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Dyno camparison stock vs stg 2-3-4-5


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Hey guys,

 

I went to Dynodoc yesterday in Montreal for a little dyno session to compare after a year and a half since last dyno session with that same guy. I also had my car dynoed in Detroit, but they use a different dyno, which, according to Dynodoc guy, is reading a bit more power than his dynopack. Instead of putting the car on rolls like at Livernois, the dynajet requires that you remove the wheels and you plug a machine to each wheel.

 

When I went to Detroit, I was dynoed, when it was almost 100F outside at 380hp/400lbs with stage 4+. Now everyone that upgraded with mycal and stage 5 agrees to say that there is a noticeable difference between 4+ and 5, so I would have expected my dyno numbers to be a bit higher... But I am happy with them anyways.

 

However, and I will talk with Rick/Dan at Livernois about the sults, I noticed that the boost reads under what I expected... with max aroun 16psi going down until 13psi... I thought that it was about 2psi higher than that with stage 5.

 

Also, The torque seemes not to hold as much as before, I wonder if it would be possible to adjust the tune to maintain it between the 2,000rpm and 4,000rpm...

 

Finally, the ARF seems to run a bit too rich towards the end as it drops to 11. Would it be better/possible to maintain it above 11.5?

 

So, don't get me wrong, the car runs very well.... I am surprised at the way the graph looks (if I compare it with BPD Mike's recent graph) or even with my own dyno graphs of last year, it seems that there are a few points to adjust... or maybe it is just the dynopack machine that reads wrong???

 

I really believe in Livernois' capacity to develop tunes that are very performant/efficient and reliable. I know that Dan passed many many hours working on tuning our ecoboost. I also know that before mycal, the tunes got better and better over the months, so I am wondering if stage 5 could get better and better too since it is with a new device with many more tables. So I hope that my graphs can help to discuss furthermore the current tune and help our friends at Livernois in their continuous effort to unleash the hidden power of our cars.

 

Thanks and here are the graphs (first is May 2011 with stock, stage 2-3 and stage 4(2 runs of stage 4)); (second graph is the one of yesterday with stage 5). Note that in May 2011, my car was bone stock except for tuning and H&R... Since then, it has Airaid intake, custom exhaust and methanol injection:

 

steve_taurus_SHO_2010_wtq_whp-1.jpg

DynoDoc_Steve_TaurusSHO_stg5_wtq_whp.jpg

 

Now the discussion is opened on how much drivetrain loss there is. Since I was 281hp stock and Ford states 265hp, that would be about 23% loss. But most of the companies understate the real power of their car. The guy that dynoed the car yesterday thinks it should be more around 25%... Now it is debatable also what conversion should be done for torque. Normally, people use the same as for hp (wheels compared to crank), but again, looking at initial numbers, I was at 300lbs torque when stock and Ford states 350lbs (only 14% loss)... One thing for sure is that Livernois' tune crank the torque a lot, but I don't konw if we can apply the same 23-25% or the 14%???

 

So, my average numbers, excluding runs 2-3 (littles issues), so for runs 1-4-5-6 is 376hp/421lbs. Using 25% drivetrain loss for hp and let's say 20% for torque (in between) that would give me 500hp/525lbs...

 

That is my guess... Now Chris has the same setup and he was dynoed at 403hp on the rolling dyno, so it is more an indicator than a precise tool...

Cheers!

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I adore/despise this sort of conversation because while I will talk numbers with anyone until our ears fall off (or fingers I guess) there is ultimately NO good way to estimate crank hp from whp. I've been watching "experts" duke it out on the internet about this for as long as there has been an internet. The bottom line near as this "expert" (because everyone is an expert online right?) can tell this is how it goes:

 

1: Every dyno is different and will read/produce numbers differently based on load, ramp speed, etc. These can be manipulated both by the manufacturer as well as the user. There is no one type of dyno that is more accurate than any other. Like any good tool it is only as proficient as its user.

 

2: People like to lie. Well, maybe they don't like to but they do. Fish stories are all too common...especially when egos or business are on the line.

 

3: Mechanically, drivetrain losses increase with rpm. That is why torque #'s are usually closer to manufacturers specs than horsepower is. This is also why you can never use a flat % to calculate drivetrain loss. It's just too variable! You can perhaps estimate within reasonable percentage what the loss will be at a given rpm, in a given gear, at a given load but that'd just be a snapshot of one instant and not tell you anything meaningful dynamically.

