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About Redracn

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    Ferry's Protegé

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    991.2 GT3,997 TurboS, Cayman R

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  1. Yep corrosion is one of the reasons along with the use of loctite. Surface oxidation of aluminium is a really good insulator as is loctite. Then there is also the technical issue of shared current paths of signal and high current devices including ignition coils and the radio frequency and DC from them being injected straight into the ground cct of the sensors for the ECU to read. Single wire sensors were simply NEVER EVER going to work. Running excessively rich until it warms right up is very bad news. Cylinder wash down is real. I have seen race teams use no coolant sensor but they properly warmed the engine with external sources before starting.
  2. The primary use of coolant temp is for engine warm up. Oil Temp is way to slow to rise and is a poor proxy for the engine temperature. Far better to use head temperature and do it reliably. Also with head temperature corrections can be applied to improve engine performance and protection that can not be done using oil temperature.
  3. Yep replace the bolt with one that has an integrated sensor.
  4. Yea I have fond memories of the carby on my rotax powered KTM600 dirt bike icing up after a long blast at WOT. Kill switch became my best friend. Yours is a good situation as you have tapped into the alloy rubber to head transition piece. With the O ring seal not hindering heat transfer from the head and the rubber isolating the ITB and runner from it it would be difficult to improve upon other than some thermal transfer paste on the adapter flange. Amazing how much difference some thermal transfer paste makes when between two flat surfaces.
  5. A reasonable solution might be to drill down the bolt from the top and put a small NTC thermistor a few mm from the tip and bond it in with a thermally conductive epoxy. You could also only drill the bolt with a smaller hole for the wires and mount the sensor past the tip and fill the cavity in the head with thermal paste. If you when for a thermocouple a 1.5mm drill would do. Perhaps something like this could double as the mount bolt. Seems to be lots of sources. https://www.bosch-motorsport.com/content/downloads/Raceparts/en-GB/58273931119693579.html#/Tabs=58279435/ https://www.msel.co.nz/epages/motorsportelectronics.sf/en_AU/?ObjectPath=/Shops/motorsportelectronics/Products/SENTEMSSM6
  6. First thing I would do is check the calibration of the sensor in the ECU and if any doubt a simple and easy field test is an ice slushy for 0C and boiling water for 100C. Its hard to tell from the picture but it looks like the sensor is on top of the bracket? Is the sensor itself mounted further up the what looks like an electrical eyelet? I wouldn’t mount an ECT sensor on an ITB as the temp there is also a function of airflow especially if an insulation spacer is used and you also have the issue of the fuel standoff in the runner causing substantial cooling in the inlet tract. Runners and ITB can become quite cold when flat out and quite hot when stopped due to heat soak.. The temperature of the cooling fin is also a function of the rpm so while better than an ITB still far from ideal. If you can mount the sensor under the bracket and direct to the head and use an insulating washer between the sensor and the bracket would be a good improvement as would some thermal transfer paste between the sensor and the head. The idea is to get as much heat to the sensor while not having other items such as the bracket drain it away. A lot of cars have thermal insulation washers/spacers on the fuel rails.
  7. I didn’t mean to scare anybody. I was just pointing out some issues with Lambda measurements. Where you measure the mixture matters especially if all the cylinders(injectors including fuel rail resonance) are not identical. You could put in individual sensors for each cylinder but often they are close to the engine and the mixture is not fully burnt at this point so readings can be leaner than reality. Or put in multiple sensors around the pipe to get an average. But in the end unless you are racing all this is not necessary to have a reliable engine that performs well. That’s why fuel settings are usually set conservatively. Engines are surprisingly tolerant of mixture variations. Measurements after turbos tend to give a good average , measurements before turbos can overheat the Lambda sensors giving incorrect readings and shortening their life. When tuning race engines on an engine dyno the mixture is adjusted for maximum torque and the resulting Lambda recorded so that the same mixture can be set when doing the final tuning at the track. Reality is you have 6 x 1 cylinder engines that are interconnected in various ways and interact with each other. While we would like them all to be identical that is never the case. The challenge is of course to get them as close as possible and then tune each one individually within the limitations of the tools available. Glad to see you have the sensors angled from 2 to 4 (clock face) as that is the best angle. With them right next to the vbands you need to ensure that the vbands absolutely do not leak and are perfectly sealed. Yes air can be drawn back up the exhaust. When doing tailpipe measurements you want the pickup at least 500mm into the pipe. Yep close enough to have a bias to one of the cylinders.
  8. Some more hopefully useful info regarding Lambda measurements. Back in the early 90’s when I was designing my first Lambda Meter we did extensive testing of the sensor location in the exhaust. What we discovered is that the exhaust gas flow from a cylinder after say a 4 to 1 would not fill the entire pipe but remain as a smaller diameter flow in the larger pipe. It could also spiral along the bigger pipe. This means that often the lambda sensor if placed within a meter of the collector will mainly read the lambda of a single cylinder and not necessarily the one you think based on any spiralling which can also change with rpm and load. So without seeing the installation it is highly likely that the so called “ Bank “ sensors are actually mainly reading the lambda of individual cylinders.
  9. Yep some improvements. For the next run get on the throttle very slowly to reduce the accel enrichment used or disable it all together it certainly seems to be excessive and holds on for a long time. There should be a channel you can log that shows the amount of additional fuel the accel function is supplying. So before going any further you need to sort out the ECT (head temp) so that there is no compensation being applied at normal operating temperature. As it stands you will need to add 5% (or whatever is at 39c in the table) to the entire fuel table after fixing head temp to get back to where you are. Also check all other compensations such as IAT and MAP etc. Are the injectors a matched set or have you had them flowed? While ideally each bank should be identical it is seldom the case. A quick check of throttle blade angles and linkages as they progress to full throttle. A quick compression test would be good just to confirm no issues otherwise it is what it is. Worst case you should be able to tune each bank individually. After that if you are chasing the absolute most the engine can make is individual cylinder tuning. 😁
