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I know I'm pegging an old thread, but I found an on-line converter that could clear this up for future inquiries.

http://www.onlineconversion.com/volume.htm
Just in case you want to add it up on your own, I included .01

.01ci = 0.1638706 cubic cm
.12ci = 1.9664477 cubic cm (2.0)
.15ci = 2.4580596 cubic cm (2.5)
.16ci = 2.6219303 cubic cm (2.6)
.18ci = 2.9496715 cubic cm (3.0)
.21ci = 3.4412835 cubic cm (3.4)
.25ci = 4.096766 cubic cm (4.1)
.26ci = 4.2606367 cubic cm (4.3)
.27ci = 4.4245073 cubic cm (4.4)
.28ci = 4.5883779 cubic cm (4.6)

So, really, a .21 doesn't even round up to a 3.5, it's a 3.4 by normal rounding and the .25 rounds up to a 4.1
 
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ahh see, that's what I was gonna say.

great information olds..

8,062.4355221 cubic centimeter <---my mother's old 492ci cadillac

the trx 2.5 is a .15ci engine with an elongated stroke (why it's tall) the bore is still .15ci. the change in displacement made the jump to the 2.5cc category. also, the marketing benefits as stated earlier in the thread.

wiita
 
Originally posted by HumboldtBlazer
Block size is way different than displacement. .12 and .15 share the same block size, same crank, and same conrod. The diff is the piston/sleeve size.
Click to expand...

all .21 (.22, .23, .24, ,25, .26, .27, .28) and above to my knowledge have a 3.5 block.
 
Now, that's just crazy talk.

Probably is the same block with a thinner sleeve and fatter piston or bigger crank/longer crankshaft with different porting.

I was just posting for the displacement amounts. Regardless, it's all just a bunch of numbers that people throw around. Anyone really measure any of their engines?... me either.
 
I am not by anyway saying I am an experst so if anyone knows any better please clear me up. I do think that is how it works though. Deff a confusing topic that is debateable.
 
my Force .25 says 3.5cc right on the block.

The TRX engine didn't start as a .12. It's a .15 bore with a longer stroke (than normal) Can't say I know the displacment measurements on stroke and bore of .12-.21ci engines. and no, I've never literally measured mine piston/sleeve sets. I can only hope the engine manufacturers did :)

wiita
 
If you want ACCURATE information, get it in this forum. If you just want rumors or lame conversation, get it from your LHS.
The only time you trust the info you get there is if the guy shows up at your track with 3 different cars. If he doesn't own any, he's just a salesman.
The guy that sells encyclopedias, doesn't know everything that in them.
 
Originally posted by HumboldtBlazer


all .21 (.22, .23, .24, ,25, .26, .27, .28) and above to my knowledge have a 3.5 block.
Click to expand...

He is right! Anything bigger then a .21 has been moded with either a larger piston and sleeve or a longer stroke or both but, have the same crank case size. The reason they did this is so they fit into alot of .21 trucks on the market without having to make a different engine mount and other mods to make it fit. Most of the engine company's are in the engine manufacturing business and not the chassis (motor mount) business.
 
My HotBodies .26 says 3.5 on the block. I found out that it's just a typo. Says so right on their website. Who can blame them though? I wouldn't melt down all those misprints just for appearance sake.

- bomber
 

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