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In our quest to find the mechanical limits of the 2AZFE motor, dyno tuning on the Scion Speed project tC continued on April 2, 2005. Our project tC test vehicle has now been upgraded to Stage 3 specs.

The upgrades include larger 3" downpipe, larger GT3540R ballbearing turbocharger, larger RC engineering injectors and new map.

At the end of the session we managed to squeeze a simply amazing best of 426.15 WHP and 374.64 FT/LB of torque @ approx. 17-18psi of boost pressure on 103 octane VP unleaded fuel. This equates to approximately 491HP and 428 ft/lb @ the flywheel.

UTILIZING ONLY BOLT ON COMPONENTS, we have effectively tripled the standard output. THIS IS STILL ON THE COMPLETELY STOCK ENGINE!!! We are dumbfounded at the strength and flow characteristics of this engine!

We are now at the limits of the 255lph fuel pump. As seen after 5000 rpm on our dyno sheets, the Air Fuel ratio started to lean out due to falling fuel pressure.

In an attempt to break our previous 12.5sec ¼ mile record, we attended the NHRA Import racing event in Palm Beach Florida on April 3, 2005. Due to the new found HP and very high grip of the track, our passenger side axle sheared in half during qualifing rounds, ending our day at the track. We have sourced a new axle and will make another attempt in the next coming weeks. STAY TUNED!
 

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The 3540 is a pretty good sized turbo. I'd start worrying about rod strength now. I'd also be concerned about block strength and cracking at the tops of the cylinders. Each one is making almost 125 hp now, that's pretty strong.

Did they post a dyno yet? I'm curious to see how it makes power.
 

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Originally posted by Ryan'sTc@Apr 9 2005, 09:14 PM
Hey low do you know if this means you could put a 250 or 300 shot of nos down it's throat without blowing the engine sky high?
Sort of. You'd need a staged setup that progressively increases the shot (and the fuel), and you'd still want to dial in some ignition retard as the pressures go up. I've heard of a few setups like this, but never worked with one.
 

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I did some quick calculations and a little investigation on the power numbers for the 2AZ vs. the 2JZ. First, the mean piston pressure required for 374 ftlbs of torque is almost 250 psi. That's not so bad. A 2JZ making 650 ftlbs of torque (and there are quite a few) has a little more than twice that pressure at 509 psi. Keep in mind these are AVERAGE pressures, NOT peak pressures. It is not unreasonable to believe the peak pressures are MUCH higher, especially since these calculations are based on having the full radius of the stroke for leverage, which only really happens when the rod is at 90 degrees to the crank, the rest of the time, the force is a vector calculation based on the rod's angle relative to the crank.

Anyway, total cylinder pressure at that mean pressure is over 2200 lbs. Yes, there are frictional losses in the bearings, and there is torsional vibration and flex eating up power in the crank, but we know to get 374 lbft of torque, there has to be more than 2200 lbs of force on the crown of the piston. Simple physics.

Another interesting factoid: the piston pin is the same diameter as the 2JZ, but the rod and main journals on the crank are not. So, it is not possible to do a 2JZ rod swap with the 2AZ. Damn! That would have been too easy. Also, the bore for the 2JZ is 86mm, the 2AZ is 88.5mm, so no easy swap there either. Besides, the 2AZ piston has a special shape for squish, and using anything without that shape would likely significantly reduce combustion efficiency.

Some other interesting light reading.
 

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Actually, yea... pretty simple physics. Learned that in Engineering Physics 1 here at Auburn.

Is it sad that after reading his post equations started popping into my head and I started planning out how to solve it?

And personally, I don't know if I would be proud of shearing off the passenger side axle. That much power to the wheels is definately not what I'd want.
 

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It's a common problem, but it's nice to know it took more than twice standard output to do it.
 

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Originally posted by Ryan'sTc@Apr 10 2005, 12:32 PM
Hey low is the point of making the engines so strong that they last a long time or to handle the tuner crowd abuse? I would think making an engine this strong would undercut profits.
It is more expensive, but it cuts down on warranty claims. It also puts you at or near the top for both initial and long term quality surveys. Toyota really does overengineer their stuff like no one else does.
 

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Good to know that the engine can handle that kinda stuff. If this SC ever does come out I imagine its pretty safe to run it on all-stock internals. Excellence.

Better product = more business. Any profit loss undercut by the overengineering of their engines is probably made up for 10x because of toyota's excellence reputation for reliability. Everyone I know just about will never buy a pontiac or a chevy or a dodge because most of their products just suck through and through. Won't see me on one of their lots. Ever.
 
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