GSL-SE Intake and Exhaust Port Timing
04-21-08, 12:00 PM
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GSL-SE Intake and Exhaust Port Timing
Hi-
I'm trying to located the timing specs for the intake and exhaust port opening and closing. Does anyone here know what what the stock 13B numbers are? I.e., at how many degrees ATDC does the intake port(s) open and close? Same for the exhaust ports.
Cheers,
Mark
I'm trying to located the timing specs for the intake and exhaust port opening and closing. Does anyone here know what what the stock 13B numbers are? I.e., at how many degrees ATDC does the intake port(s) open and close? Same for the exhaust ports.
Cheers,
Mark
04-21-08, 12:55 PM
#3
I don't know the actual numbers, but I do know the exhaust ports open late and close late compared to early US-spec 13Bs. This helped keep the burning mixtures in the 'chamber' longer which resulted in slightly more time to push the eccentric shaft around. This equates to more torque and a little more high RPM overlap at the expense of turbo-spooling ability, which was fine since there was no turbo on that particular model.
To compare to a 12A turbo of the same year, those exhaust ports open early (at US spec for old 13Bs) and closed 10° later than US-spec 12As and early 13Bs. Kind of like a mini street ported exhaust. j9fd3s has commented on these before.
I'm experimenting with a set of J-spec early 13B rotor housings which have the same port timing as GSL-SE. My goal is more torque than would be otherwise available from idle to at least 4500 RPM. Anything above that is a bonus. It is a rotary baja project. Wish me luck.
To compare to a 12A turbo of the same year, those exhaust ports open early (at US spec for old 13Bs) and closed 10° later than US-spec 12As and early 13Bs. Kind of like a mini street ported exhaust. j9fd3s has commented on these before.
I'm experimenting with a set of J-spec early 13B rotor housings which have the same port timing as GSL-SE. My goal is more torque than would be otherwise available from idle to at least 4500 RPM. Anything above that is a bonus. It is a rotary baja project. Wish me luck.
