jaksc ·
I'm having a go at screwing together a 1776 for everday use. What compression ratio do i need to run. Doing the measurements it is currently at 9:1. How do i go about raising it or lowering it. Thanks Aaron
Aussieveedubbers · Tech Talk
Compression Ratio
https://forums.aussieveedubbers.com/threads/92009/compression-ratio
Paulc1964au ·
Am Interested to see if u r happy with the 1776 why have you selected a 1776
hellbugged ·
was it just a displacment change or other things as well?
jaksc ·
Had a 1776 built afew years ago by a reputed vw specialist. Had too much end float movement from when it was built. Had about 1000miles on it. Stripped it down and couldn't find anyone to put it back together. Lots of brand new parts. So having a go myself. just need to be pointed in the right direction. Aaron
hellbugged ·
So it's stockfish or big cam, heads etc?
Counterweighted balanced?
Counterweighted balanced?
hellbugged ·
And how have you worked out the c.r?
jaksc ·
Basically stock. Aaron
hellbugged ·
spacers under the barrels or "flycutting' the heads or combo of both
jaksc ·
What compression ratio do i need? Aaron
jaksc ·
Anyone with some tech advice on what ratio I should use. What does it depend on.
Bizarre ·
low 8's??
9 is a tad high for a stockish motor - but what would I know
It all depends on the cam, heads, valve size, deck height and a whole heap of experience.
Did you cc the heads??
9 is a tad high for a stockish motor - but what would I know
It all depends on the cam, heads, valve size, deck height and a whole heap of experience.
Did you cc the heads??
Ollie ·
Go 14.5:1 and you'll just love it 🙂
I lie.
As all above have mentioned, A good strong engine is the sum of it's parts, rather than one standout performance enhancement.
IMO a stockish 1776 would benefit from somewhere between 8 and 8.5:1 compression. It should give it that extra zap without causing too much stress to the engine.
That said, I could be so far wrong It's not funny!
Ollie
I lie.
As all above have mentioned, A good strong engine is the sum of it's parts, rather than one standout performance enhancement.
IMO a stockish 1776 would benefit from somewhere between 8 and 8.5:1 compression. It should give it that extra zap without causing too much stress to the engine.
That said, I could be so far wrong It's not funny!
Ollie
BiX ·
My old 1776 with stock bottom end, mild port and polish and W100 cam had about 8.5/9 ish.
But in the end, that was selected by the engine builder based on the engine combo.
But in the end, that was selected by the engine builder based on the engine combo.
jaksc ·
I worked out the ratio by
cyl volume + head volume + deck height volume
_______________________________________
head volume + deck volume
Stroke = 69mm
I am getting confused. Am i going to to much trouble. Just bolt the barrels down and forget about it. Thanks Aaron
cyl volume + head volume + deck height volume
_______________________________________
head volume + deck volume
Stroke = 69mm
I am getting confused. Am i going to to much trouble. Just bolt the barrels down and forget about it. Thanks Aaron
Bizarre ·
check your answer against this calculator
http://www.aircooled.net/gnrlsite/resource/specgeninfo/calcs.htm
We are just saying 9 is on the high side
You could put a small spacer under the barrels or open the heads up a bit
The spacer mucks you deck height up and that mucks "squish" up
You could whack it all together and see what happens - you might just have to run 98 octane to keep pinging at bay
http://www.aircooled.net/gnrlsite/resource/specgeninfo/calcs.htm
We are just saying 9 is on the high side
You could put a small spacer under the barrels or open the heads up a bit
The spacer mucks you deck height up and that mucks "squish" up
You could whack it all together and see what happens - you might just have to run 98 octane to keep pinging at bay
Gracey ·
Impossible to say without knowing what cam you've got.
jaksc ·
Bizarre, I used the calculator and came up with a figure of 8:1 ratio. I think I am going to go with just bolting everything up as is. There was a lot more involved to this topic than I thought. Thanks for the help guys. Aaron
RISKY4LIFE ·
i think that you could run upto 8.5 for every day use if it was built right
but im no engine builder!
but im no engine builder!
Bizarre ·
jus go for it and see what happens
Only way to learn 👍
Only way to learn 👍