Can anybody suggest the reason for the "knees" in the torque curves for runs 122 and 123 in this dynosheet? The run number 093 was a previous map overlaid over the more recent map. I do have a slipping clutch, could this be the cause of this anomaly? (is this even an anomaly?). Also the power and torque curves are lower in these later runs, could this be explained by the clutch condition?
Anyway, I'd like to hear some thoughts on this. I'm interested in learning what seems to work or not work in my car.....

 

The knees in the Hp curve correspond to the spike in torque at 3k rpm, most likely caused by a boost spike.

 

Thanks for the input, but I don't think it's aboost spike. I should get and post the boost curves and A/F graphs as well. The boost is very steadily held and no spikes at all....

 

I'd say the tuning is definitely the difference, and not the clutch. If you want proof to support this, go back to the dyno after your clutch install for verification. For racing applications, your car would definitely be faster with the map from run 93, as that's the area where it lands after upshifts. All that gigantic torque on the later runs will be of no use to you once you're past 4000rpm.

 

Hey Noize, I think the tune is extremely conservative but you are right in that the clutch might not play such a big part in the power output. However, the very crappy launches I was experiencing are very likely the result of the clutch problems. Also, all those 2+ seconds 60" times are bound to affect the ET as well as the TS...... After the clutch is done, I'm definitely going back to the dyno for more data collectiing and possibly more tuning......

 

I'm sure the clutch is definitely what killed your 60' times. That is some gigantic low end torque, and a weak stock clutch that is on its way out would defintely slip under that kinda twist.

 

Will you post the AFR and Boost graph from the different runs. Cause different boost levels or airfuel will change the output of an engine.

 

Yeah, I'll do it or I'll make sure I send them to you. I apologize for not posting the whole thing... In my consternation about the clutch I neglected to get the printout of the A/Fs , boost, etc. If I remember correctly, the boost was very steady at around 19 p.s.i. with a very minor surge to 20 p.s.i.(not spike) around the middle of the rpm range. The A/Fs were a bit on the rich side but not extreme.
I'll get the rest of the sheets posted as soon as I can get them. Of course, these dyno runs are definitely inconclusive. There is no way they can represent the true output of the engine to the wheels due to the slipping clutch.