DynoJet Vs DynaPack
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From: San Jose, CA, USA
DynoJet Vs DynaPack
Previously, I have only taken my car to facilities with DynoJet and the only difference between these two dynos that I have read from Honda-tech is that one reads a little higher and one lower.
Well, I thought I'd share what I learned over the weekend with you guys and some dyno newbies like me. Please feel free to correct me if I made a mistake or mistatement.
Currently on the market, there are 3 popular dynos: DynoJet, DynaPack, and Mustang Dyno. I've never even seen a Mustand dyno in person, so I can't say anything about it.
The common belief among the dyno non-experts(like me) is that the difference between dynojet and dynapack is WHERE the power is measured. Dynojet measures at the point of traction, hence the WHP(Wheel Horsepower) and dynapack measure at the wheel hub, hence the BHP(Brake Horsepower.)
As many of you already know BHP, or even FHP is what manufacturers use to advertise a vehicle's HP rating. Generally, these numbers don't take into consideration some of the losses in power through rotating masses and results in higher numbers compared to WHP. The drivetrain loss is not constant and different even between same model, year vehicles. There are too many factors that come into play.
The rotating mass that come into question when comparing dynojet vs dynapack is obviously the size and weight of the wheel/tires. Depending on the material used and manufacturing methods, the weight of the wheel differs quite a bit. This is the reason why DynaPack typically reads higher numbers than a DynoJet, it does not take into consideration the effect of inertia of wheels/tires combo.
Well, before this weekend, I used to think: "If that's the case, I'd rather use DynoJet than to get inflated numbers from a DynaPack." And from people that I've met, this seems to be the general consensus. What do you expect, I didn't know better and no one that I've met cared to explain the difference between the two machines.
Well, I thought I'd share what I learned over the weekend with you guys and some dyno newbies like me. Please feel free to correct me if I made a mistake or mistatement.
Currently on the market, there are 3 popular dynos: DynoJet, DynaPack, and Mustang Dyno. I've never even seen a Mustand dyno in person, so I can't say anything about it.
The common belief among the dyno non-experts(like me) is that the difference between dynojet and dynapack is WHERE the power is measured. Dynojet measures at the point of traction, hence the WHP(Wheel Horsepower) and dynapack measure at the wheel hub, hence the BHP(Brake Horsepower.)
As many of you already know BHP, or even FHP is what manufacturers use to advertise a vehicle's HP rating. Generally, these numbers don't take into consideration some of the losses in power through rotating masses and results in higher numbers compared to WHP. The drivetrain loss is not constant and different even between same model, year vehicles. There are too many factors that come into play.
The rotating mass that come into question when comparing dynojet vs dynapack is obviously the size and weight of the wheel/tires. Depending on the material used and manufacturing methods, the weight of the wheel differs quite a bit. This is the reason why DynaPack typically reads higher numbers than a DynoJet, it does not take into consideration the effect of inertia of wheels/tires combo.
Well, before this weekend, I used to think: "If that's the case, I'd rather use DynoJet than to get inflated numbers from a DynaPack." And from people that I've met, this seems to be the general consensus. What do you expect, I didn't know better and no one that I've met cared to explain the difference between the two machines.
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From: San Jose, CA, USA
Re: DynoJet Vs DynaPack (Allmotormonsters)
The difference:
If you're just going for a dyno day and want to see how much power you're making, which machine you go doesn't make a difference. It's all WOT measurement. But if you're tuning your car for street uses, or road race/track uses, there are differences between the machines that are worth mentioning.
DynoJet is a roller dyno that is not capable(at least the ones I've seen) of putting any load on the car. Hence the car spins a roller and the measurement is taken from how fast the car can spin the roller. Roller in dynojet works like a wheel on a good set of rollerblade. You spin it it'll just roll forever. As you might see, this doesn't really apply to street driving. The car has to push itself and depending on the road condition such as incline, it might have to push harder than normal to gain the same acceleration. This is fine if you're tuning your car for WOT only and mainly for DRAG racing as no one races drag at 50% throttle, but you can see that it might become a problem for cars that are getting tuned for uses that require pedal modulation such as drifting, road racing, auto-crossing, etc.
DynaPack on the other hand slightly different. First of all, it is safer. Your car doesn't have to go on a lift 6ft above ground(in most cases) to spin a roller. Your car stays on the ground and the dyno is attached to your wheel hubs. And since the driveline has nothing to put its power down to, even if it falls out of the dyno, your car won't go anywhere. It'll fall and break the rotors, axles compared to your whole car flying off the dyno into wherever its headed.
Dynapack and I believe, Mustang Dynos are different from DynoJet in a sense that these 2 are load bearing dynos. You could adjust the load on the drivetrain to simulate many of the road conditions. Also more importantly these dynos have the capabilities to lock in the RPM range for tuning by increasing and decreasing load, not the throttle. You can tune different ranges of RPM at different throttle position. For example:
2k-3k RPM @ 0% - 100% throttle
3k-4k RPM @ 0% - 100% throttle, etc etc.
Where as DynoJet, you can't tune for specific RPMs or it's harder because the roller will just spin faster with more throttle/power output. It's literally 0 - redline @ 100% throttle.
