So now onto basic setup and first drive:
Once the motor warmed up, first order of business was to sync the timing. The sniper touchscreen allows you to lock the timing to a static value, say 15 degrees. Now you can use a timing light to rotate the distributor until it also reads 15 degrees. Tighten the bolt down, clear the static timing and the ECU is now synced with the distributor. Amazingly I was only 7 degrees off, so that plastic cap dealie actually works pretty well.
Next up was idle. The sniper controls the idle using an IAC motor, but you need to make sure itās operating in a certain range. Once the motor is up to temp and idling in neutral, they want the IAC values between 2 and 10%. Thereās an idle set screw just like a carb would have on the linkage. This allows you to slightly open/close the butterflies to get the IAC operating where it needs to be. Out of the box the throttle was open too much. Engine was idling really high and the IAC was showing 0%. I had to back off the screw a good bit to get the IAC to start opening.
Overall the system worked really well on the first drive. Idle was very smooth, and for the most part cruising and acceleration felt really good. A couple things I noticed though:
-The throttle was very sticky coming off idle. This made it very hard to be precise and the car would jump when you tried to accelerate smoothly.
-There was a stumble when getting on the gas hard. Like an accelerator pump issue on a carb.
-Deceleration was a bit pronounced, like an engine braking effect rather than coasting when you take your foot off the pedal.
After a few more miles of driving the acceleration stumble and decel issues tuned themselves out completely. To fix the throttle sticking, I had to modify the linkage. Out of the box, the sniper does not have the large 1/2" hole on the top of the linkage that most Holley and Edelbrock carbs do. So I moved the connection point for the rod to the smaller 1/4" hole further down. This hole is closer to the axis of the throttle shaft, so less leverage which translates to more pedal effort. I ended up having to use this adapter to add that 1/2" hole on the top of the linkage arm.
Hereās the old location:
And the new location with the adapter:
Moving the attachment point up made a huge difference in pedal feel. Went out for another drive and the issue was gone, made it very easy to roll into the throttle now. It actually felt almost too light, so I went back to a double return spring and that seems to be the ticket.
One thing to note with the bellcrank/rod style throttle on the 68s, itās going to be impossible to achieve absolute wide open throttle on the sniper when the pedal is floored. The problem is the shape of the bellcrank, it contacts the intake manifold which prevents you from getting the range of travel needed to be both fully closed off the pedal and fully WOT on the pedal. It does get very close though, the TPS values are only 7% down from true WOT. On a stock 302 Iām fine with that, doubt it makes any noticable difference. To correct this, I think youād need to either bend the upper arm on the bellcrank or possibly switch to a cable setup. I plan on leaving it alone.
Once the throttle linkage was fixed and the unit had a good 25 miles to self-tune, I was really impressed with the drivability. Every condition- cruise, accel, decel, idle, hard acceleration all felt very smooth and refined compared to the old carb. Will need to see how it runs in warmer weather in a few months, but so far Iām really happy with the performance.
The steering wheel pad I found was much better than my old one, but still shrunken a bit so the bezel would not sit flush inside. I sanded down the ends until I could get it fitting relatively well:
