Balor_Gr

Ok guys im in the plans of forging my engine to try to hit what ever that evo X turbo is capable.
Lets do the usual forged pistons/rods a set of GSR cams and valve spring/retainers and call it a day right?
After all this turbo max flow is like around 350whp only.

~~ Well according to both my tuner(not a pro on FI btw) and my mechanic the stock sleeves will crack. ~~
The reasoning is the sleeves are kinda tired after all this years and 130k miles( Sleeves get fatigued really?)
and the the turbo is small so ill need too much boost.

Now after so many years searching around this forums that sounded like overstatement but after all this years i started to search
for small turbo 93 fuel results, and guess what. A lot of people cracked a sleeve below that 400whp that "just required a good tuner".
So as you can understand im confused.And going all the trouble and cost of sleeving the engine for 350whp sounds not worthy at all.

So is it low end torque due to quick spool and high boost that cracks sleeves?
What about if you run it with water injection to lower the knock chances?
Is it detonation or too much cylinder pressure?

2kdrift

believe its cylinder pressures at maximum torque. If you get detonation cylinder pressures skyrocket which obviously is bad. I wouldnt say its quick spool.....more so maximum torque figures (more likely on a bigger turbo).

sub 400 should be just fine with a good tune, I do think sleeves lose strength over time not much but it is a factor

9TechNine9

Using a more knock resistant fuel will be much "safer" than pump 93.

k20z1ej1

Cylinder pressure breaks sleeves. For what it's worth, there are guys making 400-600 on stock b series sleeves. I don't think you have to worry at 350.

turbomaniac

Like other members said, b series stock sleeves are capable for up to 600 whp.

I believe cracking is a combination of temperature and pressure factor.

On high performance turbo engines there must be a short period (2-3 minutes) so that the engine oil can cool down and so the engine. If not, constant load and high temperature can brake down every moving part (starting from rods) and even crack the sleeves.

Detonation, AFR, quality of the lubricant and RON are also crucial.

Sleeve can also crack from failed rings due to bad piston-cyllinder clearence after a bad rebuild.

IMO stock sleeves are fine for up to 400 whp for almost any stock engine, if correct procedures are followed.

Balor_Gr

Ill check about it further and ill come with more results.Im still kinda confused with mixed opinions really.