ktm Posted May 25, 2008 Share Posted May 25, 2008 If I remember correctly, and someone on here will certainly back me up or correct me, running rich will glow your turbine housing. That could be your whole problem. Running rich or retarding your timing will increase EGTs. Running leaner or advancing your timing will lower EGTs. I know that lean makes high EGT's but dumping fuel into your turbine will turn it into a jet engine headed for meltdown. Not quite. Running leaner/advanced timing will increase cylinder temperatures and result in a hotter engine. Too lean/too much timing can result in too much heat and melted pistons. However, a lean condition will lower EGTs. High EGTs are a result of unburnt fuel from the combustion chamber, resulting from too much fuel or timing retard, burning/combusting in the exhaust manifold. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 25, 2008 Share Posted May 25, 2008 This is how you blow up a turbo: Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted May 25, 2008 Share Posted May 25, 2008 actually red, that's a very good point. the only reason why I'm putting up with all the things wrong with my 78, is because there is very very little rust, and whatever rust that's there, can be fixed with sand paper and a can of spray paint. the floors a big dome from someone bottoming out wicked hard, but there's no holes anywhere. so imo, rebuilding the engine, and putting about 1500+ into a car before I can drive it, is WAY worth having to do rust repair, when i have NO TOOLS needed to do rust repair (grinders, welders, etc) Quote Link to comment Share on other sites More sharing options...
zmaster Posted May 25, 2008 Share Posted May 25, 2008 well ZI have beeen waiting for a new video of your car but thats not what I had in mind. Quote Link to comment Share on other sites More sharing options...
RedEvilrps13 Posted May 25, 2008 Share Posted May 25, 2008 yeah m4xwell, i agree. like i said in the 2+2 owners thread, if i cant get it running right with the parts im getting from another member on here in two weeks, she's done and im getting another one in way better shape. here's a reminder of what im dealing with, and its worse in person... and yeah its worse underneath. sorry for the thread jack phil. Quote Link to comment Share on other sites More sharing options...
big-phil Posted May 25, 2008 Author Share Posted May 25, 2008 Phil, I don't have audio on my laptop... What happened to the turbo? Did the bearing section fail? Or the wheel? Evan the rear oil snap ring thing welded itself to the shaft. Quote Link to comment Share on other sites More sharing options...
big-phil Posted May 25, 2008 Author Share Posted May 25, 2008 Big-Phil, I gotta ask: "Handjob"? Umm did I miss something in the video, and glad I did? In all seriousness, what was your injector PW and duty cycle when in boost? You said your AFR was going "off the scale, beyond 10:1". This would lead me to believe that I could get away with injectors half the size (or there abouts) that according to calculations should support the HP your producing. with the 720cc injectors on the dyno it was like 60 ish duty cycle, but I have methanol injection so that adds some fuel. Chris with the blue 240z made 402 whp on 550cc injectors and perfect AFR's 11.5 ish at 17 lbs of boost. (BASTARD:fmad:) Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 25, 2008 Share Posted May 25, 2008 with the 720cc injectors on the dyno it was like 60 ish duty cycle, but I have methanol injection so that adds some fuel. Chris with the blue 240z made 402 whp on 550cc injectors and perfect AFR's 11.5 ish at 17 lbs of boost. (BASTARD:fmad:) Thank you, that gives me hope for the injectors I have, and plan to use. I figured that the alky injection was adding to the AFRs as well. It almost sounds like you're simply running it too fat, and causing some of the problems. Quote Link to comment Share on other sites More sharing options...
big-phil Posted May 25, 2008 Author Share Posted May 25, 2008 I'm running 20 deg of timing at 25lbs of boost but it goes way rich. The last time I was tunning thats when my LSD rear leaked fluid and left my calling a wrecker. Should I put a small fan behind the oil cooler? I have an adjustable oil pump so I have lots of oil pressure. I've read about oil restriction things does that go in the return line from the turbo to the pan? Should I look into that? Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 25, 2008 Share Posted May 25, 2008 I'm running 20 deg of timing at 25lbs of boost but it goes way rich. The last time I was tunning that when my LSD rear leaked fluid and left my calling a wrecker. Should I put a small fan behind the oil cooler? I have an adjustable oil pump so I have lots of oil pressure. I've read about oil restriction things does that go in the return line from the turbo to the pan? Should I look into that? The restrictors go in the feed side. Restricting the return would only make any blow-by/seal leak problems worse. Have you tried running more timing than 20*? I've found that on other applications you can "lean out" a mix by adding some timing, at least to that point just before knock starts. I am really thinking that you just need smaller injectors, or at least reduce the PW up top. Quote Link to comment Share on other sites More sharing options...
