miami1lt

Super...what is your speculation on what deleting the primaries will gain? I know people are gettin 40-50whp with LTs...

My concern would be noise like Brian said. Since I don't track (at least not until I leave this God-foresaken island), I'm not sure the extra HPs (and associated noise) are going to get me much other than tickets.

And Brian, I agree, the sound is just beautiful with both x pipes...I almost want to hear what the X vs. XX difference is, as I've fallen in love with the new sound, and am curious what difference the resonator removal makes. It is amazing how tied up the exhaust is stock (even though I think the stock C63 exhaust is one of the best I've heard).

superlubricity

Not 40-50. I've got a head-start with my PLM manifolds with their larger collector outlets. A nice 2.5" catless downpipe will make power over the stock downpipe with it's shrunken inlet tube and restrictive primary cat. It's just a question of how much and where in the powerband.

The beauty of this mod is it would be hot-swappable. Two bolts per manifold, one bolt on each down pipe and unscrew/screw in the O2s and you are stock or catless. To me, this is perfect for a track only application.

Brian, need me to send a deposit?

avengerboater

But then you would either need two ECUs with appropriate maps for each set-up, or something like the Renntech RAT or Cobb Accessport.

superlubricity

I disagree here. I've got some good data from the changes I've already made to my exhaust system (manifolds, x-pipe) and every time the ECU gets the A/F right. This last step will definitely increase airflow but it isn't going to be as dramatic as a long tube system with four 1 7/8" primaries going into 3" piping per side.

I'll get re-tuned to prevent CELs, but that's likely it for the first test. If the data comes back unfavorable, I'll figure something out . . . but I'm pretty confident all will be good.

BTW, my A/F @ 6000 RPM:

w/ Kleemann K1 - 12.38
+ PLM Manifolds - 12.42
+ GT PRO X-Pipe - 12.47

avengerboater

Aaaah, I see I see.

bluejae

that's a good question by Even Money...

so the XX takes the place of the sec. cat and the resonator?
the single x takes the place of only the sec. cat?

your LTs removes the prim. cat and the sec cats?

i guess i'm trying to figure out from an upgrade point. the XX sounds like something i might be interested in, but if i decide to go LT in the future, what parts would i end up with... and could it be sold for someone else to use?

will the double xx require a new tune? or is it mainly sound and not much gain?

Sincity

Didn't Jeffield replace his exhaust from the manifold back?

MikeG_C63_AMG

Brian,

Is there any ECU update/modification needed for this product?

Unbreakable1

thats correct


neither one of the pipes (single X or XX) require a tune.....also, power gains should be similar to what has been previously seen in the single X because as far as i know, removing the resonator does not free up any more power.
However, i dont think anybody has before/after dyno'd a XX...unless Brian has

Brian GT PRO

Yes, just at unbreakable1 just stated, he is 100% correct (thank you for helping me out here)

MikeG C63 AMG and bluejae: The Single X or the Double XX are engineered to be used with or without a tune, and will pick up power both ways as we've shown on the dyno. The Double XX does really make the car sound "right". LT's will not be able to use the Single X (front pre cat delete) however you can retain the Single X R1 (resonator delete), So..if you go LT's in the future, you will have a Single X to sell.

Regarding power on the "SingleX" and "DoubleXX" I have not seen much if any difference power wise adding the SingleX R-1 (resonator delete), so I tell guys that the R1 is to tune sound, not power, however I will tell you this somewhat depends on the tune as well, because on my car, the torque curve is much broader vs the "other cars" I've tested with "other tunes" when I added the SingleX R1 to my set up.

Super...LOL yeah yeah I'm working on it brother, trust me, you are my first call.

superlubricity

miami1lt

i should be ablt to dyno next week, showing K1 vs K1 + XX. i'm hoping for 10-12whp peak gain and 15-20whp mid-range. it definitely picked up mid-range...it smokes now between 30-50mph in 2d gear where after K1 smoked only 45-55whp in 2d gear. as soon as i can get back to dyno shop, you'll know the gains.

superlubricity

Miami, when you go back to the dyno, bring a USB/Flash drive and ask for all of your runfiles. When you get home, you can load them in to WinPEP (Free download from dynojet.com) and play around with the data and even make custom graphs. It's pretty cool stuff.

miami1lt

will do. yeah, i forgot the last time, and kept asking the guy to email them to me, but he never did...kept saying "tomorrow" and never got them.

I downloaded winpep and have used it a few times...it is pretty cool...between that and Vbox, I'm having a blast.

I'm going to try and run down tomorrow. Its my anniversary though, so not sure how that will go

I'm VERY curious on the power gains, because I can definitely feel it strong in the 1st/2d gear range from about 20-50...it is really pulling much harder...I just hope the results support that (and its not the sound deceiving me).

miami1lt

Results are back from dyno and NOT very good.

I went from 408whp/376.7wftlb to 395whp/363wftbl.

Run File 005 was post Kleemann K1 tune
Run File 001 was post Double XX with K1 tune (5th gear)
Run File 006 was post Double XX with K1 tune (4th gear)

if you look, the car was running really rich...my 5th gear run was even lower (384whp/356wftlb).

looks like i need a retune to get my a/f squared away...but for now, in higher gears, the Double X is costing me power

miami1lt

by the way, i still back my claim that it smokes in 2nd gear from 30-50...makes sense, because the a/f is only bad in higher gears where back pressure is gone. I still think in 2nd-3rd gears, I may have picked up some horses...esp at lower RPMs...it is the higher gears and top end where I lost some...

