Dyno/drag/plug problems *LONG*
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Dyno/drag/plug problems *LONG*
*Pictures at bottom*
1999 NBM TransAm M6, Torquer V3 231/234 .643/.598 111lsa, LS6 Intake, Ported TB, PS LT, PS ORY, Cutout, SLP Lid, 127k miles
Went to the track the evening of the dyno/tune. Long story short 2.2 60' 13.6 @ 106. This was with TCS, didn't realize it cut itself back on and didn't catch it until I was about to leave(1st non TCS run I had a 2.0 60ft[with traction issues] but missed 3rd)
366.8@6200 HP DYNOJET
353.5@4700 TQ
Right now I am trying to figure out why I had low numbers...
The night after the drag/dyno I decided to check if the plug wires where arcing. The front passenger plug wire was arcing to the header. Not only that, it was popped off of the plug, backed off about an inch. SES light wasnt flashing. ---- Only problem is I think the tuner would have noticed this while tuning and on dyno.
Think any damage to the rings might of been had from gas washing the rings clean.
Should my injectors be at 105% duty cycle with this power level(26lb)?
I did a compression check on the front four cylinders. Depending on how long I cranked it I would get 150-180psi. 2-3 seconds and 3-4 respectively. Also all the cylinders plugs have <400 miles on them and are white. Although some look greenish white w/e green means. I attached pictures of the plugs in order. Are you suppose to crank until max psi or a certain time?
It was running rich before the tune(smell) so could the A/F been tuned with one cylinder pouring gas causing the lean condition? Then again I was at 105% duty cycle so there is a lot of fuel. Maybe it was just misfiring? Or is it too consistent on the graph and the wire probaly popped off at the track?
Could it have ran lean because I need bigger injectors?
Thanks
cyl1-185
cyl2-180
cyl3-180
cyl4-175
1999 NBM TransAm M6, Torquer V3 231/234 .643/.598 111lsa, LS6 Intake, Ported TB, PS LT, PS ORY, Cutout, SLP Lid, 127k miles
Went to the track the evening of the dyno/tune. Long story short 2.2 60' 13.6 @ 106. This was with TCS, didn't realize it cut itself back on and didn't catch it until I was about to leave(1st non TCS run I had a 2.0 60ft[with traction issues] but missed 3rd)
366.8@6200 HP DYNOJET
353.5@4700 TQ
Right now I am trying to figure out why I had low numbers...
The night after the drag/dyno I decided to check if the plug wires where arcing. The front passenger plug wire was arcing to the header. Not only that, it was popped off of the plug, backed off about an inch. SES light wasnt flashing. ---- Only problem is I think the tuner would have noticed this while tuning and on dyno.
Think any damage to the rings might of been had from gas washing the rings clean.
Should my injectors be at 105% duty cycle with this power level(26lb)?
I did a compression check on the front four cylinders. Depending on how long I cranked it I would get 150-180psi. 2-3 seconds and 3-4 respectively. Also all the cylinders plugs have <400 miles on them and are white. Although some look greenish white w/e green means. I attached pictures of the plugs in order. Are you suppose to crank until max psi or a certain time?
It was running rich before the tune(smell) so could the A/F been tuned with one cylinder pouring gas causing the lean condition? Then again I was at 105% duty cycle so there is a lot of fuel. Maybe it was just misfiring? Or is it too consistent on the graph and the wire probaly popped off at the track?
Could it have ran lean because I need bigger injectors?
Thanks
cyl1-185
cyl2-180
cyl3-180
cyl4-175
#2
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Yeah, those plugs are showing a lean condition. The air fuel on your graph looks like it is at 14:1 between 3500-4500 RPM and 13:1 everywhere else. That's a bit too lean for me and IMO shouldn't have left the dyno that high. You're injectors should be fine up to 390-400HP without maxing out. You need to check your fuel pressure, because if it's low the injectors will max out quickly. As far as the plug wire, it was most likely unplugged by the dyno operator when he removed the lead.
Last edited by 5.3LJimmy; 05-28-2008 at 11:59 PM.
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Where would I hook up a fuel pressure gauge(shrader valve or w/e at the end of the rail?) and I assume I can pick one up from advanced? You recalled what the lsx psi is? I am probaly going to redyno incase the wire was unplugged while being dynoed. What lead are you talking about that the dyno op would have removed. Should I change the plugs?
Any idea why I dynoed so low?
Any idea why I dynoed so low?
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They attach an ignition lead that clamps over the number one plug wire like a timing light to read the rpm while on the dyno. Yes you should be able to pick up a fuel pressure gauge at advance and it does hook to the shrader valve on the fuel rail(visible in your second to last pic). Stock fuel pressure is 55 PSI.
My best guess for the low dyno numbers is that the engine is lean, but the fact that air fuel wasn't perfected makes me worry about the rest of the tune.
My best guess for the low dyno numbers is that the engine is lean, but the fact that air fuel wasn't perfected makes me worry about the rest of the tune.
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It dosen't look lean on the dyno graph does it, except mayby near the mid, but at the time I didnt know how dead on A/F had to be.
Hmm, my ls6 intake came from an '02 Z28 and came with the fuel rail and I believe injectors. If I recall correctly those are 28lbs on 98/01/02 years.
Imma get it dyno with those and check the fuel pressure.
Imma check th one plug I did replaced that wasnt getting spark at the track and see if its lean.
Hmm, my ls6 intake came from an '02 Z28 and came with the fuel rail and I believe injectors. If I recall correctly those are 28lbs on 98/01/02 years.
Imma get it dyno with those and check the fuel pressure.
Imma check th one plug I did replaced that wasnt getting spark at the track and see if its lean.
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I checked the one plug I replaced and it is lean as well now in 50 miles, I also threw a P0121(TPS) and am going to look into that and see if it could cause me to run lean.