Page 3 of 31 FirstFirst 123456713 ... LastLast
Results 41 to 60 of 609

Thread: Injector Timing? Reference Periods? refereencing what?

  1. #41
    Tuning Addict WS6FirebirdTA00's Avatar
    Join Date
    Jan 2005
    Location
    Concord, NC
    Posts
    8,093
    Interesting conversation. Would be cool to see some dyno results. I've been meaning to play with this but have not had my car out in some time.
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  2. #42
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by WS6FirebirdTA00 View Post
    Interesting conversation. Would be cool to see some dyno results. I've been meaning to play with this but have not had my car out in some time.
    I'm going to play with it today on a heads/cam corvette

    I dont know if I'll have any results to share tonight as I have a bunch of stuff to do and wont get a chance to make data presentable right away.
    -Scott -

  3. #43
    Advanced Tuner
    Join Date
    Jul 2008
    Location
    Louisville, KY
    Posts
    417
    Quote Originally Posted by soundengineer View Post
    I'm going to play with it today on a heads/cam corvette

    I dont know if I'll have any results to share tonight as I have a bunch of stuff to do and wont get a chance to make data presentable right away.
    All of this is awesome discussion. It only makes sense that if a valve event moves fuel timing for that event would need to move too.

    Good stuff.

  4. #44
    Tuning Addict WS6FirebirdTA00's Avatar
    Join Date
    Jan 2005
    Location
    Concord, NC
    Posts
    8,093
    Cool, let us know. I would be interested in the results based on your logic (and small deviations of it). I only question the complexity of it based on engine speed/scavenging. I also wonder if the changes may increase fuel economy also result in power increases (of if they are inverse).
    Sulski Performance Tuning
    2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
    2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB

  5. #45
    Senior Tuner LSxpwrdZ's Avatar
    Join Date
    Dec 2008
    Location
    on the Dyno
    Posts
    1,825
    Quote Originally Posted by soundengineer View Post
    unfortunately I dont know the @.006 for the stock LS1 cam...
    I know my cam specific valve events for .006 and .050
    so I went off of .050 since thats what I know for the stock cam

    the majority of our aftermarket cams have about 25* between .006 and .050
    give or take a few depending on the lobe

    even then, its still quite a ways from 300 and even further for the exhaust valve closing..


    the ideal is that velocity point...which I'm sure with some serious math that I dont feel like diving into, could be calculated for a new cam.
    but I'm not about to dive into a 3 week design in Matlab just to come up with something I may be able to test on a dyno sometime soon..LOL


    theres no overlap in the stock cam....so theres no velocity benefit from the exhaust... they are basing all of their velocity on the opening of the intake valve on the stock LS1 cam

    by that logic... why not get the same or similar velocity from backing up the timing and making it fire sooner with a larger cam

    with the overlap, you will get some reversion, so you potentially could keep some fuel by spraying it on the back of the valve as opposed to inside the cylinder
    Looking at my valve event's, mine is currently set for the end of injection at the exhaust valve closing point which is 375*. So looking at that with a small 2ms 60# injector firing at idle it is starting the injector with the intake valve already open. Now larger pulsewidths and various rpm will change exactly where the injector will fire on the intake valve side of it. For whatever reason I played with my timing without knowing any of this formula and this so far is what has made mine drive the best...

    cam is a 247/260 112+3

    Quote Originally Posted by DrLoch View Post
    There has got to be more to the formula. If you use Bluecats equation everything looks plausible when ECT is at operating temp. What about when ECT is @ 68, the number comes back @ 30.570317.

    Makeup must have some influence on it. Need to instrument a running motor and see how changing the numbers influences the injector start pluse....
    To me it still makes sense because the point of it firing so early is to evaporate the fuel and on a cold engine will take longer because the engine isn't as warm. So technically it'd take longer. Also have to realize that it could be emission's related. There are a million reason's but I don't suspect the formula to be off with all the test data he put into it. Maybe he will chime in and give some more insight.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  6. #46
    Advanced Tuner
    Join Date
    Oct 2008
    Location
    Mebane NC
    Posts
    475
    Quote Originally Posted by LSxpwrdZ View Post
    To me it still makes sense because the point of it firing so early is to evaporate the fuel and on a cold engine will take longer because the engine isn't as warm. So technically it'd take longer. Also have to realize that it could be emission's related. There are a million reason's but I don't suspect the formula to be off with all the test data he put into it. Maybe he will chime in and give some more insight.
    That makes sense..... Just need to have some data on the exact meaning of the end numbers of the equation based on TDC or cam pulse.... something that we can see and understand.

