: Dyno Questions



TMC CL65
05-05-10, 12:55 PM
I am going to get a baseline dyno this afternoon. I have done some research to make sure that the dyno operator is doing it right (i.e. auto is in 4th gear and Stabilitrak is off). I had problems getting a tach signal in my previous car (MB made it way too complicated/time consuming to get to the coil packs). Is it pretty simple for the CTS-V? Any other helpful hints as the dyno operator is trying to squeeze me in for a quick dyno (my fault with the short notice).

Thanks!

Tom

Gary Wells
05-05-10, 01:38 PM
If you dyno on a Dynajet or a Dynopack please psot up your chart(s) and or type of dyno, date of dyno run, correction factor, auto (A6) or manaul
(M6), RWHp, RWTQ, or readings at axle if dynapack.

newcadman
05-05-10, 06:48 PM
If you dyno on a Dynajet or a Dynopack please psot up your chart(s) and or type of dyno, date of dyno run, correction factor, auto (A6) or manaul
(M6), RWHp, RWTQ, or readings at axle if dynapack.

GARY

In addition to the suggested dyno posting information do you think it would also be worthwhile to report on the A/F numbers for each pull?

Gary Wells
05-05-10, 06:55 PM
GARY

In addition to the suggested dyno posting information do you think it would also be worthwhile to report on the A/F numbers for each pull?
Probably, newcadman, but I am working on a Mac on Microsoft word, and I am not that used to it. I am trying to build a base on the things or characteristics that affect RWHP & RWTQ the most, and I am just about out of room on my current charts. If I figure out how to do this on a spread sheet, then I will probably add the A/f mixture. Definitely thanks for the suggestion / idea though.

GMX322V S/C
05-05-10, 07:59 PM
I am going to get a baseline dyno this afternoon. I have done some research to make sure that the dyno operator is doing it right (i.e. auto is in 4th gear and Stabilitrak is off)...Note that 4th in the auto isn't quite 1:1. It's actually 1.15:1, so the final should be entered as 3.23 * 1.15 = 3.71...

GMX322V S/C
05-16-10, 04:03 PM
Probably, newcadman, but I am working on a Mac on Microsoft word, and I am not that used to it. I am trying to build a base on the things or characteristics that affect RWHP & RWTQ the most, and I am just about out of room on my current charts. If I figure out how to do this on a spread sheet, then I will probably add the A/f mixture. Definitely thanks for the suggestion / idea though.Gary,
Here's a bit of interesting reading from Sean Church of Church Automotive Testing: http://home.earthlink.net/~spchurch/churchautomotivetesting/id12.html. We all know a Dynapack typically reads higher than other roller/inertia-type dynos, but removing the inertia from the wheel/tire combo is but one component; the tire/roller interface is quite another--not from slippage, per se, but from deforming the tire "beyond flat," that is to say "concave" against the roller(s) vs. flat as against a road. It gets worse with very high-output cars because the strapping has to be more aggressive, or you get slippage--there's only so much power you can transfer through the contact patches under any given set of conditions...

I thought this might interest you in case you wanted reference it along with any Dynapack readings you've collected.

Gary Wells
05-16-10, 04:44 PM
Gary,
Here's a bit of interesting reading from Sean Church of Church Automotive Testing: http://home.earthlink.net/~spchurch/churchautomotivetesting/id12.html. We all know a Dynapack typically reads higher than other roller/inertia-type dynos, but removing the inertia from the wheel/tire combo is but one component; the tire/roller interface is quite another--not from slippage, per se, but from deforming the tire "beyond flat," that is to say "concave" against the roller(s) vs. flat as against a road. It gets worse with very high-output cars because the strapping has to be more aggressive, or you get slippage--there's only so much power you can transfer through the contact patches under any given set of conditions...

I thought this might interest you in case you wanted reference it along with any Dynapack readings you've collected.

Thanks, Mas, great idea. I just added it to the chart that I have for Dynapack
dyno results.

Gary Wells
05-16-10, 04:55 PM
One of the things that I have noticed regarding the Dynapack type of dyno is the closeness, or lack of variation, if you will, of the lowest to the highest #, especially on the horsepower #'s. It is only fair to state, though, that 2 of those sets of #'s are off of the same Dynapack dyno. That would be Craigs, (D3's) and mine, both dynoed on CAT's dyno, but over a times-pread of over a year. Somewhat interesting (at least to me), to be sure.

Cad ’09 & up CTS-V bone *stock* RAHP & RATQ (Auto & Manl) (Dynapack):


rahp----ratq-----corr ------date------state-------owner--------tranny

491-----496-----sae-----04-20-10-----md-----thebigjimsho-----m6---
493-----519-----xxx-----01-29-09-----cal-----d3 (craig)---------
493-----511-----sae-----04-28-10-----cal-----fleadh-------------m6------
498-----515-----xxx-----01-16-09-----cal-----garywells---------a6---

Auto & Manual bone stock RAHP & RATQ (Dynapack) 4 samples:
RAHP Average: 1975 / 4 = 493.75 average
RATQ Average: 2041 / 4 = 510.25 average


For interesting and informative reading about how a dynapack works, and the differences between it and other types of dynos, please see the following:
http://home.earthlink.net/~spchurch/churchautomotivetesting/id12.html