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Post by highpockets on Dec 26, 2010 17:39:50 GMT -7
First,let me start by saying I have NO professional experience tuning street cars and do NOT do these for a living(tuning) That said,I also know there are several members who DO tune and have more experience as well as experience with different platforms( DSM comes to mind here ?) that may chime in as well.I will however attempt to answer some questions posted regarding tuning my car as well as different programming setups. For starters,there are several Programs that allow you to modify the stock LS PCM as well as custom OS to allow you control of boosted/ open loop/MAF less type setups should you want/choose to do so. Probably the most common(at least for the DIY) would be a "canned" tune or programmer such as Predator/Superchips and the like.These offer a known good(but safe) tune based on common mods done to our cars.You can also get mail order tunes done by sending in your PCM for even more adjustments/specific requests/setups.Once again,the mail order ones are based on known good tunes performed usually in house on a dyno with a like setup.NOW,with that out of the way,we come to more specialized or "custom" tunes.I will go ahead and use my car as an example. Most street tuned LS series cars run closed loop/MAF based tunes for all around drivability/emissions friendly and little upkeep(tuning adj due to weather variation/altitude and such) The most popular tuning software for this seems to be HPtuners and EFI Live,with various other programs avail(LS1 edit comes to mind)On mine I am using HPtuners to adjust/modify my tune as well as allow me to run a custom OS as I noted before that gives me the ability to tune more accurately while under boost(at least to 2BAR)This is also avail with EFI Live,and obviously alot of aftermarket setups,FAST,BigStuff3 and others come to mind.On my car I am running a stand alone O2 feedback based NOS controller as well as an electronic boost controller which are both setup/programmed independently of the Engine PCM. I DO however LOG WBO2 as well as Fuel pressure and boost on my car with the aux inputs avail from the HP tuners Pro interface.You can also do this using by writing a custom PID and logging from the unused EGR circuit as well. OK,enough for now,that should get you started,let me know where you want to go from here and either I or hopefully Nick will chime in and see if we can answer your questions ! ;D I will update this periodically with additional info and perhaps some screenshots from my laptop if that will help.
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Post by zr6sbc on Dec 27, 2010 18:52:59 GMT -7
Thanks for the information and the new thread. This is a totally honest question but I think it's going to sound odd . Sorry in advance. Compared with your setup, why/how can the LS9 engine run with the single tune and use the MAF? For godzilla and an LS9, what are the redlines? wheel HP? Boost PSI?
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Post by highpockets on Dec 28, 2010 0:16:15 GMT -7
Thanks for the information and the new thread. This is a totally honest question but I think it's going to sound odd . Sorry in advance. Compared with your setup, why/how can the LS9 engine run with the single tune and use the MAF? For godzilla and an LS9, what are the redlines? wheel HP? Boost PSI? I believe you have several actual reasons.First,the card style MAF,as well as the 08 up computers,which will allow more resolution/flow in a given sq in area(MAF tube),thus allowing a certain amount of boost before MAF fail(flow exceeded) mine,with stock Z06 MAF,fails around 8psi I think. second,obviously GM is limiting the boost on the LS9 from the factory. Tuners are suggesting up to 15 psi on a properly scaled LS9 MAF with the newer computers.I know some running a 4" tube with the LS3/LS7 MAF on our older (Pre E38) style computers,I should probably try this on mine.HPtuners offers extended MAF tables as well in the new 2.5BAR tune for these cars(newer ones) As for redlines,my car is set(personal preference) at 6800 RPM,shift at 64-6600 usually.Power with the cam I am running flatlines about 6500,car has made 797/920 at the wheels on 16psi,NO meth,conservative timing. I have run as high as 21 psi on the dyno,the 4-bolt style heads start to lift(seep coolant) at about this level unless EVERYTHING is perfect(fuel/timing/coolant temp) The stock LS9 redline by comparison is 6600,making factory claimed 638HP at the flywheel at 10.5 psi factory boost setting. All in all,a truly impressive setup right from the factory with a warranty and very nice daily driving/all around manners.
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Post by kyrosnick on Dec 28, 2010 8:47:17 GMT -7
I'll have to download a zr1 tune later and look at it just for fun.
Like Vince said, the newer card style MAFs with a large inlet pipe can be tuned to pretty high airflow levels. Even at 550rwhp my car barely sees 9300Hz and it goes up to 13500Hz without doing any tricks to extend that table.
LS9s make 540-560rwhp. With tune/headers/pulley they can make a solid 620-630rwhp. The newer cars use the MAF and Map sensor in a hybrid mode. Most of the time once you get past ~4000 rpms the cars are MAF only. At lower RPMs air turbulance and fast throttle transistions can cause some MAF reading issues so they use the hybrid mode to fix this. A lot of LS tuners disable this. My car runs MAF only. I've got mail order tunes from LG and Quality Motorsports and both of them like to run MAF only on E38 and newer cars.
