Scottie-GNZ Posted March 27, 2001 Share Posted March 27, 2001 Hey, I resemble that remark This is the log from the 11.20 run. Let me help clarify what you are looking at. I am displaying 5 parameters, labeled in the top-left corner. The vertical line is a point in time and that point is on the bottom of page - 2.85 secs and 154' into the run. The value of each parameter at this point is on the top-right corner, so the Speed=61, RPMs=5125 at the top of 2nd gear, etc. The numbers on the right of the box is the value range of that parameter. The large font on the right are critical parameters that are always displayed and do not correspond to the "box" next to it. There are 14 displayable parameters and by continually pressing the 1 key e.g., I can make the top box display any of the 14. At the bottom-right of the screen you see the update rate=18.2 frames per sec and pressing the L/R arrow keys move the vertical line 1 frame at a time. With an 11.2 sec 1/4-mile, do the math and you can see how many frames I have to look at. So, at this point in time, the car is doing 61mph and it took 2.85 secs and 154. There is so much info there I could write a book on just this pass, but I will touch on a few. Notice how fast the RPMs ramp up in 1st and how quickly the 1-2 and 2-3 shifts happen. If I had bad wheelspin or tranny slippage, it could be seen in how the RPMs ramp up. Something nasty happened to the fueling at the top of 1st and the O2s went wacky and spiked down to about 550 and the chip reacted by backing out some timing. I showed this to the chip maker and he said "oh yeah, I can fix that". Oookay. You will also notice that the O2s are at 839 and there are some points where it is even higher, but as load increased, it started coming down. That is what I am referring to when I say it ran rich. My target O2s is 780mV at the top of 3rd. About halfway through 3rd the RPMs flatten out for a moment and that is me locking up the converter, a little late. Now for the top-end problem. Notice the nice sharp angles on the RPM bar at the first 2 shift points, then notice that the 3-4 has a hump and the RPMs are a little higher. I lock the converter by pressing and holding a button on the shift knob (yes Jim, the red eject button). That drops the RPMs a tad and I spend more time in 3rd building boost. What I am trying to do is make the 3-4 shift and unlock the converter at the same time to raise the RPMs and limit the RPM drop but the shifter hung up and I released the button. This caused the RPMs to shoot up to 5650 and the chip backed out a massive amount of timing, 9.5* to be exact. The impact can be seen in the Speed as the car just died and stopped accelerating which is why the MPH was only 117.95. The same information can be displayed in a Text and a Dial mode. In those modes all the parameters are displayed and the Dial mode looks like a dash where the key parameters are in a dial guage. Lots more info there but harder to read as you scroll the frames. For some reason I cannot do Print Screen on those. It is hard to say just how much quicker the car could have gone if it was a "perfect" run, but I can tell you when the chip backs out timing you can feel it. Enjoy. ------------------ Scottie 71 240GN-Z Scottie's GNZ [This message has been edited by Scottie-GNZ (edited March 27, 2001).] Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted March 28, 2001 Share Posted March 28, 2001 I guess I resemble that too! That's cool stuff Scottie. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted March 28, 2001 Share Posted March 28, 2001 *drool* more more more!! I love it. Maybe I should have sprung for datalogging. Feel free to edjumicate us some more Scottie. ------------------ Richard Lewis - 1972 240z, Powered by a Nissan 2.8L Turbo Inline 6. Drax240's Turbo Site Beginners Turbo FAQ & Answers Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 28, 2001 Share Posted March 28, 2001 Yea-too cool! (Addict Here!) Scottie, Question; what is the knock sensor sensing, doesnt this also tell the puter to retard timing? When you say "rich" do you know what a normal patter for O2's should look like from idle thru a full 1/4mile run; do you have a base pattern from someone else's datalogger...& I know you cant compare apples to oranges-but you have to have a base to compare/what is good-bad? Where can anyone go to for Dyno printouts of a GN engine? I've always been curious as to the engines peak HP/Torque points. Hey if you're already well in to 3rd/5100 rpm's w/in a couple sec's...you definatley need different gears as I can see how you run out of cam by the end of the 1/4 & have to shift into o-drive.....man/what a bummer! However; You are definately booking! Kevin, (Yes,Still a "Non-Datalogger/Non-Turbo" Inliner) [This message has been edited by Kevin Shasteen (edited March 27, 2001).] Quote Link to comment Share on other sites More sharing options...
pparaska Posted March 28, 2001 Share Posted March 28, 2001 Scottie, you have the ultimate gear head/computer geek tool there. I want one! Just to be able to play with all the cool datalogging/tuning is a big reason I want programable EFI - just for the fun of it. 0-61 in 2.85, 11.20s. I need to get down your way somehow and get a ride! Quote Link to comment Share on other sites More sharing options...
