View Full Version : Analyzing this Dyno Graph - - Help needed

10-08-2004, 04:23 PM
I need some help with analyzing this dyno graph of my buddies SC. There is a spike in the middle of the graph were not sure as to why this is, and what is the accurate estimate of his cars HP. It spikes somewhere close to 340+ but doesn't sustain it. Would a stall converter affect this in any way? Here is the link the the pictures. Any comments about the graph are appreciated, the guy who owned it before my buddy had it dynoed so were not sure what to believe on it. Thanks.

PS: You may have to copy & paste the link as the hyperlink was not working.


XR7 Dave
10-08-2004, 04:39 PM
He's letting it shift on the dyno. The car makes about 290rwhp and 335rwtq. If they did the pull in 3rd only you'd have seen a higher torque reading.

10-08-2004, 04:47 PM
Thanks dave. Yeah I had thought that maybe it did downshift but it seemed that the power had already begun to build so I figured it had already been floored. But maybe he just got on it half throttle then punched it?

David Neibert
10-08-2004, 04:51 PM
The peak hp of about 288 sounds about right and 375 or so rwtq is also pretty much wdhat you would expect. The jagged torque line looks like the transmission downshifted then went back up to third, notice how high the rpms are...I can hit my throttle hard until 3100 rpms or it will downshift.
I don't know what's going on with the HP spike, but if I had to guess I would say it's an upshift into OD. It happens on a lot of cars with trans-go shift kits at just about the MPH shown on the graph. The A/F ratio looks okay and the dip between 80-90 MPH is probaly is related to the HP spike.


10-08-2004, 05:23 PM
Cool, thank you to david. What do you guys think an estimated 1/4 mile for this car would be assuming he could hook up. He ran it a couple of times and ran 14.0 @ 99 mph. That was during the summer months. We assumed it would be faster but he was having traction problems. Obviously theres no way of knowing the exact time without running it w/slicks, but we want to have an idea of what its roughly capable of so when we do get some slicks we know we've hit our plateu.

David Neibert
10-08-2004, 05:32 PM
I'm guessing mid to low 13s.