Since I got my HP tuners in March I've done 2006 z06 2006 z06 2007 z06 2000 C5 2000 z28 2002 z28 2007 G8 GT 2008 Silverado 1500 2005 GTO 2004 GTO
All I've got out of doing all these cars is the one guy with the Z28 brought me dinner for my time.
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Post by zr6sbc on Dec 28, 2010 18:58:58 GMT -7
This is a good discussion.
Sounds like common MAF sensors are flow rate limited and/or the controller can't deal with the low load versus high load requirements. Guessing that the high flow MAFs have poor resolution at low flow rates which warrants the hybrid control.
Since OEM controllers can run in speed density mode, how do they compare to aftermarket units runnings speed density? Do they have more or less map resolutions than an XFI FAST?
I've read that wideband O2s under boost loose accuracy. Would you use closed loop wideband control under high loads or open loop?
I'm still searching for the tripping point that would make someone strip out the OEM controller for an aftermarket unit.
Is anyone else here benefiting from this thread as much as me?
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Post by highpockets on Dec 28, 2010 21:24:10 GMT -7
I think there are several reasons to go aftermarket. As you pointed out,integrated WB input,NOS control,Larger/stronger injector drivers for HUGE injectors,multiple integrated 2-3 step control,integrated downloadable built in scan/logging data,SD,MAFless,hybrid the possibilities are nearly endless. I think probably the big determining factor for most is #1 Retain full OEM integration/street car #2 Custom setup,duel fuel ,maybe(E85),high boost,crank trigger,multiple NOS, or a more RACE oriented,less ,shall we say,able to pass OBD2 testing currently required on most 96-up cars on the road today.
As for the WB controller question,on my car and most I have observed,resolution is not necessarily lost under boost,however you may find you need to increase counts or "hits" per sec by reducing unwanted PIDs being recorded/monitored to allow a reasonable average # of "hits" per cell while tuning under boost. For instance,on an average(for my car) ten sec pass,the car is in boost roughly 9.4 sec,and obviously because I shift(stick) it goes up and down the boost scale(map). Typically,when I look at the data points after my run,I see hits in the boost cells in the 20-30 cts range based on these runs,with more counts near the peak and off boost levels and relatively few hits in the sweep up the curve.I typically log multiple runs,average the +/- the cell count(referring to either rich/or lean and make slight changes depending on past experience as well as how far out of line the car is compared to the weather that day/night.
Usually I find once the car is dialed in,assuming I dont lose a O2 sensor,foul a plug(havent yet) develop a boost leak(yep,ask Izabel about that one) or kill the clutch(talk about throwaway data) I keep the tune relatively close. I usually try to adj boost only,via the Blitz EBC rather than multiple reflashes as it sometimes takes a couple min to "relearn" idle control and idle fuel trims.
As far as resolution on aftermarket systems,I think on our scale,or perhaps average street car/street track( NOT Pro/Pro stock or the like) the systems we are talking are relatively similar as far as size/resolution on the MAP/MAF/ PE/VE and Spark tables. I know for instance on my car I have at least3 spark tables I deal with normally and some have four(typically idle spark in/out of gear) and High octane(or low octane) spark tables. You would also have Idle spark A/C on both in and out of gear making a total of 6 adj spark tables on some models. The MAF tables are a little different and I hope Nick will join in as he has played more with the E38 C6 type computers which run a different style Maf as we talked about earlier.While I find them less friendly to tune,I suspect its more because my lack of experience. As for the Accel,Wayne should chime in(maybe even Ross or Mark) as Wayne is running a Gen7 in his car. I know a member on the Musclecar board is running a stand alone FAST with seperate inj driver box on a stroked big single turbo car but it just BARELY hit the road so his initial tuning impressions have not been posted.
I also know another member posted his continual issues with a twin turbo 502(or larger ) BBC Camaro running a Megasquirt I believe.The car was very unrepeatable as far as drivability or so it seemed but DID put down some big power before a fuel/oil leak caused an untimely demise to his project. Hope this has helped,I will try to find out some details on MAP tables with different setups as I too am curious about this,good questions !
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Post by highpockets on Dec 28, 2010 21:28:23 GMT -7
Here are some details on the BS3 for comparison sake,I will add a post with highlights of several other systems as well.
