what is the difference between the s4 and s5 turbos? can i use a s4? will it be okay for my 12a?

 

a s5 turbo was better than the s4 turbo u can use the turbo on your 12a but u need to get a custom made manifold if you are going blow thru hit up rotaryshack best in the bussines . and if you are planning to go fuel injected visit rx3mist.com you will need plenty of things to do either setup good luck

 

Either turbo will work, with a stock manifold, but will require some modification to make it fit. (RB manifold fanges made into a spacer of sorts) Getting in contact with Rene from rx3mist.com would be your best bet in my opinion, because he will make you an equal length tublar manifold for a good price. ($250-300ish)

A s4 turbo is considered a better turbo by some, I believe mainly because they find that when using the s4 manifold that porting and modification is less complex. Bryan at BNR has said he prefers them over s5 as well. However if going with a custom tubular manifold as I mentioned, either would be a good choice. When looking at initial cost of the turbo, an s5 will cost more, also when doing hybrid modifications, such as a BNR, the stages are slightly cheaper with a S5 turbo charger.

Either way, either turbo would be ideal for setting up a turbo application on your 12A for a beginning turbo setup. With the proper supporting modifications, 250hp should be easily obtained, if not slightly more. When you have the money, and time to go wtih further modifications, either turbo can be built into a hybrid design with a 60-1 compressor.

I will be running a s4 turbo charger on my setup though...

Contact Robert at Rotaryshack.com for pretty much everything
Rene at Rx3mist. com for you manifold
FB II and many others for advice and tech. info. There are countless posts on how to do this. Zac has been a TERIFFIC help so far with myself.

~Chris

 

Also Steve84GS TII is a great source for turbo information. Either turbo is great and both have their own pros and cons. I'm personally running an S5 turbo, well I have it but it's not on the car yet. It's really about personal choice.

 

thanks guys.. yeah i have already been in contact with robert.. he is boost preping my side draft dellorto for me.. and making me a carb hat thanks for all the great info.

 

Kick ***! Soon the turbo SA/FB's will dominate Ohio Rotaries!

 

hells yeah.. and as soon as they fix the registration problem loki wants to join/

 

In stock form,the S5 well dominates the S4 turbo.The manifold design is better,the wastegate is FAR superior and the exhaust A/R is less restrictive.

The compressors are identical for both,meaning they will both move the same CFM of air into the engine.But the S5's split manifold flows better and the wastagate has better control since it regulates flow from both runners and it has more volume.The S4's wastegate can be made big enough to flow and control boost on an upgraded setup,but if you have the choice between the two,in stock form, with a stock compressor....take the S5.

The 12A engine with it's smaller ports will allow the 13BT turbo work much easier when supplying 8-12 psi to the engine.With a 12A,You should be able to hit those boost numbers easily with either a S4 or S5 turbo...anything higher and you'd better run a S5 turbo or be ready to port out the S4's wastegate.

 

I was waiting for Steve to chime in with his argument for the S5 and now I'm waiting for Zac(FBII) to chime in with his argument for the S4 LOL. It's a much heated battle LOL

 

The main thing I want to convey,is that a specific turbo is good for a specific application.Whether a S4 or S5 is better or worse,depends entirely on your engine and expectations.

On a stock engine with a stock turbo,it'd be hard to say that the S4 is better than the S5......or why would Mazda have bothered to change over in 89?Evolution of car technology USUALLY results in improvements of an item/system over the previous model.
The S5 is simpler and more capable at or near stock boost levels.Once you start swapping,porting and hybridizing then it gets more application specific.

 

okay thanks.. reason i am asking is because i have found a S4 cheap and i was going to snag it if it would work for my setup.. i have a 12a with a side draft dellorto and RBheaders the engine is stock.. but i am looking into porting it later when i blow something.. lol