Why am I hitting a power wall with my stroked RB25?

[TurboTapin]

I was back on the dyno again yesterday after completely revamping my methanol injection system. I was making 440kw at 19psi. Great, this is more then I was making last summer with my old meth system at that pressure, and I figured it would be smooth sailing up to 30+psi. We continued increasing from there and by 25psi, I had only hit 455kw. Dyno sadly lost utility power at this point and I left. We seemed to be on course to hit the same power wall as last summer (477kw@27psi).

This is a built RB25 S1 stroked to a 2.8. Built and ported head with Kelford 272/262 cams. Precision 6466 Turbo. Tuner last year believed the power wall is a mix of RPM limitations (Hydro lifters/Limit set at 7600RPM) and fueling. With my new meth system, we're seeing zero knock now but it still won't go up. 

What else can I do at this point? Here's my train of thought. 

- It's clear from the dyno graph that I would easily make power to 8500+RPM but I'm limited to 7600RPM. I could risk increasing my limiter, but hydro lifters have me worried. What are my options here besides going NEO head or solid lifter conversion? I'm rocking a 1.05AR turbine on my 6466. Would dropping down to a .84 help shift that power down in anyway?

- We're only seeing roughly a 30kw difference at the top end with VCT on or off. Is this normal? I want to confirm VCT is working properly.

- Should I look into other cam options? 

- Should I just keep increasing boost and see if she wakes up later on? I would expect to hit 600rwkw around 35psi with my 6466. 

 

Edited 4 hours ago by TurboTapin

[Dose Pipe Sutututu]

A few suggestions:

• Do you have the option of retarding your exhaust cam gear to bring the power band over to the left?
• VCT would be turned off after you make peak torque, you see the power/torque will decay faster with it left on all the way to the limiter
  • Once VCT is turned off, you'll find the motor will take a bit more timing being ramped in
• Send its mum, more boost!
  • Of course, depends on your exhaust pressure.