Jimmy-D

I have been reading this closely and you all are right to be candid. You all have very good points of views.

At this point though, I will refrain from any further comment until I see the results of the (3) GT4s with (3) diffferent headers being tested within the same/close parameters. I know it may not be perfect but that will tell me all I need to know.

Nobody will be able to refute those results if it is done unbiased- at least not to my eyes

Skeptikal12

If I dyno'd my car and it "only" put out 10 more whp on a dyno with my modification, I would not care IF I was putting bus lengths on a stock GT4 in the real world.

Ultimately, it seems like a lot of coaxing and variables in play to show a certain result where the point of the mod is not for it to read out a high dyno number BUT be a faster car in the real world. Roll race these cars knowing that there will always be variables, like someone suggested pages back, and call it a day.

Jamie@dundonmotorsports

For those that are interested, take a look at the dyno study we did on the 2016 991 GT3 RS.

http://www.dundonmotorsports.com/blo...y-surprise-you

This is what weve seen and documented. Intake air temp control isn't "sock color" or some other "BS" it's the crux of consistently testing a modern Porsche and coaxing the power out of it.

We've seen this effect in our development on the GT4 as well, very early on we saw when we didn't block the air from the radiators and push lots of cool air into the air intakes the car didn't make power. All of our testing including baselines and comparative tests shown were all done the same way.

Dyno testing a car is supposed to mimic what a car does on the road. On the road the car has plenty of cool air getting into the air intakes, and plenty of air speed to carry the hot air from the radiators away.

Just plopping a fan in front and running the car isn't good enough to get consistent repeatable results with these sensitive cars.

When you're trying to emulate results from another shop and you don't get the same results, a discussion should occur, understanding why they do what they do is important.

This is why I've asked for the dyno files from the testing done at DeMan. I've asked via email and was ignored. There is fruit in sharing this data. Getting the .abg files from the two cars run with Dundon Headers would help us to understand what's going on in both the setup of the dyno and confirm that things are truly apples to apples. The onus of understanding these results is on us, getting some data from the shop that did the testing would help a lot. There's no downside to sharing the data and would speed this investigation along for the community

We strive for understanding, are committed to reporting true and accurate data and are hopeful that we can interface with open minds as we continue to get to the bottom of this...

Anyone that knows or has been following us, knows we truly pride ourselves on sharing our data with the community good and bad.

belfo

"We have logs from the first Dundon GT4 that was dyno'd at DeMan, and a few things show up immediately, Intake air temps on those runs were not stable..."

Jamie, can you unconfuse me and explain where the log data from the DeMan dyno'd car came from if not from DeMan? How does the data you got the IAT numbers from differ from that in the .abg files?

Pictures of your air ducting and fan setup for the dyno may help clarify for other shops looking to run tests on the Dundon headers.

Were you ever able to explain the difference between the Cobb Stage 0 and Porsche baseline maps? Seemed like an open variable that I didn't see solved.

Thanks.

Jamie@dundonmotorsports

The owner of the car took logs with the Cobb AP, this is where the IAT's came from. It's the only logging we've been given of a car running on a dyno outside of our shop.

An .abg file is the dyno file used by the dynapack, it stores the torque data, setup, gear ratios used, Ambient conditions etc...

Here's an phone shot, it's not pretty the cardboard and all, but it does help keep the hot air from getting into the intakes...



The cardboard is behind the front tires and to the wheel well, the fans on the intakes are on both sides and directed at the scoop to get as much air as possible. We're not doing crazy things with funnels and the like, just enough so the engine gets cool air to run on...


Nothing yet on the Cobb Stage 0 vs stock. We're waiting for MQandil to come back once he's able after the family emergency. We are hoping that after a reasonable adaptation period that the car shows a bit better results. We see adaptation needed for the 991 GT3 and RS as well as the 997.1 and 997.2 GT3RS.

For the test we're doing we'll uninstall the Cobb and run the car on a stock DME, then reinstall the Cobb...

KareemGT4

That is not true. I had a 2015 lexus RCF before the gt4 and i bought a headerback exhaust from Gthaus meistershaft. I dynoed stock around 350whp and 340wtq and after the exhaust 380whp and 375wtq approx. So those are huge gains with just a simple exhaust system. If the exhaust is restricted then the aftermarket one will make good power. The stock RCF exhaust was a joke.

John@Fabspeed

I see what you are saying in opening this up to performance packages in general competing for your dollars. However, this opens up your comparison to hundreds of motorsports shops in the world as anyone can (and have) put together exhaust/intake/tuning components from whoever to make a performance package for their clients. Every one of those shops would want the best product to fit their clients' goals, and having been around long enough would have tested and would further test different configurations to best make that happen.

