Dyno Sheet

[81CJH]

A couple of things...

Firstly, there's nothing wrong with that torque curve, it's just fine. It looks weird because the graph is in portrait, not landscape. Grab your own dyno sheet and compare speeds and kw figures. I've attached mine as an example.

You'll also note that my graph peaks within 10km/h of the same place, which for the record is about 5000rpm in 3rd (mine is also a 4sp auto).

The concerning difference is that you can see my boost taper off above this point (stock valve springs) and the power drops accordingly, yet ugy's boost does not. So why, when Ugy's has valve springs and injectors and all the good stuff, does it drop off so dramatically towards redline when the boost holds all the way to the end of the graph?

It is interesting indeed. All I can suggest is that maybe your tuner has retarded the timing a bit towards redline, perhaps to prevent detonation?

I'm not really sure on that one, but as has been said - quiz your tuner as to what's going on there, because it certainly seems strange.

[rob82]

A couple of things...

Firstly, there's nothing wrong with that torque curve, it's just fine. It looks weird because the graph is in portrait, not landscape. Grab your own dyno sheet and compare speeds and kw figures. I've attached mine as an example.

You'll also note that my graph peaks within 10km/h of the same place, which for the record is about 5000rpm in 3rd (mine is also a 4sp auto).

The concerning difference is that you can see my boost taper off above this point (stock valve springs) and the power drops accordingly, yet ugy's boost does not. So why, when Ugy's has valve springs and injectors and all the good stuff, does it drop off so dramatically towards redline when the boost holds all the way to the end of the graph?

It is interesting indeed. All I can suggest is that maybe your tuner has retarded the timing a bit towards redline, perhaps to prevent detonation?

I'm not really sure on that one, but as has been said - quiz your tuner as to what's going on there, because it certainly seems strange.

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Your boost doesn't drop off because of your valve springs its probably more to do with exhaust restriction or the tune. You will most likely find that uprated valve springs will make no more power if not less if you installed them and its still not likely to keep boost in the top end.

Back to the original post I see nothing at all wrong with it, as the rate of increase in power decreses the torque falls off - textbook graph in my opinion. The only thing is that it looks as though the boost could be ramped in a little harder to get more mid range torque. You will probably find that your at the limits of the standard IC piping especially the crossover pipe that feeds the throttle body.

[81CJH]

Your boost doesn't drop off because of your valve springs its probably more to do with exhaust restriction or the tune.  You will most likely find that uprated valve springs will make no more power if not less if you installed them and its still not  likely to keep boost in the top end.

The boost actually tapers off on mine because it was tuned that way to protect the stock valve springs, not because I'm getting valve bounce. Sorry, badly put on my part.

[ugy]

Thanks guys makes great reading. I dont think there is much wrong with the tune as I have got 116.2 mph at the end of the quater mile.

Thanks for the input.

Bill