blackz97

I used the search function but was unable to find much information about my specific question.

From what i have found mustang chassis dynos read lower numbers then a dyno jet. The performance shop thats going to be tuning my car has a dynapack dyno. I was wondering if anyone has any experience with the numbers that this dyno setup will produce, i mean in comparison to say a dynojet or a mustang chassis dyno.

Steve

Injuneer

There was an article in Hot Rod magazine in 2004 comparing results for the same car (unfortunately a power challenged Mustang GT) on 4 or 5 different dynos, including the ones you mentioned. There is a thread on the "Advanced Tech" board discussing this article, and one of the posts has a link to a scan of the article. It will answer your questions, and point out a number of critical (and potentially misledaing) issues in dyno testing.

http://briefcase.yahoo.com/bc/robss9...dir=/My+Photos

[EDIT]
A summary of the articles results for the GT:
(All corrected to "standard" conditions)

Dynapack Hydraulic:
208.9 HP @ 4,646rpm
253.4 lb-ft @ 4,202rpm

Dynojet Inertia:
226.9 HP @ 4,950rpm
269.3 lb-ft @ 4,200rpm

Mustang Eddy-Current:
219.1 HP @ 5,000rpm
239.3 lb-ft @ 4,250rpm

SuperFlow Eddy-Current (in "inertia" mode):
225.0 HP @ 5,085rpm
269.4 lb-ft @ 4,101HP

The numbers would suggest that the Dynapack produces HP results about 8% lower than the Dynojet, and the Mustang produces HP results about 3% lower than the Dynojet.

Torque numbers are a bit more variable.

The results also indicated that if the results were corrected to "SAE Net", rather than "standard", they will be about 4% lower. [EDIT]

This topic also needs to be moved to "General F-Body Tech & Info", since it isn't really specific to LT1/LT4 Engine Tech.