Originally Posted by romandian

"car stays between 6000-6800 RPM the whole pass"

how so?

Originally Posted by Turbo-Geist

Lot's of good info in here. It's interesting that track performance shows up in a dyno thread. I'm all for it actually because you can't cheat the track as far as all out effort. There is no correction factor when you pull around to the time shack for your slip. The scoreboard doesn't show ET and MPH and then the correction factor that was used to obtain the numbers. I'm sure some people would appreciate it because then maybe their car would actually run what the shop's dynosheet claims.

Don't misunderstand me. I understand traction issues, or some mechanical errors happening during the run. However if the car makes a clean pass in every gear like the dyno sheet shows with no hiccups in power delivery, it should get close. A true 1400hp car should be able to fall out of bed and run an 8.99 on a fair pass.

Originally Posted by DOUG @ ECS

IMHO, there is no such thing as a "dyno record". Only track records.

I saw this in C7 section a few times, there were claims of dyno numbers that were simply impossible because the fuel system would not support the power posted. Anyone who tunes them regularly knew it but we can't say anything.

Originally Posted by Turbo-Geist

At the same time, it's easy enough for a shop to just keep setting records at the track while the other shops can't back up their dyno numbers at the track.

On the 1400hp comment, I'm not saying it takes 1400hp to run 8s. It can be done with way less. However, when shops are blasting dyno videos all over facebook, youtube, and on here of their 1400hp monster and it barely runs 9s @ 15x, just know we are paying attention.

Originally Posted by Turbo-Geist

On the topic of waving a dyno sheet around: no problem if it makes you feel good. On the other hand, claiming some type of record, it’s going to require a closer look.

Claim: 899 rwhp

What were the weather conditions that day for the closest weather station at the time the dyno pull was made?

Weather station data
Temperature: 95 degrees F
Pressure: 29.85 in
Humidity: 13%
Elevation: 2,516 feet
DA: 5,511 feet
Actual Correction factor: 1.12

Dyno sheet weather data
Temperature: 97.97 degrees F
Pressure: 26.94 in
Humidity: 13%
Elevation: 2,605 feet
DA: 9,194 feet
Dyno Correction factor: 1.14
Actual Correction factor: 1.27

Actual correction factors above were determined by using an online calculator and inputting elevation, air temperature, altimeter, and dew point. This calculator calculates density altitude as part of the algorithm to determine the correction factor. Pay close attention to the DA the dyno was projecting by using a pressure of 26.94 in. 9,194 feet above sea level? Maybe the dyno was at the peak of Mount Cory in Alberta, Canada?

So how much power did the car actually make based on SAE standards? Let’s remove the hidden correction that was created by entering the pressure as 26.94 in when it was actually 29.85 in.

899 * 1/1.27 = 708 rwhp


For the benefit of the doubt, multiply by the 1.14 correction factor shown on the dyno sheet.

708 * 1.14 = 807 rwhp.


Good numbers? Yes.

Record breaking? No.

Originally Posted by Milan

Guess we are just a bunch of redneck hillbillies in the US that don't know how to setup any of our tools

Originally Posted by ajrothm

Dynos are certainly a good tuning/diagnostic tool, and when used with the SAE correction, a general "ball park" for comparison purposes, but ultimately, trap speed doesn't lie... granted there is a ton of variables that affect trap speed, and even more that effect ET, but generally speaking, if the car is setup right and geared right, the trap speed/weight/DA equation pretty much tells you your true HP...or at least the HP that counts.

I've seen so many 1000-1200 rwhp cars trapping 150 mph and I just SMH...

I will agree though that BIG hp cars will show the HP/MPH more on longer tracks where there is more time/distance to make up for lack of traction and efficiencies.

Originally Posted by BLOWNBLUEZ06@RKTPerformance

When I first dyno'd 1021whp, I got a lot of crap from people in the background saying it was BS. I went to 5 other dyno's throughout the DFW metroplex, dyno'd 1000+ at each site and drove home. When I started track tuning my car, I was able to run 151 in the 1/4, but one very significant thing that I discovered is that gears 1 through 3 were lean. I tune the car in 4th gear and it was spot on. With this tune-up, I would back half the **** out of the 1/4 and the 1/8th was no biggie. When I set the tune to better satisfy gears 1-3, I picked up 10mph but lost my back half. If I was ever able to figure out how to satisfy all the gears, I know for a fact I would have been in the 160's, which would have been more reasonable. For the record, this anomaly is something that have seen many times in the manual cars and never see in the autos and I credit that to the load being more evened out throughout the 1/4mi pulls.

Something I've rarely seen mentioned is what all the dyno settings were when someone gets on the dyno. It's something I prefer to know when using a dyno because there's no point in having corrections otherwise. If you're in the general area of what a local weather app reads, I would say you're close enough. All of the above is for comparing notes amongst others. The dyno is really just a great tool for measuring deltas though, something to get you to the track so that you can get it dialed in properly IMO.