Mazdaspeed Protege Build - Feels Good To Be Back

Got a response from Sam on the Boundary Oil pump. Thought I would put it here to help others in the future.

"
It’s a small operation over there. Not sure the
coating is worth the fee.

You wouldn’t too high is also just as bad as too low pressure.
They increased the redline to like 8k or more, installed a long plumbed remote filter/ oil cooler system that dropped pressure, constant high rpm race use.

I would only run the 60 psi setting on the boundary. Most cars I just use OEM pumps. I installed one with a Boundary on a 60 psi, but that customer never gave me any feedback since I shipped him the engine.


I’ll let you read the ai explanation below, too high is not good either."

1. Increased Stress on Seals and Gaskets
🔹 Why It’s a Problem:
High oil pressure can overwhelm the seals and gaskets, causing leaks that reduce reliability and require costly repairs.

🔹 FS-DET Specific Issues:

GT25 Turbocharger Seal Blowout: The stock Garrett T25 (GT2554R) journal-bearing turbo has a small oil feed restrictor, making it sensitive to excessive oil pressure. Too much pressure pushes oil past the turbine and compressor seals, leading to:
Blue smoke from the exhaust (burning oil in the hot-side turbine housing).
Oil in the intercooler piping (reducing efficiency and causing carbon buildup).
Crankshaft and Camshaft Seal Leaks: Excessive oil pressure can push oil past the front crank seal, rear main seal, and camshaft seals, leading to leaks.
Valve Cover and Gasket Leaks: High pressure can force oil out of the valve cover gasket, leading to oil seepage and potential contamination of ignition components.
2. Aeration and Foaming
🔹 Why It’s a Problem:
Excessive oil pressure can cause turbulence in the oil system, leading to aeration (air bubbles) and foaming, which reduces lubrication efficiency.

🔹 FS-DET Specific Issues:

Oil Pickup Problems: The FS-DET uses a wet sump system, and excessive pressure can cause cavitation, where air pockets disrupt oil flow. This can result in oil starvation at high RPM.
Bearing Damage from Aerated Oil: The rod and main bearings rely on a continuous film of oil. If the oil is aerated, it can’t form a proper protective layer, increasing the risk of premature bearing wear or failure.
Turbocharger Oil Breakdown: Aerated oil reduces cooling effectiveness in the turbo, leading to higher turbo temperatures and premature coking of oil in the turbo bearings.
3. Restricted Flow and Bearing Starvation
🔹 Why It’s a Problem:
High oil pressure does not always mean better lubrication—it can actually reduce flow rate in critical areas, starving key components of proper lubrication.

🔹 FS-DET Specific Issues:

Rod and Main Bearings: Excess oil pressure can cause oil to become trapped between bearing surfaces, preventing proper oil cycling and leading to heat buildup and increased wear.
Turbocharger Oil Flow Issues: The GT25 turbo requires a consistent flow of oil, not excessive pressure. If oil pressure is too high, it can overwhelm the turbo’s oil drain, leading to oil pooling and seal failure.
Cylinder Head Oil Starvation: The FS-DET’s DOHC valvetrain relies on oil galleries to lubricate camshaft journals and lifters. Excessive pressure can disrupt proper flow to the head, causing premature cam wear and lifter issues.
4. Excessive Heat Buildup
🔹 Why It’s a Problem:
High oil pressure increases friction within the oil pump and lubrication system, generating excess heat that breaks down oil and reduces efficiency.

🔹 FS-DET Specific Issues:

Increased Oil Pump Load: The FS-DET’s oil pump is gear-driven. If pressure is too high, it adds unnecessary strain, potentially causing oil pump gear failure.
Oil Viscosity Breakdown: Excess heat can cause synthetic oil to degrade faster, reducing its lubricating properties and increasing engine wear.
Turbo Oil Coking: The FS-DET is prone to turbo oil coking, where excess heat causes oil to burn inside the turbocharger, leading to shaft imbalance and failure.
5. Overloading the Oil Pump and Drive Components
🔹 Why It’s a Problem:
The oil pump is mechanically driven by the timing belt system, and excessive oil pressure can overload this system, leading to premature wear or failure.

