Guest 73Turbo240z Posted March 3, 2006 Share Posted March 3, 2006 As we all can tell to a certain degree, tuning fuel is a matter of trial and error, you have a wideband, you adjust your levels, and you do a pull, you see where your AFR's go, and you adjust accordingly... With spark i'm finding it a little harder to feel out, i mean yes trial and error can work, but as i found the other night, where i felt retarding the timing was in order, it actually was worsening the problem... So does anyone have a better tips/techniques to share when tuning for spark/timing maps? this is the L28ET with AZ car pistons @ 8.2:1 CR... right now i'm getting pinging at as little as 12psi, it's very frustrating... Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted March 3, 2006 Share Posted March 3, 2006 Wanna post your timing map and we can compare perhaps? Also depends what cam is in it and a whole lot of other things as well. How are you listening for det? What fuel do you run it on? Dave Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted March 3, 2006 Share Posted March 3, 2006 car runs strictly on 93 octane, cam profile is a 83' ZXT P90a head with it's stock camshaft, were listening for detination with our ears, i've purchased a stethoscope setup, just haven't had time to rig it up to the block somehow, any suggestions there as well, i'm listening.. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 3, 2006 Share Posted March 3, 2006 IMO you go to a dyno and you change timing to increase power, and of course you'll always be watching for detonation to occur. If you advance timing right up until you get detonation (and there are various ways to detect that) then you back off "x" amount. x being how much safety zone do you want. If it is a track only car I think you run small safety zone. Daily driver on pump gas you run a bigger zone. So now you are down to the real heart of tuning the engine and answering these type of questions: How do I detect detonation when tuning? What safety buffer do I want? What fuel will I run? Is it worth the extra power to chance blowing pistons and Head gaskets? How is the environment going to change tuning day to day? This is what makes it all fun. BTW, you are running a few degrees more timing under boost than I did. The question, which has been debated a million times on here is pulling timing and running more boost better? I can look up the link, but I'm pretty sure the consensus was "you will make more power with less timing and more boost" Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted March 4, 2006 Share Posted March 4, 2006 anyone? Quote Link to comment Share on other sites More sharing options...
Bernardd Posted March 4, 2006 Share Posted March 4, 2006 If it's pinging you've got too much advance and/or it's too lean. At what rpm do you get pinging? What is the afr? Boost curve? Where are the datalog's? Looks like waaay too much timing imo. But we only have 91 up here. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted March 4, 2006 Share Posted March 4, 2006 timing needs to be lower around the peak torque since VE is high. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted March 4, 2006 Share Posted March 4, 2006 What yo2001 said! Thats massive timing dude! Here is mine: Notice the sharp drop at 15psi between 3500 and 4500. Thats where boost comes on and where it blew the h/g last time so I was being ultra careful. No det with that map, will tune it some more when I get to the dyno. I am going to take some pics of my detonation detectors and write a tutorial tomorow. Dave Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 4, 2006 Share Posted March 4, 2006 Here is a hard to read table of mine, I was running by Scottie-GNZ's rule of thumb. Get all timing in by 3000 and then drop 1-1.5degree per psi. Helix timing is lower for sure under boost. At 3K and 160kpa I'm at 26 degrees, he is at 23. Helix 14 degrees at 4500 and I'm at 24 degrees. I didn't have any pinging on 91 octane, but higher altitude. I thought at the higher rpms like 5k, 6k the engine wouldn't be loaded as much so more timing could be run? Mine was stock turbo engine running 14psi max,even though the table goes higher t3/t4 with npr IC and 12:1 AFR under boost(more like 11:1 right when boost first hit). EDIT: 14psi at my altitude gave me about 14psi+11psi=25psi manifold pressure, 25/.145=172kpa So I only ran up to 172kpa in my table MAP 220-5-20-18-18-18-19-19-19 180-5-20-18-20-20-24-24-24 140-5-20-20-22-26-30-30-30 100-5-20-26-30-34-38-38-38 90-5-20-26-30-34-38-38-38 70-5-20-26-32-36-39-39-39 50-5-20-26-32-36-40-40-40 30-5-20-26-30-34-38-39-39 rpm.4-.6-1.5-2-2.5-3-4---5 rpm in k Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 4, 2006 Share Posted March 4, 2006 Loose screws 292rwhp onthe stock T3 spark setup Bryan's older spark setup Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 4, 2006 Share Posted March 4, 2006 To tune spark I believe requires a dyno, a pyrometer and afr gauge, detonation detection, and patience. I am running a slightly modified Moby's old map to 10 psi no probs. Mario Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 4, 2006 Share Posted March 4, 2006 Am I missing something or are all you guys not controlling timing at all below atmospheric pressure? What is you idle timing? Anyway, you have way too much advance. Plus, your pressure scale is too wide, so you are not getting all the adustability you could. How much boost do you plan on running? Set the max kPa value to that number. 240kPa = 35psi. You will never run that much boost so that part of the map is not being used. 1psi=6.7kPa, so at around 10psi you are running 34+ deg advance above 200RPM. Ouch! I run around 26deg max at 12psi with a 7.5:1 L28ET. I would set you pressure scale to go from -60kPa to +105kPa. This will give you a timing adjustment range from -18inHg to 15psi. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 5, 2006 Share Posted March 5, 2006 you can tune the kPa scale down to the negative range??? what? my car idles at like 36kpa which is like -16in. hg. according to my guage Quote Link to comment Share on other sites More sharing options...
