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You have a 9-3?
Torque VS rpm.
As long as the ECU is doing its thing with the mixture, its really a function of how much air is getting forced into the intake manifold.
With the T5's, this is highly dependant on the temperature and intake restrictions and mods, maybe even an ECU mod or MBC. The effects of the intake restrictions will be more pronounced at high flow rates... high RPMs.
Take a T5 in the winter and compare its 'torque curve' to one in hot summer weather. Huge difference. What curve do you want to compare to.
So official torque curves are probably quite mythical, or of little practical use. When they get these from an engine dyno, was it with a stock IC and a stock air box with a paper filter. With the T5's, was there a turbo discharge silencer and that stupid flaw in the throttle body transistion casting? I expect not. And with that dyno they are able to come up with that lie about reaching max boost at 2200 rpm. That was done loading things up at a steady speed of 2200 rpm. When is the last time that you were doing a steady speed at 2200 rpm at full throttle? At 2200 rpm with the standard ECU etc, there is so much turbo lag, that probably nothing at all is happenning at 2200 rpm. And when they tested with an IC on the engine dyno, it is was the stock IC, how did they arrange for cooling air through that IC? Was that representative? Probably not, and I expect that they used an air to water intercooler.
So remember, curves from engine dynos are steady state and boost lag and turbo lag issues are missing! You engine cannot possibly deliver such things on the street where things are changing very fast. A 3rd gear run on a dyno jet also is almost steady state, as things take so long to occur. So take two engines that looked similar on a dyno or dynojet. Now compare them on the road. The one that spools up faster and had less boost lag will walk all over the one that does not have good dynamic response. Remember the rule on the street, "Power Delayed is Power Denied". But the dyno said they were the equivalent. So dyno produced torque curves are interesting but quite useless in some ways.
With the T7, things are a bit more straight forward, as the ECU regulates air mass flow instead of boost pressure. So the ECU is attempting to regulate torque as air flow equals torque. The ECU might have some deliberate torque roll off designed in for high RPMs.
So I think that a better measure of torque, would be a single figure. What boost pressure are you sustaining at 5500 rpm - full throttle. That will tell you a lot and improving that will be a measure of an improved system. And with that, you will get better torque with a better IC or cooler weather.
As for less boost lag, you need something with the characeristic of a spring-ball MBC or a good electronic controller, but that is a whole bunch of other issues.
posted by 207.43.195...
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