Exhaust idea

[Lumpyguy]

Ok so now I have my ride running I need an exhaust, I would like to build a nice looking/ working exhaust not just a pipe dumping out the back.

I have been looking at the Magnaflow camaro muffler 12267 its a 3" inlet on one side and dual 2.5" outlets on each end, the plan was to mount it flat under the rear trans/ bumper area with a heat shield, have dual tips come out from under the rear bumper cover on each side. after measuring it should be flat to the bottom of the car it would be seen from the rear but a nice polished muffler with polished tips i think would look nice. but my question is now power? I am not building a high performance race machine just building a fun car with slight performance but more on the asthetics side of things.

does anyone think this muffler would drasticly hurt the 2.0L performance? I am still planning a belmouth into 3" down to the muffler and short 2.5" bends out to tips?

Also my reason for this was style of muffler set up was I want to put in the FF trunk insert.

cheers

[michael everson]

I would bet you will have clearance issues. If you space it away from the under side of the car at all, it will probably be too low. I have actually hit my rear diffuser on speed bumps and such.
Mike

[Hindsight]

I was planning on using that exact muffler, but mounting it above the transmission. If mounted above, it would work and shouldn't reduce power any. There are some bends to deal with but the fact that you are going from 3" to dual 2.5" makes up for that. The hardest part is going to be fabbing the bends that go from the muffler to the tips. I ultimately decided to go with a single 3" hidden tip but if you go with this, I'd love to see it finished. I agree with Mike that putting the muffler under the trans is going to be too low.

[Harley818]

If you are looking for an alternative, check out my thread.
http://thefactoryfiveforum.com/showthread.php?14763-Harley-s-818S/page5
post #179 for pics


I used the magnaflow muffler with 3 in inlet to 2 x 2.5 outlets, grafted the 3 in to a bellmouth turbo outlet and now am working on welding the outlets. One will go up and over the trans at the back, the other almost straight out.
I had to change shifters to get enough clearance for the second exhaust piping.

[Goldwing]

I played around with a stock Camaro (2010) muffler but found that although it was a perfect shape, it was just too big. I did find a C6 corvette muffler fit. I used a Cobb bell mouth right into their cat, then around an exhaust donut and into the muffler which exits behind the passenger rear wheel. I staggered the tips to follow the bumper. I cannot report much on whether the trunk kit will fit without modifying, but the muffler sits about flush with the tranny on top. Mounts worked well with the layout. I have pics at the top of the last page of my build thread (http://thefactoryfiveforum.com/showthread.php?13026-Goldwing-s-818-Street-The-Phoenix/page6&highlight=Goldwing+Phoenix) where the last post was back in May of this year (2015) in case the link doesn't take, so you can find it. I figure it was meant for one bank of a 6.2 liter engine, so a 2.5 turbo ought to work alright. Sounded just a little louder than, but close to stock. No, it didn't sound like a corvette. :p

[thall818]

I've almost finished my exhaust. My donor came with a Cobb downpipe with cat. I was able to slice it enough to fit with cat and a Flowmaster muffler. I did have to put the O2 sensor in the muffler, but should be fine.

I had leftover pipe to make an extension once the body is on. The muffler is clocked in order to get the pipe where I want it height wise, and keep it off the frame and out of the way of the trunk kit if I decide to add that.

Not much space, but I think it will work. I still need to add a support bracket from the rear of the trans.

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[Lumpyguy]

My other option is to do a 4"-5" round polished round muffler laying horizontaly in the opening behind the transmission (Mesh opening) leave it open like a Lotus?

[Aero STI]

You might consider a vibrant oval mounted above the transmission, single 3" inlet, dual 2.5" outlet. I've been thinking about it for a while.

http://vibrantperformance.com/catalog/images/10632_WEBL.jpg

http://vibrantperformance.com/catalog/product_info.php?cPath=1022_1031_1110&products_id=1837

[Lumpyguy]

I did not want to put a muffler above the trans as I am putting in the trunk insert, I ordered my can and pipeing today and plan to put it behind the transmission where the mesh goes (horizontally) I have waynes shifter so the arm goes up on top of the trans so I have room to run it behind and have it open. I will put up a few pics when its sitting in place.

[Frank818]

Lumpy, you are going 3" exhaust on a 2.0L?
I have a 2.8L and I thinking of keeping a 2.5" exhaust. I found out after trying a lot of exhaust configs over the years on the Corrado that the 3" full exhaust was hurting low-end and since I am at low-end much often than high-end, I went back to 2.5" and felt the difference.
You want a lot of high-end hp or low-end torque?


That Vibrant muffler is super expensive!

[wleehendrick]

You want a lot of high-end hp or low-end torque?

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[Lumpyguy]

Thanks for the info, the donor Subaru had a huge turbo back exhaust it looked like 3" and the car ran great. but the exhaust for this car will be super short due to the engine in the rear I have been bouncing back and forth between 2.5 and 3" and could not really find any good info on what the best size pipe to use. it makes sense what you are saying. I think I will go with the 2.5" pipe, I am stuck with the 3" inlet and outlet muffler (paid for) but I will run 2.5" on all my pipes. how much of a difference would 2.5" pipe before and after a 3" muffler make? or will I need to get a new muffler? I am not making a race car I want a nice sounding car and maintain the performance I had with the donor car.

[Lumpyguy]

here is a rough pic of what I want to do but reversed with tail pipe in the left side.

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[billjr212]

here is a rough pic of what I want to do but reversed with tail pipe in the left side.

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unless you are planning to cut back the transmission and do a side mount shifter, I don't see how there is going to be room between the trans and the body. There is practically no room back there. I would suggest you start hanging the body before you get too invested in this concept.

