user 8202

Are any of you guys running a 4 port boost control solenoid with a dual port wastegate actuator? How do you like it? Was it really hard to tune?

I just bought the new Turbosmart GenV dual port wastegate actuator and a 4 port boost control solenoid for my 97 miata running an EFR6258. I wanted this setup so I can just use a 7 psi spring, but still run up to 25ish psi.

I havent installed it yet and now I am reading all this stuff about how hard it is to tune a 4 port boost control solenoid. Is the 4 port not worth it? If I run a 10psi spring, will I be able to run mid 20 psi with a 3 port?

Thanks for the help.

codrus

I used one with my GTX2863R, it was really easy to tune but that was with an external wastegate so may not translate.

General rule of thumb is that anything over 2x base spring pressure is unstable with single-port boost control, so 10 psi spring and 25 psi boost target sounds unlikely to work well. You won't know until you try it though.

--Ian

Blkbrd69

Wouldn't 25 PSI on a 6258 be like 500HP? That is over 3x spring so not sure?
Didn't have any problem tuning mine to a flat time trial dyno curve so shouldn't be a problem to spike it up?

codrus

The compressor map for a 6258 only goes to 44 lb/min, I don't think you're going to do 500hp on that. 6758 maybe.

--Ian

rwyatt365

I used a 4-port MAC solenoid when I was using a GT 3071-clone Chinacharger (Anything over 200kPa on that setup would push open the IWG flapper and I was using the 4-port and a dual-port Turbosmart WG to hold it closed). It wasn't hard to tune once I figured out the proper plumbing of the "vacuum" lines. The only caveat that I ran into was the lower sensitivity of the 4-port solenoid (i.e. small changes in duty cycle caused much bigger jumps in boost as compared to the 3-port solenoid). When I switched to the 6758, I put the 3-port back in and it's worked a treat (so far) but I'm not having boost levels beyond 220kPa and the IWG is working just fine at that level.