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know there are a few posts on this but I thought I would share my info as well for another reference point for anyone looking at going the SC route.

I ended up with 577 RWH and 485TQ to the wheels on the Mustang Dyno. I was told by the Dyno operator that the Dynojet and the Mustang use a different process/calculations to determine power. He said on the Dynojet based on the speed and how the power was being put down I would probably be at 600-610 RWHP on the Dynojet. My Tuner actually made the same estimation. The question/debate as to which one is more accurate is still open.

My Config:
  • 5.7 stock bottom end
  • 274 Phaser Cam
  • 1 7/8 headers with 3" exhaust
  • Whipple 2.9 with 10lb
  • 4.29 gears
Some may notice it climbed fast through the pull and maxed at 127mph, that is contributed to the 4.29 gears

I didn't grab the latest graph so you will see the graph run to 573 and 477 while the data sheet has the final run results. Posting the graph anyway so you can see the power curve and the delta is very minimal.

Dyno Data.jpg
Dyno Grah.jpg
 

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Mustang dyno will be the most realistic prediction of real world performance. It accounts for road and wind friction where a Dynojet is more of a hamster wheel. Too many people get fixated on dyno numbers though. Push come to shove, they should just be considered a tuning tool. Real performance is proven at the strip :)
 

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Discussion Starter #3
If I understood the Dyno guy, the OEM's i.e... Dodge, GM and Ford use the Mustang Dyno and they also use Maximum power numbers not the WCF. He runs the dyno for them on some of their new developments.

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To me, all that matters is, before, and after and the percentage of change between them.
No matter how you look at it, impressive numbers. Must be a hoot to drive.
 

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To me, all that matters is, before, and after and the percentage of change between them.
No matter how you look at it, impressive numbers. Must be a hoot to drive.
Congratulations McCloud on your new power! I agree that it has to be a hoot to drive!

MiHiHemi said it best. The dyno is a tool for tuning (Bench Racing/Bragging too) and should be taken as such. Trap speed is a Really good indicator of Horsepower.

Before and after could be skewed though. If temperature, humidity, DA is different from the first day to the build finish, that could change numbers too, along with other variables (correction factors, load on the dyno, tire pressure, etc).

When I had my Vette on the dyno (Mustang also), they had a quarter mile simulator on their Mustang that loaded up the dyno like I was at the track and she ran 10.60 @ 131 on the dyno. When I ran her at the track, she went 10.52 @ 131. They hit the mph right on the head and were pretty close to the e.t. too. You could ask your dyno operator if they can do that or not on theirs. Just a thought.
 

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Discussion Starter #6
Thanks FreddyG.

Their dyno does have the 1/4 mile option after you sharing your results I wish I would have ran it. Speaking of, that is a good run? What are you putting to the wheels?

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To me, all that matters is, before, and after and the percentage of change between them.
No matter how you look at it, impressive numbers. Must be a hoot to drive.
Thanks! Yeah, it`s a whole new experience. Definitely need different tires. No traction at all. It took some work to control wheel spin on the dyno.

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Thanks FreddyG.

Their dyno does have the 1/4 mile option after you sharing your results I wish I would have ran it. Speaking of, that is a good run? What are you putting to the wheels?

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I was Happy with it and then even Happier when it went quicker at the track.

That was in our old Vette, so it's not really fair because they are probably a thousand or so pounds lighter than our Challengers are, but to answer your question, she put down 606 to the ground and upper 590's in torque. They input the car info and then the dyno does it's thing. I had a bit more power than you have now, but a thousand or so lbs. less makes a Huge difference.

I wish that you'd have tried it because it is a pretty cool feature and like I said, it was surprisingly close to the real trip to the strip.

Those gears in back might throw off your results too, but that's just a guess. I'd say that between the added power and those gears, you'd be right in saying that you're going to need some different tires.

Just one more story about the Vette and then I'll give it to rest.

Our Vette had 18 x 12 wheels in back that had Viper sized Pilot Sports on (335/35-18) and 285/40-18 in front on 18 x 10 CCW Classics on her. We went for a ride (Wife and I) right after the blower was finished and the first tune was done. We were rolling down the street and I told my Wife to hold on because I was going to get on it. I flat footed it instead of rolling into it and lit the tires up (this was from 35 mph) and the car did 2 donuts in the middle of the street!

My Wife was screaming at me (deservedly so) while I was pretty much messing up my pants! The next day, I ordered some Nitto's in the biggest 18" size (I believe they were 335's ) that I could find.

