1jzchris

All you guys that are running turbo on sc400 what kind of pistons are you guys using and if i choose to go stock how much boost can the stock motor handle,i have searched and it seem like 7-8 is the winning number.

ihiryu

iTrader: (7)

Seven or eight sounds right. The only piston available is Ross IIRC

2jznosht

I wouldn't go more than 8lbs on stock internals. the key to na +t setups is in the tune not so much the build parts. I've seen countless built motors give up the ghost because the tune was crap

spoolxexo

iTrader: (4)

Boost, timing, (Static) Compression.

Pick two.

MMCtuner

I´m going 12. From what I know, there are many stock 1uz with 15-17lbs with no problems.

1jzchris

are you for real 15-17lbs on stock internals............that good, roughly what kind of power are they putting out?

1jzchris

you are so right tuning is VERY important, the the stocks can only handle so much and that what im trying to figure out.

cmh

lextreme has pistons for the 400...http://www.lextreme.com/pistons-rods.html but i think ull be str8 with some cometic head gaskets and a good tune...

did u ever see the rear under mount thread on here? that guy just added turbo and a afc neo i think it was and made like 300 whp on stock internals. i think it would be safe to say that with the right tune and HG u could make closer to 350... check this out!

https://www.clublexus.com/forums/sc-...ear-mount.html

One HoT

iTrader: (5)

Fmu 7-8. Injectors and piggyback 11-14.

1jzchris

yea actually i did see and read that thread and it inspired to to try the rear mount.............thus the question lol.

1jzchris

so its safe to say with the proper tuning the stock 400 could run about 14psi max and produce roughly about 350hp...............................thats really not that bad

cmh

not only is it not bad but it will be cheap and ull be turbo... and honestly u have a 92, i would trust it with more boost with the right tunning, HG, fuel, etc.... i would try going from 7 to 10 psi gradually just to see what happens...lol but thats just me.

edit: i bet ull get closer to 400 to the wheels... i went in the wrong direction with my 97sc thats probably yet another reason why its for sale.

spoolxexo

iTrader: (4)

Like I said PSI, Compression ,and Timing (Based on what kind of fuel you have) are directly related, pick two of them.

THESE ARE EXAMPLES:

(Lots of Compression)
10.0:1 Compression, 7psi , 22* timing

OR
(Lots of Boost)
7.5:1 Compression, 30psi , 15* timing

OR
(Lots of Timing)
8.5:1 Compression , 15 psi, 28* Timing

See? So whatever fuel you have to work with , and whatever compression your engine has, is directly related to how much boost you can safely make.

I would do the rear-mount, with a AEM FIC to retard the timing under boost.

Too much of these three things results in a critical increase in cylinder pressure, the physical force inside of the combustion chamber during ignition.

This is what kills pistons and rods, etc. Not Boost by itself, or timing by itself, but a combination get it?

FMU's are dated technology and aren't boost referenced. You need a rising rate FPR to do a Forced induction safely.

This Rear-mount/ AEM FIC is a great discussion, it will help the 400 fans go turbo easily. without having to swap a JZ engine.

cmh

^^^ thats wat i meant to say lmao.... man ur good!

1jzchris

and thats how you break it down, good info man thanks