MAHA dynos.....why are they held in such high regard?
10-02-2006, 12:05 AM
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MAHA dynos.....why are they held in such high regard?
Good evening gentlemen.
First of all let me say sorry if I have put this thread in the wrong section.
Onto the question.
Forgive this very "newb" question but can someone explain to me why MAHA dynos are held in such high regard?
From all the threads I have read it is believed that Mustang and Dynojet dynos are known for being generous with readings while MAHA dynos tend to spit out the real numbers.
Can someone explain why or maybe provide a link to an explanation?
Also does anyone know if Ruf uses a MAHA dyno?
Thank you gentlemen.
First of all let me say sorry if I have put this thread in the wrong section.
Onto the question.
Forgive this very "newb" question but can someone explain to me why MAHA dynos are held in such high regard?
From all the threads I have read it is believed that Mustang and Dynojet dynos are known for being generous with readings while MAHA dynos tend to spit out the real numbers.
Can someone explain why or maybe provide a link to an explanation?
Also does anyone know if Ruf uses a MAHA dyno?
Thank you gentlemen.
10-03-2006, 12:19 PM
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Originally Posted by NightStorm
Also which other tuners from Europe has a MAHA in house?
I know RS Tuning does but how about the others? Sportec, Manthey, Edo, etc.
Thanks!
I know RS Tuning does but how about the others? Sportec, Manthey, Edo, etc.
Thanks!
Some good reading on these threads about dynos/claims/actual performance/BS:
https://rennlist.com/forums/showthre...ht=weltmiester
https://rennlist.com/forums/showthre...ht=pistonheads
https://rennlist.com/forums/993-turbo-forum/173419-60-130-mph-new-performance-measurement.html
10-04-2006, 04:57 PM
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I am pretty sure Sportec have a MAHA . I had a MAHA for about 20 years in Europe. Its a good , tough bit of machinery that seems to last forever with basic maintainance.
As a tester for comparing the effects of modifications it is quick and reasonably accurate.
Chassis dynos suffer from the difficulty in providing realistic ambient conditions
especially for turbos, intercooler temperatures etc.
Engine dynos are accurate but suffer from the difficulty in 100% replicating installed conditions and for very modern systems providing the engine management system with the required vehicle signals , say wheel speed inputs ,can be a problem.
I guess what I am saying is that both types of dyno have their + and - points .
Thats why car manufacturers use both !
All the best
Geoff
As a tester for comparing the effects of modifications it is quick and reasonably accurate.
Chassis dynos suffer from the difficulty in providing realistic ambient conditions
especially for turbos, intercooler temperatures etc.
Engine dynos are accurate but suffer from the difficulty in 100% replicating installed conditions and for very modern systems providing the engine management system with the required vehicle signals , say wheel speed inputs ,can be a problem.
I guess what I am saying is that both types of dyno have their + and - points .
Thats why car manufacturers use both !
All the best
Geoff
10-04-2006, 10:37 PM
#6
Ruf Autocentre in Dallas does not have a dyno. They do not have a standard practice of dynoing cars. Ruf does have a standard practice of under rating cars though.
I am not sure about your comments about the MAHA dyno and how it is in any regard better than a Dynojet or Mustang dyno. A MAHA dyno is still a chassis dyno, which means it is only going to show a measurement of power after it is transmitted from the engine through the drivetrain. If you are looking for the true HP an engine makes, it has to be tested on an engine dyno.
This is an incorrect statement. A chassis dyno will measure actual wheel HP regardless of conditions accurately if it is calibrated. In good conditions it will read higher and bad conditions lower because that is how the car is going to run. When it is cool you will make more power and when it is hot less. Turbo cars are effected by temperature and humidity far greater than NA cars, so yes they will be effected more. What will differ is the accuracy of SAE conversion factor to standard temperature and pressure at sea level. There is obviously a greater spread on a boosted car.
True, but not a problem. In fact, it is the opposite. HP rates are based on the output the engine with all factory accessories installed intact. They are indendent of installed options such as larger wheels and tires, 4WD systems or transmissions that could reduce the actual amount of HP that is transmitted to the wheels when the engine output is in fact the same. Engine dynoing isolates power robbing elements. The SAE J1349 standard which relies on engine dyno testing is the most impartial and accurate measure today for engine power and torque.
