THOR Racing

It just so happens I've built my own AFR and injector duty cycle monitor. I fitted it at the weekend and observed the following (please note that I'm using the stock O2 sensor and that I'm fully aware that it cannot take accurate reading above or below stochiometric AFR or 14.7 or 1 lambda. But it does indicate a general RICH or LEAN car.) Here goes..... this is on a NON VVTi car so I'm shocked that Ash is saying the VVTi is so different. anyway... The top row of LED's is injector duty cycle. I connected one of the injector control lines from the ECU to it. The bottom row of LED's is the AFR. If you start the car from cold the indicator will show LEAN. This is normal, the sensor is not warmed up yet. Gradually as the engine warms up the indicator will rise to RICH and then gradually start to pulse (Knight Rider style) up and down between RICH and LEAN. This is the closed loop response from the ECU. It's cycling the fueling to adjust the AFR to 14.7 which is 1 Lambda or Stochiometric. This is the ideal AFR. You'll also notice the injector LED is at the lowest position, one or maybe two LED's lit. If you now drive the car you'll see the pulsing get faster or if you accelerate faster you'll see when the ECU switches between CLOSED loop to OPEN loop. In OPEN loop mode the ECU does not use the O2 sensor for fueling as it's sensing the MAP pressur sensor. However the O2 sensor still senses changes in AFR. You'll see the AFR shoot towards RICH. You'll also see the injector duty rise as it delivers more fuel to your engine. Now under the worst conditions of hard acceleration the following will happen. You stick you foot down, the boost builds and you start to fly. You'll also notice that the AFR is reading steady (ish) around RICH and the Inj duty is showing probably about 80->90%. In the very very worst conditions where you are getting into trouble the inj duty cycle will rise to over 95%, ALL LED's on the top row are lit. The AFR should still read RICH! BUT if you've pushed the boost too high or the engine is NOT getting enough fuel the AFR will fall to LEAN. This is VERY BAD and detonation is sure to occur v.v.soon. At the end of the day so long as the AFR never falls to LEAN or below STOCH you'll be O.K. I think, but Ash is saying on the VVTi this happens just above Fuel Cut. Wow! I was running 1.2Kg/cm2 and the AFR never budged from full on RICH. If you notice that the Inj Duty is running hard at 95+% then maybe it's about time to invest in some bigger injectors which a few people have done. Fitting a Wideband O2 sensor close to the existing O2 sensor in the downpipe will mean the display will now read something more sensible. Essentially the stock sensors are really only any good around 14.7 (1 Lambda), taking any meaningful measurements above and below this mid point only really serves to indicate RICH or LEAN. A wideband sensor will indicate a larger range correctly. This would certainly explain a lot regarding the VVTi fuel cut scenario and why the non-VVTi NEVER has a problem! Nice one Ash. What to do about it though? Did you measure the injector duty cycle at all? Regards Pete

>TRL - chip aint much to look at but as you say i'm sure it would >look good when its boxed and actually has an LED display ! Ummm! I beg to differ. It has got LED's! They are all surface mount (see the second picture on that page) and will be viewed through a translucent window in the box. This way i can have a range of stickers that mount over the top to have bars, dots, triangles, increment bar (like on a volume knob) So I think it'll actually look better than just a row of round LED's sticking out of the top of a box. But you'll see this when I actually get it finished. Pete

Hey! No I hadn't spotted that. Good idea :-)))

Well TRL Performance to the rescue :-))) >My main concerns are the boost guages (i cannot find an >LED one rather than a dial) Check out the development of my AFRi. This has two rows of LED's, currently used to display Air/Fuel Ratio and the other to display injector duty cycle. But in the end it's just a microprocessor, an analogue to digital converter and two rows of LED's! I can program it for pretty much anything and display anything I can sample with the A/D chip. So given some more time to finish the development this would be a LED style boost guage. How does that sound? Check out http://www.trlperformance.com/afri.html Obviously it'll be in a box and stuff eventually. But you get the idea. Currently it's size is 100mm*50mm, but this maybe subject to change depending on available enclosures. Regards Pete

check out htpp:/www.trlperformance.com/supra and click on the Active Spoiler link in the useful bits section. Should explain a lot. Normally operation starts at 56MPH (90KPH) and Jap cars are the same. It's just when the speedo gets converted from KPH to MPH most importers cock this up and you end up with a spoiler that has an operational range scaled by 8/5ths as well. (due to the 5/8ths conversion of the speed signal) Pete ps. There's a lot of info on my pages about many things, always worth a look.

It could become a product but it'll be down on the list as I've got the AFR i (Air Fuel Ratio and Injector Duty Cycle meter) and TDU (Temp Display Unit) to finish first. Pete

I suppose you could modify the O2 sensor output to fool the ECU into running leaner than it should do at a particular RPM. It wouldn't be the FCD as this is used only on boost and during normal opertaion it is the O2 sensor that controls fueling. In OPEN LOOP control the ECU uses the MAP sensor (or MAF) to calc fueling etc etc, and this is when accelerating. In CLOSED LOOP control the ECU uses the O2 sensor to calc fueling. It tries to maintain the stochiometric air fuel ratio of 14.7. It does this by richening and leaning the fuel periodically to maintain an average of 14.7. This is obsereved by viewing an air fuel ratio device and watch the LED's (or what ever display it has) go up and down about every second. This is when at a constant RPM (cruising etc) and would thus be the area to tackle for the MOT. I've already considered this but I'd have to be careful not to lean it too much. Pete

Did you take any digital pictures Paul? They could be used to form an article or give better help next time. I have some as you've seen. Pete

