Clarkey Posted February 28, 2006 Share Posted February 28, 2006 Hi all, Would someone mind taking a look at these traces - that I've collect from my RLTC. Matt H did my install - firstly we having issues with one wheel sensor seeing 140 and the others seeing 60 or 70. Which was causing violent fuel cut. Since then, all I've done is get Terminator to double check my DAT file & did the calibration with the dongle. This data is in KPH from the RTLC. What I'm curious is why the rear wheels are about 5 or 6 KPH faster than the fronts ones. My understand is they were supposed to be the same-ish maybe .. plus/minus 1 or 2. Now - it appears to me the RLTC is working correctly, as I can feel and see the fuel cut occuring on my AFR gauge .. when set to DRY and going around roundabouts at a leisurely pace. Any comments welcome! Thanks.RLTC TRACE.zip Link to comment Share on other sites More sharing options...
JohnA Posted February 28, 2006 Share Posted February 28, 2006 Just a thought --- have you fitted oddly-sized wheels/tyres back or front? Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Just a thought --- have you fitted oddly-sized wheels/tyres back or front? On the fronts are 235/40/R17 On the rears are 265/40/R17 Matt H suggested might be an idea to tell RLTC the rears are 255. What do you think ? Link to comment Share on other sites More sharing options...
JohnA Posted February 28, 2006 Share Posted February 28, 2006 On the fronts are 235/40/R17 On the rears are 265/40/R17 stock is: F: 235/45-17 R: 255/40-17 So you have the fronts with a smaller diameter than stock and the rears with larger diameter than stock. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 stock is: F: 235/45-17 R: 255/40-17 So you have the fronts with a smaller diameter than stock and the rears with larger diameter than stock. Yes ... it would appear so. I thought the only difference apart from stock was the rear tyre size. But - would that explain the 5mph gap between the rears & fronts according to these traces ? And if so, is this causing a negative effect ? And if so, apart from: Getting some stock wheels & getting new tyres ... is there anything that can be done to put these numbers in line .. Link to comment Share on other sites More sharing options...
JohnA Posted February 28, 2006 Share Posted February 28, 2006 You could calculate the diameter differences and tell RLTC accordingly. Or you could try setting a smaller size for the fronts and see if it brings it within spec. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Only have time to do one run. This was wheel settings: Front: 235/40/R17 Rear: 255/40/R17 I'll play around with the wheel settings on the fronts later. Is this causing a major issue ? What's the impact of the different wheel speeds ? Link to comment Share on other sites More sharing options...
LeeT Posted February 28, 2006 Share Posted February 28, 2006 Phil would have set up your DAT file with the tyre sizes that you gave him. Link to comment Share on other sites More sharing options...
TLicense Posted February 28, 2006 Share Posted February 28, 2006 Are the different colours the different wheel speeds? Have you got an LSD? Just that you seem to have whatever wheel is the blue one going much faster than all the rest Link to comment Share on other sites More sharing options...
weinelm Posted February 28, 2006 Share Posted February 28, 2006 Hmm. Looks odd to me. The only thing that would affect this in the DAT file is the wheel diameter (calculated from tyre size in the RLTC config software) and the pulses per revolution settings (which I believe should be set to 48 all round for the Supra). If your DAT file is right, then maybe it is a problem with the actual sensors or the toothed rotors they pick up from at the hubs? Although then you might see ABS problems? Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Phil would have set up your DAT file with the tyre sizes that you gave him. He did. And those size tyres are on the car and are now in my RLTC dat - I updated it. But my question of why & how different wheel sizes to stock would cause this ... -which John raised- .. is still open. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Are the different colours the different wheel speeds? No. The different colours signify - which wheel. Have you got an LSD? Yes Just that you seem to have whatever wheel is the blue one going much faster than all the rest The blue is RPM. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Hmm. Looks odd to me. The only thing that would affect this in the DAT file is the wheel diameter (calculated from tyre size in the RLTC config software) and the pulses per revolution settings (which I believe should be set to 48 all round for the Supra). Yes the pulses are 48 all round. If your DAT file is right, then maybe it is a problem with the actual sensors or the toothed rotors they pick up from at the hubs? Although then you might see ABS problems? Hmmmm ... on startup the ABS light comes on - then goes off. I've never seen it flash on when braking hard. Here is my DAT file. I've renamed the extenstion to .doc just to attach it. But does anyone know if this inconsistancy in wheel speed ... the fronts being aprox 5mph slower than the rears .. is going to cause issues ? IE - Stopping RLTC from doing it's job. Should I be worried that my RLTC isn't working ?myRLTC_DAT.doc Link to comment Share on other sites More sharing options...
TLicense Posted February 28, 2006 Share Posted February 28, 2006 No. The different colours signify - which wheel. Yes The blue is RPM. That's what I meant. - I thought for one moment you were either single wheel spinning, (if you had no LSD) or that the unit wasn't sensing wheel speeds right. But it's RPM so that's cool. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 that the unit wasn't sensing wheel speeds right If you look at the data in the Excel sheet, the maximum I've noticed is about 10KPH faster than the fronts. Sometimes it's only 6-7 KPH. Is it possible that the signal from the ECU to the RLTC of the rears is suffering degradation in the same as RF does when you have a 10ft cable .. you start with 10dBm .. and may end up with 7dBm ? I think the proper test is to get someone to testdrive the car, who already has RLTC fitted .. so knows how it operates. Link to comment Share on other sites More sharing options...
TLicense Posted February 28, 2006 Share Posted February 28, 2006 Nah I was looking at the graph you posted. Still if it's RPM not wheel speed then not a problem. Is it consistant and is it scaling? ie. is it a %age more than the rears or just a constant offset. Wouldn't have thought it would be a signal degredation issue. Link to comment Share on other sites More sharing options...
Clarkey Posted February 28, 2006 Author Share Posted February 28, 2006 Looking at the data in the Excel & the JPEG, it seems to be consistantly between 6-10 KPH difference between the wheels. Looking at the data - there are no spikes. Link to comment Share on other sites More sharing options...
weinelm Posted March 1, 2006 Share Posted March 1, 2006 But does anyone know if this inconsistancy in wheel speed ... the fronts being aprox 5mph slower than the rears .. is going to cause issues ? IE - Stopping RLTC from doing it's job. Should I be worried that my RLTC isn't working ? I wouldn't have thought the system would be working to well. I've had a look at the DAT and your graphs and I can't really work it out. I did wonder whether the calibration has worked and that the right channels are allocated to the right wheels? You could jack up the car, spin the wheels one at a time and check that they are allocated correctly. Link to comment Share on other sites More sharing options...
Clarkey Posted March 2, 2006 Author Share Posted March 2, 2006 Thanks for all the comments guys. Posted this up - just incase someone else has the similar problem. It was exactly as Matt H said. I resized the rear wheels in the RLTC - and kept playing with the numbers. I resized the rears to 245/40/R17... now the speed difference between the fronts & rears are now about 2 KPH. On the real-time trace with the laptop - All 4 traces are pretty much inline. Link to comment Share on other sites More sharing options...
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