Rotary Resurrection - Engine Option

Streetporting (Sp) is an internal intake/exhaust modification that can only be performed while the engine is disassembled. It is similar to swapping cams on a piston engine, it affects airflow (think lift) and timing (think duration). SP’ing is to be regarded as any other airflow mod (like air filter or exhaust mod) as far as power increases go. A large Sp on a stock car, for instance, might not be as noticeable as a small Sp on a modified car. Sp’ing doesn’t really change your idle ability or rpm, though a large SP can change idle tone a bit and perhaps even make the idle lumpy. IT does affect your driveability, mainly your low end pull. Especially, for instance, pulling out on a steep hill from a dead stop.  The gains on top end are definitely worth the risk, however. Gains from an Sp on a nonturbo are not large, but still worthwhile, around 5-15% depending on mods. Do not plan on passing emissions sniff tests with a port, though it still may be possible with effective emissions tuning.

I generally keep my ports fairly conservative, which is good for a street car. Exhaust ports are opened slightly earlier but kept mild for low noise and emissions. Intake ports are opened, within reason, as much as other ports, boundaries, and water jackets allow.

I generally perform only one version of streetport for the 87-91 turbo engines which is a clean, medium/large port style. Expect to pull around 13-11” of vacuum with this port, while still maintaining a slightly lumpier stock idle. Mildly modded t2’s can expect 10-20hp gain from streetporting.

Pics of stock vs ported secondary intake ports:
Stock vs ported primary intake:
Ported exhausts:
Rotary Resurrection - Engine Option
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