Injector Timing? Reference Periods? refereencing what?

[aldrichg9]

I have read through this thread about 5 times total.
I feel like there have been two conflicting statements in it.

One says that the Normal table is added to the Boundary value to determine EOIT.
But there is a quote from Chris that states where the Normal table is the angle that injection must be complete BEFORE the Boundary.

Which one is it?


Edit:
I tried lots of different values today in Bounday + Normal and Makeup tables.
Didn't seem to make any difference in my truck.
I worked all of them up .25 at a time until everything was at 8 (can't put a 9 in)
Is there a point where there is so much overlap (48 degrees) that the fuel is just going to do its thing at idle speed?

[ctd]

By chance when you where tuning this on the dyno before changing the EOIT did you notice large changes in the AFR made minimal differences to power?

My IDC is somewhat less than yours 35% & I've been curious regarding the lack of response when making large changes to AFR. Maybe the atomization?

^^^ You are 100% correct

The only reason this picked up like it did was due to running HUGE injectors on a small NA setup. IDC is only 39-40% on this setup. I made multiple dyno pulls with either setting and both gave same results within 1-2hp.

The highest HP pull was with Boundary set at 7.0 and the Normal Table set to 6.0 in the warmer ECT regions. The lower dyno pull was with the Boundary set to 6.5 and the Normal table left the same. There is a tradeoff though. I've noticed the car misfires at light throttle and idles quite rougher with the later injection time. For shits and giggles I extended the EOIT another 0.25 and it lost a bit of power. When I get a free chance I will try to find the happy medium between 6.5-7.0 on the Boundary while not sacrificing power up top.

[outcastdon]

Older thread, but very interesting.

Am experimenting with the 03 C5 now.

408, long tubes, ported LS6 heads, underdrive crank pulley, no cats, medium cam (see attached or below), stock TB, M12 trans.

Wideband is kaput. Damn it.

Boundary at 6.50

Stock normal 5.55 - rougher idle lean at idle though wants fuel badly.
Good power at speed above 2000 rpm

6.60 normal - Better light throttle, 1500 and below. Same idle but richer STFT readings. Better higher rpm response.

7.20 normal - Better idle quality, same O2 readings. Still wants to be at 13.7 AFR at idle using VCM controls. Same higher rpm power but richer readings.

Questions:
Can I raise the boundary and lower the normal setting to achieve a higher delay in the injector timing as 8 is the highest setting for normal now?
Getting richer in the upper rpm ranges as I raise the normal, how far should I go and what should I be looking for as far as a limit?

Will post log and tune later.


617/624 lift and 231/239 duration at .050

113 lobe separation

109 intake centerline

Valve Timing @ 0.006

Exhaust
Closes 28
ATDC
Opens 81
BBDC

Intake
30 Opens
BTDC
70 Closes
ABDC



58 degrees of overlap.

[outcastdon]

Up to 7.22 boundary,
7.0 normal.

Less surge at low rpm, same throttle response.

Still need to post tune and scan.

Have a bug in the tuner as iI am unable to use/change the VE 3D model with the 1 bar MAP enhanced HP Tuners version. Anyone else with same problem??


MERRY CHRISTMAS!!

[outcastdon]

Reenabled everything and could only do a short run as the computer battery died.
No WB, cool 40 degrees outside and rainy.
Couldn't get on it much.

Slight surge/stutter at 10 % throttle, not bad.

Opinions please.
Should I delay injection further?

[WS6FirebirdTA00]

IMO, that is way too much delay and you need to get your WB in there.

[outcastdon]

Thanks for the reply.

Will try lowering it some, but I have had less issues at this point,
low rpm stuble, idle surge....

[WS6FirebirdTA00]

I would look at other areas of the tune before messing with this. That is extremely late to where you are probably spraying a lot towards the bottom of the stroke. That isn't a huge cam.

[outcastdon]

Thanks WS6.

Backed off the injector timing a bit.
Redid VE, MAF and idle X2 earlier today.
This is first scan after enabling everything. (should have date of 29th)
Has more stutter? at 10% throttle. Could this be reversion... or?
Idles well and plenty of power/torque.

