Dyno Numbers

[batlbrandon]

I have been debating on whether or not to post this or not because I know someone is going to get all uber butt hurt and cause a flame fest. Then someone else will chime in with some regurgitated "scientific" explanation. But whatever, I gotta get this off my chest.This only pertains to the shops using a DynoJet dyno. I know nothing about the Dyno Dynamics or Mustangs, or (ugh) Dyno Pack.Other than what style they are and that they all claim to be the most accurate.

Dyno numbers, what are you really making. There seems to be some debate about what numbers you get from different shops. First of all setting up your software is the NUMBER 1 most important thing that needs to be done. That means telling your dyno where you are in space. IE: We are at approximately 1050 ft here in Atlanta so keeping your software at 0 altitude or 5280 ft above will drastically alter your numbers. If you are at sea level your number would be lower than here, or if you are in Denver then your number would be higher. Also having the correct ambient air temp is essential. If you're taking air temp from the engine bay or anywhere that is hotter than your actual intake air temp then your whp number will be higher. Barometric pressure and humidity play into this equation as well. It all has to do with air density. The more dense the air is the more power you should be making.

Correction Factor (CF). This is the formula that the software uses to calculate your hp number.
-SAE is the industry standard. This is the CF that DynoJet recommends. This is the formula auto makers use to maintain a standard throughout the world because what a car makes in detroit is not what it makes in Japan. SAE gets called "The old way" but was updated in 2004 to take into account mechanical friction.
-STD is in fact the "old" SAE and does not take into account power loss due to mechanical friction, thus providing a higher end number.
-EEC is a formula they use in Japan and Parts of Europe. Although not at the manufactures. Also yields a higher hp number than SAE.
-DIN is a formula used in Germany, again not by the manufactures. Also yields a higher hp number than SAE.
-Uncorrected is power you are really making on that specific day due to the temperature, humidity and pressure on that day.

Sometimes these numbers vary greatly between CF's. Especially when comparing Uncorrected to the others. Usually (based on our own observations) SAE, EEC, and DIN are all very close. I would say within tenths to 1 hp. The uncorrected numbers do get closer to the corrected based on the Alt, Temp, Humidity, and Baro being close to that which is used in the CF formulas.

There is also the smoothing function which makes your graph lines nice and smooth with the higher the number used. Smoothing at 0 will yield a slightly higher hp number based on spikes in the graph. These spikes are generally small when a good tune has been performed, so if your tune is off then your graph line will be a series of peaks and valleys. It will look like a seismograph rather than a dyno chart! I haven't seen too many shops turn the smoothing down because it basically makes the tune look poor even when it may not be.

Lastly I think that a customer should be there when the final numbers are being put down. I know that schedules conflict and it is not possible all the time to be there when your car is being tuned. But I have seen plenty of cars come through here that had dyno charts claiming one number and then we put it on the dyno and it makes considerably less with no changes being made. This has absolutely nothing to do with the dyno but more the shop operating it. It also has led to the debate about which shop makes more power, or who is the better tuner? If everyone is using the same standard then at least you know that your chart is not being manipulated to benefit the shops image. It does the customer no good to have a fluffed up dyno chart and get spanked by a car with supposedly less or equal power. :no:

Please feel free to comment, or add insight. I will try to respond to intelligent feedback. I am just trying to educate everyone that may not understand what it all means when you get a dyno chart. Or why some people see me ask about this chart or that chart being posted in a non SAE CF.

[SleepingTalon]

BUMP!

[batlbrandon]

Your sig is EPIC!

[TS240]

Is mechanical friction like drivetrain loss?

[batlbrandon]

Yes, I would say that is a fair assessment.

[Tracy]

Good article. Put it on our blog!

[JKOBD]

Cool to see someone talk about the correction factors.

[Tracy]

Cool to see someone talk about the correction factors.
We had a discussion on this board a long time ago about changes in numbers from dyno to dyno, but the discussion went more toward it is to be expected. Then Brandon got to thinking that shouldn't really be true if everything being compared is the same—which 9/10 times, that's really the case. The dyno itself (placement of stack and such) or correction isn't being used in the "standard" way.