🔹 FS-DET Specific Issues:

Stock Oil Pump Limitations: The FS-DET’s oil pump is not designed for extreme pressures. High pressure can cause the pump to cavitate, reducing its efficiency.
Increased Engine Load: Excessive oil pressure causes the pump to consume more power, slightly reducing overall engine efficiency.
Risk of Oil Pump Gear Damage: If the pump is forced to work harder than intended, the internal gearset can wear prematurely or crack, leading to sudden oil pressure loss and catastrophic failure.
Optimal Oil Pressure for the 2003 Mazdaspeed Protegé (FS-DET 2.0L Turbo)
Maintaining proper oil pressure is key to reliability and performance. The following values are recommended for a stock or lightly modified FS-DET:

Engine RPM Recommended Oil Pressure (PSI)
Idle (~800 RPM) 15-25 PSI
3,000 RPM 40-55 PSI
6,000 RPM 60-75 PSI
🔹 If oil pressure exceeds 80 PSI at high RPM, it is too high and can lead to seal failure, overheating, and aeration.





Why Just Enough Oil Pressure is the Right Amount for Engine Health
Oil pressure is not about maximum pressure—it's about optimal pressure and flow. Too little pressure leads to inadequate lubrication and metal-on-metal contact, while too much pressure creates excessive strain, leaks, and inefficiencies. The key is to maintain just enough pressure to deliver proper oil flow without overwhelming seals, bearings, or the oiling system.

Here’s why just enough oil pressure is the best choice, particularly for turbocharged engines like the Mazda FS-DET in the 2003 Mazdaspeed Protegé:

1. Oil Pressure and Flow Must Be Balanced
🔹 Why It Matters:

Oil pressure is the force pushing oil through the engine’s lubrication system.
Oil flow is the actual movement of oil to critical components (bearings, camshafts, turbo, etc.).
If pressure is too low, there isn’t enough force to push oil through the passages.
If pressure is too high, oil can struggle to move efficiently, leading to restricted flow where it’s needed most.
🔹 The Right Balance:

The FS-DET engine operates best around 60-65 PSI at high RPM.
This ensures oil is delivered to the bearings, turbo, and valvetrain without excessive resistance or aeration.
Higher than 70 PSI starts creating more problems than benefits.
2. Too Much Pressure Can Cause Bearing Starvation
🔹 Why It Matters:

Bearings rely on a thin film of oil to separate metal surfaces and reduce friction.
Excessive pressure can force oil out of the bearing clearances too quickly, reducing the time the oil stays in contact.
This leads to higher temperatures and increased wear, eventually causing bearing failure.
🔹 What Happens at Too High Pressure:

Oil is forced through the bearings faster than necessary.
Less oil remains in the hydrodynamic wedge (the protective oil film that prevents metal-on-metal contact).
Bearings may run hotter and wear prematurely.
In extreme cases, rod bearings can spin due to inadequate lubrication.
3. Excessive Pressure Overwhelms Seals and Causes Leaks
🔹 Why It Matters:

The FS-DET engine uses rubber and metal seals to prevent oil from escaping key areas.
If pressure is too high, oil will force its way past these seals, leading to oil leaks and smoking issues.
🔹 Common Failures from Too Much Pressure:

Turbocharger Seals: Turbo seals rely on proper oil pressure. Too much pressure forces oil past the seals, leading to blue smoke from the exhaust and oil pooling in the intercooler.
Crankshaft Seals (Front and Rear Main Seal): High pressure can push oil past the seals, causing oil leaks onto the clutch or timing belt.
Valve Cover Gasket and Cam Seals: Too much pressure can cause oil seepage, especially if crankcase ventilation isn’t properly managed.
4. High Oil Pressure Creates Aeration and Foaming
🔹 Why It Matters:

When oil moves too quickly or encounters excessive turbulence, it can trap air bubbles.
Aerated oil loses its lubricating properties, reducing protection for bearings and other components.
🔹 How Excessive Pressure Causes Aeration:

