When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Has anyone tried twin loop mufflers on the VQ37 platform?? There seems to be a lot of room to install them on sedans at least. I've just been trying to think of a way to upgrade to a 2.5" exhaust but not have it be significantly louder than my 2.25" Invidia Q300. I've thought about the FI 2.5" setup with 18" resonators but it's still too loud for my tastes. I wonder if they used a twin loop muffler, would it be toned down a bit? If I were to replace my Q300, I would be staying away from a chambered muffler for performance benefits.
I tried searching for some companies that make these mufflers nowadays, and they're mostly all Ebay brands like OBX, except for Mugen that are very expensive lol. But there's also another company called Hytech that makes some good stuff and I reached out to them and it sounds like they would be willing to make me a couple mufflers if I wanted. I am guessing the price would be around $250-300 each.. but anyway, he sent me a few pictures of a few examples on other vehicles and it looks like it could fit on a G sedan with a competent enough exhaust shop doing it. I've even thought that I could re-use my Q300 tips since they are adjustable with a clamp. I would just have to get a shop to expand its inlet size from 2.25 to 2.5".
By the way, this is all just speculation and it's not something I'll be doing anytime soon, but eventually I do have plans to size up my exhaust to 2.5" without chambered mufflers like the Q300, as long as I can keep the decibels down enough for my tastes. And I'm not afraid to try new things. I would love to have FI use these mufflers for a 2.5" setup with their 18" resonators. Gosh I think that would just be perfect if it's a little quieter than their current mufflers they use.
This is what Hytech told me in an email:
"The canisters are 8" in diameter and the cases come in two length 9 and 11 inches but the OAL is 17 and 19 with the loops. The size is 2.5 in and out. Here is a few pics of the installs you can have the tip come out the bottom.
Or the top the loop and on either side of the canister. Just depends on the room you have. You need about 6" from the underside of the car to the center line of the tip. If you put the opening vertical like the pics. You can use any tip you like
if you can get it to fit the proper way."
I used to drool over both the Mugen & Hytech twin loops, though back in the day I was only able to afford the OBX knock off. I’ll be following your progress on this. Good luck.
Like I said, it's just speculation at the moment and if I do go this route, it'll be a couple years away I reckon, because I have plans to upgrade to two piece rotors, get a 4.083 diff, and change out the clutch + fw + cmak. BUT ONE DAY, I'll get a better exhaust haha
Or possibly I could just buy these mufflers and swap them for my Q300 chambered ones. I would still gain some power because of it's straight-through design. Then maybe later down the line upgrade to full 2.5" cat-back. Who knows?
Well I checked with Hytech on pricing and he said $399.00 + shipping for each muffler. Ouch! Guess I won't be going with Hytech. I'm thinking of these now:
They look like they will fit with very little modifications. Price is reasonable enough to try it out. I don't like putting "cheap" parts on an Infiniti. I've never been one to do that with my vehicles, so I'm hesitant to try these. But for the price, it's worth a shot I think, considering the fact that I can't hardly find any examples of people using twin loops to keep sound levels down but still see the benefits of a straight-through muffler. If I don't like them, then I'll just resell them at a loss. Or use one on my Chevy Cruze, rofl.
I've tried looking at some information about XForce. It seems they are an australian company that has fairly recently come to NA. Quality-wise, I would put it somewhere around low-medium from what I've researched. I would say they're better than OBX, which I didn't want to stoop that low. Their advertising says that they use a combination of stainless mesh and fiberglass as packing material and they're made out of full 304 SS. If they end up sounding a little "tinny" then I think my AAM RHFC and my Invidia cat-back resonators should help keep that to a minimum. It should be a pretty sweet sounding setup.
So maybe one day (soon?), I'll try these mufflers out. I can always put back on the Q300 mufflers if I don't like them. I just feel like my performance is being hindered due to those restrictive Q300 chambered mufflers. And I'm itching to try something new that will be slightly louder. I just want to hear more of that sweet VQ sound sometimes..
This is what Xforce said in an email when I inquired about the twin loop mufflers:
"Thank you for contacting Xforce. We have been a market leading brand here in Australia for the past 10 years. Our twin loop muffler is made from 304 stainless steel, and tig welded together. The internals of the muffler is perforated pipe that is wrapped in stainless steel wool, the can of the muffler then packed with glass fiber packing. We use this method as we believe it gives the best sound and performance gains for a muffler in the sizes listed."
Last edited by backman_66; Feb 2, 2021 at 09:25 AM.
The first one is a 2.25" muffler and the second is a 2.5". I'm not sure 100% of their actual dimensions, but doing a few quick calculations would show that in every scenario, the S10 2.5" has more volume.
If the S12 2.25" is:
10L x 8W x 5H = 400 cubic inches
11L x 8W x 5H = 440 cu in
12L x 8W x 5H = 480 cu in
If the S10 2.5" is:
7L x 9W x 9H = 567 cubic inches
8L x 9W x 9H = 648 cu in
9L x 9W x 9H = 729 cu in
Based off of volume alone, the S10 2.5" is bigger and therefore should have more of a silencing effect, right? In theory? But I do understand that the piping is 2.5" on the S10 compared to the S12 2.25".... and larger piping usually means more sound.
So I emailed Xforce about it, asking which muffler would be the quieter option and this is what they said:
"The S12 would be quieter of the two as it has a larger body and internals, allowing for better sound absorption."
Judging from my calculations though, the S10 2.5" actually has the larger body because of it's volume. The portion of muffler is shorter that the piping runs through though because it's length isn't as long as the S12 2.25".
