Need some opinions on these Dyno results.... LLT @ 350HP?

[Spicoli]

OK. OK. OK.
I am a dyno newbie. Did my first run Tuesday morning. What a blast. I thought I had all of the questions I wanted to ask nailed down, but with all the excitement, I forgot most of them.

Basically, when I finished up, I just assumed that these numbers were "corrected" for loss through the drivetrain. It did seem a bit high (I was hoping for something in the 330 HP range). I just figured that the numbers at the wheels were buried in the data somewhere. I got home after work (I went during work hours - shhh) and started looking a little harder at the printouts. The estimated 1/4 mile time looks about right. But the other two seem way out of wack.

Anyone (of all of you dyno gurus out there) know if they might have totally biffed my run, or if they might be just reporting a "calculated" crank number? I've called them (left a message) and sent an email and haven't gotten a response yet. I will probably stop in there in the next day or so and see if I can catch them face to face.

Of course..... 351HP and 293 torque ain't to shabby.







Thanks for any insight.

[Maurdib]

I might be wrong on this, but I thought most pulls were done in 3rd gear

[Spicoli]

Originally Posted by Maurdib

I might be wrong on this, but I thought most pulls were done in 3rd gear

I thought about that. In the Dyno sticky, it looks like 3rd or 4th. I can imagine why most would be 3rd. In 4th gear, I almost maxed out their dyno at 147mph (max was 150mph).

I did another run and maxed it out at 155. It was pretty cool seeing "Vehicle speed limited to 155" on the DIC.

[KMPrenger]

Well, one thing we know is your car is not making 350 wheel horsepower lol, although that would be SWEET!

I'm thinking something is off as I've never seen a dyno that didn't show rear wheel numbers. The numbers you posted above look closer to what you'd have at the crank, although I think they are probably even higher than what your crank output actually is.

Most pulls are done in 3rd, but some have been done in 4th as well.

[Victoryred69]

WOw, what did you put a 200 shot of nos LOL, thats insaine... im sure thats not rear wheel deeefinately not... but it could possibly be crank, but still thats high.. id reccomend a new dyno somewhere else preferably a dynojet or something :P nice car though!

[bee sting]

Wow my Dyno wasn't even close to your numbers ! Best I could pull was 257 HP at the rear wheels in third gear ! And thats with headers.. axel back..and a Cai setup . What mods does your car have to pull those kind of numbers ?

[bmorecam]

Facts you should know about electric current dyno(mustang, dyno dynamic, etc.)

These types (Mustang, Dyno
Dymamics) of dynos utilize rollers that usually have very little mass, hence they’re not a
true inertia chassis dyno. In order to present any type of physical load on the vehicle,
there needs to be a PAU (power absorption unit). Typically this PAU is in the form of
electrical coils that utilize eddy current technology (think of this as a big electric brake).
Now having a big electric brake is all very nice, but we need to use a chassis dyno to
measure power at the end of the day. Since the mass of the rollers isn’t known (like a
Dynojet), there needs to be a means to measure power, so how this is done is with a
torque cell, or sometimes referred to as a strain gauge. As the big electric brake absorbs
power, the strain gauge is actually measuring torque. Now here is the kicker, the strain
gauge really doesn’t know the difference between 2 ft-lbs or 200 ft-lbs until you calibrate
the device, so in doing this, you’re introducing a potential margin of error and
inconsistency. This would apply to any "loading type dyno" that uses eddy current load
control and a strain gauge, even our own 224xLC which is a hybrid inertia / electric load
style dyno. The strain gauge needs to be calibrated to make it consistent and repeatable,
but there are other user defined (by the dyno operator) variables that makes things very
interesting. Once the strain gauge is calibrated properly, the dyno operator must enter
certain parameters about the test vehicle that determine the rate of acceleration the dyno
will allow, and are ultimately directly responsible for the power and torque readings that
are displayed on the graph (WOW!). At this point you may have connected the dots and are either appalled, or still rather comfortable with the dyno graph you have in your
hands. The question that pops up, “my car made 280 rwhp on a Mustang dyno, what
would it make on a Dynojet”, should be countered with the statement, “I’m not sure, but I
do know this, you’d most likely get 10 different numbers on that same Mustang dyno, let
alone another Mustang dyno that’s installed in the field”. Now this isn’t meant to bash
Mustang dyno or Dyno Dynamics, but some dyno owners just can’t resist “tuning the
dyno”, instead of tuning your car. If you’re “measuring stick” isn’t consistent day in and
day out, then how can you be certain your tuning and modifications are actually working?
If these dynos are set up properly, they can provide relatively consistent and repeatable
results. For what it’s worth, we do not allow dyno operators to adjust “certain parameters
about the test vehicle” on our hybrid electric brake / inertia 224xLC dyno.
So, in any case, there are a couple ways that even when testing on the same model
Mustang dyno or Dyno Dynamics dyno (or even the same exact unit) that the numbers
are subject to a few variables. These variables are ultimately responsible for the power
numbers reported from the test session.

[MagnumForceGB]

He installed that electric supercharger and now has proof it works.
Or the dyno was wrong.