I am not sure about your comments about the MAHA dyno and how it is in any regard better than a Dynojet or Mustang dyno. A MAHA dyno is still a chassis dyno, which means it is only going to show a measurement of power after it is transmitted from the engine through the drivetrain. If you are looking for the true HP an engine makes, it has to be tested on an engine dyno.
Chassis dynos suffer from the difficulty in providing realistic ambient conditions
especially for turbos, intercooler temperatures etc.
especially for turbos, intercooler temperatures etc.
Engine dynos are accurate but suffer from the difficulty in 100% replicating installed conditions and for very modern systems providing the engine management system with the required vehicle signals , say wheel speed inputs ,can be a problem.
10-05-2006, 02:10 AM
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While RUF Dallas might not have a MAHA, but RUF Germany does!!
I own what I feel is the 2nd best dyno.. A Dynapack, and it will measure direct crank output.. Geared thru the trans and measured directly at the hubs..
Having used a MAHA, it is my favorite. The Mustang is a clone of the Maha. The Dynapack give you the feature of a engine dyno without tire and roller loss.
A Dynojet isn't even in the same league.. Inertia vs eddy current or load bearing dyno..
I own what I feel is the 2nd best dyno.. A Dynapack, and it will measure direct crank output.. Geared thru the trans and measured directly at the hubs..
Having used a MAHA, it is my favorite. The Mustang is a clone of the Maha. The Dynapack give you the feature of a engine dyno without tire and roller loss.
A Dynojet isn't even in the same league.. Inertia vs eddy current or load bearing dyno..
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10-05-2006, 01:51 PM
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O2 Carrera
Looks like a bit of a misunderstanding here.
Would you understand better if I said that chassis dynos have difficulty in replicating real life, road ambient conditions ? Try to imagine the fan requirements to generate a real 100mph cooling breeze !
Simple compensation for temperature and pressure does not always do the job on some systems . For example , if the engine controller halves the boost when inlet temperatures go over 50 degrees C , a compensation sum will not reflect this situation.
Providing full vehicle inputs to an engine controller as used on late vehicles is a problem for engine dyno operators.During OE motor development a controller with software revisions to ignore these inputs is used, so avoiding the problem.
Dont forget that now engine controllers take in far more information than just simple engine data.
Complicated world we live in !!
All the best
Geoff
Looks like a bit of a misunderstanding here.
Would you understand better if I said that chassis dynos have difficulty in replicating real life, road ambient conditions ? Try to imagine the fan requirements to generate a real 100mph cooling breeze !
Simple compensation for temperature and pressure does not always do the job on some systems . For example , if the engine controller halves the boost when inlet temperatures go over 50 degrees C , a compensation sum will not reflect this situation.
Providing full vehicle inputs to an engine controller as used on late vehicles is a problem for engine dyno operators.During OE motor development a controller with software revisions to ignore these inputs is used, so avoiding the problem.
Dont forget that now engine controllers take in far more information than just simple engine data.
Complicated world we live in !!
All the best
Geoff
10-06-2006, 09:02 AM
#9
Nordschleife Master
Kevin,
Your dyno does not measure direct crank output. Your dyno, like all chassis dynos measure axle torque, which in your case is divided by the gear ratio to show you torque at the rear wheels (HP is calculated using the standard HP = torque * RPM / 5252). You also have the ability to type in a drive loss factor to compute back to FWHP, but it has no capability to measure the loss on coastdown like some of the other chassis dynos. It does not have near the features of an engine dyno such as robust data asquisition, air turbine, fuel metering, multiple O2, multiple temperature probes, and multiple EGT measurement. With that said, it is a nice dyno, the brand I use the most, and one of a few that has the capability to actually load and hold the engine like an engine dyno which is required for engine mapping.
The Mustang dyno is an eddy current dyno like the Maha and Dyno Dynamics dyno. It is more closely related to a dynojet in its power readings which are user calibrated and vary widely from shop to shop. I would never consider it to be in the same league as a Maha or Dyno Dynamics dyno and its price reflects that. It is impossible to load and hold an engine on a Mustang dyno because their PID algorithm combined with the large flywheel prevents the dyno from holding the engine properly. The torque numbers will vary 15-20ft/lb on a 400hp car which prevents you from properly setting minimum timing/best torque.