[metalmaker12]

unless you are planning to cut back the transmission and do a side mount shifter, I don't see how there is going to be room between the trans and the body. There is practically no room back there. I would suggest you start hanging the body before you get too invested in this concept.

Agree 100%

[Hindsight]

I would suggest you start hanging the body before you get too invested in this concept.

That's what I did for a number of things. Very easy to set the side sails in place with just one screw per side (the same one used to secure them during shipping) and then use some clamps to clamp the rear bumper between them. Takes 5 minutes and really lets you see what you have to work with back there. I did that for the oil cooler and air filter as well as trying to figure out what I will do with exhaust.

[Lumpyguy]

that is what I did hung the body and I can actually get a 4" round magnaflow muffler back there, of course I had to cut out the rear where the vent went but It will fit and when set up with a 1 " gap between the muffler and trans block off plate it sits flush with the bumper face when you look down, where the big problem is all the pipe bends and exits, I am trying to build a clean OEM looking car and nice pipe exit, I think the more I look at this I am getting away from what my vision is.

so this being said now If I go a different direction I need to see what everyone else is running? my original plan day one was to just dump it down below the muffler so no exit or tips.

thanks guys

[Hindsight]

A hidden downward tip under the car is what I'm planning or maybe a side exit. I'll be very interested to see what you come up with though, if you choose to do something fancy.

[Frank818]

I thought of downward tip, but couldn't find a location for it, as there will be upward pressure applied underneath the car (diffuser), I don't want that pressure to be greater than the one exiting from the tip, could cause a restriction. That's all theory, but I couldn't find anything to convince me of the opposite.

[Lumpyguy]

ok here is what I have now just mocked up, the plan is a 90deg on each end of the muffler on turned back or down and one toward the turbo and what ever pipes I need to make it to the turbo, it would also give me room for a resonator/high flow cat if need be. I would have brackets coming off the trans holding the muffler so everything is atched to the engine/ trans so it acn all move together. also I might need a shield or 2 for heat protection.

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[Lumpyguy]

Ok so a bit of fabing and I got somewhere today. muffler is mounted, 1/2 inch between the shifter and the muffler body, 1.5" from the transmission, and flush with the body.

I got a exhaust tip started but need to cut it down and finish welding when set, the turn pipe from the muffler up to the turbo is sitting in place. I am waiting for the flange to come back from being cut and I will make the rest of the down pipe. also I am adding a 12" resonator between the muffler and down pipe. my downpipe is coming straight back.

Also the muffler bracket is attached to 2 of the rear transmission mounting plate bolts. So the whole exhaust,trans and engine will move together

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[Lumpyguy]

change of plans, instead of a dump out down out the back bumper I am gonna run the tail pipe around the same as the inlet pipe and bring it down under the bumper and exit in the center. I am going to have the whole thing ceramic coated and maybe leave the muffler polished. also put some heat reflective tape on the trans tail and some of the edges close to the bumper.

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Not sure everyones thought on the length? I know shorter is best but this exhaust is the same size diameter as what I had on my donor but is half as long. and I was very happy with my WRX for power.

for me its more about looks and keeping the power I had and doing something different.

[Frank818]

It's gonna look super cool with the green tape, leave it that way. lolll

[NBinSD]

I think it looks great Lumpy! I was thinking of doing something similar but went the easy route of straight out the back like many others.

[Lumpyguy]

the green tape is just to try and keep the polished SS looking nice, for me its a bit of the OCD! To me everything has to look symetrical! and having the exhaust coming straight out back off center does not look right, I wanted to go high but I want to put the truck insert in. I really just wanted to do something different just like my custom center console, electric parking brake, double hump roll bar.

[Buzz Skyline]

I think it looks great Lumpy! I was thinking of doing something similar but went the easy route of straight out the back like many others.

Wait. What? A double hump roll bar!?!? I'm gonna have to check that out.

[Lumpyguy]

It is in my build blog, Its the same mod Aloha did on his (he gave me the idea) I suits the car much better.

[Buzz Skyline]

I checked it out. You're right, it looks great. The squared off roll bar always seemed a bit wrong to me. The double humps are much better. I'm going to put on my future mod list.

[Lumpyguy]

Ok so I got a big part of the exhaust done today and It sounds great a nice deep tone and quiet idle and no raspiness.

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[Hindsight]

Wow I really like how you did the collector. For the portion over the wastegate, did you use a 2" tube and hammer it down a bit oval?

[RM1SepEx]

Video for sound like this... https://youtu.be/6SSfeUljeiA

[Lumpyguy]

I used a 3" piece of pipe to start with for the main exhaust off the flange and just made it oval and cut the side off then added and trimmed a piece to make the collector it tuned out pretty good it took a few hours, I used the flange off the FFR pipe they give you in the kit i just cut it off and opened it up. tomorrow I will finish the rest of the tail pipe.

[Frank818]

Damn, you are a great welder.

So is that a resonator and then a small round long muffler or a cat and a small round long muffler?
And it sounds not too loud?

[Lumpyguy]

its a small resonator and a round long MF muffler. it is awsome sounding very happy. I will see If I can get a good audio tomorrow

[Frank818]

I'm surprised with such a small muffler it's not too loud. But that's good!! Very good news. Fits perfect in there, man!

[Lumpyguy]

I'm surprised with such a small muffler it's not too loud. But that's good!! Very good news. Fits perfect in there, man!

Yes I was suprised myself, It maybe partially because of the length and 2 sources for sound deadning. Its about 2 times the length of most of the exhausts. You could only put the muffler in that spot if you have waynes shifter bracket on the rear, as the arm goes up it clears for room underneath.