What piston and rods do people use in a full silver top zetec turbo and what compression do they come out at? I want roughly about 7.5:1 but all the ones i have looked at are much higher than this at 8.5:1 and 9.1:1.

 

i run je pistons and eagle rods @9.7.1 so i wouldnt say 8.5.1 is high ,what sort of power do you want??

 

im going for over 300 bhp+. Maybe want to touch the 400 mark.

 

talk to your mapper and spec it that way, thats what i did.i should be running 300bhp@ the wheels very soon.

 

Which part number JE's are you running?

 

i would have to dig the invoice out but why would you want to no that??they put a standard black top in at 9.1 but not on my engine i run a st170 head and the engine has been built and cc'd @jam .

 

Why would I want to know that? So I know which pistons you're using? Going by the further information you have supplied, I will assumt they are the 'low comp' pistons JE do but on the ST170 head it ends up high! Thanks!

 

i had some forged xe pistons and just done a compression check. they came out at 9.2:1 which is to high for what i want. How do people get there compresstion down?

 

juffer- on what rods?

 

silver top rods ( will be using same size eagle). I think i have done the calculations correct.

86mm bore
88 mm stroke
48 cc head chambers
piston to deck 2.5 mm
head gasket wrc 1.3 mm

 

So hang on, you didn't do a compression CHECK - you just calculated it? You need to measure it.

The XE pistons have a slight dish in them.... and they sit more like 3mm down the hole.

 

I havent bought pistons of rods yet. Im getting information together so i can build. I already had the pistons and just wanted to do a compression test to see if they were any good. sorry if this was confusing.

 

I have just measured the dish and its 2cc. So if your correct with the 3mm deck to piston hight then the compression is 8.6:1.

http://www.johnmaherracing.co.uk/enginecalc.htm