ShakeNBake

until I see multiple products dyno'd the same day, on the same car, with the same setup, it's really just a bunch of people yelling about $5000 USB cables. The most head-scratching thing I've seen in the Dunton case is that they have "hacked" the dyno scenario to show amazing gains, and no other vendor has figured out this hack. It's not that the hack is a bad thing or that their product is not better or innovative (I think it is an awesome product), but it seems to make a massive difference in the gain reported on the dyno. That hack is essentially to tightly control the difference in temps of the air cooling the car and the air entering the motor. A 3rd party in the GT4 forum dyno'd a dundon car without using this method and it showed about the same gain you'd expect for removing the cats and using that space for longer tubes.

Here is a bit of a photo KareemGT4 posted in that thread of his car on the dyno using Dundon's instructions (I hope he does not mind). I've dyno'd a lot of cars to see perf improvements before and after, I've never done it like this. If it's a better indication of real-world use, then great - but my issue is that there is no data with everything being tested at the same time, under the same conditions, and we're all arguing about who makes the most power.

Jamie@dundonmotorsports

It's not so much a hack, as it is a way to experimentally control for the variable you're interested in, the performance modification. If you want to understand how variable the car is then don't control anything, strap the car to a dyno and do your thing... For us keeping the hot air out of the intakes is more like what the car would see on the road.

Why we did this was we found the RS was down on power when we dyno'd it stock. This lead us down the path to discover how sensitive the cars are for Intake Temps and after further discussion with Porsche engineers and Bosch engineers we understand that the issue is how the cars deal with emissions compliance as adding fuel as IAT's increase is no longer an option. (reducing cylinder pressure and by result torque output, versus adding fuel to reduce cylinder temps)

We'll keep working away and understanding how to further improve on what Porsche gave us, regardless of our popularity on the forum...

ShakeNBake

In my world, "hack" is not a bad word, it's a smart word. Work smarter I say. My point was that no one else uses this technique, and until more do, it's hard to compare.

Jamie@dundonmotorsports

Understood and appreciated.

Can't comment on when others will do more controlled experiments or if they even care to, but I agree, apples to apples comparisons are hard to come by. Best you can do is round up your buddies that have different mods and all go to a dyno together. Or it's down to investing your own time and dollars into it...

Anyone in the NW is welcome to come on over, happy to test whatever is of interest...

Likely the comparisons will happen on tracks around the country as ours and other products start to commingle in the wild...

RobbieRob

Yes, that's all I would like to see also, same day, same car, same way of testing(easier said then done,lol) of each header on the market. As I recall, KareemGT4 got his base HP/TQ using his typical way of dynoing the car, then after headers where installed is when he was told how to use the cardboard and fans optimally to gain the most,, correct? Well to me, that is like running 1/4 to get a base time/mph, but doing it in Colorado,,, Then installing my new headers and running the 1/4 again to see the gains, but this time running in Pennsylvania, different DA, way different results and showing massive gains.


I honestly think we are lucky to have such good aftermarket manufacturers that make great quality products, I'm not questioning any one product at all, just proper/equal(apples to apples) comparisons.

Jamie@dundonmotorsports

Kareem contacted us on how to do his baselines and we sent him the pictures of how to setup the car and dyno, he did this for his before and after dyno's. No shenanigans or attempts to deceive...

Also this is all covered in the GT4 area, OP is asking about 991 GT3 data. We've provided multiple dyno's ourselves, customer dynos independently and 1/4mile times... At some point the gains are real...

RobbieRob

My mistake on the wrong info I said, thought it was dynoed differently.

Jamie@dundonmotorsports

No problem, just have to be careful as this is the way rumors start and then we have a whole new bunch of misunderstanding to fix...

Alan C.

Well said

qbix

So where are those head to head runs? Stock vs headers (any manufacturer).

What I see here is just pure marketing bs.

KareemGT4

Hi, both my dyno runs stock & post headers were done same way.

I understand why DMS dyno this way.. porsches are really hard to dyno and they don't show proper gains due to lack of cool air unlike what you get on the street.

I don't understand why all the fights? Just pick the product you like and buy it.. who cares what the internet thinks? I just think my dundons sound better than the competitor products!

m42racer

The days of bolting something on, dyno testing and seeking immediate gains are over. To continue like this and say there are no gains without understanding or asking why, shows the tester has a lack of knowledge or understanding of how these new engines are calibrated.

As stated previously, the emission requirements do not allow past calibration functions to be used to control IAT, ECT and other parameters. Sensitivity of the combustion process to meet the levels of emissions allowable, require engine functions to be implements to control knock and other functions by Ignition timing, fuel injection timing, Valve timing, throttle closure, all happening often at the same time.

To test these engines today, you have to understand how they are controlled. To meet mileage and fuel consumption numbers, aero has become very important. Openings for cooling has decreased, so ECT and IAT values become critical in the algorithm.

There are very few factors that can be manipulated. Fuel grade, ambient air temp and oil viscosity. All three can effect how the engine performs. If we consider the oil and fuel used is as required by the OEM, then the only outside influences are ECT and IAT. Increase the either and the calibration has to change to control the tight emission controlled AFR and not to set off the CEL due to detonations. IAT has the biggest effect as this parameter has the biggest influence on the combustion process.

So if you want to test these current engines and come up with valid results, first you have to understand how it all works, what changes, when and why.

Alan C.

Interesting. Thanks for posting.

PhilT3 (PT3)

I bought Dundon and will continue investing because I BELIEVE Jamie and Charles are committed to true R&D in a scientific process. Controlling variables is critical to any experiment in which you wish to have accurate data.
The way modern engines are controlled via computers NEEDS to be considered and controlled in order to determine what the hardware impact truly is.
Folks who understand technology will understand that the hardware has physical limits. HOWEVER, the software has control over how the hardware is used/maximized.
The old ways of modifying and measuring a combustion engine have to change to account for the impact the software has on the hardware.
Also, I went with Dundon because of the other work they are doing to wring every bit of power out of the 991 GT3/RS.

John@Fabspeed

Dyno graphs of stock versus upgraded headers are posted previously in this thread. May I ask what you are referring to if not those?