Tuning issue on new ls3 stroker
07-09-2018, 04:21 PM
#1
Tuning issue on new ls3 stroker So I'm finally getting the dyno tune done on my ls3 stroker project. Been running a file tune for the last month or so and it seemed to be running fine. Although I haven't really maxed it out yet.
Anyway the shop doing my tune called me and said the ECM is pulling timing heavy. They suspect bad fuel.
They're going to drain the tank and put new fuel in it and see if it cures it.
Seems weird to me. I mostly get fuel from the local BP station and haven't had any issues in the past. At least not that I'm aware of. I always run 93 in it even before I rebuilt the motor.
This motor has 11 to 1 compression.
I have another LS motor in my truck with 13 to 1 compression that's tuned for 93 octane and I've never had any problems with using fuel from this place. Seems like it would be very noticeable. The stroker motor is a lot louder though. Long tubes, high flow cats, and no mufflers, so hard to hear spark knock.
In any case I'm nervous theres something else going on. Or maybe normal. I don't know.
But the valve train on the stroker is plenty loud. Solid stainless valves and heavy duty springs with a high lift cam. So I sort of expect it to be noisey.
I'm wondering though if the knock sensors are picking up the loud valve train and pulling the timing.
You'd think the dyno guys would pick up on that sort of thing though.
Any thoughts???
Anyway the shop doing my tune called me and said the ECM is pulling timing heavy. They suspect bad fuel.
They're going to drain the tank and put new fuel in it and see if it cures it.
Seems weird to me. I mostly get fuel from the local BP station and haven't had any issues in the past. At least not that I'm aware of. I always run 93 in it even before I rebuilt the motor.
This motor has 11 to 1 compression.
I have another LS motor in my truck with 13 to 1 compression that's tuned for 93 octane and I've never had any problems with using fuel from this place. Seems like it would be very noticeable. The stroker motor is a lot louder though. Long tubes, high flow cats, and no mufflers, so hard to hear spark knock.
In any case I'm nervous theres something else going on. Or maybe normal. I don't know.
But the valve train on the stroker is plenty loud. Solid stainless valves and heavy duty springs with a high lift cam. So I sort of expect it to be noisey.
I'm wondering though if the knock sensors are picking up the loud valve train and pulling the timing.
You'd think the dyno guys would pick up on that sort of thing though.
Any thoughts???
07-10-2018, 08:37 AM
#2
It is very common to see "hyper active" knock retard activity. Interpreting the data for true pre-ignition / detonation vs overly sensitive knock sensor calibration takes experience and close monitoring of spark plug readings, shape of power/torque curves, drag strip mph, etc. Many of the factory knock sensor calibrations can be de-sensitized to improve performance. Just make sure the person doing so is someone you trust.
07-10-2018, 10:17 AM
#3
Thanks for the reply 406,
thats kind of what I was thinking.
Don't know if I trust these guys or not. Sure waited a long time to get in. Have always heard good things about them. I'm just learning who to trust and who not to trust.
Guess it does make sense to verify that fuel quality is not the issue before moving forward. Better safe than sorry. But still thinking this is more a case of hyper sensitivity.
thats kind of what I was thinking.
Don't know if I trust these guys or not. Sure waited a long time to get in. Have always heard good things about them. I'm just learning who to trust and who not to trust.
Guess it does make sense to verify that fuel quality is not the issue before moving forward. Better safe than sorry. But still thinking this is more a case of hyper sensitivity.