S4 turbo setup to s5 fully divided turbo setup. PERFORMANCE WORTH IT?
 

I have a s4 turbo with ported wastegate and ported turbo inlet. Twin scroll system has already been removed.
The coldside is a T04e 46 trim wheel into a machined stock compressor housing
I am looking for no more than 280 hp to the flywheel.

I have a straight custom exhaust (it is a race car), will this little ported wastegate avoid boostcreep?

Is it worth to upgrade to a s5 hot side for a sooner spool up and turbo lag?

Advantages and disadvantages between my s4 setup and a stock s5 one. Will it be worth to upgrade to s5 exhaust manifold and turbine housing?

Thanks for your help


Some photos:

http://i43.tinypic.com/34yctoj.jpg

http://i39.tinypic.com/11gj5g6.jpg

http://i42.tinypic.com/os4osp.jpg

https://www.rx7club.com/attachment.p...1&d=1273706605

https://www.rx7club.com/attachment.p...1&d=1273706605

Mazda seems to have thought so. And the dual wastegate ports of the s5 have more flow potential than the s4 single wastegate port.

Awesome information! Can you tell me where did you take the pics from?

Thanks mate

Matsuda, "New Technology Employed for the Latest 13B-Rotary Engine" 1990

PM me with your email address and i'll send it to you. it's about 12 megs

PMed you

Thanks one more time!

And without question, you will need the better dual wastegate on the S5 turbine housing to control boost.

I am going to boost about 8 psi on a 6 port turboed engine and I don´t want to put a lot of stress throu the tired engine/trans. So would it be necessary to port the wastegate on the s5? I don´t have a dremel handy...

Aaron, how is your transmision going with all the power it is putting down? It is a whole NA trans and rear end, isn´t it? Do you know how much power would hold a Miata torsen I have installed into my NA rear end?

Thanks

The S5 wastegate can still allow boost creep with an open exhaust system. You should port it out. Also, having used both S4 and S5 turbos, I can say that the S5 has always felt more stout in the low RPM range. The graphs above seem to confirm that.

Would a huge wastegate porting job on my s4 turbine housing avoid the boost creep (big hole and welding a washer)?

I am also thinking in an external WG attached to the manifold... Boost creep is sth I don´t even want to hear about


Another question (additional injectors):
-I am running 4x 550cc stock injectors (low impedance). I had to make a resistor pack for this, and I am thinking if it is possible to reduce the resistor value for the secondaries and then run 4x 550cc low imp secondaries (plus the 2x 550cc primaries, total 6x injectors). I mean, injector impedance is near 2.7 ohm for each one, and I have 10ohm resistor for each injector so it does 12.7 ohm for each injector circuit; then if I put another injector more for each secondary plug connected in serie that will be 2.7 + 2.7 = 5.4 ohm. So I will need a aprox 7.5 ohm aprox to keep the 12.7 total ohm the ECU must have for each injector wire. And then control the fuel flow with my safc

The question is: will it work or will it interfere with the peak/hold required impedances? (So another question I have is if the impedance of the injector chages depending on the status it is peak or hold, or otherwise it will remain constant)

I don´t know if I have explained it correctly :scratch:

wait, why are you trying to run 6 injectors?

I have a spare pair of 550cc, and the safc allows just for a +/- 50% adjustment to keep de AFR ok when the secondaries kick in.

Anyway, if it would be enought to run 4x 550cc for feeding the air flow a T04e 46 trim hybrid turbo provides at 7.5 psi until the redline, I will keep the 4x550cc stock ones. I have a 255 lph fuel pump, sure

Where are you going to put the other two?

why not just change the secondaries?

I would make a pair of holes on the dynamic chamber (it is a turboed NA with NA intake manifold), I also have some fuel rails that would bolt to other pair of tappered holes. running fuel for them with some "T" will not be a problem

It will be cleaner for sure, but I already have another pair of injectors, fuel rail, safc controller and intalling this stuff is not going to be a very hard work... also, I want to know if it will work, if anybody knows about the peak/hold impedance question

just change the secondarys and install an rtek

If you use that +-50% correction on an SAFC, you will have some dramatic timing changes behind the scenes that you're not aware of. An SAFC just tricks the ECU into thinking there is more or less airflow. Airflow is part of the LOAD calculation, which determines timing. My guess is that at partial throttle, under boost, and above 3800 RPM, you'll have some severely retarded timing. Using an SAFC to correct for larger secondaries would be a much better route.

Thanks for the info

Would it be enough to run the stock 4x 550cc injectors for feeding the air flow a T04e 46 trim hybrid turbo provides at 7 psi until the redline (stock port)?

clean the injectors and rewire the fuel pump and it may be ok.

It looks like the compressor on a T04E 46 trim is very similar in size to what's used on small hybrids (ie BNR 1 or 2). It falls between a T04B V-trim and a T04B H-trim. At low boost, it might be fine. Depending on target AFR, the stock injectors are large enough to handle around 250 whp at ~85% d/c.

Thanks guys

What is your opinion about water/methanol injection? I have installed a custom intercooler, in the place where the cruiser control valves should be (back the passenger strut tower), and even with its electric fan it doesn´t cool the air as much as a fmic does, but it is less laggy, adds less wheight on the very front of the car and all the pipes to fit it were availiable in the garage from spares...

I was thinking on installing a shurflo water pump with aquamist injectors and a boost pressure switch for injection a mix 50/50 water/methanol. The reason is the low efficiency of the intercooler in that position and the high compression of the NA rotors (knocking scares me a lot). I already have al the parts here, do you think it is worthwhile?

I think you should check out the aux injection section of this forum, there are people running TMIC's or no intercooler at all (like BDC) with just injection. You just have to decide how much you want to rely on it for the health of your engine. That makes some people nervous. Other people don't want to be bothered with having to check the levels and make sure everything is working right.