Mustang Verses Other Dynos
Last edited by getusum; Sep 13, 2006 at 10:07 PM. Reason: MAKES MORE SENSE
Dynos are tuning tools. People get too caught up with them.
In general, Mustang dynos produce slightly lower results.
Dynos are tuning tools. People get too caught up with them.
In general, Mustang dynos produce slightly lower results.
Not for dyno queens.
A Dynojet is the industry standard when it comes to dyno numbers. They cannot be altered to change the output.
A dyno is a tuning tool, and a load bearing dyno is beneficial for tuning speed density based vehicles.
Ryan
A Dynojet is the industry standard when it comes to dyno numbers. They cannot be altered to change the output.
A dyno is a tuning tool, and a load bearing dyno is beneficial for tuning speed density based vehicles.
Ryan
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For starters dynojets aren't an industry standard, they just happen to be very popular in the US. However there are many many other types of dyno out there.
Depending on the individual dyno it usually follows like this. Dynojets are inertia dyno's which use a static drag weight to effectively measure HP although this is because of predetermined calulation of torque at rpm due to it being a static weight.
REMEMBER - in automotive terms HP is derived from torque at speed. Hence Bhp, 'B' standing for Brake, as HP is derived via a brake device. There are many other forms of HP but they are all measured, derived or calulated differently and have little or no direct bearing on motor vehicles.
So Dynojet = static drag brake, no load bearing.
Mustang dyno's are load bearing, which means the effect drag can be increased. This applies higher load to the engine and makes in not only more accurate in terms of real world power, but also a much better tool to tune with.
Load can be applied by various methods depending on make of load bearing dyno, typically water, hydrolic or electromagnetic are means of achieving this.
In fact on a load bearing dyno you can increase the load so much that the car will no longer be able to accelarate at WOT and remain at a stable rpms under full load. This is not possible on a Dynojet.
Also Dynojets are the evil of the US motoring world, as they make so many people think and subiquently claim there car is under rated from the factory. Like all these 330rwhp STOCK Fbody's - bollox. It's just that due to how the Dynojet works the HP is derived differently and can not be compared to to bhp SAE Net as quoted by the manufacturer. The same car on a Mustang Dyno would produce 290-300rwhp tops. Which when driveline drag is accounted for will bring you right in at around 345-350bhp which is what a stock LS1 (01+) makes.
If you need to look at it another way. Try this:
2 packets, each has $10,000 in it. So they are both dollars and both the same numerical value. However one is US$ the other Candaian$ so do they actually have the same value?
Also remember when dyno comparing numbers, there are also many other factors.
1. Correction
Many dyno runs use STD, this does not alter the figure and is what it is on the day. So a hot day HP will usually be down and cool weather a higher HP number. This means you can not compare them.
Same car, same dyno, same setup, same everything except the outside temps. The car Dyno'd in STD correction over 20rwhp difference in favour of the cooler day.
SAE figures correct for these things and make numbers more comparable. The above example dyno's less than 0.5rwhp difference in SAE correction compared to the 20rwhp difference when using STD.
2. Graph smoothing
This is exactly what is says, it simple removes the spikes and inaccuraces from the readings. So running no smoothing (as many dyno's don't) means your PEAK readings can easily be 5-20rwhp too high. Evidently too high a setting on graph smoothing and it will flatten out even the real undulations in power delivery, so a happy medium is needed.
On most dyno's these figures can all be adjusted by the operator, so even when corrected the numbers can still be massivily wrong.
If you want a dyno queen and a number to brag about = Dynojet.
If you want a more realistic number and better tuning potential = Load bearing dyno, Mustang or other.
This method is what the auto manufacturers and most engine dynos use and will increase the HP/TQ numbers by approx 5-10%. So what we call "drivetrain" losses is made up of this difference in methodology plus real drivetrain losses and why many accurate chassis dynos indicate a 20-25% "drivetrain" loss. Good info from 300bhp/ton.
Also, I guess a better question is, what industry is being considered. The aftermarket tuning industry, Aftermarket Performance Product Parts industry, OEM calibrations, or others
Each market is totally unique, and has their own requirements, with different units being ideal for each. Would an OEM choose to calibrate on a dynojet, no, Would they use a dynojet to verify power outputs on vehicles, absolutely they do. Would an aftermarket product parts company choose to show gains on a mustang dyno, no they would not, since the displayed gains/numbers are lower than the customer expects. Would a company that does tuning on stand along speed density race cars choose to tune on an inertial only dynojet, probably not.
