S5 6 port turbo questions.
 

Hi all, just wanted to get some feedback on my 6 port turbo plan.

First off, the car is a nearly stock 1989 GTUs, factory reman (stock ports) w/ 40,000 miles, compression is great.

My power goals aren't all that much, 250-300whp, I'd be pretty pleased with anywhere in that range, with solid reliability as a top priority as the plan is to use it at the track where it is regularly 100+ degrees ambient for about half a dozen 20 minute sessions on a regular day.

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Now for the parts that I already have, I had a few questions.

I also have a 10AE with a blown engine, but I was wondering if it would be recommended to use my S4 LIM (port matched of course) on my S5 block? Also, I have the stock S4 turbo available to use, but my initial thoughts are that it would be best to send it out to BNR for the "stage 1" upgrade (equal to S5 BNR stage 1 then)?

So for those of you who rather not read an "essay". Is it advisable use S4 turbo parts on my S5 N/A block or should I buy S5 turbo parts outright?

I also have a Zeitronix wideband and LCD display that I purchased several years ago (2007), I figured this would be a good time to put that to use. Unless someone can recommend a better product?

I have a full RB "turboback" exhaust from my 10AE, I have no idea if this is S4 specific or if it'll work on the S5 turbocharger as well.

Other than that, I'd like to use the stock TMIC for now, but yes, I know about the flow restrictions, heat soak and inefficiency. (I was thinking a water sprayer might help this?)

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As for the parts I don't have.

Fuel controller (ECU), fuel pump, fuel pressure regulator, "bigger" injectors, etc. Please feel free to add anything else I'd need or suggested brands/part no's.

ECU, I was initially planning on going with the Rtek for S5 N/A, but I've read several posts that made this route quite unappealing. Any other recommendations would be much appreciated. PnP is preffered, Adaptronic? Although, I'm not sure they make a PnP for the S5 N/A.

(I'd prefer to keep my OMP, although, I do premix now, 1/2 oz. to 1 gallon.)

Injectors, I was thinking 720 on both primaries and secondaries? Could I get away with 550 primaries or would it be a big risk?

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Budget wise, I'm hoping to buy almost everything used, so I'm, not looking to spend a great deal of money to gain such little power.

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I've done quite a bit of searching (for those who would be quick to just say SEARCH) and yes, I have come across the other GTUs with 6 port turbo, among many other threads. The majority are not S5 specific and also I cannot recall very many using the Rtek, I remember there was one that I read, but his was S4.

With the Banzai adapter kit I believe it make hte Apex'i powerFC plug and play other than modifiying the trailing coils..

APEXi Power FC Adapter Kit (89-91 RX-7)

FC Coil Installation How To

This is about all I know the answer to. I'd like a PowerFC to control my N/A. Then I'll have the ecu covered if I decide to go turbo one day.

Oh the exhaust will fit either one( S4 or S5) I believe.

Thanks for the links.

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As for the tmic, I just wanted to clarify what I meant by "water sprayer", I did not mean internal injection, but just an external sprayer to cool/transfer heat off of the intercooler. Since posting that though, I've read a few more threads and it really doesn't seem like that idea would work out.

I also just remembered that the TPS between the S4 and S5 is different, lol, it looks more and more like I'll need to buy a S5 "turbo" LIM, any thoughts would be appreciated.

How much money are you prepared to spend? It is most likely going to cost more than you're planning on right now.
What I would do first is find who the closest rotary tuner to you is and find out what they prefer to tune/ recommend for a standalone. I would not try to run stock EMS with a high compression S5 keg, it's a disaster waiting to happen. The standalone is also great because you can go bigger later and just have it retuned. Another nice thing is being able to ditch the AFM and not worrying about emissions.

After that, S5 TII LIM, Rising RPM adapter then an S6 UIM/TB for the better TPS. Because of this you'll need to run a front mount or a v-mount IC setup. You can stick with the S5TII UIM/TB if it's easier and you want to run the stock top mount for cost purposes. The S5 TPS works fine for many people but it's lower tech than the S6.

For the injectors and fuel pump you'll want to size according to your power goals. I highly suggest checking out the "Single Turbo RX-7's" section of this forum and reading about fuel system planning. I assure you, you will get the bug for more power so I would suggest going a little larger to allow some more headroom.

Swap out the front cover for an S5TII front cover, swap the oil pump for a TII oil pump(series doesn't matter) and consider getting an FD oil pressure regulator to bump up your oil pressure for your new turbo.

