I have forged rods and a set of 10:1 wiseco pistons. I am debating between going with 8.5:1 or the 10:1 for my turbo set up. How much boost can I safely run with the 10:1 pistons? Which piston configuration will maximize my whp output?

 

i wouldn't go past 8psi on 10:1... you could run more boost more safely with the 8.5:1... a lot of factory boosted cars use a 8.5:1 or 9:1 ratio... i guess it just really depends on what you are wanting to do, and what you are willing to risk...

 

8.5:1

 

x2

 

What turbo do you have?
Do you drag or road race more?

With 8:5:1 you car will be a dog when you are out of boost. But, you will be able to run higher amounts of boost. Its a trade off, do you want boost with power now or more boost with more power later? It depends on what you want the motor to do.

A safe boost amount can only be determined by you and your tuner. Take it one step at a time and slowly increase boost making sure to keep a close eye on temp and AF ratios.

 

with our 1.5L 1NZ-FE i wouldn't go under 9.0:1. If your not on boost you wont go anywhere, the compression is so low that without the extra oomph from the turbo your engine will be LAZY!!

 

i've got a stage 3 clutchmaster and it can hold alot! I figure that i can bypass turbo lag off the line by building up boost and dropping the clutch. however, that may not be a great idea cause i still get wheel hop even with the engine torque damper! How about 10:1 pistons, greddy supercharger and nitrous? My goal is to get 250 - 300 whp out of my little xa. I'm not looking to drag really. I'd like to make this my first conversion from a daily driver to a sweet auto-cross for what its worth.

 

not to kill your dream here, but unless your shooting 100 in N02, your NEVER going to hit 250WHP. There is this one guy running 18 lbs. with nitrous and got 263WHP and thats turbo charged. No way in hell will you be able to pull those numbers off a charger.

If you did manage to get the power and you do drop your stage 3 clutch your going to snap those axles like twigs...

I think Blown_xA ran a charger with OEM pistons (which are 10.5:1, i think) and N02 and he hit 14.7 quarter mile, which is probably 140-150 WHP, maybe more...

Dont get your hopes up with our tiny little engine, you cant expect great numbers with 1.5L of displacement and dont kill your self puttingup the boost because your next problem will be rods.

If you want a safe setup with 150+ WHP i suggest no more than 8 lbs, and no nitrous, but then again thats up to you.

 

i have crower rods and wiseco pistons so I want to be able to push the engine as far as i can. I even have an engine enroute. I bought it so that i didn't have to pull mine out and be without for 4 - 6 weeks waiting on some motor shop to the work and be car less during that time. However, now i'm trying to decide between s/c and turbo. I want s/c because of ease of installation over turbo and instant power. but seems like with way more $$$ i can get more boost out of turbo. I would be content if I could get 13 - 15 psi out of the s/c.

so here's what i already have: wiseco 10:1 .030 over pistons, crower forged rods, injectors, complete gasket set, emanage ultimate.

I need toga bearings, turbo or s/c and intercoller, afr meter, radiator, gauges...

am i going to need a boost controller?

 

twincharge, best of both worlds. run the 7psi of the blower with the 7psi of the turbo... nice smooth power delivery, would definitely go 8.5:1 though...

 

would be nice!! can't afford all of that right now though! must go with one. Plus i just found an lsd that I wanna hook up now. i'm trying to sell the 10:1 wiseco pistons but no one has bit yet.

 

LSD??!?!?!?!! Where?? and how much??

 

kaaz toyota vitz $900.00

 

Won't find many buyers for a 10:1 set. If you're looking to put out the kind of power that will neccessitate an engine build, chances are you're making a 1/4 mile only car and don't need to worry about low-end and daily driveability. Just spool boost on the line, run race gas and go.

Are you driving much off of the track? For daily driver, nitrous is probably the best and cheapest alternative. You can run N/A on the street, then use the bottle on the track. Hook it up with emanage or another piggyback unit to keep it safe and you may be able to get away with a 75 shot. If you want constant power, turbo or super will work but be advised a supercharger is non-upgradeable on the xB unless you go with a custom pulley. The Greddy pulley will slip until the engine warms up with the stock pulley, so a smaller diameter will probably slip worse. Superchargers top out at 114 whp for the xB kits.

I am seriously contemplating a twincharge build with a built motor, possibly through Dezod, all depends on what my refund is, lol. Last year it was $5600. If you go the twincharge route, use a roots-type as they are positive displacement and affectively add turbo boost to the s/c boost for total output. I believe the Greddy turbo will mate up with the Greddy s/c since the throttle body is in the stock position and the pipes don't appear to overlap. With the Greddy charger alone, I did need to upgrade the injectors as it was running lean with an exhaust upgrade. You will lose HP, however, when you ritchen it to safe daily driving levels.

Whatever you go with, make sure you find rods as well, they seem to be the first component to fail during builds. I'm buying a second used engine and will do all the build on it to reduce vehicle downtime.

 

I think that i'm sticking with the 10:1 75.5mm Wiseco Pistons with my turbo build. But we will see. Crower forged rods with toga bearings. I'd like to find valves and valve springs. Any aftermarket companies make them?

 

alright.... just ordered up a set of 9:1 wiseco pistons :D still selling the 10:1 75.5mm wiseco pistons. $300 o.b.o. plus shipping.