    Dennis

  7. #47
    Senior Tuner LSxpwrdZ's Avatar
    Join Date
    Dec 2008
    Location
    on the Dyno
    Posts
    1,825
    He posted a spreadsheet in the other thread with different values flashed to the PCM and gave result's that he saw... don't know if you saw that or not.

    I'm also wondering why changing values in the makeup table had no affect on the injector timing. The only thing I can think is that is only referenced if a certain high pulsewidth is reached and needs extra time to finish that cycle of pulse.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  8. #48
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by LSxpwrdZ View Post
    He posted a spreadsheet in the other thread with different values flashed to the PCM and gave result's that he saw... don't know if you saw that or not.

    I'm also wondering why changing values in the makeup table had no affect on the injector timing. The only thing I can think is that is only referenced if a certain high pulsewidth is reached and needs extra time to finish that cycle of pulse.

    Link to said spreadsheet?

    sorry.. replying from phone...but I'm sure others would like it too.
    -Scott -

  9. #49
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    By the way.. I have no dyno data to report back.... customers car had some issues and we were unable to tune it...

    mostly his harmonic balancer pulley bolt was backing out and his pulley developed a wobble... he's going to fix it and bring the car back so we can tune it another day.
    this also caused a front seal leak so it was slinging some oil around too...
    -Scott -

  10. #50
    Advanced Tuner
    Join Date
    Oct 2008
    Location
    Mebane NC
    Posts
    475
    Quote Originally Posted by soundengineer View Post
    Link to said spreadsheet?

    sorry.. replying from phone...but I'm sure others would like it too.
    http://www.hptuners.com/forum/showpo...97&postcount=1

    Both are in the 1st post

  11. #51
    Advanced Tuner
    Join Date
    Jul 2008
    Location
    Louisville, KY
    Posts
    417
    Quote Originally Posted by soundengineer View Post
    By the way.. I have no dyno data to report back.... customers car had some issues and we were unable to tune it...

    mostly his harmonic balancer pulley bolt was backing out and his pulley developed a wobble... he's going to fix it and bring the car back so we can tune it another day.
    this also caused a front seal leak so it was slinging some oil around too...
    I can't believe the number of "credible" shops that reuse the stock bolt. Using a stock bolt is fine. Just use a new one. It gets stretched when it's torqued. SO you can't reuse. Seen this a dozen times...

  12. #52
    Advanced Tuner Bluecat's Avatar
    Join Date
    May 2006
    Location
    Catlettsburg, Ky
    Posts
    407
    I've played with this a bunch on the dyno. Fuel timing in my experiance has little effect power wise. Any time I do see a difference in power from moving the eoit, it's only in the below 3K range and less than 10ft/lb. But I've only tried stock to 140 deg later stuff, the range I end up using to make idle / drivabilty issues better. Maybe earlier might have different results, or if you had way to much injector and the pw's were shorter it might make more of a difference. Anyway, I only worry about making eoit changes for idle and drivablity reasons, I don't even worry about it in respect to power anymore.

  13. #53
    Advanced Tuner Bluecat's Avatar
    Join Date
    May 2006
    Location
    Catlettsburg, Ky
    Posts
    407
    Quote Originally Posted by LS1Vette View Post
    I can't believe the number of "credible" shops that reuse the stock bolt. Using a stock bolt is fine. Just use a new one. It gets stretched when it's torqued. SO you can't reuse. Seen this a dozen times...
    We always use a new bolt on customers cars, but only because they are cheap and it's not worth the liabilty of the customer bitching if something does happen. We've done it every way under the sun, right and wrong, and they still come off and back out. Balancers coming off is just part of it on a ls or anything that isn't keyed. If I had to choose between a new bolt properly torqued or a used bolt drowned in loctite and rattled till hell won't have it with an impact, I'd choose the used bolt... lol.

  14. #54
    Advanced Tuner
    Join Date
    Jul 2008
    Location
    Louisville, KY
    Posts
    417
    Quote Originally Posted by Bluecat View Post
    We always use a new bolt on customers cars, but only because they are cheap and it's not worth the liabilty of the customer bitching if something does happen. We've done it every way under the sun, right and wrong, and they still come off and back out. Balancers coming off is just part of it on a ls or anything that isn't keyed. If I had to choose between a new bolt properly torqued or a used bolt drowned in loctite and rattled till hell won't have it with an impact, I'd choose the used bolt... lol.
    The only NEW oem bolts I've seen walk out are because they weren't put in right. Some seem to think it's just a torque value and it's not. It's 37ft lbs plus 140 degrees. All the recent oem bolts I've gotten already have the blue lock tight splashed on the threads.

    I guess anything can happen, and you probably have put in a lot more cams than me, but I've never had one walk with the 37ftlbs + 140*.
    Last edited by SargeZ06; 01-05-2011 at 10:41 AM.

