Jammer you asked if my dyno can hold say 4000rpm no matter what changes
and I would have to say no. It can hold a constant load and it is measured
thru a strain guage or a electronic load measurement device connected to the
pau. Any way I dont care about holding constant rpms in our turbo and supercharged tuning, I want the load to stay constant so I can set afr
and timing per cell for speed density. We load the dynos eddycurrent
pau as we go up in rpm/cell and also map/cell. We are able to go across
the X Y axis on rpm vers map row by row pretty much, just watching egts
to head off damage. I dont know about other shops but we monitor
up to 2 wide bands, vacume, psi, egt, fuel pressure,intake air temp,
and knock all with the dyno setup not the stand alone whick makes it
easy to see on the monitor when we tune in load like this. Any way
I have only owned a dynojet and this mustang dyno so I cant comment on the others out there. Thanks Ralph

 

Lots of good points brought up. Just for the record, Dyno-Jets are on the cheap side, while a 2wd dyno-pak and a 2wd dyno-dynamics run about 50k....over 100k for 4wd btw.

The dyno-paks are hydrolic and dont work well at all with automatics, so investing in on of those is more likely for those with deeper pockets and the import crowd. The Dynamics does better with the auto from what I understand (uses eddycurrent?)

I think we all seem to agree the Mustang is the better of the two when including the dyno-jet. The superflo is also said to have some issues, but I know so little I want go there.
Please refer back to 0D0LS's post above periodically.
I think this thread is somewhat enlightening to all who read, and hope we can continue to interject more facts. i dont claim to have all the answers or be a dyno expert, but just wittnessed and was "taught " some interesting things. I have watched many friends spend 20k on their LS1's and end up with a car with poor street manors and missing alot of potential power under the curve.
BTW, my car was origionally tuned on a Mustang and ran very good, but I may not even know what I was missing.

 

I am drawing a blank when you talk about autos on the dynapack. Why would they suffer on it Jammer?

Rick

 

The hydrolics in the dyno-pak (thats what controls its load) really mess with the hydrolics/converter in the auto tranny and dont allow for smooth cell to cell tuning under load at the complete rpm range.

 

First i'd like to start this post by fuel is added and used to releive the engine components of heat, so A/F is mostly about thermal management . Alot of people still think A/F adjustment is the power God. Im sure all in this thread understand its usefulness however.
When tuning on the dyno, we should observe the instantanious power and TQ readings while changing the timing values for ANY given speed and load point (while observing knock tolerance). That said, to get the best timing, we need to observe and CONTROL rpm, load, atmospheric conditions and have good fuel. If you cant view and control the enviroment completely, you lose some tuning capability (dont you?). We need to watch TQ, HP,fuel flow,ideally airflow, VE, BSAC, BFAC and BMEP's.
I guess Im getting off on a tangent...
Sounds to me like you do a nice job and probably max the potential of the Mustang as well. I have to ask... if the constant rpm cant be held, is it difficult to adjust timing and A/F for each load cell in each RPM range? I must be missing how your doing that, or perhaps you dont feel thats necessary???
Im always trying to learn to, so I appreciate the input.

 

I am actually about 99% done with making my purchace for a dynapack right now. I talked to them about the Auto thing like you said, and realy its no different than any other dyno. Its the fact that the convertor will lock or unlock. That you have to learn to control with your software, but regardless, the power goes to the axles the same way.

Rick

 

ttt, good info.

 

This is really making me wonder if I should get a dynotune when I get heads/cam or the mail order tune from Madz28....

I have an auto tranny, and if the hydraulics mess with the auto tranny, that woulnd't be good! Or am I just missunderstanding? I'll be using a dynojet.

 

After reading all the posts, what am I missing? What is the problem that we are trying to solve? Why would you want to hold a constant RPM for WOT tuning? An engine tuned at anything other then its simulated load/RPM application is not a properly tuned engine. Holding a vehicle's engine (this is not a truck or industrial application) at a given RPM at WOT and tuning it will result in a different tune then one that is allowed to simulate an actual load/RPM sweep. Taking a properly tuned engine out of one car and putting it into a lighter or heavier car is now not properly tuned because its load and rate of RPM sweep has changed. Many load bearing chassis dynos on today's market can closely simulate WOT or cruising loads for excellent part or full throttle tuning. I think that many chassis dynos are very close to simulation accuracy because when we see cars duplicate their track ET/MPH on the chassis dyno based off of their weight and air drag factor, it's got me convinced. Now a real problem is inexperienced, unknowledgable dyno operators or tuners, not our dynos.

 

Rick, I have been on the fence between the Dynopack and the Dyno Dynamics unit. Both are great units but I like the Dyno Dynamics for a few reasons;

When dynoing auto's; if the car where to down shift under a pull, the DD unit will handle this better. The direct drive of the DP does not allow a "slip" point to occur. Could be a scary experience with a high HP auto.

The big thing is that you don't have to take the wheels off. For one it's time consuming and second; I don't feel like being responsible for $ 1000+ wheels!

Finally, the DD dyno can dyno everything! Cars, trucks, bikes, four wheelers, etc....Really opens up the marketing of the unit! The road bikes alone is quite a market.

I also like that they are building these units in the states, Kentucky, and that the tech support and service is also in state. The setup is 100% complete with no "extras".

The only issue with auto's is that you need to be able to lock up the converter!

