Quote:
Originally Posted by PRAY
Just some knowledge guys. Don't take any of this as anything other than purely informational.
The cam isn't pushing through the converter due to power. It is solely due to the idle rpm required to keep the car running. That rpm I am assuming with this cam in 200-300rpm above stock. The converter is now sitting at a higher rpm starting to lock it up. That is what drives it through the brakes. Dropping the converter in there is going to be a world changer for you. You are going to have an entirely new animal on your hands.
I am no dyno guru but this dyno does not read low. 6th gear is the 1:1 gear for the A8. 4th gear is 1:1 for the M6. But since the M6 has to drive a 3.73 rear gear and the A8 has to only drive a 2.77 they will dyno much closer than people think. This helps mitigate the losses of the A8 on the dyno. I would have to do the math for the final drive ratio of the A8 in 5th. From all of my dyno testing on my car and a few others, there is always a gain from 5th to 6th. The strange thing is that if varies from car to car. My personal car picks up an average of 23rw from 5th to 6th. I have seen as little 10rw gains from 5th to 6th. I don't think the A8 is any more efficient than the older automatic's from GM. It is just a gear ratio deal when compared to the M6.
Running the dyno up to 200 mph is what it is rated for and designed for according to DJ. The factory limiter in the Camaro is 186 mph. If the car or dyno weren't "safe" at those speeds I am sure the manufactures would not have set the limitations where they are. I don't see a 2,000lb drum over coming four 5K straps on the rear and 4 chalk blocks on the front. I am not advocating doing it all the time but I don't see anything dangerous about it. I personally do all my testing in 5th and one money run in 6th to get comparable 1:1 dyno numbers.
When comparing gains on a dyno they need to at least start at the same AFR or best case scenario of max power for each combo. Unless we are only comparing tunes. Then obviously need to know pre and post.
Posted dyno numbers need to be listed in SAE, smoothed to 5, and laid over RPM to be comparable to other dyno's. But all DJ's read a little to a lot different. There are a ton of factors that go into what your dyno reads. STD usually reads about 10rw higher than SAE and depending on the run, MPH can add some rwhp over RPM. MPH may have to be used if you lost tach signal or something like that. There is more to using STD than what I am saying here. Luckily from what I have seen you can't over lay two runs with two different display factors. In the end, a dyno is a tool to get your ride performing it's best regardless of the final numbers it spits out.
|
Thanks for the information. I appreciate how you and others on this board break this stuff down. It helps someone like me who knows very little overall understand the why. Some of the dyno numbers make me scratch my head when I don't realize how they work, and what factors are involved such as the rear gearing between a M6 vs and A8.
I did want to ask what you meant by an entirely new animal when talking about the torque converter upgrade. Do you think that a good thing or a bad thing for just normal road driving? I haven't been able to find a lot of information on what to expect when you upgrade to a larger torque converter with a cam. The one I will be upgrading to is the Circle D Specialties GM 258mm HP Series 8L90 Torque Converter.