Oil Pump Overworking: A high-pressure oil pump can create cavitation, drawing in air bubbles from the oil pickup.
Oil Returns Too Quickly: When oil moves too fast through galleries, it doesn’t have time to settle and separate from air before being recirculated.
Foamed Oil Can’t Protect Bearings Properly: Air pockets in oil lead to metal-to-metal contact, excessive heat, and increased wear.
🔹 The Right Solution:

Keeping oil pressure within manufacturer-recommended limits (around 60-65 PSI at high RPM) ensures proper flow without excessive turbulence.
This prevents aeration, keeping oil film strength consistent for proper lubrication.
5. Too Much Pressure Increases Heat and Reduces Efficiency
🔹 Why It Matters:

Excessive oil pressure increases friction within the oil pump, passages, and bearings, creating unnecessary heat buildup.
Hot oil breaks down faster, losing viscosity and lubrication effectiveness.
🔹 How It Happens:

The oil pump works harder than necessary, consuming more engine power (parasitic loss).
Oil moving at higher pressure through restricted passages generates friction, leading to higher oil temperatures.
High oil temperature reduces oil viscosity, making it less effective at lubricating under load.
🔹 The Right Approach:

Keeping pressure at a moderate level (not exceeding 65 PSI) ensures that oil does its job without adding unnecessary heat or drag.
This results in more stable temperatures, longer oil life, and improved efficiency.
 
That's too much work. Just run an OEM one lol. Has less lines and less failure points. Did you run an OEM one on your mp3 build in the past? Whatever it was, it never gave you any issues did it?
 
That's too much work. Just run an OEM one lol. Has less lines and less failure points. Did you run an OEM one on your mp3 build in the past? Whatever it was, it never gave you any issues did it?
Haha, I think I'll go the Boundary oil pump route at 60psi. Not really sure about running the DOC-B, with all the lines.

I did run the OEM pump on my mp3, I can't really recall having any major issues with it. Maybe some inconsistencies in psi.

I do remember it dipping when accelerating through corners though. Not sure if that was just a oil pan issue.

Hopefully Jay Racing emails me back with good news that he found a fuel rail. Said he might have a couple laying around.

PERRIN'S Response:
"
Thank you for reaching out and for your interest!

We truly appreciate the enthusiasm from the community.

Unfortunately, we are unable to accommodate a made-to-order request or provide the machining file. At this time, we do not have plans to produce additional units.

We appreciate your understanding, and if anything changes in the future, we will be sure to keep you updated.

Have a great day"
 
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I remember for protégés that hard left turns cause oil starvation. How hard? Idk lol. Someone sells a baffle you can add to the oem oil pan.
 
I remember for protégés that hard left turns cause oil starvation. How hard? Idk lol. Someone sells a baffle you can add to the oem oil pan.
Lol, I'll never forget noticing the psi drop when I was testing out my new skunk coil sleeves.

Found it?
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Lol, I'll never forget noticing the psi drop when I was testing out my new skunk coil sleeves.

Found it?
View attachment 335536
I might have to buy that lol

keep in mind that you need a better oil filter if you're going to run higher pressure, or it'll get bypassed

so run a 2009 RX-8 filter... it'll fit.... a subaru filter also fit but I wouldn't run any of their USDM "OEM" ones because they're garbage honeywell filters (the company who owns fram, probably comes from fram)
 
I might have to buy that lol

keep in mind that you need a better oil filter if you're going to run higher pressure, or it'll get bypassed

so run a 2009 RX-8 filter... it'll fit.... a subaru filter also fit but I wouldn't run any of their USDM "OEM" ones because they're garbage honeywell filters (the company who owns fram, probably comes from fram)
Hell yeah, I'll make sure to scoop one of those if I go that route. Always coming in clutch with the information.

I noticed a guy selling a Boundary pump, only 1400 miles on it. Hopefully he comes through, much better than buying a new one. 40psi idle/80psi 8k.
 
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Maaaan, Jay really came through!

