He was mixing and matching turbo and non turbo parts when he built this engine. If the wrong dipstick was used the level won't show right. Personally I fill up til the stick shows the right level and don't pay that much attention to EXACTLY how much got poured into the engine.

A turbo engine should use the shorter stick IF the entry tube was left in place on the Turbo intermediate housing.

 

I understand he was mixing and matching, but unless he has 2-3 quarts in there the oil pressure wont fluctuate like that, I would think if he had the skill to rebuild the engine he should know it will be at least 4.5 quarts going back in, more if the cooler was drained

 

Sorry to bring up an old thread, but this is the only thread I could find that has actual measurements.

Hailers I have some conflicting information on this. I was curious why my oil changes only took about 4.5 quarts when filling up, my old RX7s always seemed to take around 5-6. Searching for answers I find this which led me to believe I had the incorrect dip stick. I ordered from Atkins Rotary N332-10-450A Turbo oil dipstick. His site suggests that all turbos S4 and S5 are the same length.

Comparing the two dips stick shows that my original dip stick is the same as the new replacement. The attached picture shows the new stick on top, old stick on bottom. Length from tip of the stick to the rubber stopper where the tube sits is 12.75" This doesn't match either of your measurements. But measuring my tube length did match your measurements. So there is something odd about the two dipsticks you've found yourself with.


S4 Turbo II dip stick length