Drax240z Posted March 28, 2001 Share Posted March 28, 2001 Kevin, I think I can help you a bit. The "normal" pattern for O2's... Well its like this. Scottie says his target is 780mV, which I am assuming is very close to stoichiametric air/fuel ratio. You make the most power when you are running on the ragged edge of pinging... Obviously this would leave no room for error or fluctuation at all. Right now the higher O2 readings are due to Scottie being cautious I am sure. "normal" or "ideal" O2's for a 1/4 mile run should be a straight line I believe. Really not too much to see. This would give you maximum power at every RPM. In theory. Tuning the car that accurately is the hard part! A knock sensor, senses detonation. And yes, this immediately tells the computer to retard timing. How much in Scotties situation, I don't know. I think Scottie mentioned that he was still getting fuel pressure fluctuations once in a while, which was why he was running extra rich. Just to avoid meltdown if his fuel pressure suddenly dropped, and there was a lean situation occuring. At full throttle, lean & pinging, you'd probably have about a second before your pistons were melted. A bit longer for hypereutectic and forged pistons. (like 3 or 4 seconds) Tuning is soooo important!! (as I am sure you have noticed) PS: If I'm wrong on anything here, correct me please. I'm not sure whether stoich is where max power is produced or not? Anyone? ------------------ Richard Lewis - 1972 240z, Powered by a Nissan 2.8L Turbo Inline 6. Drax240's Turbo Site Beginners Turbo FAQ & Answers [This message has been edited by Drax240z (edited March 27, 2001).] Quote Link to comment Share on other sites More sharing options...
clint78z Posted March 28, 2001 Share Posted March 28, 2001 I will talk a bit about A/F ratios and O2 readings. First stoichiometric ratio is 14.7:1 for gasoline, it gives complete combustion of gases and gives the best emmisions. Typically 500mv on the O2 sensor. Running leaner 15:1 and up gives good gas milage,the engine runs hot and can give bad emmisions. This is lean cruise typically 499mv-0mv reading. 499mv being above 14.7:1 and 0mv even higher. The numbers cannot be transfered to exact ratios. Running rich 14.6 and below O2 readings are 501mv-1000mv. No exact ratios can be had from O2 readings . Ok heres why Scottie tunes for 780mv, with a ton of experience of the GN guys they have determined for that exact motor that 780mv is the best number to tune to. This will probably give a A/F ratio of 13-12:1 which is the safest and produces the most power on that particular motor. Using a wide band O2 sensor would be ideal, but Scotties way is a very educated guess on A/F ratio. Quote Link to comment Share on other sites More sharing options...
Kevin Shasteen Posted March 29, 2001 Share Posted March 29, 2001 Very Educational "Gentlemen" & I use that term loosely....so dont get offended to easily. Scottie; why did the TPS & O2's flatline; any insight/thoughts? BTW: We, (& I think I speak for the rest of us) are awaiting the next printouts to be discussed! Kevin, (Yes,Still an Inliner) Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted March 29, 2001 Author Share Posted March 29, 2001 Kevin, the TPS (throttle position sensor) tells the computer how much the throttle blade is opened. In my case, WOT is 4.60 and you can see I had it to the wood. But, if you look at the TPS and RPM before the car got moving, you can see what went on during spoolup. OK, OK, you cannot see, I have to tell you . Right above the "R" in Retard, the other car tripped his 1st light and I engage the transbrake and cracked the throttle about halfway open to bring the boost up. Where you see the TPS flatten out means I am holding the boost at 7# while the lights come down and the rest is obvious. As for the O2s, I will be happy when they flatline. Sleepless in Bethesda ------------------ Scottie 71 240GN-Z Scottie's GNZ Quote Link to comment Share on other sites More sharing options...
TimZ Posted March 29, 2001 Share Posted March 29, 2001 Scottie - I'd be interested to see what the manifold air temps are doing. Normally, I'd expect to see them climb as the run went on, but it's possible that since you were staging with the engine on boost, with very little airflow through the intercooler, the manifold air temps might actually come down as the car builds speed and starts cooling the intake charge more efficiently. This might explain the change in AFRs - if no corrections are done for MAT, then cooler air will run leaner. Also, I'd be interested to see your manifold pressure (are you using speed density or MAF?). Might not be anything useful the see there, but just curious... Quote Link to comment Share on other sites More sharing options...
RPMS Posted March 29, 2001 Share Posted March 29, 2001 Heya, Scottie, I'm sure this is in here somewhere, but in my cold-medicine-befuddled state, I can't find it. What engine management system are you using? I assume to get this sort of precision with your datalogging, it can't be stock. ------------------ Scott Ferguson 1976 260-Z, surrounded by an ever-growing cloud of V8 parts... Quote Link to comment Share on other sites More sharing options...
clint78z Posted March 29, 2001 Share Posted March 29, 2001 Yes it's a stock GM ECU, they just use a serial connection to laptop. Too bad nissan didn't have the support like this. The program is Direct Scan, and I believe he has a tuner chip as well. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted March 30, 2001 Author Share Posted March 30, 2001 Tim, the MAT data on the Buick is useless because it is measured at the MAF which of course is before the turbo inlet. I thought about adding MAT capability, but after closely monitoring it with the L28T and NPR combo, I have enough faith in the NPR that it is not a priority. The datalogger was developed by an engineer who is a Buick turbo enthusiast and does it on the side. We have been pleading with him for sometime to add a MAP sensor and log boost. It sure would be nice to see boost, inj PW, O2s and timing all together. Right now I just grab glances at the boost gauge in 3rd. The chip I am using is revolutionary in the Buick turbo world but FAR from a programmable system like SDS or TEC. E.g., I can switch between street and race timing but do not have control of the timing curve. I can change fuel for cold start, idle, cruise, spoolup, 0-4000RPMs and WOT, but again with no granularity. ------------------ Scottie 71 240GN-Z Scottie's GNZ Quote Link to comment Share on other sites More sharing options...