Simple email and Bam.
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The WRX injectors will work nicely 😁 from yours truly and trusted @323
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Man oh man, so happy I got this to add to the build. Scooped up this Boundary Pump fast. The gears are also coated. Cleaned her up a bit on the front and backside.
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Man… it’s been way too long since my last update. Life has been busy as hell and this build is moving much slower than I ever planned. Definitely thought I’d be further along by now, but here we are.

Lately I’ve been bouncing between finishing up the SSAFC wiring and getting the wideband O₂ bung welded into the exhaust. And let me just say, whoever the previous owner let touch this exhaust should not be allowed near a welder ever again.

At first I’m thinking, “Cool, I’ll just unbolt it from the front, pop the hanger at the muffler, and slide the whole thing out.” HAHA. Nope. Absolutely not.

Turns out the exhaust shop decided to add their own custom hangers to “support” the aftermarket muffler. And by support, I mean butcher the underside of the car with the most janky hanger setup I’ve seen in a while. Nothing lined up, nothing made sense, and none of it wanted to come out clean.

I fought with it for way longer than I should’ve before finally saying screw it. Out came the grinder. I had to cut those stupid hangers off, and in the end I just cut the exhaust into three separate pieces to get it out from under the car.

Not how I wanted to do it, but sometimes you just gotta accept defeat and start cutting.
At this point, everything’s prepped to weld the wideband O₂ bung into the exhaust and get that knocked out. Once that’s done and I’m happy with the placement, I’ll finish buttoning up the SSAFC wiring. I don’t want to lock anything in until the wideband setup is 100% solid.
Slow progress, lots of frustration, but it’s moving forward. More updates soon… hopefully with less cutting and fewer swear words.

Now for the good news, because this build seriously needed one — I finally pulled the trigger on a ready-to-go short block. Big decision, big purchase, but it feels like the right move instead of rolling the dice on the original block.

Block fully cleaned, checked, and machined Cylinders honed and prepped, New bearings installed (clearances checked and set) Rotating assembly clearanced and verified. Bottom end assembled and ready to build on
It’s not a long block, just a solid, prepped bottom end — which gives me full control over the rest of the setup. No more guessing on the condition of the old block or building around unknown wear. Knowing I’ve got a proper foundation takes a huge mental load off and makes the slow progress feel worth it again.

Still moving slow, still fixing other people’s messes, but the direction finally feels solid again. More updates soon, hopefully with a welded bung, finished SSAFC wiring, and a fresh short block sitting in the garage.

To be continued....
 

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Man… today was a good day. Got myself a birthday present and it showed up, lol.

Fedex just dropped it 30mins early and said peace 😆...I was watching that package like a hawk at work.
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Honestly… I couldn’t have found a better person to buy this from.

No games.
No weird energy.
No “trust me bro” machine work.

Everything was documented. Clear. Straight answers to every question.

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After all the back and forth, second guessing, researching at 1AM, debating pistons/bearings/bore like my life depended on it… it’s actually sitting in my garage now. 5-Axis CNC work on the block, decking, boring, honing, ect.

• Fresh machine work
• Deck checked and cleaned up
• Line honed mains
• Balanced rotating assembly
• New bearings installed

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Beautiful 😍

Still got wiring to finish. Still need to finish cleaning up the exhaust situation (don’t even get me started). Still mocking up a few things before final assembly.

I can’t wait to get this bad mamer jammer up on the engine stand and really go through it.
 

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Thems nice and purdy right there. 😁

I had to abandon my turbo build for my Hyundai after ten years of collecting parts and knowledge about the swap.

Economic hard times and a change of plans pulled the plug for that project.
Nice to see your Mazda getting some love with a new heart. 🥰

I'm rebuilding my Protege mechanically to new having spent about 5 grand on parts but she's a keeper and honestly I'm quite happy with the Hyundai in its current configuration.

Good luck with your project.
Can't wait to hear its first start up and better post that 💩 eating grin when it's all done too. 😁😂
 
Thems nice and purdy right there. 😁

I had to abandon my turbo build for my Hyundai after ten years of collecting parts and knowledge about the swap.

