Confused about Hp gains

[eej711]

I have a 07 4.6L. I plugged in my gryphon to Pegasus and downloaded my 1/4 mile tests. The results after I put in my truck weight was 252.43 at the "estimated flywheel HP" and the stock HP is 248 . I was expecting more than just a little over 4 HP gain from the Gotts mod, SI/DO exhaust and 87 performance custom tune on my gryphon. Did i do something wrong or is that the only HP gain i actually have?

[88Racing]

That's an example of a gross estimator with built in fudge factors.....

Its an estimate.....stick yer truck on a dyno for hard numbers.....

[eej711]

Is the flywheel HP around the same numbers as the rwhp?

[Longshot270]

The flywheel HP is what the engine is estimated to make. The rwhp is what is left over after parasitic loss.

Take it to a certified drag strip to get times and weights. My programmer was off by a half second or so.

What was your time and speed?

[eej711]

Well hopefully I got such little hp gain because of a bad run. Hopefully next time results in more than just a gain of 4 hp.

82.605 mph and 17.34 seconds, not very excited about that...

I'm going to run it again soon and hopefully get a better reaction time and an overall better run.

[Lowdown89]

Does your truck feel faster to you? After my the custom 87 tune on my buddies 07 STD cab 4.6 truck the times didn't greatly improve according to the g tech meter we have but it sure did turn into a completely different truck to drive so much nicer to drive now

[Longshot270]

The programmer was saying I was running 16.1. Then I went to the drag strip and the best I could get was 17. There are many small errors that when put together throw off the entire calculation.

Also if you run with the truck stock and then programmed you'll probably have different times from different tire sizes and such. The programmer can only assume how fast you are going from what you say the tire size (and no single tire size is correct all the time) and gear ratio are. Like I said, many small factors build exponentially and throw it off.

[eej711]

Lowdown, Oh ya, it feels much faster and more power. I was just expecting better performance.

Longshot, the factors what you said which play into the results make sense. I'm going to do some more runs and see if anything changes. I did it again and it came up with 272 estimated Hp, which is much better.

[Longshot270]

Originally Posted by eej711

Lowdown, Oh ya, it feels much faster and more power. I was just expecting better performance.

Longshot, the factors what you said which play into the results make sense. I'm going to do some more runs and see if anything changes. I did it again and it came up with 272 estimated Hp, which is much better.

And what was the difference? Was it on a smoother road, different time of day, different temperature or something like that?

[eej711]

It was the same road but I just had a better take off and i also looked up the weight of the truck again to make sure it was correct, so it could of been a my own error.