A little update for you guys. I fought Lucy on the dyno for several hours yesterday.
I took the liberty of figuring out how to modify LS3 style Bosch 210lb injectors to fit the top of the rail. When it made the 435hp prior with with 65lb injectors, and the duty cycle was up around 80% on VP X98 fuel.
I spent most the morning trying to be able to make a full pull on wastegate without it breaking up from being too rich. It got to the point where I couldn’t pull anymore fuel out of the 3-5psi range on the boost fuel map.
I ended up having to play with the injector balance table to bring the secondaries in higher in the rpm range, and then also pull fuel out of the TPS map. Even after all that the afr’s were still a bit on the fat side and not as smooth as I would like but it worked. the tuning from 7psi on up was buttery smooth.
While working my way up I noticed a few drops of oil on the ground. Didn’t think much of it as I knew I need to replace the starter cover and stator gaskets.
It wasn’t until after I a made a few pulls at right at 400hp I noticed a slight tick in the top of the engine. When I got off the bike to listen closer I saw a few drips of oil on the compressor cover of the turbo. Then I noticed a more oil on the front of the engine. That’s when I saw the bolt that holds the balance shaft in was backed out and the balance shift itself was sticking out far enough you could see most of the oring. The only reason the bolt and shaft didn’t come out all the is because the bolt stopped when it touched the rubber isolator that goes around the the big main oil line off the front of the engine.
That’s when I payed attention to the oil pressure in the data log from the last run. At 10,700rpm it only had 38psi of oil pressure. Not good. I looked back a few runs prior and the oil pressure was inconsistent run to run.
For those that don’t know, the balance shaft plugs a major oil passage right of the oil pump essentially. The head is the last place to get oil. So maybe the tick will go away when I address the balance shaft. I check the spark plugs quickly, and they look perfect. So I’m pretty sure it’s valve train noise, not melty piston noise.
Lastly, the one screen shows the intake air temp at 196 degrees. I’m unsure how I want to press forward from here. When it made the 435hp pull it was 60 degree and 150ft DA vs the 1600ft and 90 degrees I had yesterday. That will swing HP quite a bit. While it did make 405 on 15psi, a bit on the fat side, it made 435 on 14psi before. I don’t see it picking up 30hp from leaning it out a bit.
Its interesting to me because on wastegate it made 270hp the same as it did before. But at 14-15psi it’s 30hp off. It does have Grand Canyon ring gaps now, but I don’t think that’s it. If I don’t lower the compression (not gonna happen) add meth, or an intercooler I have a feeling that were right on the point of diminishing gains. I have to keep timing out of it because of the compression, and keep it on the fat side to counter intake temps if I want to be able to run it down the track. At 400hp or less I think it would be fine. But I’m determined to get it over 500 for you guys. If I sprayed meth, the denser air would make a lot of power more easily. I have at least another 10psi I could throw at it, and probably more.
What do you guys think? Sorry for the rant.