21 MPG at 72 mph over 35 mile highway cruise. Not bad.

Suggestions welcome.
Thanks.

[WS6FirebirdTA00]

I thought you said you didn't have a WB, how did you tune fueling?

[outcastdon]

O2's for now. Would rather have the WB.
Got to get a sensor for one of the WB's within the next couple of weeks.
Have an indash Autometer and an AFX.
Holidays took a toll on finances. LOL

Have reread this post a few times;
Always learning from it.

Because of the current cam's 58 degrees of overlap, set the original value up so high because of better part throttle stutter/surge containment, I believe this may have been too far also.
Trim values were richer above 1800 rpm at this setting, 7.22 boundary, 7.0 normal. Leaner around idle but idle and part throttle were better.

Lowering the values today to 7.0 boundary, 6.5 normal produced stutter at 10% throttle which was more prevalent with the stock settings, same torque response, leaner idle trims.

Using the spreadsheet in this discussion, with stock boundary of 6.50, true normal would be 6.54 for my cam.

I have a theory but would like to know, what does raising the boundary do exactly?



Stock cam specs;


02+ Z06 camshaft 0.006 0.050 0.200

Intake Duration - ID 270 204 125 02 LS6 intake
Exhaust Duration - ED 277 218 135 02 LS6 exhaust
Lobe Center Angle - LSA 117.5 117.5 117.5
Intake Centerline - ICL 120 120 120

Intake Valve opens - IVO 15 -18 -57.5 BTDC
Intake Valve closes - IVC 75 42 2.5 ABDC
Exhaust Valve Opens - EVO 73.5 44 2.5 BBDC
Exhaust Valve Closes - EVC 23.5 -6 -47.5 ATDC
Exhaust Centerline - ECL 115 115 115
Overlap 38.5 -24 -105 degrees

[WS6FirebirdTA00]

If you go too late on the injector timing you end up spraying to an open inlet valve and don't get good mixing with the air (if you are towards the last bit getting drawn in. That is what you have to watch for. I don't fully understand the risks but I do believe if you spray too late you end up with raw fuel that could wash down the cylinders because it didn't properly vaporize. By changing your timing that much you could be masking other issues. I have a 236/244 cam in my car (346 motor still) and have no problems with the factory values. I have never tested on a dyno to see what light throttle low RPM torque benefits there were (if any). It is hard to find the fine line of not wasting fuel during the intake stroke but still injecting soon enough so you get a good mixture.

[outcastdon]

Thank you for responding WS6.
Sometimes hard to get one quickly or at all, though I don't post much, I read alot.

I believe everything else is set close.....timing, fueling, ect.
Car starts within the first few revs and runs great overall.
Drove it 900 miles on the SD tune for Christmas, visiting relatives.
No problems.

Had the rings in 3 cylinders in the original 5.7 engine go away and replaced it with the 408. Had this cam in both and at 10% throttle, have always had a stutter. Don't know why as all the parameters seem to be set correctly. This is the reason I think it's revision at that pedal position. Setting the boundary so high sort of masked? it?

Will have to experiment some more with the injector timing.

[LSxpwrdZ]

By chance when you where tuning this on the dyno before changing the EOIT did you notice large changes in the AFR made minimal differences to power?

My IDC is somewhat less than yours 35% & I've been curious regarding the lack of response when making large changes to AFR. Maybe the atomization?

The adjustments I made were so small that the fueling didnt vary over a 1-2% variance which isn't enough to cause issue. I did adjust fueling in some on each test I did to make sure it was still an apples to apples test.


Injector timing is a tradeoff on the Gen3 PCM. I did extensive dyno testing on my personal car on a loaded dyno and when I got idle and drivability the most stable it lost powerband up top and power. When I retarded the EOIT back to where it made peak power the car didn't drive as nice or idle as stable.

This is where the E38/40/67 etc really show their value in drivability by giving multiple tables to vary the EOIT vs various factors instead of one set EOIT at temperature.