 

4: Trap speed is by far the best indicator of overall power (notice I did not say horsepower there) that a vehicle makes. Now hold on to your hats for this part...ready? WHEN IT COMES TO ACCELERATION THERE IS NO SUCH THING AS TORQUE. Mind-bending isn't it? Well, what are the units of torque? Ft-lbs right? Where is the unit for time? Oh yeah. Torque x RPM/5252 = HP. There's your unit of time right there. Torque is just the rating for an instantaneous quantity of force. Applying that force over time is where you get acceleration and hence, horsepower. We have become conditioned over time (perhaps due to the aformentioned ego thing) to look at the peak #'s the most but in truth it is the average power generated over the rev range used during acceleration (usually the mid to higher end when racing) that matters. Vehicles that produce large ammounts of torque tend to generate better average power and thus stronger average acceleration.

 

5: I personally like the formula of (Trap Speed/234) cubed (times itself 3 times) then that # times the vehicle weight (with driver unless you have an RC car). Example: (118mph/234)(cubed) times 4500lbs = 577hp. This number closely approximates the CRANK horsepower. Another example (stock SHO): (101mph/234)(cubed) times 4550lbs = 366hp. Say...that's pretty close eh? Now I know that a few have run as fast as 103mph or so stock but this formula gets you pretty darned close. Add to that my original statement that there is NO perfect way to estimate anything and we begin to see that there are some flaws even with this formula. It uses PEAK hp. Kinda defeating everything I said before. Alas, this is as good of a formula as I have found so far. I really wish I had one that uses average hp per gear, calculates wind resistance as speed increases, considers coefficients of friction from tires etc. Gah! There's just too much to consider. I'll take close enough at this point.

 

What do you all think?

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I think Steve is mesmerized by your post there Mothball..... :faint:

 

I also think that perhaps he's also intruiged :RpS_wub:

 

Or perhaps excited :couple_inlove:

 

Either way, I find your information, and most of Steve's for that matter, to be pretty damn interesting.....

 

I'll just sit back and watch you two have your numerical fun :typing:

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That is the kind of maths I like to do... Thanks for the formula! I totally agree with all you said and had a discussion with the dyno guy yesterday about that... Peak numbers are fun to show, but in fact it is the area under the curve from mid to high rpm's that matter. And I believe that Livernois thinks the same.

For sure, when comparing one car to another or comparing the same car before and after a mod, trap speed is a good indicator (if not the best) as long as done in the same conditions. I know that the track I go is reputed to be fast. when I go, I mostly try to go when there is a tailwind, not too warm. So DA is a good indicator for commun base, but it would be good if we could do 2 runs in opposite directions to elimitate wind factor (inclination of the track if any) and then just adjust for DA... Trap speed is not supposed to be affected if spinning at launching and actually, trap speed is supposed to be faster if spinning because once you grip, you are at a higher speed with less distance done, so more left to accelrate from an already higher speed...

Finally, non-PP vs PP vs trap speed... I was reading on the internet that they compared a non-PP back to back with a PP and they obtained 2mph faster trap speed... So, that is attributable only to gear ratio, not hp.

There you go... I love numbers and love those discussions, anyone wants to chime in, looks like there are two nerds ready to debate!

Cheers!

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Aww, shucks. :RpS_blushing:

 

That is another thing I left out earlier too. Tracks. As we know, the power your engine makes varies significantly from day to day depending on weather conditions. Runs at the strip vary depending on prep and even how different tracks measure speed. We all know that some tracks are "faster" than others for these two reasons.

 

The spinning thing has always had me intrigued as well. While I do agree that it's better to spin than bog I've always felt that it depends on what happens after you stop spinning. Sometimes you spin and then bog. Might as well just coast on down the track and try again at that point. I do think that a tick of spin does seem to bring about a slightly better trap speeds too. That's something I need to learn more about. Might be moot for us though especially if we ever get the rear diff torque proportioning figured out. Nuthin' but grip then!!!

