First time on dyno
04-21-2012 | 02:13 AM
#32
Thread Starter
Staging Lane
Joined: Jun 2011
Posts: 94
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From: Norman,OK
There is no doubt in mind this is knock. The a/f does look "stoich". However, stoich (14.75) is fine for cruising around but not at wide open throttle. Fuel tends to pre-ignite before the plugs even fire when it's that lean at WOT.
It's not roughness from using an rpm pickup around a spark plug wire either. I've been using the inductive pick up on the spark plug wire for years. When the inductive pick up has trouble reading then it shows as a blank area in the line of the chart. The trouble usually stems from either lack of grounds on a car or electrical interference from another spark plug wire that's way too close to the one being used by the dyno. Sometimes if it's really brief then you can set it to speed instead of rpm and it will fill in the blank line if it's really brief but the jagged lines associated with knock will still be there and look identical.
The stock ecu can retard all the timing it wants but it's not going to make a difference because the issue is not timing related, it's fuel (pre-ignition). Hence why it knocks as bad and last as long as it does. The fact it's transmitting this bad through a torque converter which tend to mask knock from the dyno makes it even worst.
To the OP, when you get bored, do a WOT pass and pull over shortly, let it cool down and remove your spark plugs and read them. Be prepared to swap new ones and avoid WOT till you get a tune in there.
It's not roughness from using an rpm pickup around a spark plug wire either. I've been using the inductive pick up on the spark plug wire for years. When the inductive pick up has trouble reading then it shows as a blank area in the line of the chart. The trouble usually stems from either lack of grounds on a car or electrical interference from another spark plug wire that's way too close to the one being used by the dyno. Sometimes if it's really brief then you can set it to speed instead of rpm and it will fill in the blank line if it's really brief but the jagged lines associated with knock will still be there and look identical.
The stock ecu can retard all the timing it wants but it's not going to make a difference because the issue is not timing related, it's fuel (pre-ignition). Hence why it knocks as bad and last as long as it does. The fact it's transmitting this bad through a torque converter which tend to mask knock from the dyno makes it even worst.
To the OP, when you get bored, do a WOT pass and pull over shortly, let it cool down and remove your spark plugs and read them. Be prepared to swap new ones and avoid WOT till you get a tune in there.
Talk with Chris @ CircleD, he can give you advice and help you decide which one would suit your setup.
The 80E is just a little longer than the 60E, Im not sure how the CC are setup, but if you swap to a 2 peice your goin to need a mounting bracket for the swing bearing. Just get a TH400 yoke and you should be good to go if the CCSB and ECSB have the same length from the Tailhousing to pinon.
The 80E is just a little longer than the 60E, Im not sure how the CC are setup, but if you swap to a 2 peice your goin to need a mounting bracket for the swing bearing. Just get a TH400 yoke and you should be good to go if the CCSB and ECSB have the same length from the Tailhousing to pinon.
Im not exactly stock, not heavy mods but i do have Longtubes, off road y-pipe, AEM CAI, Tuned, 3.90 gears
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