DCZ Posted March 29, 2007 Share Posted March 29, 2007 Finally got on the dyno with my 73 240zt. Specs: 83 stock engine/drivetrain w/134k miles, BWT5, 7psi boost, stock ECCS, 2.5 dp/exhaust The Good: 181 RWHP, 212 TQ No fuel starvation - probably a bit rich in fact Nice flat wide torque curve The Bad: Engine falls on its face at 5K rpm. Dyno operator told me I "must have a rev limiter" but I assured him that is not the case. Plugs, wires, cap, rotor all are 6 months/5k miles old. I didn't think about unplugging/plugging the ECCS connectors until after the testing. All electrical connections are "clean" but many of the connectors are old so I can't discount some sort of connection problem. My batt. cable is grounded to the chassis like stock and I think the ignitor has a good ground. Fuel pressure was steady at just under 40psi at idle and rising with boost. In fact, the run with the higher hp was the one that we unhooked the FPR. Idle vacuum at 20 inHg. AFM passes ohm meter tests in FSM. Anyone got any suggestions as to the cause of the 5k blues? Here is a jpg of the dyno output Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 29, 2007 Share Posted March 29, 2007 Did you take the coil spring out of the intake boot between the AFM and the turbo? I had a similar problem when the intake boot was collapsing from turbo suction. If so, put the coil spring back in the boot. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 29, 2007 Share Posted March 29, 2007 Sounds like you might be blowing out your spark, which can be caused by too much plug gap, too much fuel. weak ignition system, or a combination of these plus more. What's your gap set at? Mario Quote Link to comment Share on other sites More sharing options...
ktm Posted March 29, 2007 Share Posted March 29, 2007 Are those AFR's correct? You unhooked the FPR? I am assuming you unhooked the boost reference port. If that is so, then why are your AFR's showing that you got richer with boost as opposed to leaning out? The stock ECCS does run rather rich on boost, then it starts to lean out at the higher RPMs. Your AFR curves show that you get richer with your RPMs. Here is a good link that describes a similar setup as yours and similar results: http://forums.hybridz.org/showthread.php?t=88752&highlight=stock+afr Quote Link to comment Share on other sites More sharing options...
DCZ Posted March 29, 2007 Author Share Posted March 29, 2007 Cygnus, I'll check on that. I'm sure I didn't take anything out but you never know if it was in there to begin with. After the dyno runs (why do I always think of these things AFTER!) I thought about pulling the air filter to rule out an air restriction, given the rich fuel mixtures. Mario, plug gap was set at whatever the FSM says, I think maybe 0.044 inch? Easy enough to check and maybe try a little less gap - do you have a recommendation? I'm thinking this is probably electrical in nature, due to the way it "just dies" at 5k rpm. It has a light-throttle, off-idle miss that is annoying, but once you get on the throttle it pulls great with no hiccups until 5k rpm. I've read a lot in the archives about the "crappy ECCS" and my electrical connections, though clean, are not all new and perfect. MS is definitely in the future but I would love to get it running as well as I can right now. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted March 29, 2007 Share Posted March 29, 2007 With an FMU and IC you can get upwards of 270rwhp and 300ft-lbs with that setup. I have the same setup as you with the FMU and Intercooler. Quote Link to comment Share on other sites More sharing options...
DCZ Posted March 29, 2007 Author Share Posted March 29, 2007 KTM, Yes, unhooked the vac line to the FPR. It's hard to see on the crappy scan but the red pull is the one when we unhooked the line. AFR ~13 but then dropping like you mentioned. I have no idea why the AFR would drop under boost and I can only take the dyno shop's word that the AFR is measured correctly. Quote: Here is a good link that describes a similar setup as yours and similar results: Ha ha, you would link to one of bastaads posts - he has to have the longest posts here and the subject always meanders all over the place! Good info though. Quote Link to comment Share on other sites More sharing options...
DCZ Posted March 29, 2007 Author Share Posted March 29, 2007 With an FMU and IC you can get upwards of 270rwhp and 300ft-lbs with that setup. I have the same setup as you with the FMU and Intercooler. Which FMU do you have? Do you like it? I've been researching MS because it seems like you get SOOO much capability for little $. Plus I like to inhale solder fumes. 270rwhp and 300ft-lbs - mmmmmmmm I still get giddy when I "mash the gas" but I'm starting to get used to it so . . . Quote Link to comment Share on other sites More sharing options...
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