# Mustang Dyno's How reliable
**URL:** https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767
**Category:** PittSpeed Automotive
**Created:** [April 19, 2006, 7:23pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767 "2006-04-19T19:23:14Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@dalifts](https://forums.speedlife.net/u/dalifts)
#### Post date: [April 19, 2006, 7:23pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/1 "2006-04-19T19:23:14Z")
Been searching online. And ive read quite a few people saying mustang dunos dont give you correct numbers. I know its whoever put the dyno in to tune it right. But Are they all off or can they be right. I seen people saying a stock GSR has 120whp. And i know thats way off
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### Author:  [@neonmike22](https://forums.speedlife.net/u/neonmike22)
#### Post date: [April 19, 2006, 7:34pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/2 "2006-04-19T19:34:32Z")
It depends on what you consider to be “correct”.
“correct” as in “numbers you can impress your friends with”
or
“correct” as in “as long as you leave with more hp than when you started”
it really doesn’t matter if your 100hp car reads 90hp on a mustang dyno, as long as you tune your car and end up with 95hp, you’ve gone somewhere.
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### Author:  [@burnyd](https://forums.speedlife.net/u/burnyd)
#### Post date: [April 19, 2006, 7:34pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/3 "2006-04-19T19:34:33Z")
no your way off.
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### Author:  [@dalifts](https://forums.speedlife.net/u/dalifts)
#### Post date: [April 19, 2006, 7:42pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/4 "2006-04-19T19:42:02Z")
no. Like Hp that you actually have and not some bullshit digit.
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### Author:  [@dalifts](https://forums.speedlife.net/u/dalifts)
#### Post date: [April 19, 2006, 7:42pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/5 "2006-04-19T19:42:54Z")
ive heard dynojets were the best. I know everyone has there own opinions but i was wondering
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### Author:  [@SMort38](https://forums.speedlife.net/u/SMort38)
#### Post date: [April 19, 2006, 8:56pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/6 "2006-04-19T20:56:03Z")
> [@dalifts](#):
>
> I seen people saying a stock GSR has 120whp. And i know thats way off
That’s probably about right for that car on a mustang dyno. It would probably do 140ish on a dynojet.
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### Author:  [@system](https://forums.speedlife.net/u/system)
#### Post date: [April 19, 2006, 10:02pm UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/7 "2006-04-19T22:02:06Z")
Looking for big #'s DynoJets average 8-12% higher than Mustang.
Looking to tune only the newest dynoJets can load the rollers, Mustangs always have. I have an article you can pick up SAT. about tuning, See you at 11.
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### Author:  [@KeithO](https://forums.speedlife.net/u/KeithO)
#### Post date: [April 20, 2006, 2:31am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/8 "2006-04-20T02:31:36Z")
3-4 years ago, Chevy High Performance Magazine directly compared a Mustang Dyno and a DynoJet Dyno. They concluded that the Mustang yields results more representative of the real world.
As stated above, what are your goals for your pulls?
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### Author:  [@dalifts](https://forums.speedlife.net/u/dalifts)
#### Post date: [April 20, 2006, 5:30am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/9 "2006-04-20T05:30:27Z")
baseline. And thanks cannon. Mark says the mustang dyno is a great dyno to tune on and get baselines. Ive heard from few friends dynojets give u way more hp so its not right
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### Author:  [@bics56](https://forums.speedlife.net/u/bics56)
#### Post date: [April 20, 2006, 7:26am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/10 "2006-04-20T07:26:30Z")
correct me is I am wrong but the MAIN difference is a mustang incorporates friction where a dynojet does not
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### Author:  [@imported\_jim](https://forums.speedlife.net/u/imported_jim)
#### Post date: [April 20, 2006, 7:26am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/11 "2006-04-20T07:26:59Z")
Older Dynojets read higher than Mustang dynos and since a lot of people have fragile egos (and cannot accept “real” numbers) or just want bragging rights they bash Mustang dynos and their results.
Remember, a “stock” GSR is quite a few years old right now and fairly loose. There’s no way that you’re going to get HP numbers anywhere approaching what Honda published back when the car was new, especially because they went by crank HP and not wheel HP. I also doubt that most GSRs are stock at this point anyway. Oscar jackson once said that if you gave the average Honda owner $500 to spend on his car it would almost always end up slower than stock. What he meant was that most mods are usually not appropriate or poorly installed.
After seeing dozens of cars show up for dyno appointments over the years I completely agree with him.
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### Author:  [@RebelW26GT](https://forums.speedlife.net/u/RebelW26GT)
#### Post date: [April 20, 2006, 7:44am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/12 "2006-04-20T07:44:37Z")
heh heh, I spent no money on the beretta that one day, we found an extra 10 ho po’s in there from tweaking the puter.
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### Author:  [@KeithO](https://forums.speedlife.net/u/KeithO)
#### Post date: [April 21, 2006, 2:52am UTC](https://forums.speedlife.net/t/mustang-dynos-how-reliable/181767/13 "2006-04-21T02:52:27Z")
If you are baselining and comparing before/after I recommend that you use the SAME (not just model but identical machine) dyno.
I have been doing a little research on DynoJet dynos over the last couple of weeks because impound in my road racing series is mostly comprised of scales and a DynoJet 248 dyno. Look at this graph:
[](http://community.webshots.com/photo/2488435890042620437aALlDE)
I put a 38mm restrictor plate in the car (stockish LT1) and did pulls at 185, 195 and 205 degrees of water temperature. Note that we used the scan tool to monitor the ECM water temp sensor and not the gauge in the dash. This was done for accuracy.
I then did the same with the 37mm, 36mm and 35mm restrictor plates. This was all done in this order and very quickly (as quick as I could change the plates). What I found is that the biggest influence on hp/tq was the oil temperature - not even the restrictor plates. For my purposes, the 38mm pull is completely invalid since the oil was relatively cold and my oil will be smokin’ hot in impound because we get tested right after the race.
Over the winter, I called DynoJet and talked to their engineers. The first thing that they said is that they manufacture to a 1% tolerance from dyno to dyno. This means that you could see pulls of, say 300hp, at one dyno and under the identical conditions see 303hp at another dyno and this is within thier manufactuing tolerances. I then asked about the compensations and they said that this can be a large source of variance (they wouldn’t admit to a percentage). They said that if the air, humidity, pressure, etc. sensors are not kept in calibration by the dyno operator, the variance can be significant. My best-guess is we are talking about 3% more variance. With this in mind, in the above example of 300hp, another dyno could easily show 312…
Finally, instead of getting the printouts in the above test day, I got the raw data files. I downloaded the software from the DynoJet website and used the same compensations that we used at the shop. Guess what? The numbers were DIFFERENT with a different version on WinPEP (the dynojet software). One or two hp but different nonetheless. So in the above example, we are up to 315hp on the identical motor and conditions - 5%!
I say all of this to point out two things - dyno pulls will have error in them. You need to be mindful of this (and it could get me dq-ed in races). With this in mind, if you are going to do serious work and tuning on a car, you need to do it on the same machine everytime or you might be seeing error as a change in power and not change due to the mod(s).
BTW - I paid through the nose for those pulls. Go to SpeedNation - they are more reasonable. I had to use a DynoJet or I would have gone to SpeedNation myself.
Lastly - if you want to see the pulls from the above example, click “prev” on the right and you’ll come to a scale picture. Click previous again and you’ll get through the dyno graphs themselves.