Turbo plans very soon, q and a Options

[NOVAKx17]

Long story short im hooking up with a buddy on the site and making a deal.... no details yet until it's all confirmed, but what are the major issues with boosting and what should be replaced on the car to be safe if im going to be running 8-10 lbs on a stock engine. Let's assume145k miles on it..... why? Because I don't want to swap...

[Syaoran]

Main issues on the 5S:

Durability issues:
1. Piston rings expand under boost and the ringlands crack. The piston ring to cylinder wall clearance is too small, it needs to be opened up.
2. The rods on the 5S are good, but their bolts are crap. You can use them if you don't rev past 6500RPM, but I'd get at the very least 3SGTE OEM rods and for about ~300$ you can have a reinforced bottom end. The crank is great on the 5S, it's forged steel. The pistons are good if you gap them like you'd gap a turbo engine's piston rings.
3. The oil pump isn't as good as could be, it's always recommended to get a 98+ 5SFE (Camry/Solara) oil pump since the georotor is larger. That means it's a factory High-Volume oil pump. You could shim the pressure relief spring to have the valve open at a higher PSI, good for revving higher.
4. ****ty ECU. That is self explanatory.

Power limitations:

1. Cams, cams cams! This engine has ****ty cams from the factory. Even mild upgrade cams will get you a TON of power and a much better powerband. Unless you're doing 220* @ .050" and 8.2mm lift cams (webcams 294 grind) then it's recommended to upgrade springs and retainers to 2JZ ones, which fit but require slight modification that can be done by your machine shop.

2. Valves, they're OK, but they could use an upgrade. Stock 2JZ valves are +1mm OS valves for the 5S (both in. and exh.)

Standalone EMS territory:

3. Intake manifold, the stock one is OK for the stock engine. For a turbo engine it's too small. The runners are really long, good for down-low torque but not as good for high-end power. A balance has to be achieved with a custom intake manifold. The runners are also really narrow, which is bad, and the plenum is too. I was recommended by a more experienced member of an MR2 forum that a 20% increase in runner diameter and plenum size along with a 20% decrease in runner length would be a perfect match for a 5S turbo.

4. If you upgrade the intake manifold, you'll need to upgrade the TB to a larger one. A 60mm 3rd gen 3S throttle body could be used with the stock ECU since the TPS can be used, I believe.