As usual, nothing is easy with this stuff, and we struggled for most of the day dealing with the aforementioned injector, and then with some other issues, but finally we started making pulls on the motor around 3:00 PM. This was with the motor set up like an ems-pro, in bank fire mode rather than full sequential. We ran the first pull from 3500 to 5000, and the engine was really rich, so we dialed it down over the next couple pulls and came in around 600 HP at 5000 RPM. One thing I noticed was the vacuum in the crankcase was nowhere near what I expected; the Peterson pump has two vacuum stages pulling from each valve cover, but the most vacuum I recorded in the crankcase during the dyno pulls was only about 6 inches. I think I must have a leak in the crankcase seal somewhere; usually you see this around the distributor seal but of course there is no distributor, so it must be leaking from somewhere else. I need to solve this problem before the engine goes in the car; I'd like to be running around 15" when I'm going down the track, and that would pick up some HP too. I'll pressure check the crankcase this week to try to find it.
The other issue was the engine would not idle below around 1800 RPM, but I think I know what the problem is with that. After building the upper sheet metal intake, I had never leak checked it. I'm pretty sure that when I do that I'll find some minor leaks in the welded areas, and after I seal those up the idle should come down. Just last week I machined the plate I need to bolt to the top of the manifold and seal the top of the plenum, so I'll pressure check that this week too.
From the original RPM range we increased in 500 RPM increments up to 7000. The engine made 650 HP at 5000, 725 HP at 5500, and 780 at 6000. We were making A/F adjustments all the way and running just a little bit rich. The power curve flattened out in the mid 6000 RPM range, but looked to be on the rise at 7000 RPM and I thought the engine was getting its second wind; here's the data:
The last data point in the dyno graph is always a little suspect, and that was the case here. After further tuning and running all the way to 7800 RPM it was clear that the engine was going to peak around 7000 RPM. The power band of the engine is clearly in the 6000 to 8000 RPM range. We ran a total of 18 pulls on the engine today, and the last two were with the dyno exhaust system disconnected. This engine didn't pick up power like my 519" SOHC did with the exhaust disconnected; we richened it up somewhat after the first pull with no exhaust system, but it didn't appear to improve the power of the engine any, so we left it as it was. Here's a graph of the final dyno data:
So the engine peaked at 851 HP, which is just about where I'd expected it to be. I think if the crankcase vacuum was up where it should be and we'd had the opportunity to do individual cylinder tuning, it may have made 875 HP, but I don't think its good for 900. In any case, though, I have the data I need to order the rear end gears for the car and the converter for the trans tomorrow, and I have a little time to try to tweak the performance of the engine somewhat over the next week. Here's a couple of videos of the dyno sessions, one from inside the dyno room and one from the dyno operator's perspective.
http://youtu.be/Ih3PvCgc_Jchttp://youtu.be/fy2MS3W_tVcIf I get further dyno information on this engine before I pull it off the dyno and put it in the car, I'll post it here. Finally, thanks to all the members for the encouragment on this engine build; it was fun to share the build and the results with you guys - Jay