Metro Posted March 5, 2006 Share Posted March 5, 2006 Am I missing something or are all you guys not controlling timing at all below atmospheric pressure? What is you idle timing? MS uses an absolute gauage. With the car not running, it should read around 90-100kpa or 14.7psi depending on your elevation. Quote Link to comment Share on other sites More sharing options...
Thumper Posted March 5, 2006 Share Posted March 5, 2006 Am I missing something or are all you guys not controlling timing at all below atmospheric pressure? What is you idle timing? Anyway' date=' you have way too much advance. Plus, your pressure scale is too wide, so you are not getting all the adustability you could. How much boost do you plan on running? Set the max kPa value to that number. 240kPa = 35psi. You will never run that much boost so that part of the map is not being used. [/quote'] 240kpa is 35psi. but minus 1 atm 14.7psi = 20.3 psi and 99kpa is 1 atm. We have the car not pinging anymore. Timing is very conservative and so is fuel but its all good. He might post up the timing map. I think I will give it another 1 degree at certain areas to get it more power but I just wanted to tune it so it doesn't ping anymore. Now he has a slight miss we need to find. We will try a lower spark plug gap. Quote Link to comment Share on other sites More sharing options...
z-ya Posted March 5, 2006 Share Posted March 5, 2006 Thanks for the clarification, I didn't realize that it was absolute pressure. Quote Link to comment Share on other sites More sharing options...
Tony D Posted March 6, 2006 Share Posted March 6, 2006 Thanks for the clarification, I didn't realize that it was absolute pressure. Dude, it's Kpa, not Kpg! (Like Bare and Barg) LOL Yep, the 240 is an absolute value. I agree with the above, I ran 24degrees at 12psi, and was probably conservative at that, I NEVER heard ping. Plus, that is where the old Corvair ran, and I knew that was a more strenuous environment. I have been looking at the EURO-TURBO distributor...it is a Corvair Knockoff from Datsun! Has advance weights, and a pressure retard unit on it! I would KILL to have had access to an old Sun Distributor Machine to crank it through it's paces and verify what a STOCK NISSAN curve is set to regarding first RPM-vs-Advance, then Pressure Retard Rate per PSI, and Vacuum Advance per Inch Hg. This would have given us ALL some good baseline information about what Nissan thought was prudent. Yeah, that's right, the EuroTurbos didn't have an ECCS, they had what looks like an N/A EFI ECU, No Cat, No EGR, No AAR, No O2 Sensor, and a Pneumatic Distributor---and were rated at 200hp!!! Kinda tells me something. Oh, and a NEAT quirk on their pistons is a raised crown in the center of the "dish" to promote turbulence or something. They get ALL the good stuff Ex-USA! Quote Link to comment Share on other sites More sharing options...
zguy36 Posted March 7, 2006 Share Posted March 7, 2006 MS uses an absolute gauage. With the car not running, it should read around 90-100kpa or 14.7psi depending on your elevation So sad.... up here we see 85kpa Quote Link to comment Share on other sites More sharing options...
mobythevan Posted March 7, 2006 Share Posted March 7, 2006 So sad.... up here we see 85kpa Lucky, mine reads 77kpa Quote Link to comment Share on other sites More sharing options...
materchan Posted March 7, 2006 Share Posted March 7, 2006 thanks 73Turbo240z i tried your map and now at the same boost my clutch starts to slip, so that has to show somthing improved there. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.