[BABY J]

Well I am not a punk - and I have faster/more powerful cars than my "daily" (this week it's my daily, who knows what will be my daily next week - lol) so I have no prob sharing my numbers for my B18a NONVTEC build.

I made 168whp on MSPi dyno w/ STD correction ... and I backed it up w/ 165 SAE at "The Dyno Guy" (dynojet next door to Motorvations) in Birmingham which is about right. And I'll say this... I've buried B series w/ 30 more peak HP in my wagovan which is full weight. (I make peak TQ WAY early and it's as flat as a board and doesn't fall off). So w/ that said, I'm not scared of any 200whp N/A Honda... and that's with my LS tranny. But rather than talk about it, PM me and I can show you.:goodjob: And when I get the b16 gears... it will be lights out... I can't wait. :) (none of this roll shit though, I'm a digger and that's how I get it done. Rolls are good w/ butter and accompany dinner)

But back on topic... at the end of the day, HP is an imaginary number. As long as you tune on the same rollers when you make changes the "gains" will be measureable even if the dyno down the road reads higher/lower. I do know that SAE is the "universal" more commonlly accepted standard though even though my MSP graph was STD.

You'd think that w/ all the people tuning their own shit and the tuners on the board that they will all chime in on this topic.

[BABY J]

And I can't remem if I got retuned on Crower 404s instead of the 403s while I was in Birmingham or not... it escapes me. I wonder what that graph looks like. LOL :ninja:

So Brandon... I have a q for you ... what does stack placement have to do w/ numbers... I didn't think that this mattered.

[SPOOLIN]

dynojet for dynojet should be VERY close, they are accelerometers.

When you get into mustang and dyno dynamics, they use a load bearing system so it can be different big time.


Baby J, YOUR sig is awesome.

[BABY J]

^^ check your paypal Matt - I just saw this. WTF!!

And your sig is much better than mine. LOL. Trade? :)

[Vteckidd]

I always used STD don't know why just always did. Never saw a reason to change, and like I said before , I think it started because I wanted the higher numbers. No I know that just for bragging rights.

You'd be surprised though that a lot of graphs online from other shops around the nAtion use STD and not sae

in the end it's less than 1% difference usually so I never saw a big deal with it

[Vteckidd]

Oh and I dynoed 234 whp sae at mainstream at 10am drove to batlground and dynoed there and made 227whp.

7whp variance from dynojet to dynojet in the span of an hour

[B18c1Turboed]

Who is too say your dyno is set up right also. No taking shots at anyone, but im just saying its one of those things you will never know. Some shops may do it too boost their image, but another shop might play with the dyno too make it look like they did something for the customer. A dyno is used too help with air/fuel real dyno numbers come out at the track.

[BABY J]

^^ You hit on something man!! It's a TOOL USED TO OPTIMIZE your setup (not just A/F tho, but I know you knew that already). RACERS and RICERS have turned it into bragging rights central and that's only part of the pie. B/c at the end of the day rubber on the pavement is what matters. Eggums car never saw the dyno and she continued to take every1s lunch money for years (altho it was WOT 99.999% of it's life).

I've never dynoed at BG. Only Balanced, MSP and The Dyno Guy. Wherever I baseline at is where I try to stay when I make changes so that I can see the gains from whatever baseline that was. If I relocate, then I baseline at the dyno of my choice and that is my new baseline to grow from... even if it's less whp than my previous shops numbers.

[Tracy]

No one said anyone's was right or wrong. How about adding to an informative post with your fact based information (Brandon did a little bit of research to make sure his points were valid) rather than trying to pick it apart and point fingers and start a fight. Just a thought. :) If that's not what you are doing, my bad, but that's how I took it.

We have a had a few forum debates recently about my car makes this much and this car should be making so and so—only to find out people don't know what the heck they are talking about when it comes to dyno numbers. Thus tis thread and trying to simulate some intelligent convo on the topic.

[bigdare23]

Dyno numbers don't really mean much. I basically just used them for bragging rights LOL. Honestly, what actually matters is time slips. For example, my old motor make 175hp on a dynojet, but I couldn't run a time that matched my power level.

