Thursday, April 06, 2006 - 05:21 pm, by: Peter Taplin(Mrfourwd)
Thanks Roger thats a lot of information to digest, quick question have you gleaned this info via observation or from tech bulletins etc.. I have not at this point with my vehicle attempted any fuel curve adjustments, I have relied so far on the rising rate reg to provide some extra fuel on boost, the injectors are running at about 85% at full noise 7000rpm, and some black smoke is evident in the rear view mirror so I am presuming it is rich enough at this point, When it goes in for the Dyno I will pass on the information and get them to leave the mixtures alone from about 5" to full boost this should put it outside the closed loop points you have mentioned. The SMT6 does have the ability to modify the signal to the ECU from the oxy sensor, I shall read up on this function as from what you have said if we can control the voltage the ecu see's we should be able to perform air mixture adjustments and fool the ecu into thinking it is still within factory specs... I am just not sure if the SMT6 in the mode that is required to tune the 1UZFE can perfom this function as well.. Thanks again for great info
Thursday, April 06, 2006 - 06:43 pm, by: Anish Varsani(Yomama)
Peter, according to the guy from perfect power, only the SMT6D (the version sold to dealers who want to put their own name on the unit and lock the map) allows lambda tuning, the standard SMT6 supposedly only monitors the lambda for display purposes. Having said that, if there's a spare analog out, there's no reason it can't be done.
I'm in the middle of wiring the unit in. I ran out of lugs half way through.
For anyone else installing the unit themselves, go to BigW or Kmart and get some wire splices (piercing connectors) connectors to splice and connect wires. It's easier than lugs or soldering and you don't have to cut the existing wires.
You might want to use male and female crimp lugs to connect the SMT6 in so it's easy to remove and reverse the wirings mods if you every have to make an insurance claim.
David Vaughan Goo Roo ACT UZZ31 V8 manual and Lexus IS300
Thursday, April 06, 2006 - 06:58 pm, by: Roger Costello(Roger)
Peter
Most of the information is from Toyota Tech Bulletins and direct observation while trying out various techniques to adjust mixture and timing on a UZZ31.
To clarify, it is not a problem to adjust the mixture when the engine is in open loop mode as the ECU is "blind" to air fuel ratios in open loop. You can and probably should adjust it from about half throttle up to full boost.
From what I have seen the V8's are running in closed loop at cruising speeds unless you are towing a caravan or going uphill. You have to be well above 110 Km/h to get into open loop operation at a steady speed. Once you reach about half throttle the engine changes to open loop mode.
I would have a good look on the dyno for throttle and rpm points where the air/fuel ratio changes from around 14/1 to about 12/1 or less (10/1 at some points!). The change is quite abrupt and easy to see. Monitoring the factory oxygen sensors with a suitable instrument will also help as they will go from a roughly 50% duty cycle oscillation in closed loop to flat-lined in open loop.
With a supercharged UZZ31 you may need all the enrichment the standard maps provide and then some at full throttle around 3-4000 rpm. For a normally aspirated engine there is merit in reducing the fuel slightly during open loop operation. This can improve power and economy providing you are using Premium Unleaded or preferably a 98 Octane fuel.
Adjusting ignition timing together with fuel trim can produce significant gains in maximum power, more than 10% would be a realistic expectation compared to an unmodified car. To achieve this you are trimming some of the safety margins out of the engine management system, but providing you stick to 98 Octane the risks are not great.
Ignition timing has more effect on how responsive the engine feels compared to trimming the mixture. Some choices also have to be made on the balance between maximum economy and maximum power as they require different air fuel ratios.
Keep in mind once you tune it with a piggyback ECU for maximum performance using 98 Octane it will be a complete bush pig if you run it on regular unleaded.
Finally do not use seat of the pants feel or how the engine sounds (other than pinging) for adjusting ignition timing or fuel. Maximum performance is often deceptively smoother rather than sounding and feeling more powerful. I have seen people with hand tuned engines that had far too much advance and over rich mixtures to compensate that felt "powerful" when driven but actually had poorer performance than when running at the factory settings.
Thursday, April 06, 2006 - 09:20 pm, by: Mark Paddick(Sparks)
What he said ^^ with knobs on!!! I refuse to work on cars that have them used in any of the wiring unless that work involves removing them and doing it properly.
Thursday, April 06, 2006 - 10:03 pm, by: Roger Costello(Roger)
Scotch Locks are good for some purposes. They are excellent moisture detectors, vibration monitors and one of the few methods even more dodgy than twisting the bare ends together and wrapping the mess with masking tape. They are the connection of choice for unreliable mobile phone car kits, constantly misbehaving alarm systems and shoddy stereo installs. Using them on any connection that could stop the engine from running is potentially suicidal. Do you want to rely on a connector design known to have failed millions of times as you accelerate out of the path of an oncoming truck.