TimZ Posted March 30, 2001 Share Posted March 30, 2001 Scottie... That's fine - since it's a MAF system, theoretically the MAT shouldn't effect your mixture, since it's the same air that the MAF measured before it got compressed. It's definitely a worry with speed-density, though. Also, I wasn't questioning the effectivness of the NPR - just the opposite. I was theorizing that perhaps once the car got moving, the intercooler could have been reducing the intake air temps from the temp while you were staging. This isn't usually what you'd expect in normal driving (usually the air temp goes up under sustained boost as the intercooler saturates), but staging with boost is a markedly different scenario. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted March 31, 2001 Share Posted March 31, 2001 Datalogging my Mustang with turbos... at a light the intake would heat the air a good bit. Blipping the throttle moved it down some but not much. Leaving the light the temps would drop some but matting the throttle and seeing full boost would bring me to within a few degrees of ambient I'm not sure what staging temps would look like to be honest but I'll bet it drops as he goes down the road. BTW Scottie - I had a gauge built for me by a comapny that might interest you. It uses sensors before and after the intercooler and will display the DELTA temp. In other words, intercooler efficiency! The gave me this gauge in return for feedback about the unit. However it's bigger than I can find a place to fit it in my RX7! Would you be interested in testing it out on the GNZ? I'd want it back but it might give you some good information. You could check the ambient against the temps after the intercooler and the air both before and after the intercooler just by moving or switching one sensor. Unfortunatly it's NOT a digital gauge. There's ONE company out there making one like that but they won't sell it direct and those who do sell it want a mint (grr). A friend says he can build a digital gauge but life hasn't allowed it. Would this interest anyone else? Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted March 31, 2001 Author Share Posted March 31, 2001 Jim, not sure I understand how that setup works. How many sensors does it have and where/how are the sensors mounted? Shoot me a pic if you have any. ------------------ Scottie 71 240GN-Z Scottie's GNZ Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted March 31, 2001 Share Posted March 31, 2001 I've not got a pic but... One thermocouple goes in the inlet pipe, one goes in ther outlet pipe. Both sensors are wired to the gauge and it gives you the temp difference. Move inlet sensor as required to get different readings. For instance - place inlet sensor at air intake and outlet sensor at throttle body. Temp on gauge is difference over your ambient (?) intake temp - or the effeciency of the entire turbointercooloer system! Or - move inlet sensor to the intake pipe of the intercooler. Now it reads the HOT turbo compressor exhaust. Temp on gauge is the heat that the intercooler failed to remove! Effeciency of the intercooler itself can be evaluated now Gauge is 2 5/8ths and black faced. Neat huh? Apparently not hard to make either but I'd really like a digital gauge. The digital one I was hunting had a 3 way switch on it - pos #1 was inlet temp, pos #2 was outlet temp, pos #3 was difference between the two! Very nice, very easy to make for an electronics person, and no one seems ot make them except ONE darned company who wants WAY too much for it. I can dig up URLs if this is interesting to anyone. Pete want to make some money? I'd buy one of these in a heartbeat if it was digital and not a fortune! Hey Scottie I just realized - you're out near Cocoa right? I may be driving down (ugh) in a couple of weeks! I could pack this sucker and meet up one evening. Dinner at Fat Boys maybe? [This message has been edited by BLKMGK (edited March 31, 2001).] Quote Link to comment Share on other sites More sharing options...
pparaska Posted April 1, 2001 Share Posted April 1, 2001 Jim, Andy Bayley is the local electronics guru - I'm just a hack . BTW, does anyone make a digital temp gage for these types of temps for a car? Like one that just reads one temp? If so, I'd imagine it wouldn't be hard to make up a simple switch box to go from multiple sensors (thermocouples) to the gage, and then combine the signals some how (not sure how) to get differentials. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted April 1, 2001 Author Share Posted April 1, 2001 Jim, let me know when you are coming down. ------------------ Scottie 71 240GN-Z Scottie's GNZ Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted April 1, 2001 Share Posted April 1, 2001 Hey Scottie, I would do all that fancy data logging of my runs, but I can't find anyone to loan me a supercomputer to keet up with how fast the L28 turbo reacts. Hopefully that software has already let you know you don't stand a chance against the mighty 240z Turbo. I am curious, how does that software graph an ass whoopin'!??? Quote Link to comment Share on other sites More sharing options...
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