Economic hard times and a change of plans pulled the plug for that project.
Nice to see your Mazda getting some love with a new heart. 🥰

I'm rebuilding my Protege mechanically to new having spent about 5 grand on parts but she's a keeper and honestly I'm quite happy with the Hyundai in its current configuration.

Good luck with your project.
Can't wait to hear its first start up and better post that 💩 eating grin when it's all done too. 😁😂
Ten years collecting parts and knowledge is no joke. That’s real dedication. Life definitely has a way of shifting plans on us, but the pivot always seems to end up being the right move.

Appreciate the love on the Mazda. This “new heart” has been a long time coming for sure.

And trust me… when it fires for the first time, there will absolutely be a ridiculous grin involved and plenty of videos lol.

I’ll make sure it gets documented.
 

Boost Controller Decision – Greddy vs Boost Leash​


Alright, this is going to be a long one. I’ve been really thinking through boost control on this build, and I figured I’d write it out instead of just bouncing ideas around in my own head. Maybe it helps someone else going down the same path.

The setup for reference:

  • Built 84mm bottom end
  • GT2860RS, .86 A/R, T25, 5-bolt
  • Goal is around 300–325whp
  • Street car, spirited driving
  • G-series trans (double synchros + LSD planned)

It’s not a drag build. I’m not chasing peak numbers. I just want smooth, reliable power that doesn’t shock the drivetrain — something that feels strong but controlled and makes the car genuinely fun to drive.

That’s where the boost controller decision really came into focus.

What I’m Really Trying to Control​

It’s torque hit.

At 300hp, it’s not just about power, it’s about how it’s delivered.

That’s part of why I decided to go with the .86 A/R housing. It’ll help smooth out spool compared to a .64. But even with that, housing alone doesn’t control torque shock, how boost ramps in still makes a big difference.

I came across the Greddy Controller​

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Pros:
  • Simple.
  • Clean interface.
  • Set target, adjust gain, done.
  • Proven forever.
It’s straightforward. You dial in your boost level and tune around it. honestly, part of me likes that simplicity.

Boost Leash​

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It’s more technical. More adjustable. Less “set it and forget it.”

But what it offers is actual ramp control — meaning I can control how quickly boost builds, not just where it lands.

That’s huge ( Donald Trump Voice ) 🤣

Instead of boost hitting like a hammer at 3k, it can build in progressively. That’s less shock to the G-series. Less sudden torque spike. More linear pull. For what I’m building, that’s attractive.

Where I’m Leaning​

I’m intentionally trying to soften torque hit and build something that feels refined instead of aggressive, the Boost Leash makes more sense on paper.

It gives me:
  • Controlled ramp
  • Gear-sensitive options
  • More precision over how boost comes in
That aligns with my build.

The Goal​

GT2860RS .86 A/R
0.5 bar actuator
Conservative base boost
Controlled electronic ramp

I want the car to feel:
  • Strong
  • Predictable
  • Linear
  • Smooth through the gears

Not really explosive.

If I can keep it around 300–325 with a clean boost curve, I think the transmission will live a much happier life.
 
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I'd think that with the lsd you're planning and a good clutch the transmission shouldn't be that wet noodle you're thinking may break.

What lsd are you going with?
I chose the Quaife lsd modified by Bisimoto to work with the Veloster R-Spec Turbo 6 speed for my now pulled the plug build.

Your turbo and build looks similar to what I was looking for with 300whp and has my interest.
Are you planning on going with a stand alone setup for your ecu?

I thought about that too but found a Turbo ecu that actually works in the car with much diligence to finding it.
Simple harness changes for the fuel rails and engine harness would've been all that's needed which I did get ahold of.

But seeing that all that has to ripped out and a new harness installed I kept thinking standalone and build my own harness as needed.
Expense comes to mind and my wallet was crying enough to halt everything.

You have a better grasp on what your wanting and longevity seems to be the goal as well.
Going this route takes much planning ahead.
Good thread going here.

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