I realize that not all dynos are created equal and that DynaPacks dyno slightly higher. Also that numbers generated on dynos are realative to various conditions (ie weather, alt, humidity, etc). The reason DynaPacks show higher numbers could be due to the fact that the DynaPacks are directly connected to the rear hubs (in our case) vs dynojets that are drums the wheels are spinning on. No slipping/traction problem on a DynaPack so I would expect higher number on them. I think DaveO was commenting that tuners/builders use DynaPacks because of the more reproducable, direct connection of the car to the dyno. One less complicating factor in determining the output. Tuners may also use DynaPacks just because they put out higher number too. Wouldn't you do the same!

A dyno only represents a snapshot of performance that is not terribly relative to other pulls on different days or even times of the same day. I dyno'd first that day so my numbers may be higher than other who ran after me. SAE correction is supposed to level the playing field as much as CAN be done to make the numbers generated relative. Do I sound like a scientist?, well I am

After all my parts and tuning I was more interested in the A/F mix so that I could maximize my numbers, whatever they may be. Looks like I can get more torque if I get TS to tweek my A/F between 3.5 and 5.k rpms. Afterall, hp is nice but torque makes driving fun. My last dynojet numbers at Powertrane Dynamics before a TS reflash were 262hp/ 247trq. Others after getting a reflash added 3-10 hp/ 0-10 trq to their numbers. This would put me close to the values I generated at Church's, probably a little less than than greater than. It's all good. I'm just happy that after the money I spent on everything that I see gains that make me happy I went N/A. Can't ask for more than that.

DaveO - I subscribed to the mag last nite. Can't wait for the winter issue!

 

Dynopack dyno's usually read lower not higher... I ran 10 hp less on dynapack than a dynojet.... ITS ALL about PROPPER TUNINING.

 

That is not true, maybe it was in your case but not for the general population. Maybe they had the load on the dyno adjusted differently? Im no dyno expert but isnt there also a "ramp up time" the tuner can change to give his dynapack numbers closer or in your case higher than dynojets-Im not sure of the exact term right now, but Im sure somebody will correct me.

 

Why is your gear ratio so high? What gear was this done on?

Thanks,

Jermaine~

 

The New Zealand made Dynopac dyno as has been stated, is driven by the wheel hubs. It is a true load based dyno & has the ability to record WHP or flywheel HP (crank). While it is not an actual flywheel HP the program simulation is very close to actual.
As an example we Dynoed a car with an advertised power of 147 Kw. On the Dynopack flywheel setting it read 151 Kw but we had removed the Catalyst & it had a K & N filter.
Sponge's graph shows that his car was done in flywheel mode which is a lot higher reading than RWHP

 

Most of the Japaneese tuning houses ( Top Secret, Esprit, Ect ) use the Dynopac dyno & there advertised HP (PS) figures are in fact hub HP figures using the flywheel simulation program .

 

Seems like some people understand that the absolute number has to be taken in perspective ....

Anyway, I've seen stock 6MT 350Z's dyno about 255 to 258 on Church's dynapack. The rev up motors (298 HP) dyno around 267-268, and I saw that with two separate 2005 G35 6MTs. The two cars' runs were almost perfect overlays of each other, so even though the absolute numbers there are higher than your average dynojet, the results are very reproduceable.

Even if you're comparing two dynojets in different parts of the country, you wouldn't expect the exact same results with the same car.

So the original poster is getting about +25 at peak.

 

I dynoed both on dynapack and dynojet... my dynapack numbers where slightly lower(actually almost the same). That dynpack reads higher(or a lot higher) is a missconception. I am first witness of this and hear many stories about this as well. Same for dynojet, some read higher, some read lower..

many different setups out there, compairing and generalizing between these different setups is bad idea.

 

I think that Nathan has a valid point here. I look again at the pics I posted and see "Flywheel mode" as the header on the three graphs. This could certainly be the reason for the high numbers.

Not sure what gear they were in making the pulls or even how the gear ratio is calculated in this instance. Sorry.

Base Dyno on DynoJet

Base A/F on DynoJet

This "base" dyno done some while ago before the re-flash was done to get the A/F mixture and see if I really needed a re-flash at all. I had everything in my sig but the re-flash. These values are not corrected but after applying a smoothing of 2 for SAE correction in WinPEP, values of 262hp and 247trq result. I think all that can be said of my latest dyno is that if you figure in differences in dyno's, a re-flash, and some other fudge factor?, +16hp is not out of the question. However the gain of 20trq does seem a little much considering that my A/F is not optimal in the powerband. Maybe DynaPacks read inherently higher in torque. You can see from my "base" A/F that my re-flash brought the low and high rpms closer to 13 where 3.5-5.5k rpms stayed almost fixed at near 14.3. This means another re-flash visit and dyno again in the near future - lucky they are both 50 min away. I'm sure when the A/F is set at a nice, constant negative slope I'm sure I'll see yet more gains and a smoother torque curve. Then I can think about tracking the beast!

Whatever the numbers I've made, this has been a great discussion!!! I've always understood that dynos are only semi-quantitative AT BEST. However, they are precision machines and can be made to run reproducibly. My graphs demonstrate this result. Because of this and my re-tuning that I will do and post-up here, we can see the effects of re-flashing our cars with some degree of measure. This added to all the other dynos will show a trend, whatever it is. This is all good. Real world numbers generated by real people. This is the reason why I am a member of this board. Discussions like this can bring more insight to dyno testing and really it means to mod and tune a car. That is the reason we are all here

Now if I can just decide on some lightweight wheels and tires LOL!

 

the dynapack flywheel conversion issue is manual, not automatic as far as I know. The flywheel hp feature allows you to ENTER a correction factor. You can put a % and it will add drivetrain loss... most dynapacks I have seen had this figure set at 0% drivetrain loss (=WHP). The fact it says "flywheel" does not mean a correction factor was used. (seeing the numbers, one would think one was used... if it was, it would be interesting to know what %).