CovertRussian's 05 LGT Build Thread

That is a LOT of digging. Working construction, I once had to shovel two dump trucks of sand with another guy to fill in a playground. Two days of that was absolutely horrific. And you did that by hand? That sounds like me chiseling through a dp nut by hand. Too much work.

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Yup digging it all by hand (well foot) and wheelbarrowing it to other parts of the yard. I'm also translating the grass/topsoil to my kids playground behind the house, something about clay not being nice to land on...

I have a lot of people asking me why I didn't rent equipment, most equipment was $500ish and it simply isn't in my budget, but I also sit all day so it's been really good exercise and reduced my chiropractor bills .

At this point I am glad I didn't rent anything, because I ran into couple big boulders, one of which I jackhammered, two others are TBD, I would be re-renting the equipment between the jackhammering. To top that off I found my sewer pipe, which had a cleanout that was broken and underground. With heavy equipment I would have crushed the whole sewer pipe and we would have been without indoor plumbing again (it got clogged late last year, which is actually what triggered my "must fix the house" bug ).

I get that. That's why I bought a cheap engine lift. I've used it like 7 times on 4 different days. Granted a different investment cost of course.

Well looks like you've made serious progress!

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Same way - haven't move that quantity yet (hopefully never). But sometimes it's just nice to to do stuff by hand.

There is that OT thread home improvement projects that's been dead for awhile.

I just got a boost gauge and had previously read your bit about relocating the fpr hose. Did you every fix your boost gauge needle bouncing using the old fpr port?

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I know the title is a bit of an oxymoron, a quiet free flowing exist? That's not possible right? It's been a week long progress for me to get it to that point...

 

First here is what the stock catback looks like. It's 2.4" OD at midpipe until the Y split, at which point it's 2.0" OD to the mufflers and out. This setup measured 23psi backpressure pre-turbo, 7.5psi right after turbo but before cat, and 4psi after cat.

http://legacygt.com/forums/attachment.php?attachmentid=254303&stc=1&d=1503120834

 

I had a bunch of 3" 304 stainless pipes laying around, decided to build a simple single muffler setup with it using my MIG.

http://legacygt.com/forums/attachment.php?attachmentid=254297&stc=1&d=1503120740

 

Key to keeping the exhaust quiet is using stock like mufflers, but they are usually fairly restrictive and small in diameter. I bored out the entry and exit pipes to be 3"

http://legacygt.com/forums/attachment.php?attachmentid=254304&stc=1&d=1503120834

 

Then afterwards I pulled out the two trumpets. This essentially make the muffler straight through, I could see day light from entrance, but there is that wall to break it up a little bit still.

http://legacygt.com/forums/attachment.php?attachmentid=254305&stc=1&d=1503120834

 

Everything welded and ready to be installed. I did my best to avoid any 90* bends since they restrict flow, so used all 45* bends. Later I found out that lack of the 90* bends is what contributed to the exhaust being louder then expected.

http://legacygt.com/forums/attachment.php?attachmentid=254298&stc=1&d=1503120740

 

New catback installed. This setup measured 1psi backpressure after the cat, and 20psi at the header (downpipe only measured 19psi at header). Which tells me that pre-turbo backpressure is linear and not exponential.

http://legacygt.com/forums/attachment.php?attachmentid=254299&stc=1&d=1503120834

 

Unfortunately the exhaust was still too loud, and very raspy (thanks to the equal length header). I stole a 5" Borla resonator from my G20 and welded into the straight portion right after the flex pipe. This reduced the raspyness majorly, but still was too loud for my taste and droned too much.

http://legacygt.com/forums/attachment.php?attachmentid=254300&stc=1&d=1503120834

 

Now I know why the muffler was loud, with it being almost straight through, the exhaust gasses didn't hit the walls couple times. If I inserted the entry and exit pipes past the center wall like stock does, I think it would be much more manageable. I started cutting my welded 3" pipes off, but that was starting to take too long, and I was worried it would still be loud. This is where I decided to scavenge an STI muffler from my wrecked Sentra (I've been using ~07 STI mufflers on my Nissans for a long time). Real downside to STI mufflers is they are bigger and longer, making for a much tighter fit on the legacy.

