That's what I'm thinking also I think they are working against each other

 

realistically how much of a diff are we talking in either mph/et. i've thought about this many times like why x and h but im not sure i'm ready to sacrifice marginal gains for how much louder the car is going to get.

 

who's tune are you running? You should have felt a major gain with the headers. Seeing how you barely gained 1 mph something is wrong. Most see 3 to 4 mph or so gain at least. Check your intake gaskets for a leak.

 

Oetuning file

Not sure how much it makes a difference but tonight I used m mode in every pass.

S+ was short shifting ..it would hit 3rd gear before I hit 60mph but I didn't floor it because track prep was horrible like alwas at ned.

Going to take xpipe out and run 300 cell cats and see what happens.

 

I ran this guy 3 times and beat him so bad .the slips above is 2 times we ran.




Just to give you an idea on how low ned trap speeds are.

He was trapping 113-114 all night and I was consistently 4-5mph faster.
​​​​​​
​​Also a cls63s was only trapping 112-113 and he was blown away how hard I pulled on him from 2nd to 3rd gear and he had all wheel drive and killed me off the launch.

 

if that's the case you're probably hauling the mail.take it to atco lol

 

Lol that track is a joke lol we would all trap 125 there

 

Well first of all Atco is not a joke, it's arguably the best run and fairest track in North America. Great track prep, great organization, the place is a finely tuned machine. And at just a couple hundred above sea level, which is exactly where the DA calcs even out (200').

Secondly, just stop talking about the X and H pipes 'working against each other'. That's just total stupidity. The exhaust is all going in one direction and to one place - out the back of the car as quickly as possible. The combination of X and H has worked for many others, and they're not causing clashing exhaust streams or whatever idiocy you guys are thinking of. It has close to zero effect on how fast the exhaust is leaving the car and it's not your problem. Plenty of headers cars with X and H pipes are trapping in the 120's.

Third, you don't need Hoosiers to get a decent 60'. It's pretty easy, the secret it in the tire pressure and heat. 24psi in the rear, 55psi in front. Avoid the water and do a huge burnout and hold it for 5-10sec once your up on it in gear. The launch is the trickiest part, and you have to powerbrake it just for literally a second then go. Don't time the light, who gives a sht about that. Stage, powerbrake when the first light comes down while mashing the gas, and release the brake after just a second you should launch at around 3k rpm. Sport traction with trans in manual, shift 500rpm before redline. You can do 1.7 60' on street tires. Drag radials are a waste of time unless you have more power IMO.

Finally, it takes awhile for the headers tune to really shine in my experience. The first time I went with headers I was running the same as without. It was frustrating. Each time after that I got faster. I don't know why, but it takes time for the ECU to adapt. For what it's worth, my V5 headers tune off the shelf ran way too rich. Jerry worked with me on a few files until it was leaned out and running just right.

And use race gas. Even without a 'race' tune, it's worth a couple mph.

 

Everyone is posting about this. This must be some kind of poor quality reverse engineering of the factory software.
Here's why: In the Subaru world, this whole process of after a tune you have a not so much power, but then later, you have everything it should, is all based on ignition timing.
The ignition timing has an adaptive process, based on a multiplier.
If there's knock found, the multiplier gets downgraded until knock stops.


So the first thing you do when you open up a log is you look at the status of the multiplier: if it's maxed (16), then your tune is good and you don't have knock issues. If it's 14 or so, then there are problems.
SO the OEM tune has a feature, where after each reflash, the multiplier starts at like 8 and then slowly moves up to 16.
Your experience, seat of the pants, reflects this.
However, there is a setting in the tune, a checkbox "Start with maximum multiplier after tune", you check that and skip the BS (taking a chance).
All tuners use the checkbox.
In the Mercedes world, the checkbox has not been found by the "reverse-engineers" and therefore everyone has to go through this waste of time of waiting to see what the tune does.

 

Your track is one of the best track for prep and running best times.

