ZPI to produce yaris turbo kit and exhaust

[ZPIracing]

Originally Posted by yarisTOONR82

This post was originally from the ELPrototypes website, and I was just wondering what ZPI Racing is going to do in order to get around the problems listed below.


Turbo charging the 1nz-fe has proven to be chore. It responds to boost quite nicely with a properly sized turbo. But its downfalls are the internals and its engine management.
Lets touch on the internals. First and foremost are the rods. Although quite strong for their size, they are designed for normal aspiration only. A half point higher in compression is about all they can handle daily without failure. Once boost is added to the equation, it becomes Russian roulette as to when they will let loose. You may last eight months with 50,000 miles or blow it the first pass down the street; there are no warning signs. We know this because of the testing of our turbo kit for the last year. The testing started on the Echo then was transferred to a Scion. The testing was controlled and only once was it taken past its set 7-psi mark while in our possession. Its one time high boost pass on the dyno was done to see how much the turbo would produce at maximum efficiency. Fueling and timing were changed to handle this. Every month the pan was dropped and there were no signs of abnormal rod bearing wear. The compression was straight across the board every time. The first motor lasted 6 months with about 35,000 miles. Its life was cut short while at the paint shop. Rumors placed it at the local street races near the paint shop, which they had for 3 weeks. All the baked on rubber in the fender well was the first clue. It let loose on its way back from them. A fresh motor was installed ASAP to continue the testing. The old motor was broke down to find the rod broke right above the crank pin. The dangling rod was beaten into the walls and punctured holes on both sides of the block. The second one let loose 12,467 miles later. It had seen one race with 3 passes at 9 psi. Fueling and timing were also changed to handle this. Other than that it was daily driven. The rods let go again, the same way, only this time it punctured the water jacket and destroyed the head. These engines have the crankshaft offset 12mm to the thrust side of the cylinder bore centerline. This reduces the side force generated at maximum compression, for reduced friction and improved fuel economy. Toyota calculates the offset crankshaft configuration reduces fuel consumption by between one and three percent. Unfortunately, this throws the angle of the rod way out on its upward travel causing the rod to just give up under boost and snap. If there is any detonation or pre-ignition this breakage will occur at an accelerated rate. The movement and breakage of the cylinder walls is the same as Honda’s open deck. Although we have yet to split one, we designed a block guard just in case. This product keeps cylinders from moving around and from splitting open the top of the bore. We are currently designing a forged replacement rod as well as a rod piston combo for high boost applications. The first of the sleeved blocks is being tested now.
Now for the ecu. It cannot handle boost in its stock form. Its timing is set for the stock parameters only. It will not handle larger injectors either. Piggyback or stand-alone management is needed to fuel the turbo properly, end of story.
From what we have seen, these issues probably were found by the likes of Blitz and Greddy long before we did. That’s why the boost on their kits was so low. The stock injectors will supply enough fuel for 3 to 4 psi if the MAF reaches full voltage and gets the injectors to 85 percent duty. Unfortunately you end up with a 15:1 AFR at peak rpm this way. Good for passing emissions but bad for the motor. The RS turbo Vitz has an ecu calibrated for the larger injectors that feed 150 ps at the flywheel which in turn is 127 ps at the wheels. The blitz s/c was turning 122 hp to the wheels without an ecu for the US market. With the ecu (JDM only), the s/c put down 129 ps to the wheels. It seems like the kits are limited to 150 at the flywheel but no one says how long it will last. Our turbo kit produced 144 hp and 150 tq to the wheels. That’s 170 hp at the flywheel. We have worked with several management systems and we will inform the public of the best one for our kit. We will release our kit soon but cannot warranty it except for workmanship. This kit will push your engine over the edge in the long run but if you build it our kit will be able to provide up to 250 hp at the flywheel. That’s 217 at the wheels. With all this said, it is up to you, the consumer, to decide whether this kit is right for you.

All this sounds like is the rambling of a guy who is trying to sell turbo kits after he blew his car up. We have made more power than this on the 1nz for a longer period of time. Tuning is critical but we have ran 7psi with no engine management and made 181 at the wheels doing so. We have been over 200whp and we beat the crap out of the car far worst than anyone would do to their own car and we are yet to have any issues.

I am not to say these engines are bullet proof but we dealt with this same type of criticism on the tC engines until we made 376whp and 420ft lbs on a stock engine with a stock manifold hacked and welded with no intercooler.