Stock piston Question

[aronmatic2]

people i simply want cp pistons, not je nor something else. i would be greatfull if someone can tell me the correct specs of the stock one.

why do you like cp? do you like the box color better. do you know, what is the difference between je and cp. the name of brand. all of them are the lowest quality, cheap forged pistons.

[Billman]

i like cp because of their nice marketing and the fact that they are a daughter of Pankl! can someone help me out now or should we go further with off topic comments?

[quattro84]

Yup, CP = Pankl = F1 supplier

[Billman]

since we dont have accurate data on the rest of the combustion chamber we are going to calculate the new piston specs according to the stock one paul provided! (hopefully Mark didnt machined them down to drop the compression on the old ABY engine).

Quote: "If the sample is 9.0:1 and we change the bore to 81.5mm, the stroke to 95.5mm you need 15cc dish and VP cc to drop the CR to 8.5:1 The dish needs to be 5.97mm deep and the valve pockets 1mm deeper to get the 15cc required."

[Billman]

and a CAD picture of the new dish

[Flat on my back]

.

This is my JE custom 82.5mm piston for the 92.8mm crank, CR 8.5.

[Jamo]

JE 82mm 155.5mm rods 95.5 crank 8.6 cr

[Flat on my back]

.

Jamo, are you prepping the top of the piston in any way?

Sorry for off topic...this is turning into a piston porn thread...

[Jamo]

Well no, do you believe they needed it? they are in the engine now :lol

[Flat on my back]

.

I'm going to deburr any and all sharp edges on the top surface down to a 20 thou rad., then polish...not sure if my tuning guys are not taking the piss on this one...

[Billman]

quite deep dish on all of them!

[GazzaG60]

id check them for bits but not modify them.

most important thing is matching bores and sorting ring gaps

[Jamo]

I'm going to deburr any and all sharp edges on the top surface down to a 20 thou rad., then polish...not sure if my tuning guys are not taking the piss on this one...

I think they are, JE are used out the box to great effect by a lot of big power guys.

There are no burrs on them.

[Billman]

Hi, i need some help here:

Block material?
Bore material?
Are the bores coated?
Max rpm?
Max hp?
Max boost?
*
Rod small end width?
What is the thickness of the material in the rod above the pin bore.
The oem piston has an oil squirt notch in the skirt, do you need this?* We may not be able to position*the heigth correctly due to the stroke change.
The OEM pistin has offset pin bores, we do not use offset pin bores on this type of piston is that ok?

thanks

[quattro84]

Cast iron
Same
No
Depends on your setup. If the turbo isn't boosting anymore it is useless to continu revving. Another guideline is max pistonspeed & acceleration @ TDC/BDC
+1
+1

The last four questions are up to the designer of the piston.

Those are some serious choices mate, nothing to guess really but up to the specification of the customer and the knowledge of the designer.