On this note, I'm about to get my exhaust made.

2.5" cat-back, x-pipe. So secondary cat, resonator delete. Also going to extend my exhaust tips a bit further out so its a touch beyond the bumper. I get annoyed at the soot that comes out of my car and shows on the rear bumper.

Depending on how this sounds, I may or may not go and add the sport muffler.

Hey Majesticking,

I just watched your video, is your car stock. It appears that there is a power adder.

Is that so

Andy

Malbec 56 Beast wrote:Hey Majesticking,

I just watched your video, is your car stock. It appears that there is a power adder.

Is that so

Andy

I don't think he's here anymore...upgraded to an Audi S7 so he's probably on an Audi forum. He was running a 2-1/2" dual X-pipe syatem from the exhaust manifolds back. He sold his exhaust system to me and I installed it on my car, with a little modification since his was RWD and mine is AWD...a slight fitment issue around the AWD transfer case which was easily remedied with flex connectors. He was running the stock mufflers and I think he did a muffler delete on a few runs. I am running the sport mufflers which are a straight through design. It does add a little more power and sounds awesome.

I'll try to pattern mine after yours

Have you heard a Stillen exhaust, what is your comparison of the two?

Thanks for the reply

Andy

I'm middle aged so not looking for a old school muscle car sound.

Malbec 56 Beast wrote:I'll try to pattern mine after yours

Have you heard a Stillen exhaust, what is your comparison of the two?

Thanks for the reply

Andy

I'm middle aged so not looking for a old school muscle car sound.

There are two types of Stillen; axle back and cat back. The Stillen axle back and the Infinit Sport mufflers are pretty much identical as they are both polished stainless steel straight through design. The cat back Stillen replaces the resonators as well as the mufflers. Stock pipe size is 2" diameter, and the Stillen may be larger but I am not sure.

Mine is definitely louder, because I replaced the entire exhaust system from the exhaust manifolds back with a larger 2-1/2" size plus added an X-pipe. My exhaust does not have resonators either. It's definitely muscular in sound, but more refined, more Euro IMHO. I'll be 54 in August and I love it.

Based on your comment, I would go with the Stillen cat back. It's a direct bolt in replacement you can do yourself. It sounds great but I wanted something louder. There are YouTube videos you can look at and probably get a feel for the sound.

Infiniti M35 M45 M37 M56 Fuga Enthusiasts Group has a Facebook page. There's a used Stillen catback exhaust for sale - $500, if you're interested.

joined it

After reading several articles and doing research for almost a yr, I finally purchased and installed exhaust system for my 2012 Infiniti M56 S. Its a Catback system with built-in High flow dual res and it sounds great. I purchased it from Top Speed Pro and they custom build and manuf the products. It looks very similar to Stillen exhaust but $$ half and sounds much better. They originally made it for Infiniti M37 but I'm the first customer and only so far installed on an M56.

Did you have to do any slight modifications to the exhaust system since they were made for a M37? I've been looking to put an exhaust on my M56 for some time now but I want an aggressive sound but not too loud at the same time..do you have any website or contact info for them?

I upgraded to Stillen exhaust and it sounds great. I have an issue however.

I got a custom Y pipe delete with a custom 2.5" x-pipe and now am having issues downshifting at freeway speeds. When I step on the gas to change lanes for example and I am expecting the car to speed up, it hangs for a bit while the engine revs then drops it very abruptly into a lower gear. It's startling and probably not great for the car, not to mention dangerous that my car doesn't go when I tell it to.

Any idea what the issue could be? Those 2 mods listed are my only things I have done to the vehicle.

Should get it tuned after changing the exhaust...UpRev and (I think) HP can tune the M56. Tune after exhuast upgrade also improved driveability for me.

Thanks for the reply.

I had the car tuned after the exhaust and I believe it helped to an extent, but the problem persists. I intend to get it tuned again by someone from this site who has had success with this exact modification. Hopefully that will do it.

Before you spend money on another tune, I'd have the transmission checked. I don't know how well you've kept up with fluid maintenance at your odometer mileage, but that's always good maintenance. It sounds like a control issue to me though, so maybe they can reflash the transmission... Unless you modified the exhaust and IMMEDIATELY AFTER (like leaving the shop), you started having these issues.


