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So, I haven't done a launch control 0-60 yet, but I have watched the Dyno Graph on my TH. I've done a few WOT runs, and I've never seen the HP rating go above 600. I have about 1K miles on it, so I'm past that 500 mile break in period. Is this normal or am I experiencing the missing HP I've read about? Suggestions?


Thanks!
 

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I would think that's because 707 hp is what the average production engine (as tested by the engineers) makes on an engine dyno, with full dress (smog, accessories). But the 600+/- is the actual in-the-car output.

I believe there's generally about 15% drivetrain loss in an AWD vehicle like this.

Other thoughts?
 

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Please go out and do a couple of 0-60mph runs on flat ground and see what your on-board accelerometer says. Even in the heat of the summer, you should be in the 3.7-3.8 range or so... if you are close to sea level and its 70^ out, you'll be in the 3.4-3.5 range if you are making advertised power.

I would take this as a much more accurate form of confirming engine power than the on-board dynomometer.
 

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So, I haven't done a launch control 0-60 yet, but I have watched the Dyno Graph on my TH. I've done a few WOT runs, and I've never seen the HP rating go above 600. I have about 1K miles on it, so I'm past that 500 mile break in period. Is this normal or am I experiencing the missing HP I've read about? Suggestions?


Thanks!
Mine tops out at 600 too. I’ve already posed this question in another thread, 600 on the graph seems to be the maximum output of this engine. Others have confirmed the same.
 

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Since I had my "key issue" resolved...Ive seen 680. We did a 3.1 0-60 on the onboard timer with me (220lb) and my son (190) on a 5% upward grade. Don't know how accurate that timer is....
 

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While the dash screens are cool and are almost video game-like, the real horsepower rating that matters is what is hitting the pavement. We dyno'd a warm TH and it made 613/612 AWHP/AWTQ.
 

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Since I had my "key issue" resolved...Ive seen 680. We did a 3.1 0-60 on the onboard timer with me (220lb) and my son (190) on a 5% upward grade. Don't know how accurate that timer is....
Blockdoc, what did your hp top out at prior to getting the key fob issue fixed?
 

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Like to see different TH graphs to see the differences especially in cooler weather. I did a quick run yesterday, weather was 68 degrees and so far this is the best result I received so far. At 80 degrees I was getting 600HP to the wheels. Since the weather was cooler yesterday it looks like the TH produced around 625 to 630HP. I wonder if it will pull a little more in the winter?
 

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Discussion Starter #16
I did a few runs, with my family in the car, best time so far has been 3.7, according to vehicle dash read out. So, I'm good, fun to drive!
 

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Blockdoc ,new to forum but believe my truck has problem u recently had fixed .I live in CA
Can u tell me the dealer who performed repairs,ones in my area have no clue
 

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Get a dyno done. 707 is quoted at the crank, and any vehicle will lose something like 10-15% at the wheels. And then as mentioned there's temp, and inaccuracies in the onboard data. Dyno is always the way to go. I'm planning on getting mine done when it cools down a bit here in Chicago. I haven't seen any dyno charts - anyone ever post an actual dyno graph?
 

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On my way into work this morning, I was curious what my onboard accelerometer dyno was showing my peek HP #’s at. After my engine & transmission got up to operating temp, I put it in track mode and watched the HP readout on my dash DIC, and also set the performance pages to the dyno graph. I saw the HP # on my DIC flash 6XX before it shifted and the dyno graph confirmed the 600 HP I saw once I paused it.

This got me thinking about the differences people have been seeing in these HP #’s.
Here are the things that I think are contributing to the discrepancies we are seeing:

Elevation
Outside ambient temp
Humidity level
Fuel Octane level used
How long the engine has been run. (Is it heat soaked or not)
List any upgrades. (intake, exhaust, tires, etc.)

This morning has been the coolest morning (@ 72*) we have had since I purchased my TH.

My Elevation = 1300 Ft
Temp= 72*
Humidity = 74%; Dew point = 70*
The highest octane fuel I can buy here is 91.
Engine just brought up to operation temp. Coolant = 200*; Engine Oil = 180*
All stock.

According to the elevation calculator below, @ 1300 Ft elevation I am losing around 28 HP at the crank when compared with sea level output.

http://www.wallaceracing.com/braking-hp.php

All things being equal, I think we should be asking these questions when someone is posting higher than “normal” HP #’s. It would be hard for me to believe someone got a hellcat motor that is producing ~80 more HP than another one…. This is just my 2 cents.

Disclaimer:

***Remember the onboard accelerometer dyno is not measuring the engine HP output at the crank, but rather measuring the HP it “sees” being put to the pavement using an accelerometer dyno. Even the HP to the pavement #’s can be questioned and is more of a ballpark #. The only way to know for sure is to use the same all-wheel dyno at the same time and place with the same fuel. ***
 
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