I guess the point of all of my babble is that first of all, Please Drive Safely and second, Please get some good tires (and just be smarter than I was, which shouldn't be hard :) )!
 

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Mustang dyno will be the most realistic prediction of real world performance. It accounts for road and wind friction where a Dynojet is more of a hamster wheel. Too many people get fixated on dyno numbers though. Push come to shove, they should just be considered a tuning tool. Real performance is proven at the strip :)
There are more than one model of dynojet dynos. Dynojet makes both interia and eddy current designs. Eddy current being the same design as a mustang dyno brand. 224xlc is an eddy current dynojet that can do everything mentioned including 1/4 mile runs. Dynos are 50k precision measuring instruments that unfortunately get a bad rap which is almost always caused by operators that dont calibrate properly, fail to do maintenance on the drum and weather station, dont understand all settings or even understsnd the math behind each CF or worse yet apply the wrong correction factor based on the engine setup. Clsssic example is applying STD or SAE J1349 on a FI setup when right in the math its based on ambient aka natrually aspirated leading to falsely high dyno numbers and charts. You see this all over the internet. Completely agree strip is a good performance test but so can a properly maintained dyno with an operator that actually knows what they are doing.
 

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Welcome to Challengertalk ;) Interesting info

A Guy
 

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Discussion Starter #11
There are more than one model of dynojet dynos. Dynojet makes both interia and eddy current designs. Eddy current being the same design as a mustang dyno brand. 224xlc is an eddy current dynojet that can do everything mentioned including 1/4 mile runs. Dynos are 50k precision measuring instruments that unfortunately get a bad rap which is almost always caused by operators that dont calibrate properly, fail to do maintenance on the drum and weather station, dont understand all settings or even understsnd the math behind each CF or worse yet apply the wrong correction factor based on the engine setup. Clsssic example is applying STD or SAE J1349 on a FI setup when right in the math its based on ambient aka natrually aspirated leading to falsely high dyno numbers and charts. You see this all over the internet. Completely agree strip is a good performance test but so can a properly maintained dyno with an operator that actually knows what they are doing.
Good info! The Dyno operator said the same thing. We went into the discussion while I was waiting for the revised tune. I got the impression he primarily sticks with the Mustang is because of the work he does with the OEMs. He showed me the information he had put in to make sure the WCF was accurate and how you use that data for future dynos with the same car to maintain accurate subsequent tests. He did say however the Dynojet does tend to read a little higher, but again depending on the versions you mentioned will make a difference in the results.
 

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McCloud thanks for sharing this info. You helped me make a decision I was struggling with from this thread. That being said why did the operator click off at 6500 rpm. The cam can rev out to 7400 if I’m not mistaken? If what you said about the hearing is true that was the limiting factor correct?


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McCloud thanks for sharing this info. You helped me make a decision I was struggling with from this thread. That being said why did the operator click off at 6500 rpm. The cam can rev out to 7400 if I’m not mistaken? If what you said about the hearing is true that was the limiting factor correct?


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Yeah my tuner builds Hemi`s he doesn't just tune. He knows these engines inside and out. He said the rods in the 5.7s don't do well at high rpm.. He recommended not going into the 7k range. The cam would definitely hold or keep building power but the rods would go especially with 10lbs at 600hp.

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Makes sense to me. I spent my 5.8 to 8200 on stock bottom end but it was with Nitrous. Not as much force


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Makes sense to me. I spent my 5.8 to 8200 on stock bottom end but it was with Nitrous. Not as much force


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That's good to know.. I was thinking about pushing to 7k since I don't plan on running this 5.7 much longer, but I do at least want to get through this summer with it. I was running it up to 6800 NA. I have a about 15 more hours of my tuning class left. Maybe by the end I will know enough to correct my RPM hunt issue and extend the limiter to 7k. If you were holding up for a while at 8200 I think I can push it. I'm sure my tuner was thinking about it living longer.
 

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Makes sense to me. I spent my 5.8 to 8200 on stock bottom end but it was with Nitrous. Not as much force


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8200 rpm on a 5.7? Maybe I misinterpreted something but that's 25m/s piston speed
 

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Yeah I mistyped that. It and to 7200. I shifted at 7k regularly at the track. No way would it make it to 8500. Not on stock bottom end without heavy modifications.


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Discussion Starter #20
Yeah I mistyped that. It and to 7200. I shifted at 7k regularly at the track. No way would it make it to 8500. Not on stock bottom end without heavy modifications.


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I thought maybe there was something with that.. :) I do believe that would take solid lifter setup in addition to a new bottom end...
 
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