* Sequential fuel control for 4, 6, 8, 10, 12 and 16 cylinders * Capable of driving 16 low impedance injectors Stage! * Dual wide band O2 sensors for individual bank, closed loop fuel control * 128k RAM for internal data logging 40 user selectable channels, 10bit resolution, 50Hz acquisition rate * Capable of driving smart and dumb Coil On Plug (COP) ignitions with stock sensors (LS1, Mod 4.6L) with current feedback and tach output * Individual cylinder fuel and timing control * Injector phasing, at the start or end of injection event * Programmable peak and hold injectors drivers with current chopping * Software configurable ignition interface (GM HEI, Ford TFI, LT1,V6 DIS, IPU) * GM or Ford IAC control * Controls GM 4L80E/4L60E transmission (optional) * V10 Viper version coming soon! * Additional data logging capabilities: o Fuel pressure A/C on Turbo shaft RPM o Drive shaft RPM Input shaft RPM MPH o Clutch or trans brake input Brake pedal TCC % Slip * Auxiliary control of: o Fuel pump o 2 spare high side & low side outputs o Torque converter clutch o 1 spare PWM high side & low side output o 2 or 3 stage boost control o Reverse lockout o Fan Hi - Fan Low * Configurable Load & RPM axis to enable optimization in desired range * Improved EMI algorithms * True Speed-Density algorithm allows for easier tuning * Closed loop PID WBO2 heater control to insure accurate AFR control * Self learning capabilities * Improved transient fueling algorithms * 1, 2, 3 & 5 BAR MAP sensor compatible * Seamless decel fuel cut-off
The BigStuff3 GEN3 PRO SEFI system is the first programmable powertrain control module for todays SEFI, Coil-on-Plug (COP) engines and electronic controlled transmissions. The GEN3 PRO SEFI system offers many unique features that sets it apart from the competition. Features such as dual Wide Band Oxygen (WB02) air/fuel ratio control, individual cylinder & spark compensation and on-board data acquisition are just the beginning!
The optional dual WBO2 functionality eliminates left and right bank base engine and transient fuel calibration guess work by providing accurate and consistent air/fuel ratio control (9.5:1 to 15.9:1). The individual cylinder fuel and spark compensation allows intake manifold inefficiencies to be calibrated out. The on-board data acquisition feature allows selected powertrain management variables to be recorded in real-time as fast as 50 times a second, with 10-bit resolution, for up to 5.5 minutes. Once recorded, the data can be analyzed off-line with the BigComm software.These features, along with many others, make the GEN3 PRO SEFI system the most technologically advanced, cost effective SEFI powertrain management system on the market.
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Post by highpockets on Dec 28, 2010 21:39:43 GMT -7
Now,just to throw a wrench into this discussion,I am looking into the possibilities of logging wheel speed data vs. dr speed data,perhaps log one of the front wheel speed sensors and one rear.This would show me how much wheelspin off the line,how much if any during shifting as well as if the fronts are locking(even partially) while stopping at the end of the track(see Marks thread on safety of 10sec cars) I know on the autos you can log turbine input speed/output speed as well as wheel speed to check for converter slip/trans slip in gear(kinda cool huh ?) I also monitor my IAT (intake air temp) to verify proper actuation of the Meth system(regularly see intake temps UNDER 100 deg F ) at the END of my runs in the summer !!! I have it setup to pull timing in the event intake temps do NOT drop under boost/load in order to prevent detonation.I have moved the sensor on my car,just downstream of the twin METH nozzles so that the reaction time is relatively quick.I also monitor the meth system with its own low level warning light and progressive LED pump actuation light.
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Post by kyrosnick on Dec 29, 2010 8:44:02 GMT -7
"Sounds like common MAF sensors are flow rate limited and/or the controller can't deal with the low load versus high load requirements. Guessing that the high flow MAFs have poor resolution at low flow rates which warrants the hybrid control. "
Not exactly. MAF sensors just can't react as fast. When you blip the throttle and go from a low air flow to a higher fast, there is a small delay. That is why the hybrid systems help with low RPM throttle response. The maf can read accurately low airflow, just can't react quickly to quick throttle transistions as well as a map sensor.
Aftermarket systems vary so much it is hard to compare to them. Some have great resolution others do not. Some nice things I've seen that the aftermarket provides is real time tuning (can be done with HPtuners with some ECUs and extra credits to unlock it), input/outputs, and one of the coolest newer features would be flex fuel.
I remember in Arizona we used a switched output on an AEM box to turn on some neon underbody lights we installed on my friends car. When he hit 4500 RPMs they would turn on. It was months before he found it.
I've seen some supras using proefi boxes with ethanol sensors in them. Amazing setups. Saw a supra dyno 650rwhp on 91octance. Then drive down and fill up with e85. Drives back to the dyno, puts it back on and made 1040rwhp. The proefi used a ethanol sensor to dectect the ammount of ethanol and adjusted boost/fuel/timing automatically. That was a sweet setup.