[BABY J]

LOL. B18C1TURBOED would like butter and syrup on his pwncakes.

I think Mike hit on something too... w/ 2 appointments on the same day (roughly the same conditions) w/ the same car and the same brand of dyno. For me, the rollers are for optimizing and when I get on the road I see if the performance is there. When my car made 168 at MSP, that didn't matter to me as much as how "the street" accepted that number... the Fagovan rolls the fuck out so I'm happy.

[B18c1Turboed]

Thats not what i am doing. Understanding how a dyno works is a good thing, alot of people dont really know how it works. But just becasue one person dyno higher at another shop and then goes somewhere else doesnt mean that their dyno numbers are wrong. Thats all i was stating.
Example if i go too dyno A one day and dyno when its 70 degree outside. Then i go too dyno B another day, where do you think my dyno chart would be higher?

[BABY J]

Good point Dare. I am still interested in the stack placement discussion though (just for my knowledge) and how that correlates to HP or measured HP. I travel a lot - so if I can just look at stack placement and "know" something when I walk into a new dyno that makes me a more educated customer about my reading even before I strap down. I never knew stack placement mattered - but that's expected b/c I'm an idiot.

[Tracy]

Good point Dare. I am still interesting in the stack placement discussion though (just for my knowledge) and how that correlates to HP or measured HP. I travel a lot - so if I can just look at stack placement and "know" something when I walk into a new dyno that makes me a more educated customer about my reading even before I strap down. I never knew stack placement mattered - but that's expected b/c I'm an idiot.

The stack placement is what Brandon was researching. I had to leave before he was finished, so I don't know how that goes. I know he said it can "trick" the numbers.

And I am glad that everyone in here so far realizes that dyno numbers are to be taken with a grain of salt, but you'd be surprised how many people base their life on them. LOL. It's such a pain when people don't understand them and the variables.

[Formally...]

Here is the way I look at Dyno's. This is a personal opinion and that is it.

I look at dyno's as a testing and tuning device. THEY ARE NOT A PENIS ENLARGEMENT TOOL, if you make more power on one dyno then the other that does not make your penis any bigger. Numbers on paper are just numbers on paper. Numbers at the track are the real thing.

I know there are ways to "fool" the dyno and get higher numbers. People have been doing it since dynos were first invented. Here are some things that can "improve" your numbers:

Higher tire pressure (less rolling resistance)
Thinner tires (185 instead of a 275, also less rolling resistance)
Strap the car a little lose (don't really suggest this but again less rolling resistance)
Place fans directly infront of intake pipe (ram air effect)

Now with that said I will give you an example that I tell alot of my customers. Take your car to shop "A" and get dynoed and make 200whp. Go to a test track and do a timed run from 50 to 100 mph (this will take out most of the driver error and traction problems etc) Bring you car to me and dyno and make 210whp with no changes (same day and everything). Now go back to the same test track and do the same test. IS YOU CAR FASTER NOW? That is what I mean by dyno numbers are just numbers.

Now on the other hand dynos are used for tuning and your before and after runs should be on the same dyno. Most dynojets are pretty consistant with eachother. I have had a customer dyno at Z1 and then drive straight to our shop and dyno again. Peak power was within 1hp between the two dynos and they even have the 248 and we have the 224.

As for the correction factors they are just that. A formula in the software that will try to take into account the atmospheric conditions and correct the power numbers. The difference in the CF are nothing more then different numerical valves in the formula that is used. IT IS ALSO TO BE KNOWN THAT YOU CANNOT DO A BASELINE RUN IN SAE AND THE FINAL RUN IN STD TO MAKE THE NUMBERS LOOK BETTER. Also, you can go and change the CF at any time (again since it is just a mathmatical equation that the program does). If you look at the dyno charts you can see what the CF is. Most of the time it is only between 1.02 and 1.07. This means that if you car makes 200whp uncorrected then it will make 204whp with the 1.02CF and 214whp with the 1.07CF. Again though the car will go the same speed at the track. From what I have seen the humitity makes the biggest difference in the CF. We have changed the altitude from 1000ft (what we use) to 6000ft and done back to back pulls and saw no big change in power numbers.

