Safe amount of boost?

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oosterveld

Member

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2003.5 Mazdaspeed Protege

• Jun 30, 2017

• #1

My protege is headed to the shop to get some forging done, entirely new prebuilt motor head, k1 rods and to be decided on Pistons. My question is what is a reliable boost range since I know the rods are the first to go on the stock engine.

 

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hornsfan10609

Certified Mazda Tech

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2003.5 Mazdaspeed Protege x2

• Jul 1, 2017

• #2

How much boost depends on what turbo you want to use, your engine management and how you feel about transmission swaps.

I run about 15psi on my forged motor but with the piggyback or on the stock ECU it still hits fuel cut over about 12psi.This is on a T25.

 

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oosterveld

Member

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2003.5 Mazdaspeed Protege

• Jul 2, 2017

• #3

I also have a piggyback, it's the split second, I have a freshly rebuilt t25 so do you think a nice 15 pound tune would be safe or is that putting strain on the valves or transmission to an unsafe amount?

 

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hornsfan10609

Certified Mazda Tech

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2003.5 Mazdaspeed Protege x2

• Jul 3, 2017

• #4

You will be fine on 15 psi. The transmission will depend on how much torque the motor is making, if you don't try to slam the gears it will probably last a while. Some people make 300hp with a stock trans for years, and some people grenade them at 250. You will probably need a stronger clutch if you are running 15+.

 

Last edited: Jul 3, 2017

323

(u_u) ...zZzZzzz

Moderator

• Jul 6, 2017

• #5

i need to up my boost soon. dont know much about injectors. how much boost can the oem injectors take on that stock turbo?

 

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oosterveld

Member

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2003.5 Mazdaspeed Protege

• Jul 11, 2017

• #6

I was also going to ask this, I have a split second piggy back and was wondering how far you could push it until it's time for 440cc injectors.