 

Lastly, (damn I'm wordy tonight) this whole line of thinking is why I mentioned in another thread that I was a little disappointed in the power #'s from the upgraded turbos. They made 521lbs at the wheels! That's insane torque but only 435whp. They haven't posted the graph so I can't say for sure but that seems more like a VW power curve to me. They use tiny turbos that spool like mad right away and make these huge torque spikes that only serve to make launching terrible. After you are in the racing portion of the powerband they are out of breath relatively speaking. I was hoping that the turbo upgrades might carry the powerband out a little more effectively for that area under the curve we need. Not knocking them though! I do believe them 100% when they say the power is there to get into the 11's.

 

I'll talk more about gearing later. That's fun but your eyes are probably bleeding by now. Sorry.

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So Steve you thought you would be more then 415/430 on stage 5? I think that is pretty good! This is at the wheels! That is good for crank numbers! I agree on the wheel to crank' date=' it is a rough guess. All engines vary a bit from the factory also.[/quote']

 

 

So Steve you thought you would be more then 415/430 on stage 5? I think that is pretty good! This is at the wheels! That is good for crank numbers! I agree on the wheel to crank' date=' it is a rough guess. All engines vary a bit from the factory also.[/quote']

 

My reference points were that I did 380 hp in Detroit on stage 4+ with meth when it was almost 100F and Crash (Chris) did 403 hp with same setup as me with stage 5... So, I don't know about torque but in terms of hp I was expecting to be right with Chris... So it has to be mainly the different dynos...

 

But then you have BpdMike that was dynoed at 400hp and 433lbs with same setup but with downpipes, so Chris' numbers appear too high...

 

And then at the track, I trapped 117.9 mph on two different days and since stage 5, I haven't trapped under 113mph regardless temps, winds or preps... And that is in the same ball park as firstSHO (Mike) and Darrell that have downpipes and upgraded turbos... Hmmmm...

 

Finally, as mentioned, peak numbers are worthless, but it seems the way that people in the industry rate and compare power... So, when I do estimations, what I want to find is the equivalent power asnother cars...

 

Example:

 

If the new M5 rates at 560hp and does 11.9 at 120mph, the new srt8 (470hp) does 12.6 at 114, the CTS-V sedan (556hp) 12.2 at 116... And they all weight about the SHO, then I know that I have an equivalent power in the range of caddy and bmw and higher that srt8... Now what is the exact numbers, irrelevent.

 

AWD and more torque we kill those above at the red light and on the highway, we have too much drivetrain loss and M5 would take the lead, we should be close but behind caddy and very clise or slightly in front of srt8...

 

Cheers!

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Fascinating reading. Can't say I'm able to follow completely but I'll take another whack at it. Thanks for posting this stuff. Definitely mind blowing!

 

Is there a crank HP formula that would work for 0 to 60 instead of trap speed?

 

 

Sent from my iPhone using Tapatalk

 

My guess is that you would do 0-60 with stage 4+ and no suspension in about 4.6 (4.4 if car lowered). There are different sites on the web that yoy can put weight and hp and it ll give tou an idea of 0-60 et .

I will work on gathering all those sites and formulas and interesting charts and put them in a thread that I suggested very soon...

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My guess is that you would do 0-60 with stage 4+ and no suspension in about 4.6 (4.4 if car lowered). There are different sites on the web that yoy can put weight and hp and it ll give tou an idea of 0-60 et .

I will work on gathering all those sites and formulas and interesting charts and put them in a thread that I suggested very soon...

 

I'm not sure but I may have been misunderstood. My 0 to 60 is the easiest thing to establish and I've got a handle on that. I thought it might be interesting to take that number and plug it into a formula along with vehicle weight and come up with crank HP. That would be a fun formula if it was possible. Seems like if you can do it with trap speed, why not 0 to 60.

 

 

Sent from my iPhone using Tapatalk

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I've never come across a good formula for hp as it relates to 0-60 unfortunately. Since 1st gear is the only one that uses the full range of the powerband and so much depends on how you come off the line I just don't think there is a good way to relate the two. Trap speed works well because it's less affected by the launch (although it is to some degree as previously mentioned) and it's a better average over the entire distance. 0-60 can be funny too since it can be massively impacted by gearing and shift points too.

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  • 2 weeks later...
My reference points were that I did 380 hp in Detroit on stage 4+ with meth when it was almost 100F and Crash (Chris) did 403 hp with same setup as me with stage 5... So, I don't know about torque but in terms of hp I was expecting to be right with Chris... So it has to be mainly the different dynos...

 

But then you have BpdMike that was dynoed at 400hp and 433lbs with same setup but with downpipes, so Chris' numbers appear too high...