As for the smoothness this is what the sofeware does to make a "straight line" The dyno takes speed readings from the roller and uses that in the equation to determine HP. It then uses this reading (along with mass of roller and time) to determine the HP of that point. If you change the smoothing to 0 it will draw a line from one point to the next and so on. This will make the graph look "choppy". If you change it to 5 then the program does a best fit line on the graph.

[BABY J]

^^ So what you are saying is that you don't want none of the Fagovan? Oh ok... I don't blame you.

:) Good info Charles.

[Vteckidd]

in the end its all subjective. I know about what a car should make given its setup.

you bring me a LSVTEC with PR3 pistons and ITR cams with a XXXX header i can tell you within 5whp what it SHOULD MAKE.

Just like im sure Dan knows that a supra with XXXXXXX on it should make around xxxwhp on HIS DYNO.

Ive seen from personal experience that no 2 dynoes are the same, ESPECIALLY dynojets. If you want across the board accuracy then everyone needs to buy the $100,000 Dyno Dynamics or some other load bearing.

Dynojets will always be off, they meaure rate of acceleration

[batlbrandon]

Just like im sure Dan knows that a supra with XXXXXXX on it should make around xxxwhp on HIS DYNO.


HIS DYNO? Im not sure what that means. Thats kinda the point of this thread, its a DynoJet. It should make almost identical numbers to the other DynoJets in the area. But they aren't all set up the same so it doesn't. I'll take the lower numbers we seem to get over here knowing that our cars perform on the street. I see all these flames on forums all over, not specifically IA, about how inflated DynoJet numbers are compared to Dyno Dynamics or Mustangs. We dyno'd a 500 whp WRX that came directly over here from Forged and was within 3 whp of their numbers.

BabyJ: if the stack is in a climate controlled room and the car is not then the numbers will be skewed because the software thinks that the air temp and humidity from the climate control is the same condition as the car. It will actually show less power being made. Or if the stack is really close to the engine bay or any kind of heat source and it gets that radiant heat then the software thinks its a bajillion degrees when intake temp may only be 90. That would "trick" it into displaying a higher number.

[Vteckidd]

I know what a car is gonna make on mainstreams dyno I've been apart of prob close to 300-400 cars tuned their as well as all my personal cars.

I'm sure dan knows what a car should make on his dyno.

It's a rather simple statment, you should know your dyno and that is each shops measuring stick.

All dynojets are close but wil not be specifically the same it's impossible for them to be
dead on balls accurate to each other.

My buddy made 197whp on balanced perf dyno and made 183whp on mainstreams 2 days later

doesn't mean balanced dyno was rigged or anything. That's my point

[Vteckidd]

There's no industry standard fr placement of the stack or anything like that. I get the argument but unless it's blatant people are skewing numbers on purpose it's not a big enough variance for it to matter IMO.

Everyone cheats to make bigger numbers everyone does that "magic run" we have all done it.

It's a double edge sword though imo. You'd have to be stupid to fudge numbers so badly. It's easy to tell if a 600whp car is really only making 400, or an na car is not as fast as it should be.

I could post a 280whp na b series graph but if my car runs 14s.......

[Tracy]

I don't think there is an "argument". Only information from some research Brandon did and a discussion. Just making sure that is clear.

[Tracy]

I could post a 280whp na b series graph but if my car runs 14s.......

Then you might just be a horrible driver. I know some of those (I am one of them).

[batlbrandon]

The standard is that the stack should be as close to the same conditions as the car. Not specifically the placement. 20 degrees in either direction of what it actually is, is significant. 20% Humidity is way different than %80, it does make a difference. I can't give a "close enough" product back to a customer knowing that I could have give them back something "right" for the same effort.

Saying that a 200 whp chart is the same as a 214 whp to a all motor Honda guy is false. Hell that is a difference that a seat-of-your-pants dyno can feel. And the more hp/tq you make the greater the difference between CF's it is.

I of course understand that the Dyno is a tool. However I dont think that I will have anyone coming in here and asking for a chart that is Uncorrected! That is the only CF that tells you exactly what you are making at that specific time and condition but will yield the lowest numbers.