There is groups here that plan months in advance to go down and get together to hit that track up.its also a track that is well known for high trap speeds.its just the way there radar gun is calibrated I guess.

I will give you my car if you can get a 1.7 60 ft at New England dragway.there is ZERO prep on Wednesday street nights and the best way to describe how it is is like trying to launch your car in the rain.

Having both x and h pipes can work against each other and the placement of the pipes matters also.im not talking about top end I mean low and mid range.

 

I used to race at New England all the time when I lived in Boston, so I feel your pain. I was in an AWD Talon at the time, so traction was a non-issue. But you should be able to get at least a 1.9x which might get you closer to an 11.

I don't think that Atco traps read higher than any other track, and as a top NHRA location you can be sure that the equipment is calibrated perfectly. It's the result of consistently good DA, that's all.

I also don't believe X and H pipe placement on a 10' length of 3" exhaust pipe makes much of a difference at all actually. And low-end torque isn't a problem with your traction challenges. Your 1/8 and 1/4 traps are down, and it ain't the pipe configuration. I think your tune just needs some time to adapt honestly.

 

I did about 7 passes back to back and each pass was getting faster and faster.The 2 slips above were my last 2 runs.

I don't get why our cars are like this and is a huge pain to keep having to do this every time we run.

It was the same before headers also as the last 3 runs were the high 117s-118s before headers or race gas.

Race gas does pick up about 1.25-1.55 mph from my testing but it takes about 5 passes to really get there.

I'm happy now as I beat my best time on race gas on my first pass with just 93 but my car definitely needs tweaking.

 

If you consistently beat on your car, the adaptations will stick. Also helps if you don't flash back-and-forth a lot in my experience, or disconnect the battery. I haven't switched out my tune in over 2yrs, and my car is always ready to go.

 

fantastic explanation...if true. Explains a lot

but one wonders how "long" it takes to reach that maximum multiplier and stay there. 5 min drive? 100 miles? etc

 

Probably takes less miles if you constantly drive like youre in the Indy 500. We need to beat the crap out of our cars.

 

thanks for explaining the way to get these mct cars out of the hole. it should be a sticky or there should be a how to drag race sticky

 

They're a little tricky to get right. The thing to note on the MCT cars is that if you hold the brake boost for any longer than 2sec or so, it kicks the trans into some sort of safe mode and you're guaranteed to have a bad/bog launch. That's why you need to stage quickly, get your traction and trans settings right, step on the brake, floor the gas as soon as that first light drops, then release the brake a second later.

 

I can feel the heat starting to pick up even before i post this(you know who you are!!!!)

Even though i dont have any slips or dyno pulls to back up this statement i am still going to make it. When i was going through one of the iterations of my exhaust i had removed 2nd cats, left reso(h-pipe) in place and added x-pipe after reso...when i did this it honestly felt like it was slightly down on power than before i added the x-pipe, so of COURSE the issue had to be the h-pipe in the reso was mucking up the works so out it came leaving just the x-pipe, and i swear it felt like i lost even more power....drove it like this for about 2wks hoping she would "learn" to like the new setup but no joy....went back and took out the x-pipe, put reso(h-pipe) back in and it honestly felt like i was not only back to where i was power wise, but even that i had picked up some grunt(keep in mind that i deleted the 2nds at the SAME TIME i added the x-pipe so i had never run with just the 2nd cats deleted and reso)......take it with a grain of salt but i swear that adding an x-pipe of any kind in this system actually costs you power....my $0.02 has been added, proceed with the heat!!!!

 

Nuke incoming..

 

I'll let you know how it feels after I take mine out. I'm also adding 300 cell cats so I can't do a direct comparison.

 

Cool....

 

B61 in bound !

 

I disagree with you bud

also i dont have dyno figures to back this up but having a X at the front and a H at the rear makes the car feel very flat

but i dont have any dyno sheets to back up any losses

 

If you disrupt the balance between left and right banks you can lose power. That's been proven over and over.

 

One x-pipe is enough. What are you going to do, install like 8 because more is better?