Before doing any of that though, I'd try the ECU reset instructions shared in the FAQ and HowTo threads at the top.

I recently reset ECU and I feel like it improved things quite a bit. The transmission never clunks into gear anymore after ECU reset. Probably worth another shot.

I did have the issue IMMEDIATELY after the exhaust mod. I floored it on the way home and I was shocked by the lack of response then all of a sudden it clunked into gear like dropping clutch at 4500 RPM. Tune reduced the issue, and ECU re-flash smoothed things out further.

I'm at 93K miles. I should have my trans fluid flushed anyways. I have a couple other bits of maintenance I need to do.

When I'm in 6th or 7th gear and I go WOT it takes 3 to 3.5 seconds to get to 4th where I take off. Is that normal? I'm having a hard time remembering how it is supposed to perform.

Also considering going back to shop and reducing diameter of 2.5" X-Pipe. I'm no mechanic but some 6th sense is telling me I could be having a vacuum or backpressure issue.

Also considering going back to shop and reducing diameter of 2.5" X-Pipe. I'm no mechanic but some 6th sense is telling me I could be having a vacuum or backpressure issue.

While you are correct that exhaust modifications do affect the engine in various ways, I think you're just a victim of coincidence and bad timing. Your aggressive driving to hear the exhaust pushed the transmission control system the last few steps off the cliff.
Heck, people have gotten away with more drastic exhaust work.

I recently reset ECU and I feel like it improved things quite a bit. The transmission never clunks into gear anymore after ECU reset. Probably worth another shot.

Yeah, it might be worth another shot, maybe a professional attempt this time? Dealership transmission flash + fluid change.

I understand that the timing was odd in that the issues started immediately but:
1. Was the exhaust mod permanent? If not, I would try to reverse the changes and see if the problem goes away just as suddenly as it showed up.
2. Maintenance before modification - that's my motto.
Whether or not the exhaust is the issue, I would get the maintenance addressed as you also mention. At worst, you improve the longevity of your car with no visible short term benefits... At best, your driveability issues go away immediately after the maintenance service; plus you can keep exhaust sound if you like it.

That's how I'd go about it, so I'm not chasing my tail making changes and then spending money to return the car to a stock tune/performance.

Yea I think that is probably the best course of action. I'll update with results in a few weeks. I'm on the road for a bit for work.

- The exhaust custom X-pipe is welded, so semi permanent? I could try to go back to stock but it would be a pain.

- The maintenance makes perfect sense because it's a freebee in a way. I already should be getting the transmission oil flushed at around the 92,000 I have, and I plan to keep the car as long as I can, so whether or not that affects the issue doesn't really matter. If it fixes it, all the better.

My local shop did an absolutely fantastic job. I opted to keep the SLP loudmouth resonators I had purchased, and ran 2.5" pipe straight back, deleting secondary cats. The sound is perfect. At warm idle it is almost silent with a beautiful PUT PUT. At WOT it snarls.



I am also UpRev tuned, which helps.
Here is a cold start video with a little break in before a rev or two.
https://www.youtube.com/watch?v=XVyCHzDK0UI

Same. I had my local guy hook me up with a custom exhaust as well . I had him run 2.5" pipe from the oxygen sensor up front to a X pipe, back to the stock cans. We deleted the secondary cats, flex pipes and resonators. It sounds a like a Mustang GT with an exhaust. I also put in K&N air filter’s and the power difference is completely noticeable. From a standstill I can light my tires up and slide sideways at will. That’s with 285/35/20’s on the rear. At Rocky Mountain Speedway I ran a 13 second quarter mile.

Love the color.

paranoidjack wrote: ↑

Fri Mar 01, 2019 10:12 pm

My local shop did an absolutely fantastic job. I opted to keep the SLP loudmouth resonators I had purchased, and ran 2.5" pipe straight back, deleting secondary cats. The sound is perfect. At warm idle it is almost silent with a beautiful PUT PUT. At WOT it snarls.