What do you guys think!? I'm leaning toward the 2.5" one, even though my current cat-back is 2.25". The reason is because eventually, I will upgrade to a 2.5" cat-back and probably re-use these mufflers if they turn out well.
But if there's a good argument for the S12 2.25", I would still consider using that one instead. It would certainly fit better, although I think both can fit without much of a problem because there is a lot of space under there for sedans to fit mufflers.
I have purchased a muffler and taken some pics. It's the Xforce S12R-2.25 Twin Loop Muffler. The quality of the welds and material seems to look fine to me, although I have no welding experience so I wouldn't be able to know for sure.
I wasn't exactly sure what to expect in terms of size and dimensions just going from what I've seen online, so I was curious what this thing actually measured and how it will fit compared to my Invidia Q300 mufflers.
Well to my surprise, the dimensions are very close to the same! There will only need to be minor modifications made to get it to fit after removing the Q300 mufflers. It's nice because the inlet is 3" long so it can be cut shorter if needed to make the overall length appropriate at the outlet tip.
The only thing that doesn't seem to line up right is the outlet tip under the bumper. It's going to be about 1-2 inches too far to the right. This can be solved by locating the muffler a little further up on the exhaust piping, utilizing the extra length of that 3" inlet tip. I'm not sure if the exhaust shop will just want to cut the Q300 pipe a few inches back and weld the Xforce on, or just remove the Q300 mufflers at the flange and weld an entirely new flange and pipe back to the Xforce muffler.
The other thing I was concerned about was the overall height of the muffler with the loop up top. I measured from the bottom of my Q300 to the heat shield above and it was about 8.5", whereas the Xforce muffler from bottom to top of the loop is only about 7", so it looks like it'll have plenty of clearance and wiggle room! Also, the location of the loop that you would normally be able to see from the rear of the car will be hidden mostly by the way the bumper is designed, and you'll mostly only be able to see the tip for a cleaner look.
The bad thing is that only the S12R model has been in stock, and I can't find the S12L in stock ANYWHERE right now. So it's going to be anywhere from 4-10 weeks I've heard from talking to some vendors until I get the other muffler shipped. I was really hoping to be able to get these swapped out sooner so I can take my car for a before / after dyno. I planned to dyno it regardless so this will be a nice test to see how these mufflers affect performance compared to the Q300 on a moderately modified car. I'm hoping to see a 4-5whp+ gain.
The benefit of these compared to a chambered muffler? Maintains a level of quietness utilizing different methods of sound cancellation, good throttle response and torque characteristics, while being able to flow better under high load. Take this picture from Mugen's twin loop as an example.
Man, these are great pics of the process and analysis of these cans. So is there enough vertical clearance for these things?
The sound better be worth it, because OMG these look silly. Then again, the looped pipe is somewhat out of sight.
Side tips instead of centered. Hope this works with the bumper cut-out, seems iffy.
Yep the vertical clearance should be good. My Q300 measures 8.5" from the bottom of the muffler to the heat shield on the car. These twin loops are 7" tall.
I don't expect the sound to be worse in any way compared to a typical straight-through design used by other brands. The point is that I'll be able to keep the noise levels down under light throttle and cruising, but it should open up nicely when I want it to!
The muffler shop will have to modify the piping coming from the last flange to make these work, but it shouldn't be too hard for a decently competent welder to make the tips line up with the bumper cutouts. The 1 thing I worry about is that the shop I used to fix my exhaust yesterday, uses crush bends. That's no bueno for me. So I may need to order the appropriate mandrel bent tubing online and just have it welded onto the new mufflers to make them fit right.
Well I got the twin loops installed. I had an exhaust leak (even before I installed the new mufflers) that I had to fix to the best of my ability, before I wanted to post any sound clips. They fit pretty well, the installer had to make a minor modification to one of the exhaust hangers though. I wanted to be able to easily swap my Q300 muffler back on if I didn't like the sound / performance of the twin loops, so I always have that option. Since I've fixed the exhaust leak and gotten a better chance to hear these mufflers, I have to conclude that I do like them more than the Q300s. Keep in mind, I have the Q300 2.25" ID catback, I just swapped mufflers to get a bit more sound and flow.
I planned to have it dyno'd August 3rd to see the difference in power between each muffler, but the shop had some problems with their dyno and had to cancel. They're supposed to call to reschedule, but I don't know if I'm going to do it because it will be over $200 and I recently had to get some dental work done, so I feel guilty spending the money just to see some numbers on a screen. If anyone wants to donate, I may be willing to change my mind! hehehehe
The Q300 mufflers weighed about 19.5lbs each with the connecting pipe and flange, whereas the twin loops weighed about 12.5lbs each. So about a 14lb weight savings.
Before video with Q300 mufflers and exhaust leak (sounds louder and better than it should, lol) -
After video with Xforce Twin Loops and a fixed exhaust leak. There's a little bit of a metallic buzz that comes from an exhaust repair job where they used a pipe expander to slide one pipe inside another, so it rattles / buzzes under heavy load -
The twin loop looks great from the rear profile. It sounds like the original Invidia mufflers have a slightly deeper tone compared to the twin loop during the initial acceleration. The twin loop sounds louder but still very civil. i like it.
Yep I don't like the sound of this setup as much as the Q300s. But, I still like it, so I'm going to keep it like this for now. I really wanted to get that dyno done to see if there was a difference in power. That was part of my overall goal, make a bit more power and a bit more sound. If I do end up dyno'ing and there's no power gain, I'll probably switch back to the Q300s. My butt dyno is telling me that I have picked up some low-midrange power, it just feels a lot more responsive. It also seems like the tires spin more when shifting from 1st to 2nd during WOT.
