I'm thinking of doing an automatic b20 vtec in my eg. Has anyone had experience with this ? I also want to know if the transmission can handle the higher Rpms. I know the automatic Jdm gsr has a lower red line. People with ls automatic turbos say they have no issues though.

 

It is not a question of RPM, it is more a question of applied torque. Applying too much torque to the input shaft will cause clutches to slip during shifts at the least, or not hold at all.

You should consider larger accumulator springs, higher friction clutches and oil, main line oil pressure increases, and so on to increase the torque handling capacity and longevity of the unit. Some valve body modifications can be made to exhaust oil during the gear shifts to prevent a lot of shift flaring. With these items in mind, your weak points will be the gears and the torque converter only, which is where you would want a failure to occur.

 

1. Where is the clutch located in an automatic transmission, is it the same as the torque converter unit or is it inside the tranmission?
2. Is the accumulator spring inside the transmission?
3. I've kind of jumped the gun since this post and slapped on the automatic transmission. I did not do the things you mentioned, but I will definitely find a higher friction oil. To be honest i just wanted to have fun, not spend too much, and with a little luck have a running automatic b20 hatchback. I will keep anyone interested posted.

PS. Is there oil weight you would recommend for the tranny oil? Thank you

 

Honda Automatics are more like manual transmissions than other automatics.
There are gear sets just like in a typical manual transmission. Instead of shift forks there are clutch packs for each gear, when a gear is selected manually or via the TCU/PCM the four shift solenoids will have a combination of ON/OFF to properly apply fluid pressure to a given gears circuit to apply the clutch packs.

Accumulator springs keep a valve closed until enough pressure is built to overcome the spring pressure. Rather than dragging or blending a gear in for a smooth shift, the higher spring pressure requires more pressure to apply a gear. This gives a faster/firmer shift. You do not want TOO harsh/hard of a shift as that can break other driveline components, but you also do not want a soft Cadillac like slush shift that is slow and in efficient. A firm shift for quick solid shifts.

Use the latest Honda ATF fluid or possibly the Dexron 6 for best protection.