Originally Posted by
codename Bil Doe
After reading so many help posts and finding out people are making changes that will kill their motors real fast, I thought I'd post up some info that's been learned - often the hard way - over the years.
Pushing these limits on a stock motor doesn't make you a genius. It means you'll be spending a lot of money soon rather than not.
Boost:
Stock rung lands can only hold a max of 25psi. This is the limit that is already equal to a quick death. 24psi is pushing it. 23psi all day. This inlcudes boost ramp up overshoot.
Stock sensors will only read 23.5psi. That doesn't mean you stopped at 23psi. The little k04 will boost over 30. This is bad.
The k04 is a heat pump above 24psi. Boosting above 23psi with it is really a waste as you will have to lower timing due to increased charge temps. Plus see above.
Timing and octane:
Unless it's noted as from another thread, this is directly from me doing months of testing. This is from street and road racing at 23psi peak which is pretty much the stock limits. I wouldn't advise going higher than these. Mid range you'll need to figure out for what the engine likes. With that,
91 octane - 11° peak
93 octane - 13° peak (several east coast peeps running this np)
100 octane - 18° peak
105 octane - 20° peak
110 octane - 23-25° peak
E47/E85 - 23-25° peak (E85 threads)
If there is any other basic safety info for stock engines feel free to post.