like wadzii sad there is some fab work that has to be done to make the stock rods work with the aftermarket pistons.

 

got my pistons back today from mahle. see if they fit now. ill let u guys know what up in the next few days

 

Any update?

 

the chamfer thats being added will bring the diameter of the top of the piston down to about .6mm less than the diameter of the smallest chamber we measured (they ranged from 86.1 to 86.8mm).

The head I sent them when they were designing the pistons had a chamber diameter of 86.8, which the OS pistons fit perfectly fine in.

I talked to the OP's engine builder, the OP's head had a diameter of 86.3mm and one of my other spare heads had one chamber that was 86.1mm. Its strange that honda would do that but I have seen stranger.

 

Hey wadzil do you know if the pistons SOS has forsale are the updated chamfered pistons? Or is there an updated part number? I'd like to save myself the turn around time if I purchase these...

 

I cant speak for SOS, I dont know those guys.

the 3 sets I have instock are going back this week and they are going to add the chamfer to mine and all the others Mahle has instock.

There is not a new part number.

 

it took less than a week to get them back when we sent them out. i was happy with the turn around time.

 

I just want to vent and say that 8.9 to 1 is absolute stupidity at work.
Someone who i promise does not understand dynamic compression is the person who would couple a compression ratio that low with the vtec cam profiles.
We arent building nissans here people. How do you think that this engine STOCK has been capable of making mid 700s to the tire?
Because when the vtec cam lobes are in use, the dynamic compression is PEFRECT for boost.
IF you are worried, or an inept tuner, then i would say to drop the compression MAX 1 point.
To 10 to 1.
NO LOWER with the STOCK cams.

 

Explain dynamic compression and why?

 

wow.. you dont understand

On a turbo motor the static compression is directly related to the amount of power you can make on a specific amount of octane.

On pump gas 8.9:1 compression on a 2 liter will be safe to 500-600hp ish.

stock compression is lucky it works as well as it does, 350-400 is about all you'll get on stock compression with pump gas, even then every motor I have torn down that was making that much power, regardless of who it was tuned by showed signs of detonation or pre-ignition on the wrist pins and rod bearings... big cams work well in alot of situations including 8.9:1 in an s2000.

11:1 is just too high for a pump gas turbo motor.