  15. #55
    Senior Tuner LSxpwrdZ's Avatar
    Join Date
    Dec 2008
    Location
    on the Dyno
    Posts
    1,825
    The only problem I've had is on my own car with new and used bolts. The only time I didn't have a problem was with a used bolt drowned in locktite put on with a 6' long breaker bar!

    I will be upgrading to an ATi SuperDamper that has a keyway slot in it. My ASP doesn't have a keyway but my crank does.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  16. #56
    excellent thread, am anxious to do some testing.

    as for the crank bolt issues, we've noticed a trend that indicates seldom issues under 450 rwhp, while incedence dramatically increases at power levels over 500 rwhp, particularly with nitrous or turbo applications. i think parish lost his at slightly over 480 early on.

    i've heard various opinions, aluminum blocks do, iron blocks don't-not sure if there's anything to that or not. our solution is to drill and pin using your typical supercharger pinning fixture any time the balancer bolt is out, and use a new bolt. success rate has been 100% so far, up to bout 1150 rwhp....

  17. #57
    Advanced Tuner
    Join Date
    Mar 2010
    Location
    New Orleans, LA
    Posts
    628
    i'll reference the ford ecu's because i know them pretty well, i think this is relevant none the less



    the ford ecu's base injector timing off the camshaft degrees with a total of 720 (2 spins of the crank shaft)

    0-180 combustion
    181-360 exhaust
    360-540 intake
    541-720 power

    the ford ecu's are mass air for the most part, load is calculated VE based off of the sarchg (engine size) and air mass (maf)

    the idea is to fire the injector after the exhaust valve closes and get the full charge in before the intake valve reaches max lift

    on a small block ford typical performance values would be around 400 cam degrees at low loads and cruise and 440 at higher loads and WOT

    you can find the sweet spot by steady cruising adjusting the injector timing until your fuel consumption is reduced, logically where ever you consume the least fuel to maintain stoich is optimal
    Last edited by decipha; 01-05-2011 at 06:23 PM.

  18. #58
    Advanced Tuner MikeGyver's Avatar
    Join Date
    Feb 2006
    Location
    Suburban Chicago
    Posts
    268
    This is what's been circling the water in the toilet flush in my head since the start of these two threads:

    It seems to me that end of injection timing must be an emissions thing. There has to be an improvement (in my mind) in economy or just an improvement in idle quality by not injecting until the exhaust is closed in a cammed engine, but just at low engine speeds. If you could time it to hit the closed valve until warmup to help evaporate fuel, and then after the exhaust shuts with low kPa at low engine speeds after warmup, seems ideal for cams with overlap. Then maybe back to hitting the closed valve at above perhaps 1600 rpm. That is, if there is benefit.

    The reason that I am suggesting that it is only for emissions is that they only give a ECT table. If it were meant to be something that you would change in a performance situation, like a cam with overlap, or the different reversion characteristics of headers vs. stock manifolds, or even maybe different intake manifold design, then there would be a timing vs. rpm table. Or timing vs. rpm vs. ect.
    2000 GMC 2500 2-bar SD
    Stock LM7, LTs, TBSS intake manifold

  19. #59
    Senior Tuner LSxpwrdZ's Avatar
    Join Date
    Dec 2008
    Location
    on the Dyno
    Posts
    1,825
    Once you get past a certain rpm it doesn't really matter when it's injected anyway aspecially if your running higher duty cycles. Remember 100% duty cycle means the injectors are held open, which means 1 cycle or 100% is 720*. So if your running a targeted 80% duty cycle there is only 20% dead time there to move around and it's not gonna matter really where that is.

    Under around 3000rpm is the only benefit to this unless your running 160#+ size injectors that have a really low pulsewidth until boost or something else comes in. I don't see there being huge power gains if any by adjusting these values however it will greatly increase driveability and tame alot of bucking and fuel smell.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  20. #60
    Advanced Tuner
    Join Date
    Jul 2008
    Location
    Louisville, KY
    Posts
    417
    Quote Originally Posted by LSxpwrdZ View Post
    Once you get past a certain rpm it doesn't really matter when it's injected anyway aspecially if your running higher duty cycles. Remember 100% duty cycle means the injectors are held open, which means 1 cycle or 100% is 720*. So if your running a targeted 80% duty cycle there is only 20% dead time there to move around and it's not gonna matter really where that is.

    Under around 3000rpm is the only benefit to this unless your running 160#+ size injectors that have a really low pulsewidth until boost or something else comes in. I don't see there being huge power gains if any by adjusting these values however it will greatly increase driveability and tame alot of bucking and fuel smell.
    That seems like a valid point.

    Sarge