Dyno Dynamics dynos are very much like Maha and are a standard in Austrailia, just like the Maha is a standard in Europe. They are very good dynos with similar function to the Maha and the ability to properly load and hold an engine.
The largest problem I see with chassis dynos are not the dynos themeselves, but the dyno cell itself. I rarely see one that sufficiently removes carbon monoxide from the room, provides sufficient cooling to the engine and maintains proper room temperature. This is particularly difficult on an air cooled Porsche where the cylinder head temperature varies widely (from 100-200c for instance) which affects power output. Further, most just have a fan blowing back towards the engine cooling fan which takes spent exhaust and hot air from under the car and sends it back through the engine for cooling and intake as its "fresh air" charge. A properly designed dyno cell for a Porsche will have some type of evacuation mechanism to remove the hot air from under the engine.
If you spend a lot of time on a chassis dyno, you can set up your test scenarios so you can get repeatable results within the range where the dyno correction to standard conditions will work properly. This will provide you with information you can compare car against car on the same dyno using the same test scenario.
Your dyno does not measure direct crank output. Your dyno, like all chassis dynos measure axle torque, which in your case is divided by the gear ratio to show you torque at the rear wheels (HP is calculated using the standard HP = torque * RPM / 5252). You also have the ability to type in a drive loss factor to compute back to FWHP, but it has no capability to measure the loss on coastdown like some of the other chassis dynos. It does not have near the features of an engine dyno such as robust data asquisition, air turbine, fuel metering, multiple O2, multiple temperature probes, and multiple EGT measurement. With that said, it is a nice dyno, the brand I use the most, and one of a few that has the capability to actually load and hold the engine like an engine dyno which is required for engine mapping.
The Mustang dyno is an eddy current dyno like the Maha and Dyno Dynamics dyno. It is more closely related to a dynojet in its power readings which are user calibrated and vary widely from shop to shop. I would never consider it to be in the same league as a Maha or Dyno Dynamics dyno and its price reflects that. It is impossible to load and hold an engine on a Mustang dyno because their PID algorithm combined with the large flywheel prevents the dyno from holding the engine properly. The torque numbers will vary 15-20ft/lb on a 400hp car which prevents you from properly setting minimum timing/best torque.
Dyno Dynamics dynos are very much like Maha and are a standard in Austrailia, just like the Maha is a standard in Europe. They are very good dynos with similar function to the Maha and the ability to properly load and hold an engine.
The largest problem I see with chassis dynos are not the dynos themeselves, but the dyno cell itself. I rarely see one that sufficiently removes carbon monoxide from the room, provides sufficient cooling to the engine and maintains proper room temperature. This is particularly difficult on an air cooled Porsche where the cylinder head temperature varies widely (from 100-200c for instance) which affects power output. Further, most just have a fan blowing back towards the engine cooling fan which takes spent exhaust and hot air from under the car and sends it back through the engine for cooling and intake as its "fresh air" charge. A properly designed dyno cell for a Porsche will have some type of evacuation mechanism to remove the hot air from under the engine.
If you spend a lot of time on a chassis dyno, you can set up your test scenarios so you can get repeatable results within the range where the dyno correction to standard conditions will work properly. This will provide you with information you can compare car against car on the same dyno using the same test scenario.
10-06-2006, 02:37 PM
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Geoffrey as you know, if we have the printed gear ratio or settle the gear ratio in from RPM of the hubs vs engine RPM we can pinpoint the gear ratio. With that said, I was making reference to the fact that with this dyno we have a direct drive or PTO measurement from the hub to the flywheel. (I wrote gear thru the trans) As close as one would get with the known gear ratio. In the software we see the overall torque developed and then the calculated torque/gear ratio.
We will see geartrain losses, however if you do not use any correction factors and leave it at "0" you are measuring very accurate numbers. Forget the "loss" what's read on the screen is actual HP and Torque delivered to thru your drivetrain.
The ability of this dyno to measure "change" between hardware changes or tune puts it ahead of the pack. Not having to worry about destroying a set of rear tires and dealing with tire loading is a bonus for me.
