• Got the Contributing Memberships stuff finally worked out and made up a thread as a sort of "How-To" to help people figure out how to participate. So if you need help figuring it out, here's the thread you need to take a look at -> http://www.corvetteflorida.com/forums/showthread.php?t=3581 Thank you, everyone! Rich Z.

Confused about dyno chart displays....

Rich Z

Rich Z

Internet Sanitation Engineer
Staff member
OK, maybe my brain just doesn't work as well as I would like.... I've been looking at dyno charts that people post, and sometimes they just don't make sense to me. The following two charts are from STS's website showing the difference in horsepower (first chart) and torque (second chart) between a stock Z06 and one with the STS system with just 5 pounds of boost:

C5-Z06-5-psi-rwhp.jpg


C5-Z06-5-psi-rwtq.jpg


What puzzles me, is what the heck are those charts showing me between 1500 rpm and 2700 rpm? It looks to me that when you put on the turbochargers, the car is basically comatose in that rpm range. Obviously that cannot be correct, as I can't imagine anyone wanting to have their car idle at 2700 rpm! So PLEASE someone tell me what I am missing here. There is probably a very logical sound reason for the charts looking as they do, but it just is not intuitively obvious to me at all. :crazy03:
 
well assuming they dynoed in 1st gear it will show power from idle-redline
my guess is that they where already in 3rd or 4th gear when they started the pull. it would be nice if the graph showed mph
 
Not sure but there might be a bit of turbo lag at play here too. I don't know much about their system but my Grand National buddies complain about the lag all the time with their single turbos. It takes the turbos a short time to spool up, hence the term turbo lag. Just a guess.
 
But it still doesn't make sense to me. Look at the torque graph. According to that one, at 2700 rpm, the stock Z06 is making 300 ft-lbs and yet the TT is only making 200 ft-lbs. I can't see how ANY booster device could take away 100 ft-lbs of torque. I would think at the very least the boosting would ADD to the already existing torque at that point. No matter, what the lag, it still shouldn't produce LESS torque (nor horsepower) than the standalone engine.

If so, extrapolating the data, at 1500 rpm, the engine wouldn't have enough power to even move the car with the turbos installed!
 
I think you're interpreting the graph wrong Rich. What you're seeing at 2700 rpm is the TT car climbing UP to 400 lb ft and then going higher from there. Just as at 1500 rpm you see the stock car climbing UP to 300 lb ft. The stock ZO6 doesn't just start at 300 lb ft. It starts low, as does the TT car, and climbs from there. You don't think our cars produce 300 lb ft at idle do you? The dyno graph seems to start recording at 1500 rpm too. The eng is producing torque prior to that, you're just not seeing it. Hopefully some of the tuning gurus will chime in with some better info.
 
Mark Dalton said:
I think you're interpreting the graph wrong Rich. What you're seeing at 2700 rpm is the TT car climbing UP to 400 lb ft and then going higher from there. Just as at 1500 rpm you see the stock car climbing UP to 300 lb ft. The stock ZO6 doesn't just start at 300 lb ft. It starts low, as does the TT car, and climbs from there. You don't think our cars produce 300 lb ft at idle do you? The dyno graph seems to start recording at 1500 rpm too. The eng is producing torque prior to that, you're just not seeing it. Hopefully some of the tuning gurus will chime in with some better info.
Click to expand...

I can't disagree with you that I am interpretting it wrong...... :shrug01:

I see these charts all of the time, and many of them DO make sense. These two just don't compute for me..... And I am sure it is ME and not the data that is being represented that is off kilter..... I just want to know what it is REALLY telling me....
 
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