scoooby slayer

iTrader: (4)

just wondering which gives the lowest compresion ratio and how to tell the difference between the two.

jonnyboy

2wd head has two lugs on the exhaust side for the turbo damper,as for the c/r the resident experts will not doubt help you out

scoooby slayer

iTrader: (4)

cheers mate ive got 2wd head then. may be able to get big spec head but told its 4x4 wonder what itl do to c/r ?

westus1

iTrader: (6)

i didnt even know that the head made a differance to comp, there are a few other differances in the heads but as above the turbo damper mount is the easiest way to tell

scoooby slayer

iTrader: (4)

im not sure thought i remembered someone saying 4x4 head gives lower comp ? maybe its pistons then ?

westus1

iTrader: (6)

i'm not saying your wrong, far from it, i just didn't know that so i'm interesred to find out, by the way what you doin with your old turbo? lol

scoooby slayer

iTrader: (4)

?

NEEDFORSPEED

i didnt think it made a difference either apart from thickness ie if its been skimmed will be interesting to find out for sure

scoooby slayer

iTrader: (4)

up

Nash

iTrader: (3)

If you fit a 4x4 head and you had a 2wd one on before it will raise the comp ratio.

I 'think' 2wd head and 4x4 pistons works out to be around 7.8:1 but i am sure someone can confirm that.

scoooby slayer

iTrader: (4)

well im pocketed pistons 7.5 comp with 2wd head, 4x4 head a big no no then for 550 hp

scoooby slayer

iTrader: (4)

btt

CossieRich

iTrader: (1)

Stick a 4x4 head on and you will raise the c/r

Martin-Hadland

iTrader: (2)

2wd pistons/4x4 head increases comp by about .3
4x4 pistons/2wd head lowers comp by about .3

col cos1

iTrader: (5)

you can also tell by the face of head,the water jackets things are diffrent on 4x4

sort of tear shaped where a 2wd are same both sides

scoooby slayer

iTrader: (4)

thanks martin. my pistons are 4x4 according to paperwork and supposedly 7.5 with pocketed 4x4s and 2wd head. so in theory a 4x4 head will put me at 7.8 c/r. do i dare ?

westus1

iTrader: (6)

sounds to me more like your actualy running 7.2-1 if your using a 2wd head, if its 4x4 pistons they'll be meant for a 4x4 head so if you put the 4x4 head on it'll take you to the 7.5-1 that you thought you were at already

Nash

iTrader: (3)

If the engine was built correctly and CC'd it will be 7.5:1 like is written on his paperwork.

scoooby slayer

iTrader: (4)

thanks mate. if thats the case il try gettin the 4x4 head thats been done.

scoooby slayer

iTrader: (4)

paperwork just says 7.5 comp v bowl pistons from burton and 4x4 pistons.

Nash

iTrader: (3)

Tbh mate as the heads coming off anyway why not CC the engine so you know the comp for sure? With the power you are going for i wouldnt take anything for granted as it will end up costing you alot more money/time.

polly_x

iTrader: (2)

Do you really think you will notice? 7.5 or 7.8, pretty sure your tuner will be able to map it for what you require.