Hey bro in your exhaust setup using the SLP LOUDMOUTH RESONATORS did use the stock mufflers, add sport mufflers or just did muffler delete and added tips?

Two videos:

Stock (sport exhaust) vs just addition of SLP loudmouths:


vs.

Secondary Cat delete, Y pipe delete, straight pipes (no X, Y, or H) from o2 back to the Infini Sport mufflers. I love the sound. Quiet in the right places and sounds really, really mean at cold start and WOT.

Sounds sweet! Here’s an old video of mine. A cold start to idle drop, and a few revs. It definitely has a muscle car sound in person. It sounds a lot like my bubbies new Mustage GT.
I had a valet tell me it was the best sounding car he’s driven so far the other day. Haha.

EdBwoy wrote: ↑

Tue Feb 26, 2019 12:55 pm

Also considering going back to shop and reducing diameter of 2.5" X-Pipe. I'm no mechanic but some 6th sense is telling me I could be having a vacuum or backpressure issue.

While you are correct that exhaust modifications do affect the engine in various ways, I think you're just a victim of coincidence and bad timing. Your aggressive driving to hear the exhaust pushed the transmission control system the last few steps off the cliff.
Heck, people have gotten away with more drastic exhaust work.

I recently reset ECU and I feel like it improved things quite a bit. The transmission never clunks into gear anymore after ECU reset. Probably worth another shot.

Yeah, it might be worth another shot, maybe a professional attempt this time? Dealership transmission flash + fluid change.

I understand that the timing was odd in that the issues started immediately but:
1. Was the exhaust mod permanent? If not, I would try to reverse the changes and see if the problem goes away just as suddenly as it showed up.
2. Maintenance before modification - that's my motto.
Whether or not the exhaust is the issue, I would get the maintenance addressed as you also mention. At worst, you improve the longevity of your car with no visible short term benefits... At best, your driveability issues go away immediately after the maintenance service; plus you can keep exhaust sound if you like it.

That's how I'd go about it, so I'm not chasing my tail making changes and then spending money to return the car to a stock tune/performance.

I hope this formatting comes out correct.

I just want to say thanks for your insight on this issue. I tried the maintenance before modification method and changed transmission fluid, and now it shifts perfectly. I feel so thick for getting so wrapped up in troubleshooting the mod rather than just listening to the car. In any event, the car sounds great and runs even better now! Good times ahead.

Nice. It’s always better when she’s purring.

billsindabowl05 wrote: ↑

Thu Apr 04, 2019 8:13 am

EdBwoy wrote: ↑

Tue Feb 26, 2019 12:55 pm

...
2. Maintenance before modification - that's my motto.
Whether or not the exhaust is the issue, I would get the maintenance addressed as you also mention. At worst, you improve the longevity of your car with no visible short term benefits... At best, your driveability issues go away immediately after the maintenance service; plus you can keep exhaust sound if you like it.
...

I hope this formatting comes out correct.

I just want to say thanks for your insight on this issue. I tried the maintenance before modification method and changed transmission fluid, and now it shifts perfectly. I feel so thick for getting so wrapped up in troubleshooting the mod rather than just listening to the car. In any event, the car sounds great and runs even better now! Good times ahead.

Awesome! That's great to hear, and you are welcome. You took care of some maintenance AND kept the sound you wanted.
I appreciate the update.

Sitting here in St. George Utah waiting for the wife. So I thought I’d drop a new pic

http://a63.tinypic.com/n37xoi.jpg

DKASM37 wrote: ↑

Mon Sep 19, 2016 1:46 pm

That being said I picked up 20-25 hp and nearly 2 mph in the 1/8 deleting the post cats and adding a 2.5" X-pipe into the stock rear mufflers. I gain another 2.5 mph in the 1/8 with the cut-outs open. That is about a 40 hp gain with the stock exhaust manifolds and primary cats in place.

The HPS intake tubes and K&Ns work very well for me too.

I can also tell you that a $0.25 680 ohm 1/4 watt resistor was worth nearly 2 tenths in the 1/8 on a 95°F day. IAT based spark retard KILLS the performance of these cars.

Don't take this the wrong way but I'm just gonna say what's on a lot of people's minds... "We don't believe you, you need more people"!!!

