CR piston rebuild

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Miguel_S#

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hello good people

i need new piston, i will buy 82.5mm.

my daught is in the piston cr.
with big turbos people said very good with cr 8:5
i have only a hybrid k04-023, in your opinion and experience with an hybrid turbo is better cr 9.5:0 or 8.5:0
 
thats what i think
what is the max bore i can get 83.5?
 
I have read that you shouldn't exceed 83mm on a road car but you can go 83.5mm
 
not sure what you would be using for a head gasket with 83.5mm bores.. There is'nt much wall thickness there between cylinder bores
 
The ALT code gasket used for 83mm pistons is thinner than the std 1.8t one so consider this when choosing cr for the pistons... This and head skimming etc will raise cr... I don't know the figures though... You would have to measure this yourself...

I went 82mm bore and 9.5:1 so I could keep some bore wall thickness and use a std gasket...

This decision does not appear to have affected it's ability to make power...

<tuffty/>
 
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What is the standart compression ratio in BAM engines?I`ve been reading mixed reviews and my tuner said is 8.9.1,is that true?
I`m asking because i`m in the middle of process to rebuild the engine and i will use volvo t5 2,3 247hp turbo with custom exhaust manifold and dp.
 
audi upgrades
The alt gasket can accommodate 83.5 but lifts cr by .25 cr as it's .4 mm thinner too. Watch the wooseners as the cut outs are less than oem especially if you use an alt gasket and vvt with rubbish quality con rods
 
bumping an old thread.

I need a head gasket for my new pistons (83mm).

I ordered 8.5:1 cr pistons but got sent 9.5:1 cr instead. Due to the hassle (international shipping to return them) I would prefer to stick with the 9.5:1 (I'll be using e85 so I should still be able to run a fair bit of timing anyway).

Just wondering if there are any head gaskets I can use to lower compression instead of raising it. My head is brand new never been used (so it wont be skimmed), so a headgasket with stnd thickness or even a little thicker would be ideal.

Otherwise, can someone confirm this is the correct headgasket?

http://www.ebay.com.au/itm/AUDI-A4-...900?pt=LH_DefaultDomain_3&hash=item1c2159706c

My mechanic said to make sure I get one that is multi layered steel which this is.
 
sometimes Pistons CR are listed with use of X thickness head gasket. You should find out what thickness the pistons are quoted with. As it's not just piston that determines the CR.
there is an oem solution but it's thinner than the stock 1.8t gasket.
 
thanks for the reply mate.

the figure quoted is with 1.4mm head gaskets apparently, I don't know how thick the stnd one is.

I put an eBay link for the oem alternative in my previous post. I would go for it but it's a little thinner as you said so I'm considering the cometic head gasket I previously linked. Just wondering if anyone knew anything about them, in particular the 83mm one I linked
 
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