I keep reading about the "low compression rotors" from the turbo threads. What is the most boost that should safely be applied to a sidedraft NA rally ported 4 port 13B ? Is 8-10 safe ?

Is it the same amount ( pounds of boost ) for supercharged as well as turbocharged ?

I have searched extensively, but am not fully comprehending or getting all the particulars.

 

it really depends on your whole setup. most 12a "stockport high compression" guys are hitting anywhere from 8 - 16psi and doing just fine. a ported to hell 13b will probably take 8psi no problem. just gotta be completely dead on with timing and fuel. run it a bit rich and retarded to be safe till you get it on a dyno with a wideband to make sure everything is right.

 

I've seen 12A Turbos running 22 PSI all day long on pump gas.

It's all in the tuning.

 

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Cool ! So say I only want 8-10 pounds of boost through the NA street ported 13B ? What kind of performance gains ?

 

I have heard 12psi is safe, but someone on this forum is pushing like 28psi or more with over 700 hp ! ! !

HIs name is like 680rwhp12a or something like that?

 

I ran 18 psi on my stock ported 12a on pump gas. Then I ran 16 psi on my street ported 12a on pump gas.

The performance gains will depend on the turbo you plan to use. Remember, the higher compression rotors you have, the more power you will get at the same boost level. You will also have more power "under the curve." But, in exchange for this extra power all over the powerband, you give up some engine reliability. You will be putting your engine through more thermal stress than you would with lower compression rotors at the same boost level.