i know there is a few topic on the subjet but my question is a bit different and i didn't wanted to highjack anyone topic :S

so having 1.8L piston in a 2.0L would raised compression at about 11:1 .....


the thing i was wondering with that kind of CR ratio what fuel would i have to use would 89octane regular still be enough or would i need supreme at 91 octane ?

 

I don't think 89 would be enough... besides, with such compression, you would get more power from the 91 gas than from the 89 (assuming the 89 does not knock).

 

I thought 1.8 liter pistons lowered CR.....

 

I had the same question!

We run 95 unleaded in South Africa, so I asked two mechanics from different shops

The one guy says ideal compression ratio for 95 is 10.5:1 to 10.8:1
The other guy who isn't out for my money says ideal up to 11.2 and 11.8 maximum for 95


Im sure a google search or call to a decent shop could get you an answer quick enough

Let us know what you find

 

^^ If you run 1.8lrods will lower the compresion not the pistions for turbo app. BUT if you use 1.8 rods and pistions in a 2.0L block you can boost up to 25psi and they will hold..

for N/A sets up i suggest to use the following

bore the block 1mm over

use 1.8 pistions and 2.0 rods

Airram intake

272 int/Ext cams

shaved the head 0.07mm "if you want" this will up the comp more buy 0.8 to 1 point

XD head gasket "metal type"

BBTB and headers and 65~68mm catback

That was my old set up..

make sure you check all clearances.. to include the pistions

 

I'm gonna stay on topic here, and just sift through the many duplicated topics to post my loads of questions!

Thanks for your specs Mad_John.. but what fuel did you have to use with that?
What sort of power were you pushing?

I was aiming for 11.8:1 with the pistons and head shave, I wonder if that would be safe with 95 octane lead replacement petrol?

 

i was running mogas aka cheap ass army fuel, it ran ok but any thing 92 and above is better noticed a smoother ideal

what you want to do is fine i dont see any problems

 

so having the 1.8L piston i would have to use prenium wich over here is 91-92 .....

what kind of power where you gettin out of that set-up mad john ?

it about the exact set-up that i want.... i want to stay N/A and single TB since it's a daily driver

 

I am going the N/A route right now john, but I don't want to pull the block and do the 1.8L pistons, too much work and money. I will do that when I go turbo. My question is, is the beta 2 head gasket thinner than the beta 1? I measured my beta 1 and got .029".

And is it safe to mill the head .070"?

The machine shop I am at says he will need to take off about .004-.010", but I would like to raise compression to about 11:1. So it would be ok do take off say .040" even with my oversized valves +1mm?

Thanks.

 

^^ you dont gotta pull the block to do pistons mang

pull the oil pan

unbolt the 8 bolts for the caps

drop the piston and rod combo

take it to a machine shop have them heat it out and install the pistons(your lookin probably about 40 bux hell they probably will install the rings too)

reinstall

seriously you could do it in a weekend with a lift and some tools (torque wrench to measure the rod bolts) and whatever you dont have autozone will probably have