argon, or nitrogen for examples, the sensor will see less oxygen and report a rich condition.

[MikeGyver]

But now we are in a system that little oxygen is present. If you run a motor at 5000 RPM (by driving it with another motor) and simply inject fuel but do not burn it, I would imagine it show oxygen as a percentage rather than AFR because it would be high. I think the added vapor that is unburnt will still show up lean.

It will show lean because, to add to my above post, the unburned fuel is not using the oxygen, and more oxygen is hitting the sensor than would in a stoich condition.

[WS6FirebirdTA00]

I agree.

[SargeZ06]

Won't the changes cause the AFR guage to stop showing nutty swings in AFR caused by raw fuel passing over the sensor?

[WS6FirebirdTA00]

Should

[ElecTech]

If it's a loaded dyno I would play around with this at partial throttle and monitor HP/Torque at light loads under 3000rpm. That would be a good indicator on getting the injector timing pan'd out.

In your test drive did your setup run smoother at lower RPM's 1500-2300rpm? That is where mine really woke up and smoothed out.

If you have access to a Road Runner, you would be able to see imediate feedback while you adjust those values on the dyno.

[WS6FirebirdTA00]

Well I just got back from a log, going to review it. First glace doesn't seem like a whole lot really changed. I haven't driven the car in almost 3 months so it is hard to say if it is better or worse. I did start up cold with the whole table moved up, plus 2 on the cold end. Cold start seems a little rough but I don't know if that was from just sitting for so long. I did drive it fairly cold and it did not break up like it normally does though.

[WS6FirebirdTA00]

Looking at idle, my injection start point is approximately 10.5* BTDC and finished 95* ATDC. My EVC at 0.050" is 9.5* ATDC.

I think I am going to try using my cam 0.020" values for the start. If that doesn't change much I am going to try to put it in there so the injection does not start until the EVC at 0.020" happens. This should make sure I get a good spray without any loss through the exhaust. If I see no changes here then I don't know lol

[WS6FirebirdTA00]

Just ran at idle from stock values all the way up to 6.65 and nothing changed. AFR stayed exactly the same, no real different felt in how the car runs, I honestly question if anything is even changing it was that steady.

[Google]

WS6,

are you in olsd or cl?