 

http://legacygt.com/forums/attachment.php?attachmentid=254306&stc=1&d=1503120834

 

This particular muffler I bored out to be 3" years ago, part of the process I pulled out the entry trumpet.

http://legacygt.com/forums/attachment.php?attachmentid=254307&stc=1&d=1503120834

 

From the large 3" entry you can now see the guts of the STI muffler. The right most pipe is the exit of the muffler, which is also a resonator (baffled). Now with this particular muffler, I bored out the next wall to be 3" years ago, then I stuck a 3" pipe in instead of the stock one that I pulled out in the previous picture.

http://legacygt.com/forums/attachment.php?attachmentid=254308&stc=1&d=1503120834

 

With the entry pipe going past the first wall, the exhaust gasses have to go to the front of the muffler, then to the back, then out the resonated exit. Well this time around I didn't have a long enough pipe and wanted to see if I can make the entry pipe stop right at the back of the muffler. This would allow some of the gasses to go straight out of the muffler (making it slightly louder and free-er flowing).

 

Here is a little diagram of the stock vs modified flow difference:

http://legacygt.com/forums/attachment.php?attachmentid=254309&stc=1&d=1503120875

 

Now that the muffler is done, I mocked it up and got it welded, along with new hangers.

http://legacygt.com/forums/attachment.php?attachmentid=254301&stc=1&d=1503120834

 

It installed a little lower then previous setup, that's mainly due to STI muffler being taller and needing to sit lower to avoid hitting the body. I think it should have plenty of ground clearance still.

http://legacygt.com/forums/attachment.php?attachmentid=254302&stc=1&d=1503120834

 

Next is the tip, it's way longer then it needs to be for the legacy, even with the shiny surround removed. Thus I had to cut the tip more, and while I was at it, repainted it to be black.

http://legacygt.com/forums/attachment.php?attachmentid=254310&stc=1&d=1503120875

 

Finally done! Here is what the final product looks like from the back.

http://legacygt.com/forums/attachment.php?attachmentid=254318&stc=1&d=1503122416

http://legacygt.com/forums/attachment.php?attachmentid=254319&stc=1&d=1503122416

 

This setup has a deep idling sound, but it's still very quiet. At partial throttle you can slightly hear the exhaust, but at full throttle it's dead silent from the cabin. This of course means it's super restrictive right? Well I was shocked to be greeted with 1psi backpressure post cat, and 20psi pre-turbo still!

http://legacygt.com/forums/attachment.php?attachmentid=254321&stc=1&d=1503122441

 

Now the next interesting thing is what I mentioned the other day, about engine loads and MAF voltages changing with exhausts. I pulled up logs from my previous setups, all from same road and very similar ambient temperatures, this got me a very interesting Engine load (g/rev) comparison...

http://legacygt.com/forums/attachment.php?attachmentid=254320&stc=1&d=1503122441

 

The first item is 2.5in downpipe and stock catback (Blue line) = Max load of 2.36 g/rev

Next is GS 3in Downpipe and stock catback (Green Line) = Max load of 2.46 g/rev

Next is GS 3in Downpipe, 3in Catback and bored Legacy Muffler (Yellow line) = Max load of 2.54 g/rev

Finally GS 3in Downpipe, 3in Catback and bored STI Muffler (Pink Line) = Max load of 2.58 g/rev

 

If Grams/s and grams/rev have any say in airflow then my STI muffler actually flows better then the Legacy one did!

 

As I mentioned earlier, my fuel was filthy rich at WOT with this exhaust, I had to increase it by 10%, but it seems fine around town (+/-3%), which means MAF scales are not too screwed up with this.

 

Power Gains

This one is a real bummer, at 82-84F ambient temps, there were no real power gains. Everything stayed pretty identical, I'll reserve my judgement until it cools down again, cause I think stock TMIC heatsoak is what's killing 80*F+ numbers.

 

I did do a bunch of back to back tuning to see if the exhaust wanted new timing ranges, subtracting 2* of timing made me loose a good bit of power and adding 2* made me not gain any power. What this means is, the engine is happy with this exact timing range, any more or less results in power loss or knock.

 

I'm a little surprised that the car didn't want any more timing or any less, I would have expected it to want a slightly different timing curve.