[outcastdon]

"Injector timing is a tradeoff on the Gen3 PCM. I did extensive dyno testing on my personal car on a loaded dyno and when I got idle and drivability the most stable it lost powerband up top and power. When I retarded the EOIT back to where it made peak power the car didn't drive as nice or idle as stable."


LSxpwrdZ,

I believe this is my problem also.

[LSxpwrdZ]

I ended up ditching my 60lb injectors that I mension earlier in this thread with the dyno sheet and am now running 42lb green tops and the car def runs much better at low engine speeds. Dropping over 20lb/hr of injector flow really helps increase pulsewidth and atomization.

[outcastdon]

Rewashed VE, MAF and idle data after lowering boundary to 6.55 and normal to 6.50.

Idle is different, taking off "loads"? it down but I contribute that mostly to the lightweight flywheel.
Runs about the same with part throttle and pushing it.

Have Bosch 50's in it now, will have to log duty cycle.

[Monty]

ugh head hurts so bad, have read 3 times.. and have came very close to throwing my laptop's calculator into the recycle bin ha, iv also read other forums on how to calculate overlap, my calculation findings just doesn't seem right, -1.5 overlap, a negative value iv also searched negative overlap with no return what the heck is the overlap for a gm ls hotcam 218/227 112LSA please

[outcastdon]

IVO is 26.5 ° BTDC ( - indicates ATDC)
IVC is 64.5 ° ABDC
EVO is 75.0 ° ATDC ( - indicates BTDC)
EVC is 25.0 ° BBDC
Overlap is 51.5 °



From this website.....

http://www.wallaceracing.com/cam-deg-calc.php

[Monty]

IVO is 26.5 ° BTDC ( - indicates ATDC)
IVC is 64.5 ° ABDC
EVO is 75.0 ° ATDC ( - indicates BTDC)
EVC is 25.0 ° BBDC
Overlap is 51.5 °



From this website.....

http://www.wallaceracing.com/cam-deg-calc.php

OH... so this stupid website is wrong

"There are a couple different ways to calculate the overlap of the cam.

1) The easiest way is to add the intake opening times to the exhaust closing time. Seat to seat times (advertised duration) must be used. .050" durations or timings will not give the correct overlap. http://members.uia.net/pkelley2/Overlap.html "

advertised duration is in the hotcam's case .006 .. haha .050 is not the advertised duration for any cam .

edit... So the hotcam has 1.5 degrees more overlap than the stock LQ4 cam ?

PART NUMBER 12561721
116 LDA 115 INTAKE CENTERLINE.
PRODUCTION 2001 6.0L TRUCK AND 5.7L
LS1 CAR CAMSHAFT.
1.7 ROCKER RATIO
Lift:
@Cam @Valve
EXHAUST: 0.281 0.475
INTAKE: 0.274 0.463
Cam [email protected] Tappet Lift:
Open Close Adv. Duration
EXHAUST: 71 BBDC 33 ATDC 284
INTAKE: 11 BTDC 87 ABDC 278
Cam [email protected] Tappet Lift:
Open Close Duration
EXHAUST: 39 BBDC 12 BTDC 207
INTAKE: 17 ATDC 33 ABDC 196

Read more: http://www.superchevy.com/technical/...#ixzz2GrIakskJ im so confused its starting to make me upset .... seems this website is wrong too ?? ha cam card for hot cam isn't the same as what this site says. really i am so confused, i now have no idea whats going on.. 51.5 overlap for hot cam or 1.5 or is 1.5 the difference between the stock LQ4 cam overlap the stock cam over lap is 50. HUH WHAT but then i find that the hot cam overlap is 58.5 IVO is 30.0 ° BTDC ( - indicates ATDC)
IVC is 68.0 ° ABDC
EVO is 78.5 ° ATDC ( - indicates BTDC)
EVC is 28.5 ° BBDC
Overlap is 58.5 ° from this website http://www.wallaceracing.com/cam-deg-calc.php but you said it was 51.5 haha man im going