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.
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
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
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
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
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
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 -
http://www.hptuners.com/forum/showpo...97&postcount=1
Both are in the 1st post
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.
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.
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
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....
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.
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
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