big-phil Posted May 25, 2008 Author Share Posted May 25, 2008 The restrictors go in the feed side. Restricting the return would only make any blow-by/seal leak problems worse. Have you tried running more timing than 20*? I've found that on other applications you can "lean out" a mix by adding some timing, at least to that point just before knock starts. I am really thinking that you just need smaller injectors, or at least reduce the PW up top. I have to be VERY careful because I have cast pistons Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 25, 2008 Share Posted May 25, 2008 I have to be VERY careful because I have cast pistons I know people are going to scoff at this.... But Phil, do some looking around for info on the interweebnet, many, MANY people have proven the old "cast pistons are weak" theory VERY wrong, in that they will usually take LOTS of abuse before breaking down, or causing problems. What has been found is that any piston failures are usually due to a manufacturing defect, not the process in which they were made. Personal experiance, I used Hypereutectic CAST pistons in a V6 I built a few years ago, from Federal Mogul. They were stock replacements for the N/A version of the engine I built (3.1 GM 660 3.2L with the bore), I abused those pistons, with not enough fuel, too much timing, over 30,000 KMs of HARD abuse, and they looked almost brand new when I pulled them out of the block (after cleaning) and are now being used by someone else in another engine, that is also seeing plenty of abuse. Now I did have a good head on that engine, aluminkum with splayed valves and "fast burn" heart shaped combustion chambers that probably helped with some of the resistance to detonation, though at the big end of the track, when I had no where near enough fuel, the knock became so bad that the ECM pulled the timing and the truck literally fell on it's face, but would pull the front end up quite a bit when the timing would come back in. I just wish I knew then what I know now about tuning and had the equipment I might have been able to tune it better. Anyway, just saying that I'm sure you'll find that you can lean it out some and still be plenty safe with the tune. 10:1 AFR is too much for ANY engine, and surprised that you're not finding your oil level go UP after driving the car with fuel being added to the mix. Quote Link to comment Share on other sites More sharing options...
ktm Posted May 25, 2008 Share Posted May 25, 2008 Phil, sounds like your tune caused the problems like Six Shooter is onto. I would call up Coolingmist and find out what their flow map looks like for your setup. It sounds like you are running upwards of 20% of your primary fuel. This would cause your AFRs to drop by a point or slightly more. I don't believe your injectors are too large, you just need to tune for the methanol. Here are some great sites to read about tuning: www.rx7club.com www.turbobuick.com www.evolutionm.net http://www.aquamist.co.uk/phpBB2/ Six is correct that your PW is too high uptop, but for the wrong reasons. It's the meth that is causing your AFRs to be so low (I am assuming that your tune before meth was spot on - am I correct?). Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 25, 2008 Share Posted May 25, 2008 71 lbs/hr injectors not too much for his combo? Looking at RCs calculator that kind of flow at .80% DC, .60 BSFC, and 43 PSIG delta fuel pressure, would support: 570 crank HP. Big-Phil is putting down just over 300 at the wheels (330 was it?), and there's no way there's in excess of 250HP being lost through the drivetrain. There's other factors as well that point to too much injector, his reported AFRs, which yes will go up with the alky injection, but I don't see any information on comparison to before any alky injection, and even if the alky is raising the AFRs by one point that's still more than 11:1, since Phill never said what the actual numbers were, just "more than 10:1", which in any engine is way too high, the DC being only 60%, the recent turbo failure that could be and very likely is related to the AFRs being so high. I can't say for sure what Phil is making for crank HP, but it would likely be around the 400 HP mark, maybe 425 at the crank, which would still be quite a bit of parisitic HP loss through the drivetrain, and for that power level would only require 50 to 54 lbs/hr injectors (525 to 567 cc/min). Working the formula backwards, at 60% DC, it shows to be supoorting 425 HP, for 71 lbs/hr/459cc injectors. I'm all for "too large of an injector", but Phil's just seem excessive. Quote Link to comment Share on other sites More sharing options...
ktm Posted May 25, 2008 Share Posted May 25, 2008 While his injectors are quite large, that is only really an issue at idle for him. If he is calculating a duty cycle of 60%, then his injectors are sized just fine. Now, if his duty cycle was 30%, then I would agree that his injectors are too large. I think that he does need to pull fuel when spraying meth and bring his AFRs back to 11:1, assuming his primary fuel is already tuned. My concern regarding Phil's Coolingmist setup would be a failsafe. He needs for the system to switch maps automatically if there is a problem with his meth injection. Spraying 100% meth and not tuning for it may be causing some of the problems and increasing his EGTs. Methanol is a fuel, and if he is adding fuel on top of his primary fuel without removing it, then he is adding too much fuel and I believe his EGTs will rise. Quote Link to comment Share on other sites More sharing options...
Slow_Old_Car Posted May 25, 2008 Share Posted May 25, 2008 going to play left field here... what MAP sensor does phil have in that megasquirt, cause if it's the standard 2.5 bar it comes with, he passed it's read range around 22-23psi. with those AFR's i'll agree he's probally heating the exhaust side up pretty good. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted May 26, 2008 Share Posted May 26, 2008 he has the 4 bar Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted May 26, 2008 Share Posted May 26, 2008 Running rich or retarding your timing will increase EGTs. Running leaner or advancing your timing will lower EGTs. Not quite. Running leaner/advanced timing will increase cylinder temperatures and result in a hotter engine. Too lean/too much timing can result in too much heat and melted pistons. However, a lean condition will lower EGTs. High EGTs are a result of unburnt fuel from the combustion chamber, resulting from too much fuel or timing retard, burning/combusting in the exhaust manifold. Thus melting his turbine bearing from excess fuel being spit out of the combustion chambers. Quote Link to comment Share on other sites More sharing options...
ktm Posted May 26, 2008 Share Posted May 26, 2008 Cygnus, you stated that running leaner increased EGTs. I was merely correcting that statement. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted May 26, 2008 Share Posted May 26, 2008 Cygnus, you stated that running leaner increased EGTs. I was merely correcting that statement. Both lean AND rich can cause EGTs to rise. Quote Link to comment Share on other sites More sharing options...
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