[BABY J]

Well - on the "his dyno" comment I can't see that Mike being trying to be coy about that one. I'm one of the N/A guys that have had $3000 B series heads on multiple flow benches and benches vary (http://www.importatlanta.com/forums/showpost.php?p=35813760&postcount=7) (http://www.importatlanta.com/forums/showpost.php?p=35813760&postcount=7). When I was selling that head I made sure I said "on DPRs flow bench it flowed x amount" b/c benches do vary.

On the 214whp CHART vs 200whp CHART I say that it's highly possible. We are already aggreeing that people have their software setup differently. Take that car that lays down 214@ MSPi - let's add an exhaust, and it then makes 222hp @ MSPi. If that car made 200whp @ BG before the exhaust, and strap it down again... it now makes 208whp @ BG. To me, I put the car on the strip and can tell you what the ET calculators say the car makes (roughly) after 10 good passes w/ a decent driver.

Are the CHARTS different? You fucking bet!! But the GAINS over the new baseline should be repeatable/measurable and should be close (for each respective dyno). When I look at my 168whp B18A graph next to my graph at The Dyno Guy, the "characteristics" for each line was the same... peaks and dips were in the SAME spots in the RPM range... altho the HP/TQ numbers were "off". (although I drove to Birmingham to the dyno from Nashville TN... parked the car, and was on the rollers 20 minutes later so my motor was hot and the graph shows 91 degrees at the time of the pulls)

I think that educating customers what a dyno ACTUALLY IS instead of what THEY think it is means more. And I think a lot of tuners don't take time for that.

I mean, I just BURIED a bolt-on JDM GSR swapped gutted and tuned EJ coupe last night in Nashville (if ur on tennspeed you can see the thread) from a 40 kick. PEAK HP is just that - PEAK. If you build high-strung motors that "peaks" a good number you better pray to God that under the curve you got something there or you will STILL get your ass handed to you as I showed last night and as I will be showing tonight after Burgers N Cream - LOL.

Of all the cars I've had tuned, my Mustang tuner was the only guy that focused on the power under the curve. He found 4 hp (peak) and I was like WTF??? 3 hours for that? He said "go drive the car". I got back to the lot and was grinning like a school boy. He said "fast?" I said this mother-fucker is faster than a faggot climbing a dick tree. The graphs didn't look like much (peak number), but under the curve it was a MUCH more responsive and fun car - I could tell that RIGHT away.

My .02.

And to keep it on topic - I appreciate the education on the stack location - I have seen youtube videos where shops hurting for space will have a single bay dyno, and have the stack in a completely separate room... so this is def interesting tidbits to pay attention to in the future.

[Vteckidd]

So you are saying that everyone should use sae right?

I'm saying as long as the shop isn't fudging numbers on purpose it really doesn't matter because as stated before I've seem numerous shops use STD and sae. And usually it's a 1% difference at most.

An evo with a 35r at 30psi making 650whp on sae wil be at 660whp on STD . IMO the customer should know what his numbers mean. It's up to the shop to decide how to display the information.

FYI I usually posted sae and STD graphs or Gave printouts of both

[Vteckidd]

And furthermore you can tell when a shop is stretching dyno numbers , most people know when they see a graph with STD, smoothing on 0 it's obvious

[Formally...]

Of all the cars I've had tuned, my Mustang tuner was the only guy that focused on the power under the curve. He found 4 hp (peak) and I was like WTF??? 3 hours for that? He said "go drive the car". I got back to the lot and was grinning like a school boy. He said "fast?" I said this mother-fucker is faster than a faggot climbing a dick tree. The graphs didn't look like much (peak number), but under the curve it was a MUCH more responsive and fun car - I could tell that RIGHT away.

And to keep it on topic - I appreciate the education on the stack location - I have seen youtube videos where shops hurting for space will have a single bay dyno, and have the stack in a completely separate room... so this is def interesting tidbits to pay attention to in the future.

I have told customers that before also. Most people just want to see the peak numbers. Look at Mike's type r crx that we just put the cams in. I have seen people say damn all that money in cams and stuff to make 5 more whp. If you look at the power under the curve and actually drive the car it feels a lot better.