Tuning with DynaPack you can actually tune for daily driving conditions, simulating load on the car. This also means it eliminates the on-dyno and on-street AFR differences. Typically, the cars tuned on a DynoJet will lean out on the street, where as cars tuned with DynaPack will already have compensated for the load and will run just as same it did on the dyno.
This is also why Mustang dyno will put out lowest numbers of all 3 dynos b/c it counts into consideration the rotating inertia of the wheels/tires combo as well as putting load on the car.
Hope this helped and if anyone wants to add, feel free.
If you're just going for a dyno day and want to see how much power you're making, which machine you go doesn't make a difference. It's all WOT measurement. But if you're tuning your car for street uses, or road race/track uses, there are differences between the machines that are worth mentioning.
DynoJet is a roller dyno that is not capable(at least the ones I've seen) of putting any load on the car. Hence the car spins a roller and the measurement is taken from how fast the car can spin the roller. Roller in dynojet works like a wheel on a good set of rollerblade. You spin it it'll just roll forever. As you might see, this doesn't really apply to street driving. The car has to push itself and depending on the road condition such as incline, it might have to push harder than normal to gain the same acceleration. This is fine if you're tuning your car for WOT only and mainly for DRAG racing as no one races drag at 50% throttle, but you can see that it might become a problem for cars that are getting tuned for uses that require pedal modulation such as drifting, road racing, auto-crossing, etc.
DynaPack on the other hand slightly different. First of all, it is safer. Your car doesn't have to go on a lift 6ft above ground(in most cases) to spin a roller. Your car stays on the ground and the dyno is attached to your wheel hubs. And since the driveline has nothing to put its power down to, even if it falls out of the dyno, your car won't go anywhere. It'll fall and break the rotors, axles compared to your whole car flying off the dyno into wherever its headed.
Dynapack and I believe, Mustang Dynos are different from DynoJet in a sense that these 2 are load bearing dynos. You could adjust the load on the drivetrain to simulate many of the road conditions. Also more importantly these dynos have the capabilities to lock in the RPM range for tuning by increasing and decreasing load, not the throttle. You can tune different ranges of RPM at different throttle position. For example:
2k-3k RPM @ 0% - 100% throttle
3k-4k RPM @ 0% - 100% throttle, etc etc.
Where as DynoJet, you can't tune for specific RPMs or it's harder because the roller will just spin faster with more throttle/power output. It's literally 0 - redline @ 100% throttle.
Tuning with DynaPack you can actually tune for daily driving conditions, simulating load on the car. This also means it eliminates the on-dyno and on-street AFR differences. Typically, the cars tuned on a DynoJet will lean out on the street, where as cars tuned with DynaPack will already have compensated for the load and will run just as same it did on the dyno.
This is also why Mustang dyno will put out lowest numbers of all 3 dynos b/c it counts into consideration the rotating inertia of the wheels/tires combo as well as putting load on the car.
Hope this helped and if anyone wants to add, feel free.
Joined: Apr 2004
Posts: 943
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From: Lincoln, NE, USA
Re: DynoJet Vs DynaPack (Allmotormonsters)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Allmotormonsters »</TD></TR><TR><TD CLASS="quote">The common belief among the dyno non-experts(like me) is that the difference between dynojet and dynapack is WHERE the power is measured. Dynojet measures at the point of traction, hence the WHP(Wheel Horsepower) and dynapack measure at the wheel hub, hence the BHP(Brake Horsepower.)
As many of you already know BHP, or even FHP is what manufacturers use to advertise a vehicle's HP rating. Generally, these numbers don't take into consideration some of the losses in power through rotating masses and results in higher numbers compared to WHP. The drivetrain loss is not constant and different even between same model, year vehicles. There are too many factors that come into play.</TD></TR></TABLE>
BHP or FWHP is measured with a brake style engine dyno. This can be an eddy current, water brake etc. This is where the engine works against a brake (load) and power is measured.
As many of you already know BHP, or even FHP is what manufacturers use to advertise a vehicle's HP rating. Generally, these numbers don't take into consideration some of the losses in power through rotating masses and results in higher numbers compared to WHP. The drivetrain loss is not constant and different even between same model, year vehicles. There are too many factors that come into play.</TD></TR></TABLE>
BHP or FWHP is measured with a brake style engine dyno. This can be an eddy current, water brake etc. This is where the engine works against a brake (load) and power is measured.
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Re: DynoJet Vs DynaPack (346FD)
Actually, Dynojet does have certain models that uses Eddy current to load the rollers.
http://dynojet.com/automotive_...x.php
http://dynojet.com/automotive_...x.php
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Joined: Jan 2004
Posts: 3,914
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From: Charlotte, NC
Re: DynoJet Vs DynaPack (96dc2)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96dc2 »</TD></TR><TR><TD CLASS="quote">Actually, Dynojet does have certain models that uses Eddy current to load the rollers.</TD></TR></TABLE>
And it's around $8,000 to add on, if I remember correctly.
Dyno Dynamics makes a dyno very similar to the Mustang Dyno, from what I can tell, and it's very easy to use, has load absorption, etc. I believe they are a bit more expensive though, as it has a few more features.
And it's around $8,000 to add on, if I remember correctly.
Dyno Dynamics makes a dyno very similar to the Mustang Dyno, from what I can tell, and it's very easy to use, has load absorption, etc. I believe they are a bit more expensive though, as it has a few more features.
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