Just my $0.02
Ryan
Dynojets are comparitively cheap and plentiful and I think have some liason with NASCAR hence in the US they are very very popular.
But popularity should never been confused with accepted standards.
S197 4.6 Mustang – 300bhp SAE Net or 297bhp DIN
Charger SRT-8 – 425bhp SAE Net or 419bhp DIN
Just my $0.02
Ryan
Personally I’d rather have a better tune and a more realistic HP number and then simply run better times than the dyno queen making 50+ rwhp more.
Chassis dyno’s are great, but as a tool not a measure. ALL professional race engine builders and works factory teams will always refer to HP at the engine and never the wheels, this is because it is far too inaccurate deriving HP at the wheels to really be of any use except as a “ball-park” figure.
And I quite firmly believe that chassis dynos (any type) are too inaccurate to measure small variances such as 5-10rwhp on an engine like an LS1. Because you can easily see 15+rwhp variance over 5 pulls without any changes to the dyno or the car.
Sorry to I disagree, on naturally aspirated engines we constantly see a <= 1% variance on our MD-1750 chassis dyno, not to much worse then the SuperFlo engine dynos we used to use. I am confident that if we make a 5 HP change on a 500 HP engine, there will be no doubt in anyone's mind that is present that we will see it. Remove the gain and we can directly overlay the previous graphs. It is possible that lessor dynos are not as consistant.
Sorry to I disagree, on naturally aspirated engines we constantly see a <= 1% variance on our MD-1750 chassis dyno, not to much worse then the SuperFlo engine dynos we used to use. I am confident that if we make a 5 HP change on a 500 HP engine, there will be no doubt in anyone's mind that is present that we will see it. Remove the gain and we can directly overlay the previous graphs. It is possible that lessor dynos are not as consistant.
Sorry to I disagree, on naturally aspirated engines we constantly see a <= 1% variance on our MD-1750 chassis dyno, not to much worse then the SuperFlo engine dynos we used to use. I am confident that if we make a 5 HP change on a 500 HP engine, there will be no doubt in anyone's mind that is present that we will see it. Remove the gain and we can directly overlay the previous graphs. It is possible that lessor dynos are not as consistant.
If this was not the case, the gains being advertised using the parts/tuning tested would be unreliable.
However, you can make false dnyo backed claims if you start to play tricks with hot drivetrains and cold motors, resulting in higher power, and then cold drivetrains and hot motors to provide lower numbers. Unfortunately many huge companies play these games on their product claims, leaving the customer disapointed when they only gain a small % of the advertised claim.
Ryan
The biggest factor in my opinion is the integrity / technical knowledge of the shop using the equipment, no matter the brand as it is evident that similar features can be had.
Horsepower is a way to define Work, torque is actually measured on these devices, the difference is how the time/distance is calculated for the given torque.
As it has been already beaten to death simply put, "actual" Horsepower numbers are more accurately determined on a system with a load bearing feature.
That does not mean a qualified shop/tuner can't get all of the power in the car without that feature.
As unit214 stated...goto the track to measure your car's full performance capabilities.
Later on we had a chance to run this 8 second Mustang on our dyno, http://www.exoticperformanceplus.com/hotCars.php?car=44 and then the customer took it to the track with the same results.
I would have to say the Mustang Chassis Dynos are very accurate, the nice thing about having one is we can do all of our tuning right on the dyno. Bob
Its affectionately referred to as "Dyno Diarrhea" in most circles
I had my Z06 on the "load bearing" dyno and it made 474.9rwhp.(after mods) all my freinds (both of them)cried "too low" "factory pig". So i had it dyno'd on the dynojet and it made a wopping 480rwhp.(after mods). Both tuners informed me it was the difference between before the tune and after the tune that made the difference. The car was running pretty fat from the factory and after headers,haltechf1,and ported intake and the tune the car was night and day SOP difference. NEXT STOP: the 1/4mi Last edited by GoneN3; Sep 19, 2006 at 03:03 PM. Reason: add sentence







