Guest bastaad525 Posted August 11, 2004 Share Posted August 11, 2004 I still say, the power and torque curves on the recent dyno at the Vette place, certainly don't say that there is such a super lean condition. I ask again, wouldn't going really lean like that result in a big loss of power? It leans out big time at about 3300rpm, but the power and torque lines stay nice and smooth and linear. The torque curve on this dyno was much flatter than on my last one. 18:1+ AFR, and so suddenly like that, I'd expect a BIG dip in the torque and hp. Actually I'd expect a bit of a spike in power as the AFR passed thru 13 and 14:1, then I'd expect to see it fall off rapidly. Even at the 5000rpm point, the hp and torque are well above the previous dyno's numbers at that same rpm (193 to 210hp, 203 to 215lb ft), again, not much of an indication that I'm running so much leaner than on the first dyno, which topped out at about 13:1 AFR versus this dyno being off the chart. Doesn't power start to fall off significantly at like 14 or 15:1? I DO notice, that torque seems to be falling off a bit more rapidly after it's peak and during that last 900rpm of the pull... for whatever that's worth. Crunching dyno numbers is fun Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted August 11, 2004 Share Posted August 11, 2004 MSD BTM..... LARRY Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 11, 2004 Share Posted August 11, 2004 yeah if my wife's tolerance for all the spending holds up, then I'd like to be able to get a BTM soon as well. I did back off the timing a little bit to about 18 degrees (stock is 20). Quote Link to comment Share on other sites More sharing options...
510six Posted August 12, 2004 Share Posted August 12, 2004 You post made me very happy that I purchaced my Tech Edge wideband 02 . Their is nothing like seeing my 37.00 O2 sensor cycle right along with the shops O2.Still tuning with a "fuctioning " wideband is always a eye opening learning experience.Tuning boost + N20 can be a headache making experience. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 12, 2004 Share Posted August 12, 2004 Oh man... just cruising around on the 'net and look what I found: Look at the air/fuel ratio curve... look familiar? Here's a quote from the paragraph immediately preceding the graph: "I took the truck back to the shop where I had originally done the pulls and my power is back to what it had been, plus a little. (The U-shaped line on the a/f graph was caused by the hose to the sensor burning through.)" Would explain why it only seemed to get worse (leaner) even after I was turning the boost DOWN, eh?? And then the sensor just not working at all... I dunno kiiiiiinda fishy. It DOESN"T explain why DAT240Z had nearly the same exact thing happen to him... would be a big coincidence... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 13, 2004 Share Posted August 13, 2004 Can anyone confirm one thing for me at least? Would a motor even run at a/f ratios of like 20:1?? wouldn't it sputter or misfire or something? I mean besides the obvious loss of power... I'd think running so lean there'd be NO mistaking it, you'd know you were running lean. Running 12psi for a few days now and the car seems to be running GREAT, plenty of power up to 5500rpm, no sign of lean running, no ping, plugs look great... nice dark brown and no sign of detonation or preignition damage on them either, no cracked insulator, melted electrodes, or little metal flecks on them. Pretty odd for 18:1 + air/fuel at 12psi of boost. Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 13, 2004 Share Posted August 13, 2004 Can anyone confirm one thing for me at least? Would a motor even run at a/f ratios of like 20:1?? wouldn't it sputter or misfire or something? I mean besides the obvious loss of power... I'd think running so lean there'd be NO mistaking it, you'd know you were running lean. You would have noticed if you had gone to 20:1 at WOT and 12psi. Period. Probably would have seen a big fireball out the exhaust from the abrupt rich/lean transition. As others have mentioned, you really should consider some sort of instrumentation now that you are cranking the boost up. Regardless of whether that shop's wideband was bogus, you really need to have some idea of what's going on with your AFR. Does your EFI already have a narrowband EGO? If so, at least consider getting a cheap gauge for that. Narrowbands aren't as good as widebands, obviously, but they are still FAR better than nothing. Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted August 17, 2004 Share Posted August 17, 2004 years ago when i did turbo swap on my car i installed engine with new lucas injectors.if you installed a used engine with used injectors you dont know if the fuel is flowing evenly to each cylinder.before wideband o2/dataloggers where out i would see .83 to .9 v on the o2 sensor at 16 psi boost with stock ecm.but the lucas injectors are supposed to be more pressure sensative.fuel pressure would run up to 60 psi with stock regulator.car is parked with blown head gaskit after years of use(abuse).i didnt like the driveability of the oem zxt electronics.car is planned for massive engine upgrade soon. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 18, 2004 Share Posted August 18, 2004 Agreed, I DONT know how evenly the injectors are flowing, but if the color of my spark plugs is any indication, they are running very evenly. This is one reason I've been reluctant to buy larger, used fuel injectors... for all I know I could get stuck with some real stinkers and wouldn't even know it, possibly until it's too late. Quote Link to comment Share on other sites More sharing options...
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