>Pete can i just fit a set of Justin's dials and one of your speed >converters ???? Yes this is an alternative. It was just if you were stuck you could get the standard dials real cheap. I think Justin's dials are around the £100 mark and Aroo was thinking of asking £30. But yes. If you fit a replacement dial (whichever you choose) that now reads up to 180mph then you'll need a speed converter unit. Of course I'd like you to buy one of mine but again any conversion box would do. This is your choice. http://www.trlperformance.com/dsc.html Pete

Ooops! Sorry about that. That should have gone in the FOR SALE section. Please ignore this thread and reply to the thread under FOR SALE. Again, sorry. Did it without even thinking as the technical section is normally the only one I look at. Pete

TRL Performance now have Braided hoses in stock for the Mkiii & Mkiv Supras Nickel or chrome fitments with silver Twined Braded Hosing. £59.95 + vat nickel Full Set Fronts & Rears £64.95 + vat chrome Full Set Fronts & Rears They are not up on the web site yet, but you can order if you send TRL an email or go to http://www.trlperformance.com/contact.html Pictures and specs up soon. Regards Pete ps. These match the Goodridge equivalents.

Aroo's just emailed me. His address is [email protected] I've asked if he still wants the old dials or is willing to give them away or sell to someone. Pete

contact Aroo (Justin has his details, I've lost them) I fitted some white dials to his car last night and removed the old speedo dials. These were the stock Jap ones and read up to 180MPH (180KPH but the KPH is covered with a MPH sticker) So this would easily solve the problem, and I'm sure he's sell them cheap. We seem to keep repeating this speedo thing over and over again. Why's it not in an FAQ or something? Pete Pete

Info for this mod can be found at... http://www.trlperformance.com/supra or direct at http://homepage.ntlworld.com/peter.betts/supra/TechTips/injectors.htm Pete

>Pete, can you build me a Death Star please... No. But I can breath deeply (in a Vader stylie) if that'll help ? The old site is due for a revamp but like everything else it just takes time. It hasn't really changed much since I did it about 2 years ago. But most of the info is still spot on and up to date.

Note that KYB AGX's are NOT available in the UK so any dealer advertising adjustable KYB shocks mean the standard gas adjustable. These differ in price and method of adjustment. i.e. the AGX's are adjustable via a small screw in the top of the strut. How much for the KYB's in total? Price.. £115 each ....total =£460....... N.B ..Koni adjustables(Fensport) £118 each ..total =£472 and these need to be removed from the car to be adjusted..... The other KYB adjustables come from places like Fensport known as "self adjusting shocks", (Gas-A-Just) £55 each.....They dont have any adjustment on them,and the ride was crap on Darrell's car...... The KYB AGX shocks have the dial on the top of the shock to alter the damping force.Check www.kyb.com/shocks2.html for more info.... Kayaba UK dont stock KYB AGX shocks ,only available from japan or the US.. Regards Pete

In summary I'd say. Removing the CAT's decreases the spool up time of the turbos and hence the car feels more nimble. Also reduces the exhaust gas temperature as there is less restrictive material in the way of the exhaust gases. Both good things in my opinion. BUT this will put your CO levels to about 0.5% but the MOT says 0.3% You might be lucky and get away with it but with a "friendly" MOT guy you'll have no problem. If you have problems, just pop the second CAT back on, get your MOT and then take it straight off again. Your local exhaust dealer would do this for about a tenner cash in hand. Pete ps any more detail can be found in the archives.

Thanks for the links and comments. I'll try and do it without removing the needles first. Pete

I've agreed to change someones speedo/gague dials over from the stock ones to the white units that Justin sells. However! I think this is going to be a nightmare to do and wish I nevber said yes now. Would I be right in saying I have to remove the needle from each dial, remove the base pin (the thing the needle rest on when stationary) Peel off the old dial face and replace with the new dial face. Then replace the needle and pin. But getting the needle back again in exactly the same place seems to be a tricky thing to do and time consuming? Putting it back and then going for a drive. See what the error in the needle is and then trying to adjust it bit by bit. I'm thinking I not going to have an easy time of it at 6pm in the dark (and probably wet) with a torch? Anybody help or done this before? Pete

For those who have never visited my web pages... This is my car and loads of info on the Supra MkIV. http://www.trlperformance.com/supra/ This is my company for stuff for your MkIV http://www.trlperformance.com Pete

Just a little note to say that I've just fitted some KYB AGX adjustable shocks over some Eibach springs. The ride is much lower and the look of the car is great but driving is more tiring. The ride is harder even on the soft setting but the car really sticks to the road now. http://homepage.ntlworld.com/peter.betts/supra/TechTips/kyb1.jpg http://homepage.ntlworld.com/peter.betts/supra/TechTips/kyb2.jpg http://homepage.ntlworld.com/peter.betts/supra/TechTips/kyb3.jpg http://homepage.ntlworld.com/peter.betts/supra/TechTips/kyb4.jpg Take your pick. Pete

Not wanting to go against the grain here. I'm actually going to point you to a few pieces of help. http://www.trlperformance.com/dsc.html http://homepage.ntlworld.com/peter.betts/supra/TechTips/speedo.htm watch out for the page http://homepage.ntlworld.com/peter.betts/supra/TechTips/oddetail.htm (This is the page that's caused so much hassle over the last few days) Sorry but there is nothing specific for the HKS SLD only my TRL DSC (Digital Speed Converter) but the basic principles apply. The extra wires on the Auto version of the HKS SLD are really a waste of time in my opinion but we won't go into details. Regards Pete http://www.trlperformance.com