b18a engine compression

I have a 90 integra and i'm planning on rebuilding the engine, and so i had a compression test done to see just how bad i was sitting. i have the acura shop manual for my car and it says that the stock compression should read 185 PSI in each cylinder and not more than around a 20 PSI variance between cylinders. keeping in mind my engine is 13 years old, i was alarmed to discover that each cylinder read 180 PSI give or take 1 psi. 3 runs on each cylinder were made to ensure accuracy. Each cylinder was also held at this pressure for 10 mins with maybe 1 PSI leakage. I'm not at all complaining about these readings, I'm just very surprised and confused. I don't understand how an engine with 200,000 KM and this old could hold compression like this. It has never been rebuilt or anything. I realize this may be a dumb post, but i'm just tyring to get an understanding of how this may be. I have been told to expect a drop of around 15-20 PSI, but obviously i'm not even close to that. Any suggestions would help me in understanding this.

The engine is the b18a with the standard bolt on mods. I'm working on prepping for a turbo.

if you've taken good care of it, then its not all that surprising, cause honda engines run forever, compared to most.

That is kinda surprising to me b/c of the bad r/s the ls motor has, but if the car has been driven easily and not abused and well maintained then yea that is the payoff ;)

That is kinda surprising to me b/c of the bad r/s the ls motor has, but if the car has been driven easily and not abused and well maintained then yea that is the payoff ;)

please excuse my ignorance, but what is r/s?

Also, on a i-don't-know-how-unrelated note, what would a rediculously large amount of carbon buildup inside the intake manifold suggest? (I'm assuming carbon because i've searched and searched thru threads, and that seems to be what the black buildup in intake manifolds is.) The residue is very black and somewhat slimy (like stale/burnt oil). I'm trying to diagnose what causes this buildup, but i haven't found anything to indicate that. I've only found suggestions of how to clean it out. If it's carbon, where does that come from? if it's oil, does that mean my intake valves may be screwed? Any suggestions would help me understand this. Thanx.

That is normal you may want to change the PCV valve but the buildup comes from the PCV system.

Also r/s is Rod to Stroke ratio. It is the ratio of the connecting rod vs the amount of stroke the crankshaft has. Basically the lower the number the more side load you have on the cylinder walls and more wear on the piston rings and cylinder walls.

Thanx again whtteg... is there anything you don't know about honda's?