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Now...Whitesupra94
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3,251 Posts
Discussion Starter #1
well i downloaded the newest version of dynojet runviewer, and my numbers are slightly different. this version interprets the TQ converter much better on an auto car, so up until the pt. where the tq converter locks, the numbers are changed, peak #'s are the same. but i want you guys to look at the 4-4.5k range....two different dyno runs, tuned AFC vs untuned...that loop you see is when my tq converter locks, the dyno is done in manu mode 100% throttle in third gear.

for the graph, go to www.nonturbo.com then to the "NA supras" section and then to Bob reeds supra and the picture of the dyno....

anyone who can tell me why thats happening please feel free. notice how the second run with the tuned afc has less of a problem.

Bob
 

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Supra Member
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1,822 Posts
Are you wondering about the dip in power at ~4.5k? My guess would be it having something to do with the ACIS... perhaps sticking or something. I have a dip in my dyno sheet at the exact same spot, although a little more dramatic than yours.

btw, great numbers!!
 

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Now...Whitesupra94
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3,251 Posts
Discussion Starter #3
its not so much the dip that worries me, its the spike(that is really a small loop if the graph is enlarged)right before the dip. if i just floor it in third gear, theres no problem, if i dont go from a dead stop in manu mode theres no problem. but on the dyno and at the track that is a major hesitation. (.67 seconds to be exact) its not the loss in power that bothers me its what is causing the loss. ive studied many dyno graphs that people have posted, and it seems to be a general flow characteristic of our engine. but mine is exxagerated by the loop. look at my dyno graph again closely. the red run especially. there is a loop on the graph. that means under full throttle acceleration, the car stops and rev's backwards by 20 rpms or so, before continuing on. the guys at dyno jet that helped me understand the new version said its my torque converter locking, but it should lock smoothely. maybe its cause of manu mode or maybe its because of the secondary butterfly in the manifold, which i really dont know if it operates off of vaccum pressure( seems more like an actuator to me) but come spring ill have a new timing belt, cam gears, and lightweight pullies, smaller exhaust, and a re-tune with less sharp of a drop in the A/F.

BTW what is the ACIS?
 

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ACIS is the 2nd butterfly system.

The way I'm interpreting this... I don't see your motor revving "backwards" as the X-axis is RPM. To rev backwards, it'll be far off the graph on the left side in the negative region.

I think to say that the revs decreased for a moment at that time would be incorrect too. I'm not too sure about how the dyno records data, but I would think it measures torque at intervals and records instantaneous RPM, then plotting RPM and torque/calculated hp. Also, revs would have to drop at the engine (before torque converter) to show up on the graph like that if that is the case, since RPM is measured at the engine, not the wheels (after torque converter).

Someone correct me if I'm wrong.

In other words, I have no idea what's going on, and am probably more confused than you are. :p
 
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