pistons
April-5th-2004, 08:49 AM
#4
The man behind the mask
Join Date: Oct 2003
Location: Birmingham, AL
Posts: 11,572
I've always heard that the miata was very capable of being boosted.....but I believe this is due to the fact it's based on the 1st gen design...I'd say either/or, but the miata is more curent so it is potentially upgraded/heavier duty.
A first gen guru needs to check in and clear this up!!
A first gen guru needs to check in and clear this up!!
April-5th-2004, 10:05 AM
#5
Moderator/ Pocket Tuner
Join Date: Apr 2002
Location: Tampa,Fl
Posts: 4,150
well lower compression pistons are easier for a pocket tuner to turbo. so assuming you have a first gen bp that you are considering swapping pistons for, i'd stick with what you got, rather than upping to 9.5:1...your stock pistons i believe are 8.5:1, they should hold up nicely in a turbo application. If you insist on opening up the head and block to get at pistons, go ahead and re-ring the stockers and hone the cylinders, then run a copper head gasket from fel-pro and over torque it like 2-3 lbs(it'll seal better trust me), using studs instead of bolts on the head. if you turbo that, it should hold up to 16-17 psi with no probs, assuming you deliver the fuel it wants
April-5th-2004, 07:18 PM
#7
Salt addict
Join Date: Aug 2002
Location: Niagara Falls Ont.
Posts: 1,201
The 400 RWHP was on a boosted Miata.
I'm pretty sure the rods are what goes first. If you can find a set of GTR rods, they're stronger. I can't remember here, but apparently the B6T rods are compatible with the BP and are stronger than stock. How much HP are you looking for?? You should be worrying more about the tranny going before the rods. The G-series box seems to be able to handle not much more than about 350 ftlbs before it goes south, (depends on your driving habits) and thats because of the case breaking not the internals. You can get the case Shotpeened or cryo treated. Don't ask me anyquestions about either of those processes because I know NOTHING about them other than they supposedly will strengthen the case.
I'm pretty sure the rods are what goes first. If you can find a set of GTR rods, they're stronger. I can't remember here, but apparently the B6T rods are compatible with the BP and are stronger than stock. How much HP are you looking for?? You should be worrying more about the tranny going before the rods. The G-series box seems to be able to handle not much more than about 350 ftlbs before it goes south, (depends on your driving habits) and thats because of the case breaking not the internals. You can get the case Shotpeened or cryo treated. Don't ask me anyquestions about either of those processes because I know NOTHING about them other than they supposedly will strengthen the case.
April-5th-2004, 09:30 PM
#8
Protege Enthusiast
Join Date: Dec 2003
Location: Puerto Rico
Posts: 52
I will recomend you all guys to use kia sephia pistons and rods the kia rods are a heavier than the Protege SOHC OR DOHC and the pistons are flat top with full floating. The best ones would be the GTR or Pauter but they are very expensive and the GTR almost imposible to find whe have a protege here in the island running 17 psi of boost making 11.7 1/4 milles with the kia engine stock with a good set up in the fuel side.
April-7th-2004, 04:22 AM
#12
That's right i'm an Admin
Join Date: Dec 2001
Location: Ottawa, ON
Posts: 261
dont waste your time on miata pistons. the pistons are not stronger.
leave your block alone. the stock 9.0 compression you see now will be just fine for boosted means. unless you plan on boosting to 25psi on a vj23 dont worry about it.
the kia is a ******* Mazda. it is a BP, and if memory serves me right they have miata connecting rods which are weaker than the forged BP rods you have now.
as for higher compression pistons + boosted application be wary, you will have more tuning issues, and a decrease in reilability.
The SOHC had a compression of 8.9:1
the dohc has a compression of 9.0:1
only when you put sohc pison on a dohc head do you see a 8.2:1 compression: which is that of the GTR.
Cryotreatment is the act of heating up a metal in a nitrogen or carbon atm, then quenching it or rapidly cooling the metal.
leave your block alone. the stock 9.0 compression you see now will be just fine for boosted means. unless you plan on boosting to 25psi on a vj23 dont worry about it.
the kia is a ******* Mazda. it is a BP, and if memory serves me right they have miata connecting rods which are weaker than the forged BP rods you have now.
as for higher compression pistons + boosted application be wary, you will have more tuning issues, and a decrease in reilability.
The SOHC had a compression of 8.9:1
the dohc has a compression of 9.0:1
only when you put sohc pison on a dohc head do you see a 8.2:1 compression: which is that of the GTR.
Cryotreatment is the act of heating up a metal in a nitrogen or carbon atm, then quenching it or rapidly cooling the metal.
April-9th-2004, 01:51 PM
#13
Protege Newbie
Join Date: Mar 2004
Location: Texas
Posts: 9
Go read the power section of the miata.net forum. The rods are the weak link. Most folks there, and there are a lot of them, going over 250 rwhp seriously consider stronger rods. Engine life at 400hp would be very short with stock rods.
April-13th-2004, 12:09 PM
#15
Protege Enthusiast
Join Date: Nov 2002
Location: Roswell NM
Posts: 270
it's the rod bolts, not the rods themselves, that are the only weak link in the BP bottom end. other than getting better rod bolts I would leave it all stock and re-ring the bitch. Copper head gasket sounds like a good idea.