Pistons under boost

[1moreMPH]

Hey guys I am looking to strenthen the internals of my engine (2003.5 mazdaspeed) so i can run more boost. If I want to be running 15-17psi on a daily basis, is it necessary to get upgraded pistons or will the stocks do just fine? I know rods are most important, and yea i have management and all the extra jazz...just wondering how crucial the pistons are. thanks ya'll.

tC

 

[blthlt]

Pretty crutial considering the money it would take to have them machined to fit a aftermarket rod. You may want to search for your answer on this as there are several threads that explain all of the reasons.

 

[Kansei]

15-17 on the stock turbo? I thought that was getting out of it's efficiency range.

I'd say pistons would be needed at boost that high.. but I have no experience with boost that high so I'll just give this thread a *bump* so someone with more knowledge can give some input.

 

[Speed_Racer]

People have run as much as 22psi on the stock pistons. However should the the car run lean, or detonate, the stock pistons will be as good as scrap.

edit: the ideal compression for a daily driven 17-20psi FS-DE engine would be 8.5:1 as opposed to the stock 9.1:1. It can be done with some tuning however.

 

[gone_fishin]

15-17 psi baseline on stock internals is playing with fire to put it bluntly. The stock rods are toothpicks, and at that ammount of boost pressure you're asking to throw one through the block and/or spin a rod bearing. I'd at least upgrade the rods and pistons, in addition to getting head studs. If you've got deep enough pockets, just get a built block.

But at the ammount of output you'd be putting down with 15-17 lbs of boost and the mods needed to run that safely, you've got a lot more to worry about than just the bottom end. Your tranny wouldn't last long. You'd need an upgraded clutch, a welded LSD, and reinforced gears at the least. It's been said before, but the mazdaspeed protege is essentially an N/A car with a turbo. It wasn't built to run anything over 8 psi.

 

[1moreMPH]

yea im pretty sure you would be able to tune it right with programmed ems.

and yes you're right, for our turbos the max output that is worth anything is supposed to be ~ 15psi....i'd set it at that, and was allowing 17 for spikes or whatever.

any other opinions? Im looking at a set of Wiseco pistons if that helps...can they fit with Pauter rods?

 

[1moreMPH]

15-17 psi baseline on stock internals is playing with fire to put it bluntly. The stock rods are toothpicks, and at that ammount of boost pressure you're asking to throw one through the block and/or spin a rod bearing. I'd at least upgrade the rods and pistons, in addition to getting head studs. If you've got deep enough pockets, just get a built block.

But at the ammount of output you'd be putting down with 15-17 lbs of boost and the mods needed to run that safely, you've got a lot more to worry about than just the bottom end. Your tranny wouldn't last long. You'd need an upgraded clutch, a welded LSD, and reinforced gears at the least. It's been said before, but the mazdaspeed protege is essentially an N/A car with a turbo. It wasn't built to run anything over 8 psi.

yes yes i understand all of this and i have it covered, i just need to know about the pistons. Rods are a must.

 

[Speed_Racer]

Well if your interested I am selling a set of Wiseco 9.0:1 pistons. but as gone_fishin stated to run that amount of boost you have alot more supporting mods to buy before you start worrying about internals.

 

[low_psi]

do people not read the post before replying?

1moreMPH- yes the wisecos will work with aftermarket rods. they have a 19mm pin bore like the other aftermarket alternatives.