Peter Taplin Tinkerer Vic UZZ32 V8 Supercharged & UZZ32 V8 NA
Friday, April 07, 2006 - 07:13 am, by: Peter Taplin(Mrfourwd)
Anish
Have you set the global setting on the SMT6 yet? if not this will be why it is misbehaving.. Under Modes set to Mode 10 Under Ignition Set to 12 Teeth per turn and 3 Teeth per firing Set input polarity to either on or off I am using off at the moment seems to make no difference Cylinders to 8 of Course
Friday, April 07, 2006 - 08:42 am, by: Anish Varsani(Yomama)
Will do it tonight. Getting USB to serial adapter today. The unit is getting power. Once it's working I'll draw up the connections I used and post it up.
I didn't bother hooking up the 02 sensor since they are narrow band.
Just have to run the MAP change wire out to a switch. Might leave MAP B empty for the time being in case the car drives like a dog on normal fuel after the tune with 98RON.
Saturday, April 08, 2006 - 02:27 pm, by: Roger Costello(Roger)
A bit of background on fuel adjustment setup with the SMT6. For a 1UZFE with the OEM Karman Vortex AFM (91 on) set the “Global Settings", "System Config" "High frequency" disabled (“OFF”) The frequency range of the Soarer Karman Vortex Sensor is around 15 to 300 hz and the SMT6 has two ranges for frequency based sensors, high frequency "OFF" is for 10-3.3kHz and "ON" is for 80-18kHz. If you set it to ON it will result in flat fuel at low loads. If you have one of the very late model V8's with a different AFM ignore this as I don't have any specifications for those sensors.
Saturday, April 08, 2006 - 06:41 pm, by: Anish Varsani(Yomama)
I put the ignition map in and went for a drive. The car was stalling at randomly at low load and low rpm. I got an engine electics error code after one of the stalls. I had a look at the crank signal on a CRO it looks like a magnetic type sensor output. It's swinging upto 8V at idle. I've got the input level set to high so the trigger level is 4V.
Saturday, April 08, 2006 - 06:55 pm, by: Roger Costello(Roger)
Anish
Hi, check the white blue frequency output on the SMT6, it could be a problem with the setup for the AFM sensor. It should be between 15 and 30Hz at idle depending on A/C and engine temperature. If it is not there or intermittent you would get the symptoms you are experiencing. The ECU will go into partial limp mode and estimate airflow based on throttle position and rpm but unless the throttle position sensor is perfectly adjusted and working like new it runs fairly cr*p at low throttle openings.
Saturday, April 08, 2006 - 07:26 pm, by: Anish Varsani(Yomama)
I put in a zero map and it worked fine. I had added a few degrees into Peter's original map for low deflection and RPM where it was 0. Must have had to much advance.
Sunday, April 09, 2006 - 03:01 am, by: Roger Costello(Roger)
I do not want to encourage people to try tuning timing and fuel without a dyno and a wide band lambda sensor. It is inevitable that the temptation to try will be too strong for some so keep the following in mind. This is not intended as an aid to tuning, just a warning that fuel and ignition maps are directly interrelated.
The rate of combustion is affected by the air fuel ratio. Under most circumstances for air fuel ratios between 12/1 and 16/1 the richer the mixture the faster it burns. At low RPM this is not very important but at full throttle high RPM it is critical. As you reduce fuel the timing needs to be advanced to compensate for slower combustion. If you don't do this you will not get peak combustion pressure at the right crank angle, consequently fuel efficiency and power will suffer.
The chances of a very bad thing happening like holes in pistons also increases as you lean out the mixture past 12.5/1 at full RPM and full throttle. 12.5/1 is usually close to maximum torque on a 1UZFE. If for example you reduced the fuel from 12/1 to 15/1 at 5000 rpm wide open throttle you will need to advance timing a lot to compensate for the slower combustion. In some cases more than the SMT6 can adjust it. Adding fuel is similar to advancing the ignition timing in how it affects the crank angle at which peak combustion chamber pressure occurs.
Adding fuel beyond 12.5/1 normally reduces power output but is sometimes done to enable a practical spark advance angle at high RPM. Adding fuel also keeps things cooler and reduces the possibility of pinging, unlike advancing the ignition timing which generally gets the combustion chamber hotter and makes pinging more likely. Balancing the two to get maximum power without grief is best done on a dyno with an accurate wide band oxygen sensor and someone who is experienced and understands what is going on in the combustion chamber.
Just because someone has a dyno in the workshop does not mean they know what they are doing. Do not choose on the basis of the first workshop that can fit you in. Ask around and be fussy. If you get a good result make sure they provide a copy of the maps and post them, along with a full description of all the modifications, ECU version etc.
Every car should end up with different maps. Small differences in sensors, fuel systems and exhausts will change the optimum settings. Deciding the balance between economy, responsiveness and maximum power also means different approaches in the settings. By all means use someone's setup that worked well as a base to start from, but fine tune it for your car. If you have the time install a switch and use the dual maps facility to chose economy or performance. Alternatively tune it separately for 98 RON and whatever you have to fill up with in the bush.
Finally, as you enjoy the extra power and/or economy that come from optimally exploding the the refined essence of rotting dinosaurs remember that having achieved all these gains by removing some of the conservative safety margins that were put into the ECU by our clever cousins across the sea, you now need to maintain the thing properly.