As far as fans are concerned, you can never have enough. I have a 4500CFM fan for rear engine cooling and 2400CFM fan for IC cooling. And two 2400 CFM fans for the front of the car.. The front fans will provide enough airflow to cool and remove warm air under the car..
We will see geartrain losses, however if you do not use any correction factors and leave it at "0" you are measuring very accurate numbers. Forget the "loss" what's read on the screen is actual HP and Torque delivered to thru your drivetrain.
The ability of this dyno to measure "change" between hardware changes or tune puts it ahead of the pack. Not having to worry about destroying a set of rear tires and dealing with tire loading is a bonus for me.
As far as fans are concerned, you can never have enough. I have a 4500CFM fan for rear engine cooling and 2400CFM fan for IC cooling. And two 2400 CFM fans for the front of the car.. The front fans will provide enough airflow to cool and remove warm air under the car..
10-06-2006, 04:23 PM
#11
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"In the software we see the overall torque developed and then the calculated torque/gear ratio"
The torque shows the torque measured at the axle, not the overall torque, which then has the gear ratio divided into it to see the actual engine torque including drivetrain losses which is RWHP, not FWHP as long as the TCF is set to 0.
I like the Dynapack for similar reasons, because you don't have tire contact, the dyno is much quieter and you can hear better what is going on. It also has advantages in that it is safer since there are no rollers to worry about. It is also highly repeatable and I have had several engines on a DTS engine dyno then on a Dynapack and they have produced the same "loss" with the same transmission.
"The front fans will provide enough airflow to cool and remove warm air under the car.."
No, they won't, and that is with over 4000 hours of dyno experience with ECUs that measure cylinder head temp. Further, the air moving under the car is mixing with exhaust behind the car and getting sucked back into the engine. You really need a grate under the engine with an evacuation system for the hot air.
The torque shows the torque measured at the axle, not the overall torque, which then has the gear ratio divided into it to see the actual engine torque including drivetrain losses which is RWHP, not FWHP as long as the TCF is set to 0.
I like the Dynapack for similar reasons, because you don't have tire contact, the dyno is much quieter and you can hear better what is going on. It also has advantages in that it is safer since there are no rollers to worry about. It is also highly repeatable and I have had several engines on a DTS engine dyno then on a Dynapack and they have produced the same "loss" with the same transmission.
"The front fans will provide enough airflow to cool and remove warm air under the car.."
No, they won't, and that is with over 4000 hours of dyno experience with ECUs that measure cylinder head temp. Further, the air moving under the car is mixing with exhaust behind the car and getting sucked back into the engine. You really need a grate under the engine with an evacuation system for the hot air.
10-06-2006, 11:55 PM
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Originally Posted by Kevin
While RUF Dallas might not have a MAHA, but RUF Germany does!!
I own what I feel is the 2nd best dyno.. A Dynapack, and it will measure direct crank output.. Geared thru the trans and measured directly at the hubs..
Having used a MAHA, it is my favorite. The Mustang is a clone of the Maha. The Dynapack give you the feature of a engine dyno without tire and roller loss.
A Dynojet isn't even in the same league.. Inertia vs eddy current or load bearing dyno..
I own what I feel is the 2nd best dyno.. A Dynapack, and it will measure direct crank output.. Geared thru the trans and measured directly at the hubs..
Having used a MAHA, it is my favorite. The Mustang is a clone of the Maha. The Dynapack give you the feature of a engine dyno without tire and roller loss.
A Dynojet isn't even in the same league.. Inertia vs eddy current or load bearing dyno..
Why do you rate the MAHA as number one?
I am not technically gifted as some of you gentlemen so an easy to understand explanation would be greatly appreciated!
Thank you.
10-07-2006, 01:02 AM
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When equipted with full OBD2 data links it can give you some nice data recorded with the torque and HP numbers. Such as Timing. If you strip down the features of the MAHA the DynaPack starts to show it's merit. $135K MAHA vs $83K DynaPack (2 wheel drive). For tuning a car steady state I really enjoy the software with the DynaPack.. I can also change turbochargers and get full access under the engine and trans with the car on the dyno. With a roller, it can get in the way..