Pkades

Looking for peoples opinions, pros/cons, and personal stories about different compression pistons.
I've read that no one uses 8.5:1 anymore and people stick with 10:1.

I'm planning on running high boost and am currently looking at upgrading turbo (currently running a t3t4 setup)

Thanks in advance!

2kdrift

10:1

/end thread

Pkades

can you explain please as to why they're better over the 8.5:1's???

2kdrift

Well there's no reason to run lower cr with today's technology all they will give you is a less responsive car and will make less power. Search there is plenty of info on this, seems like this question comes up about once a week

turbomaniac

one more vote to 10:1.

the b18 engine has low dynamic compression ratio due to high degree cam at vtec phase, so you don't want to lower it more.

Chance EG

Go 5:1 and run 1 million pounds of boost.

But yes, 10:1. Improvements in ECU control/tuning, more consistent fuel quality, better hardware and a general abundance of knowledge over these platforms lets us safely push the CR a fair bit further than we used to. Only yields benefits.

2x0

If/when I do a rebuild I will be going to 10.5 or 11:1

Nothing worse than a laggy, peaky turbo car on the street....

LightningTeg

Low compression is for the birds

Pkades

Low compression is for the birds
__________________
07' FA5, DD
98' DC4, Race car

Hahahaha - what is this supposed to mean? :p

Pkades

Thanks everyone for your feed back - what about 9.5:1's??

TheShodan

iTrader: (14)

If you can go 9.5:1, you can go 10.0:1... Plain & simple

2kdrift

Aim for 10:1 due too differences in various areas such as head selected, amount of milling etc. Your never going to be exactly at 10:1 if you do end up a bit higher or lower such as 9:5 It's acceptable

JRCivic1

9.5:1 compression is better than 8:1... 10:1 compression is better than 9.5:1. The key is you want a FLAT TOP piston and not a "laggy" dish type piston. The compression will be in the 10:1 range with a flat top piston type... unless you use a super thick head gasket or something. LOL. The compression can be altered +/- about a half point with a custom pin location... but this isn't an off-the-shelf product, so delivery times will be lengthy and replacement if you damage the pistons will also take longer.

1HGEJ2

iTrader: (1)

10:1 if u have premium gas or e85......9:1 if u want drive low octan like low octane soup

Pkades

thanks for the reply bro, appreciate it.

will be running 98 pump gas (NZ)

Pkades

this was an awesome response, thanks heaps really do appreciate the help

gorillaglue#4

I was told by my local honda turbo guru not to go below 8.5. If you are going to lower it why not stoke it as well?

ZC1.8crx

I went 10:1 on my engine.