As for the stack being in different areas I somewhat understand that but I would like to do a test and see what kind of difference it makes. Like I said I normally only see a CF of 1.02 to 1.07.

[Formally...]

Saying that a 200 whp chart is the same as a 214 whp to a all motor Honda guy is false. Hell that is a difference that a seat-of-your-pants dyno can feel. And the more hp/tq you make the greater the difference between CF's it is.

However I dont think that I will have anyone coming in here and asking for a chart that is Uncorrected! That is the only CF that tells you exactly what you are making at that specific time and condition but will yield the lowest numbers.

I think you may have misunderstood what I meant by my statement. Lets say someone goes to dyno shop "A" and makes a run and the CF is uncorrected and he makes 200whp. He then drives to dyno shop "B" and makes a run and the CF is SAE (say 1.03) and he makes 206whp. Finally he drives to my shop and makes a run and the CF is STD (say 1.06) and makes 212whp. When he leaves to drive it home it will be just as fast as when he started that day even though he "picked up 12whp". I didn't mean actually making changes to the car.

Also, I really think the uncorrected is the best thing for actual hp. The CF can only do so much.

I will find some graphs of a car we did that dynoed multiple times within a few weeks. One of those times it was raining and the humitity was like 90%. The car made like 10whp less the the other times even though the CF should have taken care of this.

[Z0_o6]

This is why I (as a customer) use the tuner and dyno that I do, even though he is located in Charleston 4 hours away. He has a Mustang AWD dyno, that from what I understand reads quite low compared to most. My car was like Baby J's, low PEAK numbers but awesome power curve and midrange- even for a big laggy turbo it had a large enough powerband to be usable and a lot of fun. He tunes to make the car fast, not for you to go around bench racing with imaginary numbers. He flat out told me that when I met him to get my car tuned the first time. "If you are here to make big numbers and go home to brag, you are at the wrong place. This dyno is the 'heart-breaker' so take whatever number you think you will make and take about 30-50whp off of it. You still might be too high" LOLOL

I return there, because I know what I made on his dyno before with my setup so I have a baseline, I know what HIS car made on the dyno, and I know what 1/4 mile times he ran with the power his car (same as mine, very similar setup) made on his dyno. Therefore, I can set a whp goal, because it directly correlates to the 1/4 mile time goals that I have also set forth for my car. Just for arguments sake (hypothetical #'s), I know that (driven properly) 500awhp on his dyno should get me in bottom 11's-high 10's in the 1/4. Is it guaranteed? Of course not, it all hinges on driving ability, track conditions, and sometimes it even comes down to dumb luck. But I know with that number on THAT specific dyno, the vehicle should be CAPABLE of the given E.T.

If I am wrong in my understanding, I would like someone to explain to me what perception I have incorrect, so that I will hopefully learn a little something from this conversation :)

[BABY J]

I have told customers that before also. Most people just want to see the peak numbers. Look at Mike's type r crx that we just put the cams in. I have seen people say damn all that money in cams and stuff to make 5 more whp. If you look at the power under the curve and actually drive the car it feels a lot better.


QFT.

Bc unless you road-race and your car lives at 95 - 100% throttle postion for an hour at at a time, how often are you at PEAK? Not long... and guess what turds.... when you DO get to peak in a drag race what happens next ... SHIFT!!!:D Wooops, now you are not at peak anymore... bummer dude. Now what do you have to rely on? The power under the curve.. you know... the part of the graph that you are not looking at while you were bragging about how much peak power you made? Yeah... THAT part. LOL. There is lots more into it than peak HP. Where do you make peak TQ - do you sustain it or does it fall off. How fast do you get there (gearing, vehicle weight). Can you drive? Etc.

I think this is a great topic. And I like what Charles said about the dyno not being a penis enlargement tool. I also like Identity_Crisis said about the dyno being a heartbreaker... both of those statements ring true. Awesome topic Brandon and kool that all the shops and guys w/ experience can chime in.

[SPOOLIN]

my car makes peak power about 2,500 rpms before i shift :)

[BABY J]

^^ Showoff. LOL