There is no vested interested for DeMan to see the OP fail, his shop like countless others has the means to test and provide their honest feedback to the Porsche community for better or for worse. If anything, i'm sure he had high hopes for the possibility of providing an even better performance package for his clients using these products. Take away brand names and money from the equation, and replace them with genuine automotive passion. This forum will always be first and foremost a hub for sharing knowledge, for the rest of the community to make an educated decision on whatever they choose to research about today. There are people and vendors here on the forum that deserve the utmost respect for their dedication to motorsport and the betterment of the Porsche community, and that is what brings them business. Rick DeMan is one of those people, period. To imply otherwise for the sake of competition on the forum? That is laughable, he doesn't need to be on here nor care to waste his time with petty stuff like that. Anyone who has met Rick or been to his facility knows this to be true.

Also in regards to your performance/dollar ratio...peak number gains mean little, what matters is maximizing the delta of performance increase under the curve. If you want to truly maximize your ROI, this is what you should be looking at. Take a ride in a 4.0L GT4 with full bolt ons sometime, i'm sure DeMan or BGB would be happy to oblige. If you don't think that 4.0L's torque would smoke a bolt-on 3.8L you better get your butt dyno re-calibrated haha.

Jimmy-D

May be with their set-up we will see similar gains with Cargraphic and Fabspeed which would be ideal. Then we all will have 40 hp

OlsenMotorsports

This.

To be clear none of us want the OP to fail, on the other hand as business owners all we want is to have a high quality product with aggressive margins that we know works and we can sell. Its a numbers game for us. And while I sell Fabspeed, Akrapovic, Capristo etc etc I have zero skin in this game as far as what vendor etc. Because every customer has a different liquidity and might not want to spend X on a component.

I deal with vendors as such: I have to be able to make money, need the product yesterday, it has to work as advertised, and most importantly if in the case that something goes wrong the vendor has to have my back and support his product.

I was the first person to have these headers on a dyno back to back and I have been very quiet as of late. But the way Rick has been treated really irks me. We made the same power delta he did (actually a few HP more IIRC it was 18). In order for any vendor-shop relationship to work there has to be respect for the others abilities. Maybe we all did the dyno testing wrong? Who knows. But at the end of the day you cannot market and produce a product making claims that are not easy to duplicate. If we went back and forth (the dyno that we use is off site) to the dyno all the time to get that number we would be upside down on the job.

I think the back and forth needs to stop. These headers make a FEW more HP than the competition? Yes. Are they built well? yes. Do they sound good? yes. Those are the facts.

Also it was known that we had a car on the dyno etc. For the record no one ever reached out to us asking why we didn't make the numbers on the posted data here. Why? because we stayed off the forums is my opinion.

Rick and John are both beasts at what they do. You don't stay in business that long buy not knowing your tradecraft. Respect them for who they are. They have earned it.

My .02

-T.O.

stout

+2. What a great post.

The idea that Rick DeMan is being chided for providing hard data to the community, and doing so in such a respectful, high-road manner, is as sad as it is crazy. He is not only a shop owner who had the tools to offer the community hard data and spent his own money to do so, he is a potential customer or even dealer for Dundon.

This is not the first time I've seen "reversal truths" spun on this thread—taking a thing and calling it the opposite. I opted out of the conversation some time ago, deciding not to post my response to what I felt were plainly false and illogical statements—none of them authored by anyone at Dundon, but rather from a group of what might be termed "Dundon apologists." But now to see posts attacking Rick for not having courtesy or respect for others truly shocks me. Bit pot meet kettle?

One tuner recently lamented a new generation of GT enthusiasts, calling them "dumber and more tillable" for choosing parts from new and/or unknown suppliers with big claims and little or no track record over established companies known for quality products, honesty, known gains, and good service. I don't have a fully formed opinion on that, but I am definitely getting the sense that there is a shift here on Rennlist, one in which newcomers don't approach the forum with an attitude that they might learn something here alongside the rest of us. Instead of working with new information and discussing it, they attack the source and/or shade the data. That's not completely new on RL, but I do sense a shift. Am I alone? Can we maybe move the temperament of this discussion back to something more in the spirit of RL?

jlennox

What is a reasonable price to have my Dundon headers installed? I was quoted $500 which does NOT include before and after dynos...

The quality looks amazing by the way. Thanks Jamie!

Alan C.

John, I understand the area between the curves and I'm not interested in a DeMan motor. I narrowed the text down in an effort to help you understand.

Alan C.

That sounds like about 3 hours of labor. I would think someone could do it in 2 hours if they are familiar with the car. Dundon includes a good set of instructions with their headers which should help.

Eric5280

Can more actual owners please come forward with their experience, independent dynos, etc? It sounds like the customers are all happy and Jamie will immediately take them back if they are not. Hard to believe the turns and posts on this thread from others expressing their opinions on everything from global warming to venders posting gains without a curve. I am a willing and able buyer that is looking for customer feedback on this product which is why I am in this thread. If/when that comes through, please post your experiences. Thank you.

Alan C.

I did not dyno my set. Based on the products previously supplied by Dundon and the reviews of those products I saw no need to dyno the headers. Another RL member with a GT4 went with me to pick up my car after the install. We both felt the car was noticeably better after the install. The same impressions were shared by the tech after he went out in the car. The tech also said he didn't have to force or pry anything into place. Easy install.