Air box modification - Printable Version

Air box modification - Printable Version

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Air box modification - flash - 07-02-2017

the aftermarket header has its ups and downs. i did some testing on this, when i felt something contrary to what data i had seen. it loses low end torque, but gains some hp up top. i thought it fell flat on its face below 2.5k, but definitely snappier up over 5k. it's a LOT louder. you have to weld the OEM cat onto it. it will not work with the supercharger. it is not legal in california, and a number of other states with emissions testing. that being said, you may be able to get it passed anyway, as long as the OEM cat is there and you have the D1R heat shield, because it's a lot harder to see the header.

there is a mod that can be done to the OEM header that provides almost all of the upper end gain, without the low end losses. it is not easy, cheap (though it is a lot less than the aftermarket header), or fast, but it works. i haven't done the write-up on it yet though. just too busy.

Air box modification - RS Barn - 07-03-2017

My data on both Stahl Header and my new Stainless Header has always shown Big Torque gains in mid range (2800 - 5000) and decent HP gains above 5000. I'm still testing combinations after 13 years. Helps that I tune now rather than rely on outside tuner under time constraints. I have as much dyno time as needed at a really sweet dyno with an enclosed room with temperature control and exhaust evacuation.

These results are with aftermarket exhaust with or without OE cat.The OE cat flows really well. There are now several levels of sound available. None are quiet like OE, but the newer cat backs I use aren't raspy like the previous designs and have the deep sound people desire.

Exhaust combinations should be tailored to noise tolerance and State rules.

Air box modification - flash - 07-05-2017

my testing showed noticeable torque loss in the low midrange, using a few different cat-backs. so did my butt-o-meter. i did it both with and without the airbox mod, and with the supercharger. the header alone, with no other changes to the car, showed the biggest loss. the results were substantially the same though, once you started doing things like chips, airbag mod, etc. there was a "hole" right where you typically let the clutch out, which tended to make the car feel "flat" off the line. i did all of my testing on a eddy current design dyno, as a standard dynojet cannot provide resistance to simulate real world conditions, thereby making those readings useless. to date, i have never seen any charts to indicate that my testing was wrong. in fact, the only chart i have ever seen on that header also had a chip and filter on the car, which would skew the results. it wouldn't necessarily invalidate them, as often these things contribute to each other, but it would have been nice to see a chart of the header swap alone.

this is exactly what you would expect from a 4 to 1 header, and every header designer will tell you that. that's why porsche used the tri-y. they did not want to give up the low end, and instead chose to sacrifice some top end. that being said, once you got past that point, it was fine, and did in fact show some small increases in hp above the dual resonant intake point (no torque gain though).

i did just about as well in upper end power with a modified OEM header, without the big dip at the low-mids, and at about 1/3 the cost. as soon as my hard drives and such get here, i can post more details about where to send the header, what to do, and all of that fun stuff.

that being said, if i were building a race car, or even a serious DE car (though that is a contradiction in terms - lol) i would use the stahl header, as i would not be concerned about low-mid anything, and would only be looking at everything over 4k rpm

it's all about priorities and budgets.

Air box modification - 94SilverCab - 07-05-2017

And we thought Bob was going to soften when he moved abroad...why don't you guys get a room?

Jay

Air box modification - RS Barn - 07-05-2017

Believe what you want. Many people have been to dyno with me. I don't hide results. And my stuff works. Rock

The stock 4/2/1 is very lean on part throttle and at low rpm. That's why all chips help at low to mid range .

If you install a K&N filter or Header with stock chip, they are even more dead at low rpm.

So don't mix an match mods from stock and expect good results.

But if you match chip, Header, airbox mod-results are excellent. Exactly opposite of what naysayer posted.

Expect a long detailed cross examination using many variables to counter my input. But that's expected. My access has blocked for several years and hasn't had anyone to counter all knowing knowledge. Now with new ownership, the filter has been lifted.

So for my limited time here I will tell the truth and not be intimidated .

Air box modification - az968 - 07-05-2017

So, Pete, with my air box mod and K&N, RSBARN Stage 1 chip and cat back exhaust, is there a header that would add more low-end torque without increasing noise levels past the point of "wife-tolerance"?

Air box modification - 94SilverCab - 07-05-2017

Quote:So, Pete, with my air box mod and K&N, RSBARN Stage 1 chip and cat back exhaust, is there a header that would add more low-end torque without increasing noise levels past the point of "wife-tolerance"?

I have the Stage 2 chip (Required with the header) and cat back from RS Barn. The header does add some rasp, even with the resonator (that was added when mine was installed). Noise level is more with the header, I like the sound, wifey does not complain (or the sound drowns her out, either case win/win)

YMMV.

Jay

Air box modification - az968 - 07-06-2017

It seems like there are several header options? Some louder than others? My current set-up isn't too loud so maybe a header could be an option for add low end torque? I don't need more power at high rpm, don't spend a lot of time up there.