Well beyond what I am capable of, kudos. I'm fairly new to the world of legacies, just bought one where the previous owner had installed aftermarket uppipe, downpipe, and catback. I don't mind the sound, but my wife thinks it is way too loud. My thoughts were to initially have a resonator installed to help with the droning, but read up that it doesn't really do much for the actual dB that the exhaust produces. I am now looking to replace the aftermarket catback with a stock one. Would you recommend this for noise reduction? Also, any potential issues I might face in switching out? I know this will affect backpressure and performance, but will it be significant? THanks

Well beyond what I am capable of, kudos. I'm fairly new to the world of legacies, just bought one where the previous owner had installed aftermarket uppipe, downpipe, and catback. I don't mind the sound, but my wife thinks it is way too loud. My thoughts were to initially have a resonator installed to help with the droning, but read up that it doesn't really do much for the actual dB that the exhaust produces. I am now looking to replace the aftermarket catback with a stock one. Would you recommend this for noise reduction? Also, any potential issues I might face in switching out? I know this will affect backpressure and performance, but will it be significant? THanks

Resonator helps reduce the higher pitched "raspy" noises on cars, but the inefficiency of unequal length headers already does that, thus resonators don't seem to do much. A lot of aftermarket exhausts use too small of mufflers, there's just not enough volume in them to reduce noise.

Your options are to go back to stock, which honestly is more then sufficient for these cars (if mine wasn't so rusty I would've went back too, since gains were tiny). The alternative is to start hunting for better/bigger mufflers and paying a shop to fab it in place.

I like your license plate .

I just changed it, got tired of people butchering it either the comfy part or the STI part. Now it's a little more self explanatory.

FWIW, my wagon now has the magna-flow knock off mufflers back on the car. Mated to the stock mid pipe off my Spec B. I had the same exhaust shop cut the Y pipe they made up years ago to the stock midpipe before rear diff. those last pipes were 2.5 from the mid pipe. Now it appears to be 2" from the muffler flanges on the stock midpipe/Y to the same old mufflers.

The car is pretty quiet inside. The mufflers in the2nd photo are now back on the car.

I have one car with invidia catted dp+stock mid/Y pipe+avo (outback) mufflers, and one car with invidia catted dp+3" pipe (no resonator) all the way to the quad tip mufflers (stromung). The former is pretty quiet. Basically sounds like a stock sti, maybe a tad louder at idle. It does drone a little around 70mph which I dislike on long road trips.

The latter is definitely louder . Almost obnoxious if you gun it. I like it but definitely not for road trips.

Just realized the bottom photo are the two Pro Lab Tuning mufflers that were straight through. Those were loud and with the short tips, nasty drone on the highway.

They cut those inlet pipes off and welded them to the knock off mufflers.

Aha! The twin tip one is probably very quite:

That Q300 twin pipe was very loud on the wagon, its much better on the Spec B.

Other then the rear bumper the wagon had a catless DP at that time that was the only differences in the cars.

The cats actually help reduce the noise a lot, that's part of the reason it was louder. But chassis design has some to do with it too, on a sedan the trunk and seats sound deaden a good bit, while on a wagon it all resonates in.

I've seen sound deadening mats, would those in the spare tire space in the trunk in the sedan help reduce noise as well?

I don't have much experience with those. I've tried layering the butyl sound deadening mats, but it did melt a bit. I didn't notice a difference because my setup is quiet enough not to matter.

Thanks. Even without experience with the mats, you think that targeting the trunk would be the best location to dampen exhaust noise?

In a sedan you might want to also target seat backs, rear deck, etc. Anything letting noise into the cabin from the trunk. Who cares how loud it is in the trunk except your kidnap victims.

I've wondered about the back seat floor area. But I'm a long way from messing with interior panels.

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Covert, different topic: have you looked into this?

---> https://legacygt.com/forums/showthread.php/thoughts-reviews-getadomtune-cylinder-4-chamber-cooling-systemi-281855.html

If not, you should do some testing and see what you find

Any thoughts about it though?

I haven't but subscribed. I have to replace my two radiator hoses in the future anyway, so might just do this while I'm in there.

My biggest concern is the use of silicon hoses, silicon hoses tend to slowly leak/evaporate coolant. Leading theory is the membrane size is not small enough to stop coolant from passing through it.

Interesting. I did not know that.

As for me, my concern is the slight raise in EGTs across all other cylinders, as I mentioned in that thread.