Still missing above 5000 rpm
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Still missing above 5000 rpm, nitrous elminates the miss? Dyno charts! I'm still playing with this thing. Above 5000 it misfires. Note I no longer use the cap and rotor since I have the Delteq. I've backed timing down to 32 total at WOT. Changed fuel filter two days ago. No codes. Plugs are a week old. I don't want to change the opti but I have next on the list MSD Superconductor wires and MSD DIS-4. It seems as if it misses worse at some times than others. Sometimes it feels like only a slight hesitation that someone may never notice. Thoughts?
UPDATE: got to looking at some old dyno charts and it looks like there were a few misfires which caused blips in my runs. When nitrous was injected, the misses were gone. The two WinPEP charts were with the old optispark setup with MSD Digital 6. The third chart is my recent run at Thunder Racing with the Delteq coils. I also got to thinking that during the old run, my opti was relatively new. For my recent run, I had since fixed an oil leak coming from my waterpump drive so that oil could have possibly gotten in my optical.
UPDATE: got to looking at some old dyno charts and it looks like there were a few misfires which caused blips in my runs. When nitrous was injected, the misses were gone. The two WinPEP charts were with the old optispark setup with MSD Digital 6. The third chart is my recent run at Thunder Racing with the Delteq coils. I also got to thinking that during the old run, my opti was relatively new. For my recent run, I had since fixed an oil leak coming from my waterpump drive so that oil could have possibly gotten in my optical.
Last edited by dhdenney; Jun 29, 2005 at 10:47 PM.
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Forgot, the two WinPEP charts are also with a 224/230 cam and the latter is the cam in the sig. BTW, why are my numbers so low?????????????????? I was hoping for a 425hp/450tq readout
Originally Posted by dhdenney
Forgot, the two WinPEP charts are also with a 224/230 cam and the latter is the cam in the sig. BTW, why are my numbers so low?????????????????? I was hoping for a 425hp/450tq readout
who tunning it ??? heads cam combo play a big factor on a stroker.
have you run a data log while on the dyno to see if you see anything weird..
any history codes in the comp.
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Well the data logs don't show anything weird. I've run several on the street and everything is pretty consistent. I was on another dyno a week ago but didn't get the charts. Pretty much the same thing as above. I've been doing a lot of the tuning but it is very similar to several cars of the same type so I know it's not a 40+rwhp difference. See my post on oil in the combustion chambers. I'm starting to worry about a loss of compression. I'm leaning more and more to the optical being the source of the miss. Kinda odd that the misfires would go away with nitrous, no?
how many miles on the motor???... mine started off low then after 1k-1200 miles she woke up first dyno numbers where in the 380's with mine
as far as the oil issue on the back 4 cyl i have no clue what could be up
how long is the cam dowel pin sticking outta the cam.
no history codes been set. mine had several but no light
as far as the oil issue on the back 4 cyl i have no clue what could be up
how long is the cam dowel pin sticking outta the cam.
no history codes been set. mine had several but no light
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I was at the track tonight trying to solve my heavy RPM miss since my delteq install. Best I got again was a 13.9 (I used to run consistent 13.6's). Next time I go I am installing the wires to the opti and running the stock opti. If I manage a 13.7 or better the Delteqs going back. I have tryed everything that I can think of. Only thing I have yet to change is the plug wires that came from Delteq (I never liked them)
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welcome to my world, i've been fighting the same thing for a few years now.
http://www.mofbody.com/blkchevyz/fmsdyno.jpg
mine doesnt normally do it till around 5800
changed opti's a few times, coils, ignition box, ignition module, added more grounds, changed valve springs... the only thing i havent changed was the bottom end.
http://www.mofbody.com/blkchevyz/fmsdyno.jpg
mine doesnt normally do it till around 5800
changed opti's a few times, coils, ignition box, ignition module, added more grounds, changed valve springs... the only thing i havent changed was the bottom end.
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Originally Posted by Z284thgen
how many miles on the motor???... mine started off low then after 1k-1200 miles she woke up first dyno numbers where in the 380's with mine
as far as the oil issue on the back 4 cyl i have no clue what could be up
how long is the cam dowel pin sticking outta the cam.
no history codes been set. mine had several but no light
as far as the oil issue on the back 4 cyl i have no clue what could be up
how long is the cam dowel pin sticking outta the cam.
no history codes been set. mine had several but no light
I now have about 8K on the clock so that's not really it. The cam has the long dowel pin but I have the first gen opti so there's no conjuction of the pin and the opti. My dad said he would adjust my valves again since that could be causing some blow by and the miss.
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Originally Posted by HBHRacing
I was at the track tonight trying to solve my heavy RPM miss since my delteq install. Best I got again was a 13.9 (I used to run consistent 13.6's). Next time I go I am installing the wires to the opti and running the stock opti. If I manage a 13.7 or better the Delteqs going back. I have tryed everything that I can think of. Only thing I have yet to change is the plug wires that came from Delteq (I never liked them)
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I get paid Friday so I will have new wires ordered and my DIS-4 should be in at the beginning of the week. However, in the back of my mind, I'm banking on that opti being bad. If you'll look at the Thunder chart, the miss starts exactly at 5000. Heard several people say the opti will crap out at that speed.
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there really is no set RPM that the opti will tend to fail. It's different every time. But when it does you will usualy get a low and or hi res code from it. I never did but I replaced the opti anyway. I figured that if I never could find teh issue and had to go back to the opti at least it would be brand new.
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Well I'm not getting any codes either. It really puzzles me. In the first post I noted that my waterpump drive seal was leaking oil and I just wonder if I got oil in the optical. It'll miss slightly before 5000 but beyond that it's all she wrote. Plus, the optical I have is a reman but 3 years ago I didn't know any better. Shane at Thunder thinks that's the culprit. BTW, what do you think about nitrous smoothing the curve on the first two charts? The misses magically disappear.
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It's really hard to say. I'm not much of a nitrous guy so I don't know teh interactions very well. Possibly it's cooling the intake charge and not letting a hot spot develop and ignite. Do you have a way to monitor knock retard?
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Well I removed the KS so no. With the hot spots, wouldn't pulling timing help that problem? I've backed advance down to 32 at WOT so I'm thinking it's that damn opti.
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Ever thought about worn or weak springs. Higher rpms put exponentially greater stress on springs and you could be missing because your springs cant keep up with the valvetrain and start to float or cause the valve not to seat properly.
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That's why I'm adjusting my valves soon. Perhaps too tight. However, springs shouldn't be bad. They've just got 8K miles and they're good for .700" lift. I'll inspect them when I get the covers off.
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Any particular symptoms I need to be looking for? I've got a little oil in the back 4 combustion chambers (cyls 5-8), those plugs are rich, misses a little above 4000 and a lot above 5000. Today I drove it and one time it was like a big cough, almost like it was out of time.
