These have some of the highest gains for headers in the C8. I’m wondering who has them, whose dynod them or who has a seat of your pants opinion?

They just released a new dyno vid 3 days ago

Claims Gains up to +25 WHP and +27 FT Lbs of TQ.

 

Hard for me to believe any headers showed that kind of gain on a C8 all by themselves but I have no first hand knowledge. I watched their video but am still skeptical.

 

I found it hard to believe but they are reputable and they replied to many comments asking if you’re bone stock and add these as you only mod they’re pretty confident at 25whp

 

Well....it appears that horsepower and torque is there. But I would like to see how those gains translate to any track. You would have to feel the additional power across the powerband.

 

First let me say that I like Paragon as a company and I like what they're trying to do with their videos and testing.

I admit though I'm torn with their videos because on one hand they say the right things that they are data logging with hpt to make sure starting iat are the same etc but then they are using the STD correction factor which inflates all numbers by about 4 percent as well as the highest level of smoothing of the results (level 5)...


.

Then for some reason when they show the "all stock except headers" car on the dyno you see a titanium full flow through exhaust on it. They said that's for the video just to show off their exhaust but it wasn't on the test car. If you're trying to show and explain in each video (which they do) how they controlled for conditions why show a video of a run then with the car in a different configuration than you tested?



They've also been using the same "stock" dyno run for all of their videos since the started....

The air filter shootout...





The air intake shootout....





Now the headers....






I'm not saying they are doing anything improper. It's "fine" to use the STD factor that gives higher numbers if you apply it to all runs as they'll all be corrected the same way.

But you'd have to ask why use the same "stock" dyno run AND the STD factor and certainly one reason would be if you did 12 stock runs (which you should if you are trying to do power testing) and decided to keep the lowest "stock run" for comparison purposes instead of the average of all controlled-condition stock runs.

But the problem with taking a low stock run is people might notice it looks a bit low on the dyno jet. In this case SAE corrected that stock run might be around 423whp.

Again not saying this is at all the case. Maybe their 435whp STD run was the median valued run or mean valued run (roughly) that they did for stock runs. Maybe they messed up and just did one stock run when we know this car continues to make power through at least run number 3 on dynos without any mods done to it. Maybe anything. it's just very hard to do dyno sessions without significant error rate that goes uncontrolled.


That's a long winded way of saying yes it would be great to see folks use a testing ground and a vbox and test 40 to 100 mph or 60 to 130 mph before and after each modification as that will give us a better idea. 0 to 60 times and quarter mile ET will not.

 

The fact they have 2.5" outlet flanges, which is smaller than stock, immediately rules them out for me.

 

Perhaps I'm a bit jaded (after almost 6 decades rebuilding cars) but this thread prompted me to watch only my 3rd YouTube video, and then I watched more of their product videos, they seem to be consistent in the way they test though I have to wonder how you offer airboxes to customers that essentially do nothing by your own test results. I own a few companies one supplies telecom equipment to companies, groups and government agencies. We get manufactures all the time wanting us to try the next big thing. Rarely these units end up being better than what we already offer, so we say no thanks. From what I see, we would be saying no thanks to a lot of products they offer since they don't seem to do much of anything and cost hundreds of dollars. That being said I'm sure people buy the stuff anyway.

 

Oh nice catch @Kracka I almost missed that on the product page. What does this mean performance-wise from your experience? GM did a great job with this car as evidenced by the hit or misses with aftermarket versions, with some even losing power lol. I was looking at these before I read your comment, so likely going for ARH at this point. Snowblind swears by em

 

Kooks loses power because of the restrictive outlet flange and Paragon's being smaller than stock definitely has me concerned. My opinion is that there are two good header choices for the C8, being aFe & ARH, and the rest are a pass. The two I mentioned also happen to be CARB-approved as well which is nice for the guys who need to stay 50-state emissions legal. I personally have aFe's titanium ceramic coated headers on my car.

 

Nice thanks sir! Yeah from my limited understanding you can go smaller and try to pick up torque in exhaust parts, but you sacrifice top-end hp in doing so and a lot of the time under the curve too. Probably best to stick with one of those you mentioned. GM probably made it that diameter for a reason. Thanks again

 

I asked Paragon for this and this was their reply:

“We're using the same factory flanges as the step up to 3in is wihtin the cat itself. If we were to do a 3in set up, it wouldn't re-use the factory gaskets.

 

That is not accurate. aFe has 2.75" header outlet flanges for which replacement Genuine GM gaskets are included. Paragon is free to use whatever flange they prefer so I'm not going to argue that with them, just stating facts based on my personal measurements and install. By comparison, ARH has 2.875" outlet flanges and does not reuse OEM gaskets.

 

I also appreciate what Paragon does, and there's nothing wrong with STD correction IF all runs are shown using STD. Yes, it inflates the numbers slightly vs SAE (the better correction factor), but again as long as they are consistent in use, it's fine. The bigger concern is as you pointed out, that they are using the same baseline for comparison for everything. Assuming they put the car back to stock for each different part tested, you're still going to get changes to the car between runs over time, especially if it's being driven as the fuel trims will adjust, the quality of gas from tank to tank will change, the spark plug wear will change, etc. And yeah, on top of that, are they cherry-picking the lowest stock run to compare to the best modified run. Ideally, they should be doing several baseline runs right before they install the part (i.e. 3 runs), then install the part, do the after runs (again doing at least 3 runs), and compare the average of the before runs to the after runs. I bet you'd find the difference is much less than advertised doing that.