 

And then at the track, I trapped 117.9 mph on two different days and since stage 5, I haven't trapped under 113mph regardless temps, winds or preps... And that is in the same ball park as firstSHO (Mike) and Darrell that have downpipes and upgraded turbos... Hmmmm...

 

Finally, as mentioned, peak numbers are worthless, but it seems the way that people in the industry rate and compare power... So, when I do estimations, what I want to find is the equivalent power asnother cars...

 

Example:

 

If the new M5 rates at 560hp and does 11.9 at 120mph, the new srt8 (470hp) does 12.6 at 114, the CTS-V sedan (556hp) 12.2 at 116... And they all weight about the SHO, then I know that I have an equivalent power in the range of caddy and bmw and higher that srt8... Now what is the exact numbers, irrelevent.

 

AWD and more torque we kill those above at the red light and on the highway, we have too much drivetrain loss and M5 would take the lead, we should be close but behind caddy and very clise or slightly in front of srt8...

 

Cheers!

 

first off let me say, 117 is a great trap speed especially given the daily drivability and functionality of a SHO.

 

I do like you idea of ballparking according to other stock vehicle performance numbers.

 

But i do find it funny that you chose 3 RWD sedans to compare your power levels to. Why not the Audi S8 or E550 4Matic or 550i xdrive??

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first off let me say, 117 is a great trap speed especially given the daily drivability and functionality of a SHO.

 

I do like you idea of ballparking according to other stock vehicle performance numbers.

 

But i do find it funny that you chose 3 RWD sedans to compare your power levels to. Why not the Audi S8 or E550 4Matic or 550i xdrive??

 

You are right... But on the 1/4 mile, usually trap speed should be less with AWD because of drivetrain loss... So, we still can compare having that in mind... In another thread that I started in the drsg racing section, I compare the 0-60 and 1/4 mile with other AWD cars such as Panamera, S6, etc. I guess my subconscious wanted me to choose different cars...

 

Thanks for your comment

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4: Trap speed is by far the best indicator of overall power (notice I did not say horsepower there) that a vehicle makes. Now hold on to your hats for this part...ready? WHEN IT COMES TO ACCELERATION THERE IS NO SUCH THING AS TORQUE. Mind-bending isn't it? Well, what are the units of torque? Ft-lbs right? Where is the unit for time? Oh yeah. Torque x RPM/5252 = HP.

 

?

 

Mothball, could you have misquoted on the above??? I have always heard over the decades that there is "NO SUCH THING AS HORSEPOWER" Horsepower is just a calculation derived from measureable entities such as Torque and RPM. Your formula above shows this.

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Mothball' date=' could you have misquoted on the above??? I have always heard over the decades that there is "NO SUCH THING AS HORSEPOWER" Horsepower is just a calculation derived from measureable entities such as Torque and RPM. Your formula above shows this.[/quote']

 

The way I see it is the torque is the power at lower rpm and hp at higher rpm. So if your hp numbers are strong from 4-6k then you need torque to launch from 1k to 4k and then hp takes it from there. If your shifts keep you where your hp numbers are strong you will acceperate well. That is why the cars with a lot of torque can pass a car easily on the highway without downshifting (which is harder to do with an auto transmission).

So, there is nothing like torque... to launch, but once over a certain rpm, there is nothing like hp...

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  • 2 months later...
  • 2 months later...

old thread but....

 

I have always wondered about the "percentage" formula for drive train loss.

 

Let's say a car has a drive train loss of 25% and makes 200 HP. That means the drive train consumes 50HP.

 

You then modify the engine and now make 400HP. Why would the same drive train now consume 100HP?

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In a word, no. Drivetrain loss is a complex and hotly argued topic but the easiest explanation is that it's a sliding scale. As you make more power your %loss will decrease but the absolute number of hp lost will increase. Some exaples using a totally make-believe car to help illustrate:

 

Stock: 250chp (crank hp) 200whp (wheel hp) A loss of 50hp or 20%

Minor Mods: 300chp 245whp A loss of 55hp or just over 18%

Big Mods: 500chp (double stock!!!) 420whp A loss of 80hp or 16%

 

I'm not trying to say that this is a perfect illustration of how it works but it should at least demonstrate the principle that the drivetrain takes more energy to drive as you make more power but less of a percent of overall power being made. I hope that made sense and I hope it helps.

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