| Message |
Amazing Z, amazing potential that has been maximized and extracted - Dee's Sport600 powered TTZ is a rocketship at the peak of performance standards for a Z32 with the modifications he has chosen. Tuning this vehicle was certainly a lengthy process involving a multitude of different configurations that varied with fuel type and water injection. The fact this car has tubular inconel manifolds and camshafts mean that this engine is very capable of moving a lot of air very efficiently, and the water injection gives these turbos a healthy efficiency boost at the high boost pressures were were running them at. I wanted to first show how the water injection affects performance with boost staying the same, and also when boost is increased.
|
The comparison of runs #38 and #39 was specifically to show that with the injection of water, your power and torque actually suffer. I have seen this three times now with different vehicles and am convinced this is due to the fact that the water is absorbing enough thermal energy from the combustion process that the effective cylinder pressure is lowered - thereby lowering torque and horsepower. In these two runs, you can see that the power fell by 16HP and 5ft/lbs torque at their peaks, but there is notable area between the curves showing this difference. I have seen this same phenomena now with 3 different vehicles.
In order to benefit from water injection, you must also increase your boost pressure and/or ignition timing. My findings have been that they actually like to run more boost and leave the timing alone. This is convenient as changing ignition timing is more complicated than turning up the boost for the average user. Turn the water on, turn the boost up, and hold on to your panties.
|
|
|
In runs #20 and #26, the only thing changed is the boost pressure - both runs have water injection activated and both are running pump fuel. From the addition of water and increased boost, we were able to realize another 52.7RWHP and 69.43RWTQ safely at 1.65bar. When the boost was increased to 1.70bar, detonation was detected around 5500RPM and I let out of the pull.
In essence, if you run water injection, you must also increase boost in order to realize any power gains, but the fact that the water helps suppress detonation so well, you are able to do this without any problems.
The fact that we have been able to safely increase power by 50RWHP and almost 70RWTQ by simply adding water and increasing boost is quite amazing - it is almost analogous to a nitrous setup if you overlook the spoolup advantages that nitrous has. The combination of nitrous and water injection has yet to be tested by us, but that will be coming sometime in the near future. My prediction is that the water injection + N2O will express a degree of synergy and the total output of the two together will exceed the total of the two seperately. We will have to see, but for now, the water injection is definately showing a significant advantage - putting pumpfuel into the 500RWHP level and racefuel into the 600RWHP level.
|
|
One other element of tuning a vehicle is the setting of the VTC release point. This process is done by simply performing a run with the VTC on for the entire run, and then making another run with it off during the entire run. The point at which the torque curves intersect is the point where you want the VTC to release the intake camshaft advancement. The reason behind this is that intake camshaft advancement will benefit torque and spoolup because the intake valves are opening slightly prior to exhaust valve closing. This is called valve overlap. This allows the scavenging effect of the exhaust to 'clean' out the small amount of burnt gases in the combustion chamber that would not normally be flushed out by the exhaust stroke. While this helps at low and midrange RPM, at higher RPM there is enough backpressure in the exhaust manifold that it exceeds the intake manifold pressure. During the event of valve overlap, the higher exhaust manifold pressure actually begins blowing more dirty exhaust gases into the combustion chamber and even as far as into the intake manifold. This will lower engine output as well as excessively heat up the engine internals. Typically, the point at which you want to release the intake camshaft advancement with these turbos is around 5900RPM, but because Dee's car has tubular exhaust manifolds that breathe so much better, we found that leaving the camshaft advancement on over its entire RPM range was a benefit of about 20HP and 10FT/LBS! In the end, I think the only two things this car can benefit from are 500 camshafts and a full 3" exhaust. Dee currently has a 3" exhaust from the downpipes to the midpipes, but the cat-back is 2.5". This sharp reduction in pipe diameter is offering up a few HP resistance to the exhaust. With the 500 camshafts and exhaust, the engine would continue to make torque beyond 6500RPM and the horsepower would continue to climb - putting this car somewhere along the 615-625 RWHP level. After that, there's really not much you can do to make more power short of pulling the engine out and starting all over with larger turbos, portwork, valves, money, money, more money, and a lot more money. =) I just wish all of you could have gotten the chance to boost this car just once. For more information on the Z1 Water Inection Setup:
[ http://300zx.com/Products/Power%20Adders/powerplant-performance-poweraddersystems.asp ] And you know our site, [ http://www.300zx.com ]
[ ashleypowers.com ]
[ agpowers@bellsouth.net ] [ Zemulator Information Sheet ] [ Z1 Motorsports Website ]
.JPG) Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
Albert Einstein
|
 |
DYNO Notes: Dee's Sport600, Inconel Manifolds, H2O Injection - 
