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Jeremy Towers

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Everything posted by Jeremy Towers

  1. Jeremy Towers


    Thanks Simon That's fair enough. I am pretty happy with my MAP tune. I think I may have found a bug in the MAF flow values. Either that or I am having a brain fade. I am logging Mass air flow in grams/sec and also grams/cylinder. The values for grams/cylinder look incorrect, so I have calculated grams/cylinder as follows. From a point on my log, mass flow = 57.8 grams/sec. My engine speed was 2372 rpm = 39.53 revs per second. The Mass/revolution should be 57.8/39.53 = 1.462 grams/rev. Engine is a V8 so mass/cylinder = 1.462/4 =0.366 However the PC log shows grams/rev(x100) as 72.4 (or 0.724 grams/rev). The mass/cylinder(x100) = 18.2 (or 0.182). Both these values seem to be half what they should be when compared to the raw flow in grams/sec. Could someone have a look at this for me please? Unfortunately my log file was too big to upload. Thanks,Jeremy
  2. Jeremy Towers


    Hello I am just in the process of wiring a MAF sensor to my G4 Xtreme. The engine is already tuned for speed density, but I wish to use gram/cyl on my ignition table to help tune spark advance. It will help me find the relationship between MAF and MAP for my engine. It seems that I can achieve this, but I have noticed one serious limitation. The MAF is calibrated using a standard cal table on the G4. Given that the table only has a resolution of 16 entries (with fixed increments), it is almost impossible to both have adequate resolution in the low flow ranges and at the same time measure up to maximum flow. There is a very noticeable error between 0 gram/sec and the next value. Although I can manipulate the values for my experiment, it seems that for someone wanting to do a full MAF tune on their engine, it would be virtually impossible to get a MAF translation that is anywhere near accurate over the full flow range. So am I missing something here? Is there a more accurate table available for the MAF? Maybe in the G4+ ? . I understand that most people won't be using a MAF to measure engine load, but it might be a bad idea for those that do.  Jeremy
  3. Thanks Kelly. So it's not just me. I do load maps a lot. It's because I use logs to correct the fuel table etc when the ECU is off line. Having knock control turn off after loading a pcl file is certainly not what anyone could call a safety feature! Perhaps Link could fix this one. Jeremy
  4. Hi I am running a silver G4 Xtreme using internal knock control. I seem to be getting valid knock readings when the system is working. The problem is that every time I load a saved pcl file from my laptop the knock control turns itself off. It can take several attempts and stores to switch it back on again. Can you suggest what might be causing this? Also, on the 'knock setup' page there is an entry for 'Freq' and 'Gain', then lower down there are two more entries with the same names. Are there two lots of filters? Can you clarify that? thanks. Maybe my settings are causing the problem above. I am running PCLink and Firmware. Knock sensors are the standard LS2 ones. Cheers, Jeremy
  5. Hi Ashley I hear what you are saying, but I still think it's a good idea. A lot of other functions in your PCLink/ECU also require a higher level of understanding, but not all users have to implement them. Most high performance V8 engines have the O2 sensors at the collectors. That is some distance from the engine, so O2 data is always delayed. As far as 'actual' delay goes, I can see and measure the delay in mS between a throttle position change and an O2 response in the logged data. It is just frustrating that I can't compensate for it! Jeremy
  6. I have been pretty successful tuning my engine with a Wideband O2 sensor and data logging on the G4. No Dyno There is one hitch though that messes up my logged results. That is LAG from the wideband sensor. Is there any provision for entering Wideband sensor Delay when analysing data? Even a single delay time entry would improve accuracy a lot for road or track tuning. A 3D table would be awesome. Maybe it is possible now to edit the log file in Excel by shifting all the Wideband data by the delay time, then loading it back into PCLink? But that sounds like hard work. I know the Vipec guys use 'Mixture Map' and I am sure a method of correcting the errors from wideband delay would make that tuning tool WAY more accurate. Your thoughts or suggestions please. Jeremy
  7. Awesome Dan. Just what I was looking for! Cheers, Jeremy
  8. Ok. I fixed it by upgrading the Firmware also to V4.9.8 Thanks
  9. Hi I have the original Link G4 Xtreme with Internal knock sensing etc. My knock sensing used to work ok but at some point (Firmware upgrade?) it turned itself off. Everytime I try to turn knock sensing on the ECU/ PCLink turns it back off. I have been using V4.9.7 and V4.9.8 software. Both have the same problem. Please Help me get my knock sensing working again. Jeremy
  10. I think it might be 78 degrees, but my timing light will answer that. Thanks
  11. That's great news, thanks Dave Any idea what the trigger offset should be for the LS2? Link? Jeremy
  12. Hi I have a Holden L76/LS2 motor which has been running VERY successfully with a Link G4 Xtreme. The engine runs a 58 tooth crank wheel and 4x cam sprocket. It is also set up for sequential injection. I am just in the process of changing the cam and timing set. Unfortunately the new timing set has an old style 1x (50/50) cam sprocket . My question is can I possibly reconfigure the Link's triggering to run with the 1x cam sprocket instead of the 4x sprocket? and still run sequential injection? Thanks, Jeremy
  13. Thanks Scott. But those are time consuming/expensive solutions for me or anyone else who finds this problem in the future. There is nothing special about the standard Tremec/GM speed sensor in the gearbox. I did do a test on a spare DI and maximum frequency readable by the G4 is around 1600Hz. This corresponds to my 180km/h. I don't see anywhere in the manual that it mentions this frequency as a maximum though. I can guess the limitation is due to DI sampling speed or digital noise filtering in the G4. Is there any chance of updating the code so it is compatible with these newer transmissions (higher pulse speeds)?? or is there a hardware limitation?  Thanks, Jeremy
