differences in s4/s5 engine plates
 

I'm currently having my engine street ported. It was originally an s4 turbo block.
What parts are worth switching over to s5 parts? Such as the tension bolts...i've heard the s5 bolts are much better and they are being used, using an s5 turbo, etc. Now the reason the motor is being pulled apart is because I somehow got a crack in the front engine plate on top where a small engine line bolted into it.

This didn't look like a major stress area to me so I don't know how it cracked. Anyway, my next question is...what would cause this area to crack? It wasn't from overheating. The only thing I can figure is that the plate had a stress crack that couldn't be seen during the 1st rebuild. SOOO, now that it's out, decided to go ahead and have the motor street ported. I was also advised to use s5 plates this time. What are the differences strengthwise, portwise, etc between s4 and s5 plates?

Supposedly the oil filter pedestal is reinforced on the S5, but I just did an S5 13BT for a customer that didn't have this reinforcement. :(

The area where the turbo oil supply line taps into the front iron will crack under detonation.
If you're talking about that area, it doesn't surprise me. :(

The tension bolts doesn't matter.
The S4 ones don't break, so there's no reason to run stronger ones anyways.
If you're paranoid, go look at the 20B tension bolts. :)

Grab the S5 stat gears if you can - they are hardened from the factory.


-Ted

Thanks, that's what I needed to know.

where it cracked was on the top of the front, side housing? I think that's what it's called. Everybody has 10 different names for some of these parts.

Front housing

Intermediate housing

Rear housing

Front rotor housing

Rear rotor housing

Is what they call them in the parts fische.

Then in the FSM they stray a little bit and call them Side housings (front, Intermediate, and rear housings). The term rotor housings stays mostly the same.

And screw whatever other terms are used.

find me a picture of the top of an s4 block and i'll circle what cracked
haha