bonus_boy

just wondering if theres low comp or normal comp pistons, or are they all the same?

or does the headgasket lower the compression?

also how much would a good condition set of these pistons set you back (with conrods) 2nd hand?

cheers

Turbo Zetec

iTrader: (1)

knowing what engine you're talking about would be a great help

bonus_boy

1.6 cvh turbo (mfi/efi)

bonus_boy

there 8:3:1 comp

are these low comp?

bonus_boy

need to know asap please

Matt Evans

No. Not for a CVH turbo anyway.

bonus_boy

you serious?

there was some on ebay stated rs turbo fiesta/escort mahle pistons...

was outbid but he said i could have 2nd chance to buy them as the winner has not contacted him

xr4x4rs

iTrader: (5)

sounds like std rst compression ratio

anything higher is a no go though, but do you know what size bore they are and what size your block is

Matt Evans

IIRC, 8.3 : 1 was the standard compression ratio for a CVH Turbo. Dont forget the CVH turbo uses a lower comp. ratio than a standard N/A cvh engine so technically they are "low comp" pistons.

Modified lower compression pistons are available for the CVH turbo such as 7.5 :1.

So yes, i was being serious.

bonus_boy

i havnt got a block yet, i was going to buy them as i had plans to build a low comp bottom end, but just want to find out more info and see if there low comp pistons first as he isnt sure, just knows they are 8:3:1 comp

pa_sjo

I think i'd be buying the block before the pistons!

Matt Evans

Buy the block first. Then get pistons to fit that, not the other way round.

bonus_boy

lofty i thought you ment there not for a cvh turbo anyway, thats why i said are you serious... lol..

so there standard comp pistons for a cvh turbo? and not the low comp ones im after...

im pretty sure there 0.5mm overside pistsons, so if i just buy a standard cvh turbo block i can just get it borded out..

sbd16v

thats low comp to me my new engine for the gte is 8.5 :1

pa_sjo

I'd be very surprised if Mahle make a 'low comp' piston for an RS turbo... They're an OE piston supplier, not some boy racer aftermarket. You can machine down the standard pistons to get a good compression ratio with no reliability problems.

Charlie Chalk

iTrader: (1)

Get standard comp forged pistons, more than good enough for the power you want.

bonus_boy

i was pretty sure mahle did low comp pistons?

there mahle forged pistons 8:3:1 comp..

pa_sjo

I think we're just going around in circles here.

Matt Evans

Hang on.

Do you know what spec of engine your gonna be building? Ie Capacity, power figure aiming for, turbo used, management etc etc.

Only then can people advise you what compression pistons to get, although in all honesty, unless your going for massive power, the "STANDARD" rs Turbo Mahle 8.5:1 compression pistons are more than suitable.

if you want even lower compression pistons, Accralite or someone similar are gonna be the way forward.

But you need fixed in your own mind what you wanna achieve first, BEFORE you start buying used bits and mixing and matching them.

G2RSR

mahle did not make any forged pistons or low comp pistons for the cvh turbo

all they can be is the standard mahles 8:3.1 cr

CossieRich

iTrader: (1)

Bonus boy. Try listening to what people are saying mate

xr4x4rs

iTrader: (5)

hard work isnt it lol

mahle do do std ow comp pistons, but they are just standard pistons with 20tho taken off as i had some years ago

but, buy the block first then the pistons,


but as said, work out how much power you want etc

as a std bottom end would be good for 200bhp all day long

Charlie Chalk

iTrader: (1)

A fresh built CVH would be fine IMO.

What power you wanting?

bonus_boy

i have listened mate..

now i know that they cant be low comp or forged pistons then im not going to get them..

bonus_boy

well i was just going to build me a solid bottom end..

probly wanting it to handle 250/270bhp

G2RSR

yes that's exactly what the so called mahle low comp pistons are standard skimmed squeezed cast

xr4x4rs

iTrader: (5)

mahle are forged pistons, well std cossie ones are, unless its a different sort of forging they use

Charlie Chalk

iTrader: (1)

I'd be looking at rods before pistons then.

cabrio zo

Wossner do low comp forged for cvh - 7.5:1
Z

G2RSR

rs turbo ones are squeezed cast type good to about 240 bhp

it would be cheaper to buy a zetec 2.0 block and use some mahle vauxhall LET pistons which are forged for about Ł100 and give 7:5.1 cr

bonus_boy

the only reason im asking about he mahle pistons as some came up cheap (2nd hand but in vgc) but as there not low comp (which i wanted) then il just leave them...

Matt Evans

Bonus Boy - If your looking at building a 270bhp CVH turbo, the last thing you wanna be doing is buying used pistons of fleabay!

Your gonna need deep pockets as well.

bonus_boy

i thought c20xe pistons are good for the 2.0 zetec and c20let are used for the 2.1?

G2RSR

they are both 86mm so you just bore the block to 2.1

ian howell said there good for upto 400 bhp same strength has the standard cossie pistons

Charlie Chalk

iTrader: (1)

2nd that

pa_sjo

Lots of thinking and thoughts going on around here.

The difference between the XE and LET pistons is if you're building a ZVH or full Zetec turbo engine. XE is more suited to ZVH's, LET's more suited to Zetecs. You can however use either for either conversion, but they'd not be ideal.

None* of these engines are 2.1 litres. 86mm bore with 88mm stroke gives you 2045cc, which is 2.0 (well, it was when I was taught mathematics).


* most

Charlie Chalk

iTrader: (1)

If your chasing numbers, Its probably better to build a zetec, It'll be cheaper and easier to get the power you want.

G2RSR

yes true its only 2045cc but it would sound strange calling it that

i dont really know why they call it a 2.1L probably just to make it sound better

xr4x4rs

iTrader: (5)

if thats the sort of power you want, i do hope you realise how expensive its going to be to get them figures

rods,pistons,headwork,cams,turbo,intercooler,manag ement,mapping,injectors

then you will have suspension,gearbx,brakes,bushes on top of that to hanlde the power

but as said, zetec is the way to go for that power

RWD_cossie_wil

iTrader: (9)

don't bother, buy a car thats fast in the first place and won't fall apart. Will cost you less money, and you will have a much nicer reliable car. For the money you will spend on that you could pick up a very clean saff cossie or even bottom end Escort cossie, or any other good std fast car such as an EVO etc.