  14. Hi I am having an issue logging vehicle speed above 180kph (Log file attached) I have a Link G4 Xtreme picking up vehicle speed from an electronic sensor in my T56 Tremec gearbox. During drag runs my car exceeds 180kph but my logging won't show any speed above 180kph. Given that the speed it fails is always exactly 180kph I suspect it is a software or setup issue. I just noticed that my speed limit (although disabled) has an rpm setting of 180kph. That might be a red herring though. Any thoughts on how to fix this? Thanks, Jeremy drag2.llg
  15. Thanks Scott Yes, I mean damaged by me. If the layout gets messed up while I am modifying it, the only way to undo the changes is to reload the layout. But unfortunately that is not possible as explained above. Your suggestion for a check box or possibly a prompt would solve the problem.
  16. I have set up a custom 'Layout' in PCLink which displays all the things I need to tune and monitor my engine. I have had some frustration with managing the different versions of this layout page as it has developed, and I have just figured out why. There are a couple of features (or bugs) in the program which you may be able to confirm for me. 1/ On exiting PCLink the current Layout is automatically saved? 2/ When opening a new Layout the current layout is automatically saved before opening the new one?? If these are both true then it makes managing layouts a Total nightmare. For example if a Layout gets damaged while running PCLink then the only option is to save the damaged Layout over the top of the good one. Even if a new layout is opened the corrupted one will be saved first without so much as a prompt. So there is no way to protect the original layout. This feature? might be useful for people who always forget to save their work, but it is also a sure fire way to mess up a whole lot of layouts. Can you confirm the above? Thanks
  17. Great explanation. So even with MGP on the load axis the ECU is using absolute pressure (MAP) for the basis of fuel corrections. The advantage is that MGP better identifies the correct cell (VE) on the fuel table if the altitude (air pressure) changes. The assumption is that VE does not change with altitude (air pressure), and hence that VE variations with load are caused by changes in throttle position rather than changes in manifold pressure. I hope I got that right. Thanks
  18. I guess this has been mentioned before. It would be great to select which parameters are logged by the ECU. For instance, I am logging my wideband O2 values with 'Closed loop Lambda' correction running. So I need logged data for % Fuel correction, but it is not logged by the ECU ??
  19. Thanks for clearing that up. Great info. I have taken your advice and changed to "IGN Cut" for now. Perhaps some kind of progressive cut which cuts both fuel and ignition to given cylinders might be even better. Maybe one for the future? Jeremy
  20. I am hoping someone can tell me how the RPM limit works in progressive "Fuel Cut" mode. I recently activated my RPM limit on this setting and noticed a puff of white smoke form my exhaust which I would normally associate with detonation. A leaning of the mixture at full throttle sounds dangerous to me. Does the ECU cut fuel completely to certain cylinders? The explanation in the help menu is rather... limited, so hopefully someone can elaborate. My engine is running with sequential injection by the way. Thanks Jeremy
  21. Hi Matt If your calibration number is 191 and at 227kph your speed is reading 330kph then alter your cal number to - 191 x (330 / 227) = 277.7  The full calculation for a speed sensor mounted on the gearbox tailshaft. CAL# = pulses per 100m = (Pulses per revolution x 100 x Diff ratio (eg 3.7) ) / wheel Diameter(m) x Pi  For example with 0.7m diameter tyre, 3.7:1 Diff, 4 pulses per revolution sensor CAL# = (4 x 100 x 3.7) / (0.7 x 3.1416) = 673 (pulses per 100m)  You will need to know the pulses per rev from your gearbox though. Google might be the best bet. It is always a round number though.  Jeremy
  22. Thanks for the offer of help Dave. I actually had some sucess increasing the Clamp table, but sadly now I have damaged my differential, so further tuning is on hold for a while. Regards, Jeremy
  23. Hi guys. I have just completed tuning the fuel maps on my L76 Holden V8 engine. Logs from my wideband sensor show maximum +-0.5 AFR errors. I have some issues with throttle response. Using the default accel settings, the response to small throttle changes is good if not a little touchy. However under heavy throttle gearchanges, the engine initially responds but then bogs  before coming right. It feels like the enrichment is ending too soon. My wideband AFR (for what it's worth) logs seem to confirm this more or less. The engine uses an electronic throttle which is working fine. Looking at the settings, should I be increasing the values in the 'clamp table'? Do the settings in this table also alter the response to small throttle changes ?, or is that solely set by the 'accel sens'? Your advice would be great. Thanks Jeremy Towers Â
  24. Thanks for the tips guys. I imagine using both methods will get it close.
  25. Hi. I am running a Holden L76 V8 with G4 Xtreme. I didn't seem to be able to find 'Injector dead time' info for the 40lb/hr used on this engine, so I have just used data for a Bosch injector for now. I have seen with some other ECU's dead time can be measured by changing the firing rate, then adjusting dead time value so that there is no change in Lambda readings between different rates. Can I do this on the G4 by changing to 'group fire' mode then making adjustments whilst switching the 'injection rate' between 360deg and 720deg? I realise it would only be applicable for one voltage cell. What do you think? Thanks Jeremy Towers
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