87 TII s5 turbine on s4 block need a little help.
 

Well, I blew my exhaust manifold on my s4 turbo and there's a good amount of shaft play. To save money and time, I thankfully have an s5 turbo and manifold sitting in my garage with very minimal shaft play. So, I have the s5 exhaust manifold, turbo manifold, and turbo so it will bolt up to the s4 block, and i'm getting my FCD pretty soon. On top of that, on the way is a 2.5" downpipe to 3" full system. Will this setup work, assuming all vacuum lines are connected properly, to make slightly over 200hp from stock? Anything else I need?

Thanks for the help

Take all of the oil lines off the s4 and put them on the s5. Then it will bolt up fine.

Yea will work fine. before you put turbo on should port wastegate outlets as there is plenty of waste metal. it simple to do just need die grinder. makes big difference as you wont get any overboosting problems that mazda overlooked.

It'll work fine. There are no vac lines to connect, only the wastegate hose. If your S5 turbo still has the metal wastegate line with a tee in it, you'll need to cap the open nipple. You won't make any more power with this turbo over the original one as the compressors are the same, but the fully divided manifold improves response.

Actually you only need the oil drain line. The oil supply line and the coolant lines are the same.

Porting the wastegate is a good idea, but Mazda didn't overlook any boost "problems". Do stock FC's overboost? Nope. They run exactly the boost Mazda wanted.

no FCD...

You will find there should be a boost difference between s5 an s4. s4 came stock with about 4psi actuaters where as s5 came with 8psi actuaters.

Tell me If a series 5 has no over boosting why would there be a standard 8psi actuater for wastegate and at 6-7000rpm it will get to 15psi. just the way mazda intended. Mmmmm.

Both S4 and S5 wastegate actuators are the same other than the alignment of the rod. The S5's higher boost was entirely due to the addition of electronic boost control, which increases boost under the ECU's control.

Stock S5's (or S4's, or any other turbo'd car) don't overboost unless something breaks, so there was no "problem" overlooked by Mazda. That fact that the boost increases if you put a big exhaust on is not Mazda's problem, it's yours. Manufacturers don't design cars for people to mess with them in that way. Why would they? By removing intake and exhaust restrictions you're using the turbo in a situation it wasn't designed for.

Since you're wrong on both counts, your snarky attitude looks pretty silly...

I feel an murder in Auckland coming on.

Oh man! I thought it overboosted to 25psi :wallbash:

:rlaugh:


But yea, like the others said, use the s4 oil drain line and put it on your s5 turbo and it'll work fine so long as you have the s5 exhaust manifold. But I'm curious on something. On your first post, you put,"So, I have the s5 exhaust manifold, turbo manifold, and turbo so it will bolt up to the s4 block, and i'm getting my FCD pretty soon." Which other "turbo manifold" are you referring to? Are you wanting to put the S5 turbo intake manifold on your S4 TII as well??