Air box modification - flash - 07-06-2017

this one has been going on since the first day pete talked about the header 10 years ago. we will have to agree to disagree.

frankly i don't care what anybody does. i'm not in the business of selling headers, or any exhaust pieces, never was, and never wanted to be. i bought a stahl header from pete myself, very early on, in spite of what every header manufacturer said the results would be. i'm not by any stretch saying it's worthless either. i did my testing. i went through over a dozen different cat-backs trying to resolve the issues. i spent countless hours testing. i analysed the data, and focused on what was more important TO ME. i didn't like the hole, about which i complained from day 1. by the way, the stock setup also has a hole, but not quite as exaggerated. i didn't care about anything over 5k rpm, as i rarely drive there, even though there are definitely gains to be had there. i made my own decisions, for my own reasons. in the end, i sold my stahl header. others might do things differently, for their own reasons. neither choice is wrong.

my job after that was simply to post what my conclusions were, and let people make their own decisions. after all, that is the point of this site. free and open discussion about the car, products, and all that, free of biased input from vendors, unless supported by data. we never let any non-sponsor sell anything here. we insist that even sponsors support their claims with real data and information. i make room for the possibility that someone else's data is different than mine. if it was done on an eddy current dyno, and not a standard dynojet, it should be valid, i would love to see it, and if proven to be different, i would be happy to adjust my conclusions accordingly.

as for the OEM header mods, basically you have to get inside and clean up the burrs and anomalies and such, then modify the choke down spot in front of the cat, and then ceramic coat the entire thing, inside and out (you can't coat the cat though). there are only 2 places in the country though that can coat it right, and not have it wear out or burn off after a short while. it is important to note that cat-backs alter the outcome. if it is too free-flowing, you will get a low end loss. if it is too corked up, you lose top end. the big thing was that it allowed the OEM cat to be used, which provided passing emissions testing, and also did not cause things to go so lean, which also causes testing failure, and can damage valves and possibly induce detonation. as soon as my files get here, and i can get everything put away, i can dig up the contact info and such. i don't even have access to my main computer right now, as it is going through a complete meltdown. not sure if i will be able to recover everything or not. i know that i will be going through a few bottles this weekend in the attempt.

we are now WAY off track from the original topic, which was the airbox modification

Air box modification - RS Barn - 07-06-2017

There are some new exhaust options with Header to retain deeper sound of most cat back systems. This also quiets exhaust to same level as cat backs.

I built one system that was too quiet. That can actually happen now. Since returning I haven't mentioned my products until this thread was hijacked.

Now that someone is done bashing Headers. I think it is wise to move back to original thread.

Airbox mod, K&N and chip still one of the best things you can do to 968"s I still think the OE plastic piece with glove box is still available. It surrounds the airbox and keeps cool air flowing into port holes.

Air box modification - az968 - 07-06-2017

You mean the front engine shroud cover? The "glove box" reference threw me for a moment.

Air box modification - RS Barn - 07-06-2017

Yea-that

Air box modification - Kim - 07-06-2017

Yes I would like to see this thread get back on track also.

Air box modification - Kaj Hallstrom - 07-07-2017

Way off track here!!!..........let's get back to where we started..... Airbox improvements!!

Air box modification - RS Barn - 07-10-2017

I did some testing on intake temperatures measured in front of Mass Air sensor with different combinations of filters and airbox mods.. I started the car on a cold day 49 degrees F and warmed up to first coolant temp mark. Then I did several 3 mile loops with a max speed of 55mph. On the return I would always need to stop at a traffic light. The last two tests had higher starting temps due to heat sink.

The main reason for this test was for race starts. Usually cars are on grid and warmed up. At this point you get heat soak. I wanted to find out how quickly the air temps recovered to get maximum power. The cars then take off in formation and get 1-2 running laps before rolling start.

External Start Run Traffic

49 65 57 69 Stock Airbox w K&N

49 65 65 74 Airbox Mod w OE Filter

49 84 58 64 Airbox Mod w K&N

49 84 55 61 Airbox Mod w K&N and Airbox Shroud.

Air box modification - Kaj Hallstrom - 07-11-2017

I am partially done. Drilled the holes and inserted smooth rings for the flow. Also removed shroud. Now waiting for the K&N filter deal of the century. Looks like they are holding everyone hostage on the price. It's $73.99 where ever I go. Anyone know a better deal?.

Some performance improvement already noted. Small, but noticeable, maybe 5HP.

Air box modification - az968 - 07-11-2017

Based on Pete's readings, you want the shroud in place. Cooler air contains more oxygen, thus better inginion. I was surprised to see how much cooler the air at the MAF was.

Air box modification - flash - 07-11-2017

it's amazing at how much of a difference intake temperature makes. this is why it is so important to make sure that all under car pieces are in place. preventing extraneous airflow, and maximising the negative pressure behind the radiator means lower temperatures under the hood. this lowers intake temp, due to less heat soak. i did a lot of research and testing on underhood airflow management, and found a few tricks to lower those temps. remember, every 10 degrees you drop the intake temp, it's a free hp.

the D1R exhaust heat shield helps here too. a key to its design is the thermotec material. it makes it far more effective than without. unfortunately the glue they use does not hold up to the temps in that area. that's why i had to add the riveted strips to hold it in place.

you can improve things by putting a heat shield between the airbag and radiator too. thermotec makes some nice material that you can use to line those components, and further lower intake temps.

Air box modification - 94SilverCab - 07-11-2017

In case you have any doubt about the importance of cooling the intake temps...

http://www.autoguide.com/auto-news/2017/03/another-day-another-dodge-demon-teaser.html

Dodge says the supercharged Demon is the first factory production car to have a liquid-to-air charge air cooler chiller system. In Drag mode, the Demon’s cabin <a class="" href="http://www.ebay.com/sch/i.html?_nkw=air+conditioning" title="Link added by VigLink">air conditioning</a> system is diverted to chill the engine’s charge air cooling system instead, which results in the intake air temperature dropping by up to 45 degrees F.

Jay

Air box modification - gtolou - 07-11-2017

Great thread - I've used the airbox rings from RS Barn and have been very happy with that kit and their stage 1 chip.

I love the header banter in this thread. I've not gone the header route but am considering it.