Forged 4efte with wössner

[E10-2001-CT9]

hi, i am forging my 4efte. I orderd today the 74,5mm wössner pistons. Scat rods i already have recieved. The pistons make an CR of 8,0. What headgasket should i use? thought about 1,2mm?
if i can raise the CR a little an run also safe? this year i only want use oem CT9, but later hybrid.

 

[JasonGlanza]

pistons are dished? if so i will lower the hg a little to compensate

 

[sx_turbo]

try a thinner head gasket, trd do a 0.6mm one for the starlet,

or fit a 5efe mls gasket this is also 0.6mm

a cr of 8.5:1 will be more than fine with a hybrid.

but are forged pistons needed for what you are wanting?

 

[JasonGlanza]

a stock 4efte can cope with boosting around 1 to 1.2 bar from a ct9 Hybrid with correct mods, no need for forging as sxturbo said! but may have further plans for the future...

 

[E10-2001-CT9]

I only got an broken 4efte in Germany so i decited to build my own, which is save for future.

so an 1,2mm Hg is to much? how thick is an OEM gasket?

@sx_turbo
with an 0,6mm HG i only get CR of 8,5:1? are you shure?

 

[billybob]

lad a 1.2 mm one will suit you ..standerd ones are 1 mm

 

[E10-2001-CT9]

but engine doesnt make more power then my old one, if i use 1,2mm HG?
so i have to put in larger turbo? I never drive real 4efte. Only my self made 4efe turbo. think this one isnt as fast as real gt or glanza

 

[sx_turbo]

I only got an broken 4efte in Germany so i decited to build my own, which is save for future.

so an 1,2mm Hg is to much? how thick is an OEM gasket?

@sx_turbo
with an 0,6mm HG i only get CR of 8,5:1? are you shure?

i dont know what the cr would be, as i havnt worked it out,

i was just giving you an answer to the question you asked,

short of either going for stock pistons, or custom forged pistons to the stock specs theres not to much you can do to lower the compression, you can skim the head as well to increase the compressionbut i dont believe they can take massive reductions

 

[sx_turbo]

from experience of other people with a ct9 hybrid, with wiseco 10cc dish pistons and 1.2mm headgasket, they made same power as they would with stock 4efte, and the boost didnt really come in a great deal later, nothing noticeable so i really cant see it being a problem to be fair


edit: forgot to mention earlier that wossner pistons, with a 1.2mm head gasket, 40thou off the head and the block decked flat with the tops of the pistons gave me a cr of 7.84:1

 

[thefalls]

The pistons have a 10cc dish,if im not mistaken.

 

[E10-2001-CT9]

wössner said, the CR is 8:1 but dont know what they use for na headgasket. there is nothing written.
@thefalls
you mean the wossner got also 10cc dish?

 

[pockrockgtti]

Wossner pistons have a 6cc dish. You should use a calculator to figure out your compression ratio http://www.csgnetwork.com/compcalc.html when using the above calc the compustion chamber volume should be around 39cc for an unmodified head, then just fill in the blanks with your own figures.

 

[bumblebee]

lad a 1.2 mm one will suit you ..standerd ones are 1 mm

standard 4EFTE headgasket is 1.2 mm...i think the 0.6mm will be better..no need to lower the CR anymore...it'll be a pain to drive off boost

 

[E10-2001-CT9]

calculator doesnt work at my pc. dont know why, tryed also other browser.

 

[thefalls]

my bad,i always thought wossners are 10cc dished.

Calculator works well. Give it a try.

According this link above the compression ratio is 8.0:1 with the trd 0.6mm headgasket.
I think this is an ok set up,engine wont that lazy and can bump up boost to make more power.
With a 1.2mm headgasket the compression ratio is further reduced to 7.7:1,off boost this will be lazy!
Hope this helps.

 

[E10-2001-CT9]

Cr unter 8:1 is very small. think will go at 8,5:1. I'll measure head and pistons exactly and calculate again. Think 0.6mm Gasket can work fine but this time i doesnt have any information about the wossner dish. possible this can be 6cc

what is the oem combustion chamber volume in head? heard about 41cc? this is volume only of head without haedgasket?

if i think, some people use dished wisecos 10cc, and 1.2mm ahtena Hg wold happen these

[/URL][/IMG]

cr of 7,2 is very little?

 

[sx_turbo]

8:1 is fine and still give great response.


stock is 8.5:1. i dont believe you will acheive a cr of 8.5:1 with those pistons.

if you want 8.5:1 then buy ross pistons and a 1.2mm head gasket

combustion chamber in head is 39-40cc

 

[ramses974]

hi, i am forging my 4efte. I orderd today the 74,5mm wössner pistons. Scat rods i already have recieved. The pistons make an CR of 8,0. What headgasket should i use? thought about 1,2mm?
if i can raise the CR a little an run also safe? this year i only want use oem CT9, but later hybrid.

Hi german or european guy; i have exactly the same set up as yours...the wosner piston & the scat rods...i have gone to wosner due to fed up to blow headgasket at 1.2 bar with my High compression forged piston.In my island in despite of 98 oct ron official this octane can vary without any condition causing damage to tuned Jdm cars running with some standalone ...These pistons are good but if you really want something with a good spooling you can do some mods:
-if front mount intercooler, imagine the smallest length of pipe to your intake
-the smallest intercooler to your apropriate boost
-tune your cam with adjustable cam
-a low headgasket -yes TRd make it-
-an electronic boost controller that can improve a litlle the spool by holding the wastegate
I have running many years with high compression , at this use be sure to always get the apropriate full,good tune with compromise (for me it was good until 1.2bar)
i am running a td04 hybrid that s spooling better than stock td04...
Now i am with low compression wosner and td04 hybrid and i can easily go to 1.6bar without blowing my headgasket and not spending monney with 100octane special fuel racing that costing me a lot !!!

 

[HYBRID]

I only got an broken 4efte in Germany so i decited to build my own, which is save for future.

so an 1,2mm Hg is to much? how thick is an OEM gasket?

@sx_turbo
with an 0,6mm HG i only get CR of 8,5:1? are you shure?

if you are not going to boost beyond 21psi the standard hg will hold without any problems

best size for ur application is 1.2mm... the gains you may make from using a thinner hg, will be lost by having to compensate by retarding the timing, to suit for the fuel available to you.

kon

 

[HYBRID]

8:1 is fine and still give great response.


stock is 8.5:1. i dont believe you will acheive a cr of 8.5:1 with those pistons.

if you want 8.5:1 then buy ross pistons and a 1.2mm head gasket

combustion chamber in head is 39-40cc

not to sound like a total ass but the stock cr is 8.2:1 . .the oem hg albeit being 1.2mm when torqued sits just at over 1.0~1.1mm (depending on minor inconsistancies in toyota mfg of oem hg)

kon