Thread: OST-037: Under Pressure

more to come.....

Looking really good, are you going to do a before and after flow test? I bet your really increasing the flow quite a bit, it would be cool to compare with the de heads you've ported also.

I wasn't planning on it.... mostly do to added cost. It would take a day to reset the bench, then the time to run the tests.

I am planning on measuring chamber volumes both before and after, mostly so my client can determine the best piston choice for his application. As I see it, I've added about 3/4 to a full cc to the chambers, but with a thin head cut (for a metal gasket) the total volume may end up very close to it was originally.




let me highlight the areas where significant work occurred




more to come......

Ya I understand man, however we like seeing fancy numbers there's no doubt it's being improved, seeing exactly how much is always exciting.

Pistons have been purchased, I have them, they 10:1 compression.

Sorry I can't make it today, family stuff to do.

since you open the exhaust valve to 30mm....oversize valve is a must?

what you see is the intake side.

The intake valve seat has been opened to 30.1mm, the intake valve is 34.2. That means the intake seat I/D to intake valve O/D percentage is @ 88%. 34.2 x .88 = 30.096. Typically this percentage ranges from 85-90, so at 88%, we should maintain decent velocity, while allowing for more volume.




This compression ratio is based on what specifications??

some things are easy... bore, and stroke. other things less easy, combustion chamber volume, head gasket volume, deck measurement (+, or -)

thats based on a stock head and crank an stock sized rods ect.. im not sure on the differences in the stock gasket vs the sr20vet MLS gasket that will be used.. im sure we can find that info tho.

Very interesting, I didn't know there was such a difference between the valve seat diameter and valve diameter on the ve's intake

Sent from my SM-N900V using Tapatalk

I am not doubting you...... BUT from my experience with Toyota's 4AGE engines, the aftermarket MASSIVELY screwed up the details, and in so doing their "stated compression" was off by nearly 2 full points!!!

To all who are reading this.... Is there any official Nissan, or other reputable source showing the SR20VE's combustion chamber volume, and the piston's deck measurement?

edit: a stock piston dome+/dish- volume would be nice, but not necessary

http://www.neovvl.com/content/index.php/factory-service-manuals?task=weblink.go&id=9