Thanks man. I've now pushed it to 6500rpm at 10psi, but even with the camshafts, the power seems to fall off after it gets really high in RPM. I haven't got it perfectly tuned and I still need to pull some more fuel then play with the timing. I'm sure when its all tuned up it will pull steady until close to 7000rpm.thats great info man
That's not valve float you're seeing, it's just your tune or the fact that even the stage 2 cam isn't that aggressive. I've tuned a 6G74 car with N/A stage 2 cams before (roughly the same profiles as the RPW 4G64 cams I believe), and its powerband was still dropping off up top. It was SLIGHTLY better than stock, but really not what I expected. I expected it to want to continue making power all the way up to 8000 RPM. Valve float you don't ever want to encounter.Thanks man. I've now pushed it to 6500rpm at 10psi, but even with the camshafts, the power seems to fall off after it gets really high in RPM. I haven't got it perfectly tuned and I still need to pull some more fuel then play with the timing. I'm sure when its all tuned up it will pull steady until close to 7000rpm.
Yea, I know that some EVO guys have pushed a 100mm stroke to 8000rpm, but I'm not that crazy. I actually have my rev-limiter set to 6500rpm until I get the tune just right, then I might up it to 7K on the dyno just to see if its even worth running it that high. I think the limiting factor is my tune. I've been doing a 3 pull log probably every 3-4 days and making adjustments. I just don't have the time to sit there and do 3 pulls and then tune and 3 more, ect ect. Not to mention I'm borrowing a backroad to tune and doing more than 3 pulls will start to cause attention and maybe take enough time for someone to respond. On the stock cam it actually did hold the HP steady until 6300rpm or whatever the stock rev-limiter was, but it wasn't climbing. I know that the load at peak hits about 230-240 and then drops to like 200 at 6K and even falls below when it gets above 6K rpm. But even getting to 6K is progress. When I started tuning it was so rich it wouldn't go above 4K with all the ignition breakup from it being sooo rich.Wow, this is really good info.... because... the 6G72 24 V SOHC basically uses the same springs too. Same EXACT valves as well. That's why somebody needs to start mass producing performance valves for this platform. They'd work on the SOHC 4G64 AND the 6G72!
That's not valve float you're seeing, it's just your tune or the fact that even the stage 2 cam isn't that aggressive. I've tuned a 6G74 car with N/A stage 2 cams before (roughly the same profiles as the RPW 4G64 cams I believe), and its powerband was still dropping off up top. It was SLIGHTLY better than stock, but really not what I expected. I expected it to want to continue making power all the way up to 8000 RPM. Valve float you don't ever want to encounter.
That said, anything above 7000 RPM on a 4G64 is getting iffy because of your 100 mm stroke.
