Discussion
Hi,
I thought I would post some experiences I have had getting my 383 SBC / Emerald ECU tuned. Reading the posts a lot of people are now running either OEM or aftermarket ECUs on SBCs and LS engines. This may help if your engine has smoothness, drivability and power issues.
My 383 has always been reluctant to rev at medium and high speeds even with a big cam and good induction setup. Data logging the ECU with the laptop showed a lot of spark timing scatter and also any digital TV in the vicinity of the car stopped working when I turned up
so knew that I had RF noise issues with the ignition.
I thought I would try to stop the RF getting back to the ECU from the HT system. To do this I have tidied up the HT and low voltage ECU wiring runs and improved the battery power feeds to the ECU and its sensors. I tried a lot of things but the what really worked were the following;
• I shortened the crank sensor loom lead (very RF prone) from 5 feet to 2 feet and rerouted well away from HT leads.
• Smoothed the ECU power feed to the crank sensor with a number of audio grade by pass (smoothing) capacitors
• Smoothed both the 12v feeds from the car loom to the ECU, again using audio grade smoothing capacitors.
• Did a little work mapping the coil charge time to take some energy out of the spark and replaced the MSD distributor cap and rotor.
The engine now revs like a mad thing to 7k, makes more torque, more power has better driveability.
Different setups will I am sure respond differently but I cannot believe the difference these simple changes have made. This is really simple and cheep stuff to do so I thought I would post in case it was helpful to anyone.
Nick.
I thought I would post some experiences I have had getting my 383 SBC / Emerald ECU tuned. Reading the posts a lot of people are now running either OEM or aftermarket ECUs on SBCs and LS engines. This may help if your engine has smoothness, drivability and power issues.
My 383 has always been reluctant to rev at medium and high speeds even with a big cam and good induction setup. Data logging the ECU with the laptop showed a lot of spark timing scatter and also any digital TV in the vicinity of the car stopped working when I turned up
so knew that I had RF noise issues with the ignition.I thought I would try to stop the RF getting back to the ECU from the HT system. To do this I have tidied up the HT and low voltage ECU wiring runs and improved the battery power feeds to the ECU and its sensors. I tried a lot of things but the what really worked were the following;
• I shortened the crank sensor loom lead (very RF prone) from 5 feet to 2 feet and rerouted well away from HT leads.
• Smoothed the ECU power feed to the crank sensor with a number of audio grade by pass (smoothing) capacitors
• Smoothed both the 12v feeds from the car loom to the ECU, again using audio grade smoothing capacitors.
• Did a little work mapping the coil charge time to take some energy out of the spark and replaced the MSD distributor cap and rotor.
The engine now revs like a mad thing to 7k, makes more torque, more power has better driveability.
Different setups will I am sure respond differently but I cannot believe the difference these simple changes have made. This is really simple and cheep stuff to do so I thought I would post in case it was helpful to anyone.
Nick.
It runs a GM three wire digital cank sensor from an Omega, before I cut the lead it looked thick enough be screed but turned out not to be. Rather than connect via the Emerald loom (extra 3+ feet of unscreened wire) I took the sensor wire straight into the back of the ECU plug. This and the power supply smoothing do the trick. I should have also said that running a dedicated earth from the ECU to the battery terminal also helped as all of the coil and injector drivers are switched earths so a good route to earth is important.
Sadly the car doesn’t kill TV reception anymore, folks only have to put up with the engine noise now when I arrive There was something satisfying about the antisocial TV jamming feature but I am happy with the extra power 
Sadly the car doesn’t kill TV reception anymore, folks only have to put up with the engine noise now when I arrive
There was something satisfying about the antisocial TV jamming feature but I am happy with the extra power Gassing Station | Ultima | Top of Page | What's New | My Stuff