As for when to switch from a stock ECU to aftermaket. I don't think any of us are close to that. The stock GM ecus are good and have great resolution and control. I couldn't see it being worth it to swap unless your building a race car and need some of the features that aren't offered with a factory ecu. You can make 1000-1200rwhp easy enough with the factory ecu.
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Post by 500hp406 on Dec 29, 2010 9:10:02 GMT -7
I have a accel system and once you reach a certian point in the learning curve, it is a very nice system. I moved up from OBD1 to the Gen 7 and I am running a dual snyc distributar with sequential fueling, and a wide band. I now have the car running better than it ran when new. If you are running a street car and have OBD 2 I would not make the move to an after market system. The MAF in my car new did not work right and the car never ran right, so I made the change, only to find out that the As-shole that instlled it had never installed one before, yes, It was the TAS boys and Brent told me that he was a certified Accel installer.. 4 years later I have replace most of what I could find and the car now runs great. The Gen 7 system with the harware upgrades does most of what the big stuff does, but the BS contoller is very fast. The data logging is great and simple to use, tune on the go, fan control, torque converter contol, and much more. Now that I know a little more than when I started, I like it. If you are not educated in how the A/F and VE and ignition, and how all have to have to work together, and which to change and when, then a stand alone system will overwhelm you. Because there is not a Acell installer here I was lucky enough to run into Doug Herzog Motor Sports in St Louis, and He inturn gave me Eli's phone number in Wis. Eli is the Guru for Accel and he has spent a good amount of time educating me, and all of a sudden the lights went on, and I was able to understand it. I must at this time give credit where credit is due to Ross, (very smart cookie) who is always there to answer questions and spend time with me.. At this point in time I would say I am happy with the Gen 7, a giant step over OBD 1. The Gen 7 has more features than OBD 2 but I could not say it was better, but has features like launch control, boost control, and such. But for those who would like to move up from OBD 1, the learning curve is steep and frustrating, find an installer and a tuner, Los Vegas, St Louis, Portland, your going to have to travel.
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Post by ebm86vette on Dec 29, 2010 13:33:17 GMT -7
All I've got out of doing all these cars is the one guy with the Z28 brought me dinner for my time. I make more changing import timing belts than I do tuning. Come to think of it, I make more doing nothing than I do tuning.
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Post by kyrosnick on Dec 29, 2010 13:41:04 GMT -7
Exactly. No one wants to pay for it. I just help people I know, coworkers, and friends.
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Post by zr6sbc on Dec 29, 2010 17:34:07 GMT -7
Who's up for round 2? Tuning your ECU.
With the old Gen 6 and little cash on hand, outside of 14.7:1, I did the seat of the pants tuning while on the street. Yikes not the best situation.
From my reads, the best way seems to be on a step dyno, where one can achieve steady state in a give MAP vs RPM cell. At numerous cells, correct the VE's throughout the table (except full load). Clean up the table. Extrapolate the full load cells. Make a full load pass and revise the full load tables.
Interestingly, the book I read pointed out that there isn't much power to be had by perfecting the A/F. Power is in the timing.
So, again onto the step dyno, the engine is held on a given MAP vs RPM cell and the timing is adjusted to achieve maximum torque through out the table while avoiding detonation.
Sounds like a lot $ of dyno time.
How did you tune your controller?
Where the best deal on step dyno access?
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Post by highpockets on Dec 29, 2010 20:53:16 GMT -7
Cheapest dyno around(tuning wise is JC up in Ogden.Most here know him as well as how to get in touch.The Turbo cars might like Karl at AP performance( I think thats right?) on about 7800 S state as he has experience with boosted cars as well as having a Mustang dyno to provide load for tuning IN boost instead of blowing right past the boost levels you are looking for. As for timing vs. Fuel and dyno gains,my car at sub 10/9.8 AFRs makes approx 150-170 HP LESS at the wheels than running at a conservative 11.2 AFR with NO timing changes !Same boost levels,back to back runs. I think Snowman can chime in on his NA car but I know he saw gains as well with the AFR properly adjusted.I think Nick saw some nice gains as well but I am not sure how much he played with timing. Its the combination,it HAS to be right if you want the big numbers(or conversely SMALL numbers at the strip !) That said,MOST part throttle tuning can be carefully done with several street dyno sessions being logged and data extrapolated into the tune(assuming NO RTT) Making the changes on the street and reflashing then driving again makes a nice comparison,if the tune is WAY off,you can make a huge difference and see the results quite quickly,thus limiting the time spent on the dyno for WOT adjustments and some RTT adjustments to the timing to see if the gains are worth it(NOT usually on an LS engine in my exp )
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Post by zr6sbc on Dec 30, 2010 8:02:05 GMT -7
Can JC's dyno maintain wheel speed under different engine loads?
What is RTT?
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