Thread: 20V + 16VE pistons CR

5speed, thanks for link. My pistons was cracked the same way. 20V pistons are junk. I suggest not to use them in high-hp applications.

Regarding the combustion chamber volume, I will correct my numbers in a days. Just found a more precise way to measure them. Unfortunately my combustion chambers are highly modified, so I can't get the stock volume.

Rob E, just re-measured 16VE piston dash with a new precise way, I got 6,795 first try
and 6,731 second try. I will correct my calculations soon.

...... i hope that helps alittle

Can you post up a pic of your 20V pistons?

Haha, well,I wouldn't go so far as to say they are junk. Currently, have 65,000 miles on them. They have been through daily 8,000+ rpm pulls and a lot of dyno runs.

Looking forward to see your "new precise way" measurement.

Ok, I will post my burnt 20V pistons in another thread and will discuss them. Deal?

Regarding new way to measure, it's simple. I just bought a new set of precise medical syringes and I use another thick piece of Plexiglas, so it doesn't bend while measurements are taken. I've got next measurements last time:

1 cyl.: 43,11 | 43,17

2 cyl.: 43,40 | 43,41

3 cyl.: 43,10 | 43,12

4 cyl.: 43,22 | 43,14



piston dash (in bore): 6,795 | 6,731

Great precision of measurements I think.

Remember my combustion chamber is highly modified. So now I admit my mistake of first measurements. Unfortunately, I can't measure stock 20V combustion chamber volume now.

And what we get:

if we take into consideration 40,5 сс volume (more_fasterer's data) for stock 20V head, we will get 13,2:1 CR using 16VE pistons. +1mm notched pistons will bring you 12,77:1 CR.

if we take into consideration 41,8 сс volume (Andreas' data) for stock 20VE head, we will get 12,87:1 CR using 16VE pistons. +1mm notched pistons will bring you 12,42:1 CR.

My modified 43,15cc combustion chamber will bring me 12,5:1 CR using stock 16VE pistons. +1mm notched pistons will bring me 12,07:1 CR.

I think I will be happy with 12:1 CR. I'm thinking now on which cams will suit this setup.

post of awsome!! cheers dude..

Nice job SRC.

Thanks..
I will measure stock 20VE combustion chamber by myself if I get one disassembled. Currently one of my friends thinking of bumping his CR up.

Bump fo r a very informative thread......Keep it coming guys. I would really love to put my 16ve pistons in my sr20ve block and be able to drive on 93 octane gas w/o detonation!!!

I mean I am not very good at reading and deciphering your data. So when you say this"+1mm notched pistons will bring you 12,42:1 CR." you basically mean shave 1mm of the top of the pointy part of the 16ve coned pistons??? or idoes that mean something totally different? I mean as of now if anybody was to drop in sr16ve pistons in a sr20ve block the compression will be like 13 something , which is just to high for 93octane and woudl probably work on some 110 or c16... What I like about 13;1 or even a reasonable 12:5/6 is its in the 12's and $hit I will try that with some race gas in and a MUCH better tune. i will bet you that car will run maybe even mid 12's all night long with a nice tune and good set of cams of course

I don't drive my VE much and don't have a cat since it only see's 2600 miles a year, so I would pay the money for 110 or higher which should be enough for a very fast and sick VE!!!! U am so happy i ame over to the vvl world. Dont get me wrong boost is amazing, but between popping coplers, no traction, making intercooler piping its a real pain in the you know what!
Now i am DEFINITELY not giving up on boost, but next time I might go small or do a VE head with a DET bottom, the best of both

Well I hope one of you guys figure the exact formula out and explain it in laymen terms so we can all understand
There are enough smart guys on here to figure this out for us guys not as smart so we can safely do this??? Please!!! I know this motor has sooooo much more potential.

jonwepa, "+1mm notched pistons" I mean deeper for 1mm valve reliefs.

Thanks guys for taking this thread live. I really don't want to post if I don't get feedback from you. This is a place to share our knowledge and to discuss things like that.