Well, mixed success.
Last Wednesday had some successes and failures.
We spent a few more hours cleaning things up and getting idle set up, and then went over to the dyno for a few hours, finally finishing up at 11:30 PM.
The motor ran well, transmission did its bit and everything held together, which was obviously relieving.
However power was way down from where I expected. Here's a link to the 930/Supercharged forum where I describe the symptoms...
Quote:
Originally Posted by JohnJL
Had a hugely frustrating night at the dyno. On the plus side...
1. Motor held together, idles find and revs easily. Sounds great.
2. The belts run perfectly, no issues there. They are not slipping.
3. Temps are as expected, intakes never got over 34 degrees C.
4. A/F ratios between 12-13 all the way up.
5. Behaves as-expected up to 3500rpm. Builds 11 pounds of boost up to there.
Now the disappointing parts...I may have more than one problem, appreciate any suggestions;
1. Boost flatlines at 10-11 psi. In fact it hits 11 at 3000 then falls back to 10psi all the way to 6000 rpm.
2. Even at 3000 rpm and 10psi I'm not making the power I would expect. I'm getting 230 ft-lbs and 160 hp at the wheels. Torque goes straight up from 1100 rpm idle to 3000. Those figures flatline at 3500 rpm.
Here's what we've done/observed...
1. Those measurements were verified several times in several consecutive runs. Boost & AFR readings were consistent across the ECU, dash gauge and Dyno sensors.
2. We disconnected the bypass valve and verified it wasnt leaking.
3. There appear to be no leaks. If there were we would have expected different behaviors.
4. Spark is consistent throughout. Adjusting dwell time had no impact.
5. I've spoken to the supercharger dealer. At 6000 crank rpm the s/c is turning at 12,000. This is well below the s/c's stated limit. He also had no theories or suggestions.
6. The only thing we could not verify (due to time) was cam timing. I'll do that Monday. They are DC-20 cams from John Dougherty. I spoke with John and he endorsed these for this application...here are the stats...
DURATIONS .040" .050" VALVE LIFT CENTERLINE SETTING
DC 20 I 248 242 .475" 113 2.3 mm
Super-C2 E 236 230 .455"
A little video for infotainment...
http://www.youtube.com/watch?v=vltwbhvCnms
Anyone else think cam timing could be the culprit or any other suggestions? |
Since found at least 3 issues...
1. Cam timing on one side was slightly out. I was hoping to find the cams out more as this would expain the issues we were having but it looks like the 456 bank was out ~0.5mm. The 123 bank was bang on 2.4mm.
2. The TDC mark on the crank pulley was 8 degrees retarded. THis is a issue however doesnt explain the loss of boost.
3. THe idle correction settings were way off.
She now starts fine but idles with a lot of hunt and is a beast to get up/off the trailer and into the garage.
Tested compression, 125-130 on all cylinders. Plug gaps .027-.030. All valves at 0.1MM clearance on the dial gauge. All plugs and all injectors firing.
The ignition map looks crazy, I need some help here. My plan is to install the new harness over the next 2 weeks and neaten everything up. The tuner gets back from holiday then and I'd like to get right over to the dyno then. In the meantime I'd like to clean up the ignition map and would appreciate some help from others running 10-15 lbs boost. What is your idle timing, how early do you ramp up and at what advance do you top out?
your help appreciated...