what gear to dyno in ???
12-17-2004, 10:38 AM
#21
From all the dyno's I've seen, there is almost nothing common between them. Kinda like cylinder head porters, be we won't go there....
I'm sure they could apply a conversion factor to a 2nd gear pull, but that factor would be based on an average variance of 2nd / 3rd pulls over a variety of vehicles. I've never had a dyno operator apply a 2nd correction or ask to apply one. I have been told by the operator that 2nd gear numbers are a little lower, which I already knew. I personally don't think there is an accurate conversion. Rotating weight, diameter, gearing, converter, transmission, etc.. all vary so much between vehicles.
I've tried both 2nd and 3rd. Most of mine have been 2nd gear runs. The times I've tried 3rd gear runs, I found myself standing waaayyyy back. Those freaking wheels were turning fast. "Is it safe to run 135+ on the dyno?" Not likely and I don't plan on doing it again.
Yep, its about time we all meet up, pull our motors, and run them on the same engine dyno.
I'm sure they could apply a conversion factor to a 2nd gear pull, but that factor would be based on an average variance of 2nd / 3rd pulls over a variety of vehicles. I've never had a dyno operator apply a 2nd correction or ask to apply one. I have been told by the operator that 2nd gear numbers are a little lower, which I already knew. I personally don't think there is an accurate conversion. Rotating weight, diameter, gearing, converter, transmission, etc.. all vary so much between vehicles.
I've tried both 2nd and 3rd. Most of mine have been 2nd gear runs. The times I've tried 3rd gear runs, I found myself standing waaayyyy back. Those freaking wheels were turning fast. "Is it safe to run 135+ on the dyno?" Not likely and I don't plan on doing it again.
Yep, its about time we all meet up, pull our motors, and run them on the same engine dyno.
LOL!!!!
12-17-2004, 11:14 AM
#27
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[QUOTE=BigTex]Thats just like running the 1/8th mile and applying a 1/4 mile conversion factor to it. It will be close, but its not the same as running a 1/4 and knowing the truth. If you want numbers that are pretty close but not exact, try a GTECH. Why even mess with a dyno at all? 
I use the dyno to get an accurate a/f reading for the most part. I'm always trying to keep my most recent experiment from blowing up.
I use the dyno to get an accurate a/f reading for the most part. I'm always trying to keep my most recent experiment from blowing up.
12-18-2004, 01:40 AM
#29
TECH Veteran
Originally Posted by BigTex
I've tried both 2nd and 3rd. Most of mine have been 2nd gear runs. The times I've tried 3rd gear runs, I found myself standing waaayyyy back. Those freaking wheels were turning fast. "Is it safe to run 135+ on the dyno?" Not likely and I don't plan on doing it again.
That incident changed how I look at speed and also how I look at professionals who are supposed to know what they're doing. Going forward, I will not trust anyone to do my thinking for me. From now on I will be doing all of my own research, like I should have been doing in the first place, like I already do in other areas like law (lawyers) and medicine (doctors).
As far as dynoing my vehicle, any future runs will be done in second gear. I pretty much have to with a 5" x 72" aluminum driveshaft and its associated critical speed. I don't care if it shows less power. I will also be standing very far away and/or behind something from for my vehicle's and all other's dyno runs. All it would take would be some manufacturing defect in the rear end or a nail in a tire to show itself at 125 or 130 mph, and someone loses a limb, an eye, or their life.
My $.02.