 

Actually, setup time is almost the same compared to other dynos where you got to drive on a lift, roll back, strap down, ect. So to me its not that bad. And its something I am willing to give up because of the limited space I have.

For Autos, its scary on either dyno, but I see what you are saying about the DP when that happens. I guess the trick would be to "not" let it happen if you can catch it fast enough or not worry about it by locking the convertor.

As far as money for the rims, I would rather buy a set of rims than the whole car if something happens. I know nothing realy happens, but just in case.

Rick

 

dynos
what a great money maker though

 

What the hell are you talking about?

 

yeah, no kidding. Maybe you should look at the fact that with the "proper" dyno, you can tune for all the cells you need to to be able to make sure everything runs great. Remember, the track is one thing, but a good tuning tool is just that, a tool.

Rick

 

I'm coming into this late guys, but I wanted to offer my .02 cents.

I've run on Mustangs, Superflows, and Dynojets. I've had the best luck with a Superflow as far as load goes. I watched a Superflow, load and hold at a constant rpm 1100 ft lbs of torque on a Duramax turbo diesel.

 

Oh sorry. Not to offend, but I just wanted to add another view to an already contriversial subject. I was very short on time with that first post.

I meant that since the loading provided by a chassis dyno comes nowhere near correctly simulating an actual 1/4 mile pass, that it places pretty much at the bottom of any list of tuning methods for performance at the drag strip.

However comma, since it's one of the hottest things going to compare dyno sheets, the ******* (and others) are all over it handing over the cash like there's no tomorrow. I doubt there are many shops that haven't made their investment back several times over given the last two or three years. I can't say that I can really blame anyone for exploiting this fact. I'm sure you can see the dollar signs in a customers eyes when they first get a look at their sheet showing the results. You know they'll be back to dyno again, and in the mean time probably buy parts and labor. The dyno sheet has become a new bragging right, and that just spurs more business. Dynoing is easy, convenient, and requires no skill on the part of the driver, so it qualifies on all counts for the ****** catagory.

Obviously dynos can be used for a sort of tuning, yes, but this doesn't make it correct for every intended application. There are those that use the chassis dyno to tune for an oval track application, or even for the old highway-punch type of racing, and they probably do get their money's worth out of the deal. However, there are a whole lot of people out there very confused into thinking the dyno will also help them find optimum performance at the drag strip, and that's nowhere near the truth. That is what I happen to be concerned with, so that explains my stance on the subject.

This was interesting reading how the different dynos apply load in different ways. I'm sure that one day someone will design a chassis dyno that can at least come close to simulating a quarter mile pass correctly. Some people think that is already the case, but I do not.
Please continue to share information about the different dynos, and also to ask more out of the companies that design and sell them. I'm sure the better the dyno that is available, the more money you can make with it, because customers actual performance results will improve greatly.

I believe it was stated earlier in this thread about how people over-cam their cars in search of the bigger dyno numbers, yet perform very poorly at the drag strip, not to mention everyday driving. I agree. There are still many things that a dyno cannot tell you. I submit that this is a dyno fact to add to this discussion.

IMO as of this date, the chassis dyno's best use is for providing a fun activity for car enthusiasts, and for stirring up business. As far as tuning goes, I'd recommend not using the dyno... but then I'm a nobody.

 

What experience do you have with dyno's? By reading what you wrote it appears your experience is primarily with vehicles doing "full pulls". Yeah its true those wanting "dyno queen" numbers can build their vehicle's accordingly and put down some serious numbers. I think the part you are missing is the load factor for tuning. The ability to hold a load in a certain cell while making the neccesary adjustments. The cell that is a combination of Map and Rpm in most cases. If you have the ability to hold a load and you can tune your cells, be it on a dyno, or a 1/4 mile pass the same rules will apply. Sure you may have to work on a few transitions but the cell that is tuned at 4300 rpm and 142 kpa wether it be on a dyno or on the street will be the same.

The type of dyno you seem to speak of is typical of a dynojet, mustang etc without a brake. A dyno used to get a baseline on a full pull, then used again after mods on another pull to check performance gains.

I agree you are not going to get on a dyno and "simulate" a 1/4 mile run, due to the fact that you would have to simulate the proper load during a full pull equivalant to the same load as in your 1/4 mile pass. But that is not what these guys are saying or insinuating. Load bearing dynos can be used to hold a load for a period of time at a certain rpm to allow the particular fuel/spark cell to be tuned properly. The fine tuning and resoulution of a tune can be achieved much easier and with perfect accuracy via the proper dyno.

 

This right here is why I choose the Dynapack. You have to look at the car in this light.

Since a timing or fuel table is load versus RPM based, it doesnt matter what load you use on the dyanpack, because the engine only knows whats happening at the motor to translate to the table. When you can tune cell by cell, then no matter what situation you run into on the street, be it 1/4 mile or going up an incline pulling a trailer, if you tuned the car in every spot on the table, then it shouldnt matter. The motor does not know the difference between drag racing to going up a mountain. It only see's the different load and looks at the table accordinglly. So when someone says you cant simulate the 1/4 mile accurately, that is a false statement if you ask me. Because with the right dyno and tuning, you dont have to simulate the 1/4 mile. You just have to tune the car, the table will do the rest for you.

Rick

 

I agree 100%

 

IMHO, a dyno is just a tool. Some choose to use the tool wisely, others simply dismiss the tool.