  10. While the CHT reading is obviously bogas the Lambda reading from the latest video did look ok. Would be better to graph both left and right banks and not the average as that can hide issues related to the setup of each bank. Auto tune functions can be helpful in certain limited situations but often require more effort to setup and monitor than just doing the job. They are also of no use in overrun situations or any situation that the possibility of a misfire exists or with bigger cams. .i.e. All air that enters the engine must be fully and completely combusted before it reaches the lambda sensor. So as others have said leave it off for now but certainly read up on it and give it a go in the future.
  11. I’m pretty sure that the screen shot doesn’t show the ECT fuelling table. Looks to me like throttle drive by wire and idle tables. Is the engine using Electronic Throttle Control aka Drive By Wire? I also see a “mixture map” menu at the top of the screen. Click on that and see what you get.
  12. Given the discrepancy between Peter M head temps which are correct and the very unrealistic ones from Harry it would pay to look into this further. Before proceeding it also needs to be established if the ECT table has been modified to reflect the low readings or is it still setup for water cooled or real head temps otherwise it could be still supplying cold running enrichment which is very bad from a tuning perspective.
  13. What Peter is doing is correct. Work out the %error in lambda and apply that to the fuel number at that point. It assumes that the injector latency is properly calibrated but if it is not that is not usually a big issue for full throttle. New_fuel_num = old_fuel_num x actual_lambda / target_lambda. If everything is perfect the new fuel will be spot on but there are usually some errors so a couple of passes are required. As you are targeting a very safe 0.81 rather than the 0.85 to 0.88 that I would be targeting I wouldn’t worry about the size of the changes required as they are reasonable.
  14. Hi MFX It is also not advisable to turn the lambda sensors off when driving. Best to remove them from the exhaust if not being powered and properly controlled by a sensor amplifier. If you have turned off closed loop control then as long as the exhaust has no air leaks such as wrong direction slip joints (or v bands that aren’t perfectly sealed prior to the sensor and the engine is not misfiring then the reading should be good so any fluctuations would most likely be real. Could be a lot of reasons such as fuel rail resonance (dampers are available and fitted to a lot of cars) . Misfires make the lambda sensors read leaner than reality. Yep best to learn the software and tuning fundamentals before getting into it as you can waste a lot of time and do damage going in blind. Welding in the Vband has changed the flow path particularly along the exhaust pipe walls and any change in diameter (cross section area) or disruption is generally bad for the flow. Not saying this IS an issue but it has to be on the list of possibilities if you are chasing peak power otherwise ignore and enjoy.
  15. I haven’t been following this but here I am thanks to Peter. I have only reviewed the last couple of pages so feel free to correct any assumptions I make. The videos are great a lot of effort must go into each one and the result looks fantastic a lot of quality work there and on the car. Dyno Power: Not something I would be too worried about given the time between runs or at all unless you are competing. If concerned about the engine check compression, do a leak down and if really concerned get the oil tested. A couple of notes. The air/exhaust extraction on that chassis dyno looks a bit sus especially for an engine with its intake so close to the rear. Even the slightest contamination of the intake air with exhaust fumes is bad news for power production. Difference could just be the wind direction at the time. Given the time between runs there is so much that can be different not only atmospheric conditions, tying down etc but work done on the engine etc. just removing and replacing the crank sensor and/or its bracket can easily alter the ignition timing. Rule IV) Always check the ignition timing always. What seems like a small inconsequential change like exhaust connections can have a surprisingly large effect. Now if I only had a $ for every time someone told me nothing was changed. Head temp is good as long as the tables are modified to suit. Oil is way to slow to warm up. I don’t like the clamp on a fin or similar design. Good head temp is right on the head (not cooling fins) and thermally bonded using a thermal transfer compound. If a clamp must be used then it should be thermally bonded to the fin and preferably insulated from the cooling air flow. I just saw that closed loop lambda is off which is best while tuning the efficiency(Fuel) tables. It can be on if it is known that it is working well and tracking the required lambda but then you need to use the fueling offset it applied at any given point to modify the efficiency table. Some ECU can self learn the efficiency table but I don’t think the Link is one of them. It is best if the tables and various corrections get the lambda to within +-5% of what is required before letting closed loop lambda operate especially given the lambda sensor is the most unreliable sensor in the car. Logging if it isn’t already should be your best friend and a must when tuning and looking for issues. There are many more I items I would add such as lambda error(difference between what you want and what it is) or the target lambda so the analysis can show it and the error calculated, lambda correction (if in closed loop). Unless you are chasing emissions compliance it is best to delay turning on the lambda sensor heater for 30 seconds or more after engine start to ensure no liquid water in the exhaust it’s a real sensor killer. Pro Tip: when displaying logged data turn off the channel auto scaling. Showing lambda from 0 to 10.0 is a complete waste. Manual scale it 0.70 to 1.2. Same for temperatures etc that way you will always see everything on the same scale (apples with apples) each time you load logged data and can quickly at a glance see any issues. Books can and have been written on this stuff and still not covered it all.

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