[Shuffler]

Mustang Dyno. nuff said

[Cyber Gray]

Originally Posted by MagnumForceGB

He installed that electric supercharger and now has proof it works.
Or the dyno was wrong.

even if he used viagra he wont be getting 350 rwhp

[Spicoli]

All great comments my Camaro5 brethren. Shhh about the electric supercharger (actually, I'm using two Craftsman Model# 79481 gas leaf blowers).

I know I'm definitely not pulling 350 at the rear wheels. 350 at the crank? Probably not. More like 330 (crossing my fingers).

I'll be stopping in to see these guys tomorrow and see what they can tell me, and yes, I see another dyno run at a different shop very soon.

Thanks!!

[brianko]

Originally Posted by bmorecam

Facts you should know about electric current dyno(mustang, dyno dynamic, etc.)

There's quite a bit of misinformation here, almost don't know where to start. Since I do own a performance shop with a Mustang dyno, I figure I'm somewhat qualified to make some minor corrections to what you perceive as "facts".

These types (Mustang, Dyno
Dymamics) of dynos utilize rollers that usually have very little mass, hence they’re not a
true inertia chassis dyno.

I can't vouch for the DD dynos, but I can assure you the mass on the rollers of a Mustang dyno are tied to a 2000# flywheel to provide inertia to the system. The rollers themselves (at least on an MD250) provide 500# of mass to the system. I would hardly call 2500# "very little mass." In fact, IIRC, the mass of a DynoJet roller is close to the same as that on the MD250.

In order to present any type of physical load on the vehicle,
there needs to be a PAU (power absorption unit). Typically this PAU is in the form of
electrical coils that utilize eddy current technology (think of this as a big electric brake).
Now having a big electric brake is all very nice, but we need to use a chassis dyno to
measure power at the end of the day. Since the mass of the rollers isn’t known (like a
Dynojet), there needs to be a means to measure power, so how this is done is with a
torque cell, or sometimes referred to as a strain gauge.

Actually, the term you're looking for is "load cell." All current Mustang dynos are eddy current dynos, meaning they have one or more PAUs. The purpose of the PAUs is to provide additional rolling resistance to simulate aerodynamic drag and the weight of the vehicle. While these PAUs are strong enough to stop the rolling mass of just about any vehicle (they are actually locomotive brakes), the software uses a feedback loop to hold the rollers in a steady state at a given RPM.

As the big electric brake absorbs
power, the strain gauge is actually measuring torque. Now here is the kicker, the strain
gauge really doesn’t know the difference between 2 ft-lbs or 200 ft-lbs until you calibrate
the device, so in doing this, you’re introducing a potential margin of error and
inconsistency.

Actually, non-linearity for the S-beam style load cell used on the MD250 is on the order of 0.03%. For a 1000-lb load cell, that equates to 30 lbs at 1000 lbs perceived load. However, the "zero balance" on the load cell is calibrated to the nearest one-hundredth of a volt, using an iron weight stamped with a mass accurate to 0.005 lbs. So a typical calibration procedure would involve "zero balancing" the load cell so that the load cell reads within a certain range of the calibration weight multiplied by the moment arm on the PAU. IOW, calibration is accurate down to tenths of a pound.

You should ask your friendly Mustang dyno operator if he calibrates regularly, and if so when was the last time he calibrated. Typically, a "zero balance" is done prior to each vehicle running on the dyno. In the 6 years I've owned my dyno, I've never seen the load cell calibration out of range by more than a couple hundredths of a volt (equal to a few tenths of a pound mass).

This would apply to any "loading type dyno" that uses eddy current load
control and a strain gauge, even our own 224xLC which is a hybrid inertia / electric load
style dyno.

So we get to the crux of the story: You really don't own a Mustang dyno. What makes you qualified then to comment on them?

The question that pops up, “my car made 280 rwhp on a Mustang dyno, what
would it make on a Dynojet”, should be countered with the statement, “I’m not sure, but I
do know this, you’d most likely get 10 different numbers on that same Mustang dyno, let
alone another Mustang dyno that’s installed in the field”. Now this isn’t meant to bash
Mustang dyno or Dyno Dynamics, but some dyno owners just can’t resist “tuning the
dyno”, instead of tuning your car.

I usually don't see more than 1-2 HP difference when performing sequential dyno runs with the same vehicle. Actually, your statement does hold some weight: Dyno numbers will be different from dyno to dyno *regardless* of whether it's a DynoJet, Mustang, DD, or whatever.

I'm not sure what you point is here, but if you're going to bash other dynos, you might as well get your so-called "facts" in line first. There is already so much misinformation out there that you really don't help the tuning community by continuing to spread your FUD.

[brianko]

Originally Posted by Maurdib

I might be wrong on this, but I thought most pulls were done in 3rd gear

Typically, dyno pulls are done in the gear closest to 1:1 so as to minimize driveline losses (at least through the tranny; you'll still have losses in the rear gear). That said, dyno limitations (including cooling capabilities and RPM/MPH limits) might call for a run in a lower gear. Some vehicles take so long to get up to maximum HP in the 1:1 gear that it's often more prudent to use a lower gear.

Like anything else dyno-related, as long as you're comparing apples to apples you'll be fine.

[CRChevy]

Originally Posted by MagnumForceGB

He installed that electric supercharger and now has proof it works.
Or the dyno was wrong.