How much horsepower can i run on my s5 turbo swap?
How much horsepower can i run on my s5 turbo swap?
Basically as the title says. I recently swapped out my s4 NA 13b with what looks to be an s5 13bt (although I'm not sure because the car it came out of was an 87 s4 but the housings look to be s5, so idk what to think).
The motor itself is in pretty decent shape, probably less than 5k miles on it and decent compression on both rotors and on all sides.
I'm running a recently installed Micro tech LT-9C, 4 750cc injectors and a fuel pump from an FD.
Im running a racing beat exhaust that i bought off a buddy of mine. He did remove the per-silencer, so im not sure if that would negatively impact the performance, but I don't think it should be a problem. correct me if I'm wrong though.
My main concern is the turbocharger, which is stock and from what I've learned, its only rated for up to 12psi (with the stock boost running around 7-8psi). However the turbo overall is in great shape. Im also running the stock TMIC
I'm planning to get the himini racing turbo kit in the future for more serious power upgrade, but for now, how much should i expect to get out of this setup, while also keeping it decently reliable?
Any thoughts are greatly appreciated as well as where i should go from here regarding the engine
Edit: something else I forgot to mention, Im currently running a Koyorad aluminum racing radiator, and have never had a heat issue since I installed it, and have never had a heat issue since on the stock ecu
The motor itself is in pretty decent shape, probably less than 5k miles on it and decent compression on both rotors and on all sides.
I'm running a recently installed Micro tech LT-9C, 4 750cc injectors and a fuel pump from an FD.
Im running a racing beat exhaust that i bought off a buddy of mine. He did remove the per-silencer, so im not sure if that would negatively impact the performance, but I don't think it should be a problem. correct me if I'm wrong though.
My main concern is the turbocharger, which is stock and from what I've learned, its only rated for up to 12psi (with the stock boost running around 7-8psi). However the turbo overall is in great shape. Im also running the stock TMIC
I'm planning to get the himini racing turbo kit in the future for more serious power upgrade, but for now, how much should i expect to get out of this setup, while also keeping it decently reliable?
Any thoughts are greatly appreciated as well as where i should go from here regarding the engine

Edit: something else I forgot to mention, Im currently running a Koyorad aluminum racing radiator, and have never had a heat issue since I installed it, and have never had a heat issue since on the stock ecu
Last edited by Paulc19; Apr 18, 2020 at 01:25 PM.
Joined: Mar 2001
Posts: 31,837
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From: https://www2.mazda.com/en/100th/
the amount of HP really depends on the details.
you have enough fuel for about 260-270rwhp
you have enough turbo for about 220-240rwhp
the stock turbo is perfectly fine it is just small.
you have enough fuel for about 260-270rwhp
you have enough turbo for about 220-240rwhp
the stock turbo is perfectly fine it is just small.
When you say these numbers, do you mean horsepower reliably or is this the absolute max? also I heard from a few people that if you boost past 12psi your just blowing hot air into the engine, which would cause the engine to go, i assume that holds true.
My initial idea for power would have been for around 300RWHP, and that would definitely need a FMIC and a turbo and fuel upgrade, so I think I'm going to keep the tune stock until I can route the intercooler and get the upgrades i need.
Last edited by Paulc19; Apr 19, 2020 at 11:38 AM.
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From: https://www2.mazda.com/en/100th/
if it was mine i would get the tune right on the lowest boost you can get and then raise the boost slowly until you run out of injector, or the intake air temps get too crazy.
But regarding your second comment: Wouldn't that wear out the injectors though, tuning the motor just before the point where it cant put any more fuel in because the injectors are too small? or am i mistaken?
Originally Posted by Paulc19
Ok, i get what your saying.
But regarding your second comment: Wouldn't that wear out the injectors though, tuning the motor just before the point where it cant put any more fuel in because the injectors are too small? or am i mistaken?
But regarding your second comment: Wouldn't that wear out the injectors though, tuning the motor just before the point where it cant put any more fuel in because the injectors are too small? or am i mistaken?
yeah never go above 80% duty cycle. 250 wheel HP will 100% be pushing your limits. if you are looking for 300 to 350 wheel hp, a bnr stage 4 and some beefier injectors, a full 3 inch exhaust, and a front mount will do you well.
Ive heard BNR are great turbo upgrades, That, and a front mounted intercooler. after, what size injectors and fuel pump should I be looking for. Recommended brands and sizes?
Edit: as im going back into my purchase history the fuel pump I purchased is a Walbro High Flow Fuel Pump w/ 255LPH max fuel flow
Last edited by Paulc19; Apr 19, 2020 at 02:46 PM.
Joined: Mar 2001
Posts: 31,837
Likes: 3,234
From: https://www2.mazda.com/en/100th/
So If I want to reach that 300hp mark reliability, where should I go from here?
Ive heard BNR are great turbo upgrades, That, and a front mounted intercooler. after, what size injectors and fuel pump should I be looking for. Recommended brands and sizes?
Edit: as im going back into my purchase history the fuel pump I purchased is a Walbro High Flow Fuel Pump w/ 255LPH max fuel flow
Ive heard BNR are great turbo upgrades, That, and a front mounted intercooler. after, what size injectors and fuel pump should I be looking for. Recommended brands and sizes?
Edit: as im going back into my purchase history the fuel pump I purchased is a Walbro High Flow Fuel Pump w/ 255LPH max fuel flow
and yes, i'd turn up the boost until you're hitting 80% injector duty, or whatever you're comfortable with.
BNR is nice because its a bolt on, everything else you need a manifold, downpipe and all that stuff. kind of up to you, its your car.
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