Data to back it up???
[/quote]

Tell me about the 680 ohm 1/4 watt resistor?? I recently got an 2013 M56. Is this something I could do to my car for better performance?

Hey bud - this post is from 2016 so I'm not sure if you'll get a reply

JimSim20 wrote: ↑

Tue Apr 21, 2020 2:30 pm

DKASM37 wrote: ↑

Mon Sep 19, 2016 1:46 pm

That being said I picked up 20-25 hp and nearly 2 mph in the 1/8 deleting the post cats and adding a 2.5" X-pipe into the stock rear mufflers. I gain another 2.5 mph in the 1/8 with the cut-outs open. That is about a 40 hp gain with the stock exhaust manifolds and primary cats in place.

The HPS intake tubes and K&Ns work very well for me too.

I can also tell you that a $0.25 680 ohm 1/4 watt resistor was worth nearly 2 tenths in the 1/8 on a 95°F day. IAT based spark retard KILLS the performance of these cars.

Don't take this the wrong way but I'm just gonna say what's on a lot of people's minds... "We don't believe you, you need more people"!!!

Data to back it up???


Tell me about the 680 ohm 1/4 watt resistor?? I recently got an 2013 M56. Is this something I could do to my car for better performance?

JimSim20 wrote: ↑

Tue Apr 21, 2020 2:30 pm

DKASM37 wrote: ↑

Mon Sep 19, 2016 1:46 pm

That being said I picked up 20-25 hp and nearly 2 mph in the 1/8 deleting the post cats and adding a 2.5" X-pipe into the stock rear mufflers. I gain another 2.5 mph in the 1/8 with the cut-outs open. That is about a 40 hp gain with the stock exhaust manifolds and primary cats in place.

The HPS intake tubes and K&Ns work very well for me too.

I can also tell you that a $0.25 680 ohm 1/4 watt resistor was worth nearly 2 tenths in the 1/8 on a 95°F day. IAT based spark retard KILLS the performance of these cars.

Don't take this the wrong way but I'm just gonna say what's on a lot of people's minds... "We don't believe you, you need more people"!!!

Data to back it up???

Tell me about the 680 ohm 1/4 watt resistor?? I recently got an 2013 M56. Is this something I could do to my car for better performance?
[/quote]

That is a quote from one of my old posts. My 2011 M56S ran a best of 12.2 @ 112 and put down 428 HP and 434 TQ at the tires.

The resistor is added into the IAT circuit at the MAF. You will notice one MAF has 4 wires and the other has 5. 4 wires will be in the same place on both connectors and there is a 5th extra wire. Forget which MAF it is in. The extra wire on the MAF with 5 wires gets the 680 ohm resistor soldered into it. Remove the harness looming. Give yourself ample room to work. Cut the wire in half. Put a piece of heat shrink large enough to cover the resistor and both sides of the splice and a few inches extra on both sides of the splices onto one side. Strip the wires. Cut the resisistor down giving yourself about 1/4" to work with on both sides. Solder one wire to each side of the resistor. Allow it to cool. Slide the heat shrink over the resistor and splices. Now heat the heat shrink for a nice tight seal. Now wrap the heat shrink to the harness with some electrical tape to keep it securely in place and put the looming back over the wire. You will notice the car is much more responsive on warm days.

It basically tells the computer the intake air is about 15-20°F cooler. However because the sensor still reads close to the coolant temp value on initial startup the PCM does not flag an error for the sensor like it would with a fixed resistor in its place.

My M56S, my 07 G35 Sedan, Hemi Ram, both of my Titans, my 03 Dakota and my Express van all had this modification as it works equally well on all. Made a very noticable difference for a modification that takes all of 10 minutes with the proper tools.
Wire cutter/stripers, soldering iron, solder and heat shrink. I bought a pack of resistors years ago and still have some left in my tool box. Basically keeps the ECM from retarding the timing as much from high intake temps that only exist for a moment at WOT. The air entering the engine is much cooler than the sensor reads a fraction of a second after you hammer down.

From what I remember my resistors are 660 or 680 ohm and 4.7 watts.