Built Block?!?

F

funktownp5

Member
:
02 Mazda P5 Turbo
I am reading in a lot of threads that you need a built block to run more

than 10psi on any turbocharger, which I do not agree with. Just

wondering how many people are running a turbo larger than a T25 and

boosting more than 10psi with a stock block? Just trying to get some good

info before people build a motor and spend thousands of dollars.
 
Im sure it can be done with proper management but why risk a hole in the block?
 
Its really not a bad risk, especially with good engine management on a LX

or P5 ECU. IMO the MSP ECU is garbage, and was probably to blame for

people blowing their motors(even at low boost). Personally ive been

boosting on a stock block and ECU for the past 4 years, the only problem

I have had with the car is the transmission(on my third).
 
The ECU has nothing to do with the engines blowing - it's the weak stock rods. The rods are cast and are too weak to handle too much power. The ECUs are actually tuned to run really rich which actually saves the engine. 10 psi is just an accepted limit. Sure, you can run a little higher. 505zoom ran 12 psi on a GT28RS with a stock block but he also had a great tune and was pulling a lot of timing at peak torque. Youu can disagree with the convention all you want but you'll get nothing but "I told you so" when you blow your engine.
 
I just find it funny you're disagreeing with something that has long since been proven. These engines blow due to rod failure. The rods fail because too much stress is being placed on them. It has nothing to do with the ECU. If anything, the MSP ECU would be safer because it has significantly less timing advance than the DX/LX/ES ECU. You can have the safest possible tune but there will be a point at which the stock rods will just break. I'm not trying to bust your balls or anything, just trying to prevent another engine failure. The following has been said a lot:

Pick 2: Cheap, Fast, Reliable
 
Im not saying that the motor is the best, but you dont have to built it to

make over 200HP safely. I see alot of prople with built motors only making

25-30HP more than me, if I were to build a block Id be making at least

375HP and terrorizing dem skreets. (burnout)
 
Well yeah, you don't need a built block for 200 whp. Can't fault people for starting with the uilt motor though. I kind of wish I could have invested in that first as well. I'm at about as much boost as I'm willing to run (10 psi on an upgraded stock turbo) and I think I'm putting down 220-230 whp. My final goal is 300 whp which I know is going to require a bigger turbo and more boost. Not something the stock block is designed to withstand.
 
It can be done but it's walking into risky territory. The TUNE is a huge deal like was mentioned by magnumP5. The rods also very weak to take a lot of torque and can snap easily. It's a fine line to walk if you want to do it and it's not really worth it if you can't afford a rebuild. I personally ran a great Haltech tune with stock block on a 28RS up to 9PSI and made 253 which I felt was PLENTY for a stock block. I ended up spinning a bearing weeks later though and now i'm built. So there you go.... it's a risk that SOMETHING may go wrong. GL!
 
I agree that 300 is well over what it can handle, im at about 230HP I think

(12 psi on a T3/T4) which i could probably turn it up a couple of more

pounds and still be ok.
 
It's definitely a thing that is proven to be needed.. building your block if you want to boost more or at 10 psi. It's been obviously shown that the block cannot handle it, thus resulting in the ever-popular Zoom Zoom Boom club. you may not agree with it, but the proof is there, throughout this whole forum.
 
funktownp5 said:
I agree that 300 is well over what it can handle, im at about 230HP I think

(12 psi on a T3/T4) which i could probably turn it up a couple of more

pounds and still be ok.
Click to expand...

Sounds like you have done good. Depending on the power curve and how much you beat on it, it MAY last you. I wouldn't start getting thirsty for more power specially since your flowing so much air and I dont think the block will take lightly the extra pressure from the turbo. I say keep it the way it is and enjoy till you can build it...or risk it and hope it doesn't blow! :) You never know there's always cars that were built on a wed real well.
 
My motor had 90k miles with 195psi compression acrossed the board when I pulled it burning about 1/2qt every 3k miles boosted from 8k miles up to about 250whp 13psi over 3yrs of 1-4th gear burnouts -2 3rd gears! With all the right mods including a j&s safeguard. Make your next mod a knocklight they're cheap and at least you can see your limits if they've been reached.
 
highest HP made on a stock block protege was around 275 and that motor is still running. But the owner of that car does not run it like that every day. There are cars that have blown up well before trying to reach that point. if you would like to push your luck you are more then welcome to give it a go.
 
Aricjm15 said:
highest HP made on a stock block protege was around 275 and that motor is still running. But the owner of that car does not run it like that every day. There are cars that have blown up well before trying to reach that point. if you would like to push your luck you are more then welcome to give it a go.
Click to expand...

Ummmmm........ok, I thought I was already pushing it.
 
avarela86 said:
It can be done but it's walking into risky territory. The TUNE is a huge deal like was mentioned by magnumP5. The rods also very weak to take a lot of torque and can snap easily. It's a fine line to walk if you want to do it and it's not really worth it if you can't afford a rebuild. I personally ran a great Haltech tune with stock block on a 28RS up to 9PSI and made 253 which I felt was PLENTY for a stock block. I ended up spinning a bearing weeks later though and now i'm built. So there you go.... it's a risk that SOMETHING may go wrong. GL!
Click to expand...

What caused you to spin the bearing? Low oil? Hard turns? I'm not 100% sure of every possibly that causes a spun bearing.
 
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