With the S5 Turbo and front cover you'll be able to utilize the factory oil drain, for the feed line get a pedestal adapter that has port on it and run a line from one of them. For coolant, tap into the lines that previously went to the TB. You've switched up and won't need them anymore with the S6 TB and standalone.

Ditch the OMP, you already premix, just do 1oz/gallon.

Port your wastegate, get a Downpipe, and put whatever exhaust you want on it. You might want to get a. Boost controller as well if you want to run higher than stock boost.

If you be sure to ground the engine well for the sake of the standalone and strong spark.
For the wideband and gauges, do whatever you want.

I think that about covers it.

I collected all the parts for a big turbo 6-port build on my GTUs then just bought my turbo vert because it was cheaper to get than for me to finish my car. I sold off most things but still have a few sitting around, I would still like to turbocharge it later on.

Freaking a.... I just spent 30 minutes typing a response and my browser crashes....

Jebuz, anyways, long story, VERY short... I had another thread explaining the restrictions and limitations I must follow for my build.

https://www.rx7club.com/2nd-generati...ttack-1061056/

Basically, no S6 parts, no standalone, no auxiliary injection, must use "stock turbo", etc.

Thank you for your thorough reply though and I will be checking out that single turbo section.

I am using this thread as a basis for my own build, although in his current configuration (which does not seem to be restricted) puts down 340 whp.

https://www.rx7club.com/2nd-generati...inside-890359/

I'd be happy with nearly 100 hp less and with my limitations, I certainly believe it to be feasible.

why wouldn't you fix the 10AE, and then have two running cars?

Sorry to be a Debbie downer but I think you need to re-read those rules.

16-1.1 Engine must be OEM for particular make and model. No Engine swaps. Engine replacement is allowed ONLY from OEM engine from original make and model. Japan/European engine replacement is allowed as OEM factory trim. Drive wheel configuration changes are not permitted.

16-1.6 Aftermarket or non OEM forced induction is not permitted on factory naturally aspirated vehicles.

16-1.9 The OEM block must be utilized. Engine may be rebuilt using OEM parts with a maximum .050” over bore. Pistons matching OEM specifications may be used.


The way I interpret it turbocharging your 6port would not be permitted because it was naturally aspirated to begin with. I know they list make and model which would be Mazda/Rx7 which doesn't specify whether it is a turbo model or not but how deep into the trim level do they go? If the go by the vin and find that car was sold as a n/a car you may not be legal. Do they consider Rx7 the model or is Rx7 turboII or RX7 GTUs the model? That said if it is ok to put the turbo motor in, you would have to use the complete OEM engine to be legal since the 6port was never turbocharged. Now since externally they will look the same once you get your manifolds on they may be none the wiser( as long as they never make you take that LIM off. Sorry to be so negative but I wouldn't want you to build this car only to find out they dig down to the trim level and disqualify you because it didn't leave the factory as a turbo car. You may be better off to find a TII shell or use your 10th AE instead of the GTUs. So there's no gray are about legality for the class.

As for the ecu I would pick up a S5 TII ecu to Rtek not your N/A one.

After re-reading those rules again maybe you are ok. They almost read like you can't swap in a turbo motor but you can turbo yours using OEM turbo parts. I would still start with a factory turbo car just to be safe and limit any confusion/chance of being disqualified.

Suppose ably the S5 T2 Adaptronic PNP unit works with an n/a car. I have not personally tried however.

Lol, the 10AE is a long term restoration project. I wouldn't commit it to track duty.

They're not that stringent, but yes, you're correct, to be 100% legal, I'd need to start off with a 4 port block.


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16-1.6 Aftermarket or non OEM forced induction is not permitted on factory naturally aspirated vehicles.

On second thought, lol, it says "non OEM", if I use a factory turbocharger, that's OEM. Bingo, grey area.

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https://www.rx7club.com/2nd-generati...cu-s5-1071439/

Would that work for me? I'm not familiar with the connection differences between the N/A and turbo ECU's, are the harness plugs the same?

I was under the impression Adaptronic did not sell a PnP S5 T2 unit? From what I read they only sell the S6 and it can be used on the S5 with a flying lead harness?

you should ask about that. "oem forced induction" probably includes the engine. although unless they really know what they are looking at, the turbo and NA blocks look the same.

No reason to ask, the engine is visually the same with the S5 13BT manifolds.