Does anybody know a tuner out there that can correct this on my ECU?

superlubricity

Odd results indeed. Did anything else change on the car?

How many dyno pulls did you do today? How much cool-down time did you allow between runs? I've found it takes a couple test pulls before getting anything accurate or consistent. We usually throw the first two pulls out the window because they are always very low. By the 3rd, 4th and 5th pull things start to show peak HP consistently.

Any chance you can send me the runfiles?

BTW, on one run your A/F actually looks lean in the middle, on another run it just flat-lines . . . almost like the operator didn't get a good reading from your car. No reason for the X pipe to cause that.

miami1lt

First, no other changes, just the two x pipes since the K1 install.

We did 3 pulls...the first one was 384whp, then 376whp, then 395whp...remember, my K1 was 408whp.

As for runfiles, I will hopefully get them emailed to me tomorrow...didn't have a thumbdrive today, but I will gladly let you scrutinize.

Also, yes, it was lean a bit, but the operator told me it looked like the ECU was dumping gas...if you look at the flat line that is near 15, that is the K1 only...the two where it dives towards 12 was today. The one where it dives soonest is the 384whp 5th gear run...where it takes a little longer to dive is the 4th gear run at 395whp...the dive in A/F ratio definitely corresponded well with the loss in power. I was tempted to ask him to do another 5th gear run, but it was obvious that my A/F was suffering.

I noticed the other day doing 60-100 runs that my times weren't any better than before...it is strange, because I've posted some of my best (and easiest) 0-60 times (been down around 4.5 when averaging 4.8-4.9 before), but my 60-100 times aren't any better, and may be worse...that is consistent with losing higher end power, but gaining low-mid end power in the shorter gears.

I'm dazed right now, because i LOVE the doubleX, but am VERY surprised to be losing power...can't wait for you to have a look at the run files!

Of note, it was 13F hotter in there today...nearly 95F...with the two fans running, it still could have used some more cool down time. There is a chance with a few more runs and cooler conditions I'd be CLOSE to the K1 only run...but that still shouldn't be the case...there were no gains ANYWHERE along the curve...that to me is shocking!

Even Money

Is it easy for you to get a reflash?

miami1lt

^^^i'll send it off no problem...but does anybody reflash for x-pipes? most reflashes are for o2 sensor deletes, which i don't need...i need something that makes the ecu realize it has new exhaust....any thoughts?

clktoc63

I'm anxious to see if that A/F can get straigtened out, and the temp could be a factor...but I'm not surprised that a nice full Double X may cost a few horsepower. Has anyone ever seen this on ANY other stock or tuned car?

Has anyone established how restrictive the resonator is? I thought it was fairing free-flowing.

Also, I'm anxiously waiting for the primary cat delete and single X secondary cat delete!!!!

superlubricity

Inline.

Even Money

I was thinking maybe the ECU was going bad, but don't know if something like this could happen..software hangup?

Are there other dynojets you could try?

If after going back to the dyno without getting better results, maybe try reinstalling the resonator? ..just a thought. It just still seems strange that you'd need another x pipe after you already have one closer to the motor that can properly scavenge. Maybe try some straight pipes instead?

avengerboater

You don't need a reflash for an X-pipe. The increased air flow is not significant enough to warrant adding fuel...and I wouldn't want any tune that would make my car leaner so that I can make a tiny bit more rwhp. Keep in mind that when you run on the streets, there is more air flow and your AFRs would be leaner than what was shown on the dyno. I'd rather be safe than sorry when it comes to AFRs. Yours are pretty safe, other than that one semi-lean run that superlubricity alluded to. I wouldn't go leaner to gain more power if I were you. You were aiming quite optimistically high with this mod, hoping that it would yield 10-12whp peak gain and 15-20whp mid-range...nothing wrong with that, it was just unrealistic. There's nothing wrong with that, it's just you'll be more disappointed in the end.

miami1lt

Good points...i didn't want to do more runs, because as I said in an earlier post, the garage is garbage...they did the first run with the engine speed not being measured properly...it stopped at 6200rpms at 140mph in 5th gear (as you know, 7000 and 175mph are about the norm). I told the guy he screwed up, and he said, 'Oh yeah, the engine speed is wrong".. then, before I could say "wait a few minutes", he was back at it again, and that run went for 376whp. The 3rd run, I asked him to do it in 5th, and he said 4th would be best...i said, "Nahhh, need to stick with 5th"...he did it in 4th anyway, and got the 395whp...I think in 5th would have been similar, if in fact it is running too rich. Still, at that point, I needed to get out of there.

It is the only dyno jet on the island, so I am kinda stuck with them...all the rest are dyno paks.

Would adding headers or opening up the filters/intakes do anything to help the air flow w/o a reflash?

I still feel that what i may lose in the top of 4th/5th gear I may pickup in the mid of 2d/3rd...and, I still LOVE the sound...just can't believe the pipes screw with the a/f that much!!!