What size pistons should I go with?

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Drifter_85

Member
Ok so I understand why you use low compression pistons on turbo setups but I want more info.. If I go with 8.5:1 what size turbo should I use? My main type of driving would be drifting so I wouldn't wait something that takes along time to spool right? Should I stick with a stock compression and just upgrade a turbo? I'm not really get the answers when I search, I'm just reading about peoples setups and there power. I'd just like some more insite please.
 
im sure abrahams got you but do you understand the purpose of low compression pistons? when you have a turbo you are forcing a much higher volume of air into the cylinders, (and fuel too obviously), running a lower compression allows that much more space for the air and fuel to go, thus eliminating, or at least cutting down on possible engine failure (detonation, damaged pistons and connectiong rods). also running a different compression ratio will not affect the turbo to spool up quicker
 
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What are you using the car for? Racing,Drifting,Hardparked,Wangan,Anal,Autocrossing? Stock compression on a rb25 is 9:1 which is fine if you lower the compression to 8.5:1 you can run more boost but out of boost your going to be slow. I would leave the motor stock for the RB all you is a nice sized turbo, ECU, Injectors and your good to go. If i remember correctly the highest HP in a stock internal Rb25 was 650whp. If you need more info pm me.
 
Yes I understand why you use low compression. The compression should effect your turbo spool shouldn't it? That's why i'm asking, if you have a bigger turbo and you have super low compression wouldn't that mean you have lower pressure pushing the blades of your turbo? Would it be really benificial to go with a bigger bore too? Since I'm getting new pistons and rings and the price of all the sets are the same, I want to get the best setup I can. I said in the first post I'd use it mostly for drifting. One of my friends said to bore the block to rb26 specs and then use rb26 after market pistons? I just want more info. I'll pm u
 
I wouldn't worry about all that. RB25 is gonna have no problem spooling a mid size turbo. You dont need a shit load of power to drift, I mean my car is only like 230whp and I have tons of fun with it.

Just go out and have fun, I know you want response but a Stock RB25 will be plenty responsive with a T28 or a small T3. I say stop worrying about it.
 
Thanks everyone, ya in gonna take it to my uncles shop Sunday and break it down completely and check to make sure everything in fine with the motor. I got it from Jdm of Miami and he said pistons 5 and 6 were coming up low. If just the rings are bad I'm just gonna hone out the walls and put new rings and use stock internals on the block cuz I'm not looking to make 1000 hp. People say the stock internals can handle around 600 hp so I think I'll be fine staying with them.

I think I'm just gonna stick with the stock turbo at first and figure out what I want to upgrade it to after I get it running. Rb25 comes with a t3 right? I'm pretty sure I read that some where.
 
Drifter_85 said:
Thanks everyone, ya in gonna take it to my uncles shop Sunday and break it down completely and check to make sure everything in fine with the motor. I got it from Jdm of Miami and he said pistons 5 and 6 were coming up low. If just the rings are bad I'm just gonna hone out the walls and put new rings and use stock internals on the block cuz I'm not looking to make 1000 hp. People say the stock internals can handle around 600 hp so I think I'll be fine staying with them.

I think I'm just gonna stick with the stock turbo at first and figure out what I want to upgrade it to after I get it running. Rb25 comes with a t3 right? I'm pretty sure I read that some where.
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people that tell u rb25 stock internal are good for 600hp are wrong

the stock turbo is a t28bb front with a t3 flanged rear housing
 
Just if you bore it out dont go to crazy, i decided not to bore out my KA (yes i know its a different motor and situation) because the higher the boost you go, if the bore is to large you wont have enough piston wall between the pistons to dissipate heat well and your motor MIGHT have a tendency to overheat. Stick with the stock size and just go with a pound or two more to make it up. Good luck with your build, I'm envious of the RB, thats one seriously sexy sounding motor, though im happy with my KA-T ^_^
 
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