Hi!
Im rebuilding a s4 engine.
1.What cracks easily on the core engine?
2.what is the difference from the s4 irons to the s5?
3.Is there any way to make the s4 irons stronger so they can hold 400rwhp?
4.Is hardened studs from mazdatrix any point? 10mm or 12.5mm?

I have a 13bRE engine coming from jp, should i use that engine insted if its in good shape (i wont rebuild it this year).

Im gonna use gt35r turbo to achive 400rwhp.

Thanks
Sindre

 

At over 400HP, you will get cracking at the dowel near the oil filter. Mazda improved this casting on the later S4 and all S5 and newer irons. You can swap on the S5 rear iron without a problem if you are porting the engine. Emissions passages do not line up though.

There is also a weak spot at the lower water o-ring grove on the spark plug side I believe (might be on the other side). The casting is very thin and weak and has a tendency to crack or rot.

There's no real way to make the S4 irons stronger.

It's generally not recommended to run studs on a street car. The stock tension bolts are spring steel, designed to keep constant tension as the engine changes length due to temperature. If you are worried about breaking things, look at doweling.

 

Okey.. Maybe i just rebuild the s4 engine with a nice portjob and sell it with the stock turbo and wait for the 13bRE engine to arrive. Buying s5 irons and making new dowells its to mutch work atm..

The 13bRE engine can hold over 400hp without cracking?

Sindre

 

If you have a 13B-RE coming from japan USE THAT!!!
you'll have to drill and tap the intermediate housing for the FC style motor mounts.
the RE is superior from what i've and what i've been told.

 

I thought the S4 rear iron only cracks if you detonate the engine? Will me pushing 450 whp in my S4 turbo engine cause it to rack even if it's properly tuned?

 

okey, hopefully its a easy process to get the 13bRE engine to fit. Did some searching but cant find many ppl that uses the RE enigne..

 

my s4 na motor cracked at the dowell pin. its possible regardless of your tune or horsepower. granted a proper tune will probably help but its not a sure fire way to fix the problem

 

another difference: S5 rotor housings have a higher quality "chrome" coating that is more resistant to flaking and wear. This results in better compression throughout the life of the engine.

 

yeah, i have noticed some wear on the chrome coating, but i think its within the specs..

 

Here we go again. lol

 

?

 

who knows...

 

apex seals

im so clever