Megan Racing Downpipe Opinions

[RED TREAD 97]

I just orderd, a Megan Downpipe. It is listed as a 3" but I am wondering if it will work well with a 2.5" catback I already have on the cat. I feel like the size drop from 3" to 2.5" will have a negative effect on the turbo. Guys please let me know before I spend a bunch of money on a set up I may have to change.

 

[blcknspo0ln]

Ideally running a 2.5" MR o2, 3" downpipe, back to a 2.5" catback will hinder flow. Kind of like having 2 lanes on a highway, to 3, and then back to 2 within 200 feet. In reality, it really shouldn't be an issue (or at least not a negative effect).

 

[snowborder714]

I'm currently running the MR downpipe into a 2.5" Tanabe exhaust. Yes, it's possible, but I will be upgrading to the MR exhaust because of the downsizing between the dp and catback.

 

[RED TREAD 97]

Do you suggest I change the catback to 3"? The issue with that would be my muffler inlet, it's a 2.5"

 

[snowborder714]

It would be beneficial to mate a 3" catback with the MR downpipe. This wouldn't be restrictive as the 2.5" catback would be.

I'm not sure what you mean by your muffler inlet is 2.5". If you're talking about your current muffler size, that wouldn't matter because if you bought a new catback, it would have a muffler already on it.

 

[RED TREAD 97]

it's not a complete cat back.....the pipe is shop made and mated to a MagnaFlow Muffler. Homemade Catback.....if you've seen the muffler its the one with 2 2.5" outlet tips, the inlet side is a 2.5 inch also.

 

[snowborder714]

I would say just replace the whole thing. If you buy a new catback, you'll be all set. If you build one, you'll have to get a new muffler. You could do a neck down so that it fits in the muffler if you build another catback, but that's just adding another restriction.

 

[1gDSM4g63]

If you have a 3" downpipe but a 2.5" cat-back you're going to get to same performance as a 2.5" exhaust system. To get the best result you got to have a straight flow diameter exhaust without any restricting i.e. dual muffler outputs.

 

[RED TREAD 97]

Yeah, I think I'm gonna keep the 2.5" catback, luckily the muffler is a dual 2.5".... I guess I'll try it out and make any changes as they are needed. Another thing too...should I wrap the whole thing in heat wrap? I know the MR stuff is bare (ie no heat sheild) I already bought the wrap, but want some feed back on the idea of it.

 

[snowborder714]

I only wrapped from the flange to the flex section. I really don't see a need to wrap the rest of it. Here's a picture of what mine looks like. It's wrapped in Thermo-Tec 2" Generation II Copper Header Wrap and then sprayed with a few coats of Termo-Tec Aluminum Hi-Heat Coating.

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[RED TREAD 97]

OH MAN!! That looks sweet!! That's all I plan on wrapping too. Like you said, there's no need to wrap the rest. I would like to get the wrap for the hot half of the turbo, and I also need to wrap the MR O2 housing, since it is exposed. Do the clamps cause any clearance issues while installing the downpipe?

 

[snowborder714]

If you're talking about the worm drive clamps on the downpipe, no, they don't cause any clearance issues.

I can't say I've ever heard of someone wrapping the hot side of a turbo. And depending on how the O2 housing is, you might be better off getting it coated (ex. Jet-hot). But you'll most likely have to get the 1" version of the wrap as the 2" will probably be too big.

I also wrapped my J pipe which is another thing you can do.

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[RED TREAD 97]

The TurboWrap is a kit that DEI makes it's like a fiberglass bag covered in aluminum sheets, it laces around the hot half and leaves the cool half exposed. Supposed to keep the heat under the hood at bay. I'm gonna wrap the J-pipe too, thats a great idea!! if I have any left I'll do the up pipe too. Just to look obnixious.

 

[RED TREAD 97]

Guys thanks for all the help!! I was thinking about one more thing. All this and all I run is 15lbs on a small 16G. That piping should be good right?

 

[1gDSM4g63]

luckily the muffler is a dual 2.5".... I guess I'll try it out and make any changes as they are needed.

I don't see why that's lucky. A single pipe exhaust system and a muffler 1-to-2 causes restriction.

 

[RED TREAD 97]

I'd love to run a straight pipe but I'd risk sounding like a bucket of rice. Like I mentioned, I'll make what ever changes I have to make. I really like how clean the dual tip looks, especially out of the MagnaFlow, almost looks like stock on steroids.

 

[snowborder714]

Guys thanks for all the help!! I was thinking about one more thing. All this and all I run is 15lbs on a small 16G. That piping should be good right?

That's the same setup I'm running (just not as much boost yet as I'm maxing out the stock injectors at 8psi). Works fine for me.

 

[blcknspo0ln]

I'd love to run a straight pipe but I'd risk sounding like a bucket of rice. Like I mentioned, I'll make what ever changes I have to make. I really like how clean the dual tip looks, especially out of the MagnaFlow, almost looks like stock on steroids.

Pictures of said exhaust please.

 

[turbosax2]

I also wrapped my J pipe which is another thing you can do.

Just a quick note on this. snowborder714 is my brother. The main reason we wrapped the j-pipe is because it sits EXTREMELY close to his FAL fans because of his thick Koyo radiator. We didn't want to take ANY chances melting those nice fans, so we wrapped the j-pipe.

 

[talonDSMerr]

is a dual tip exhaust really going to cause that big a restriction? i'm looking at a 3" inlet, 3" dual outlet muffler to go with a full 3" exhaust, would that cause a noticeable difference?

 

[jongreene]

Im running dual 2.5in outlets and notice nothing hindering performance.

But ofcourse any kind of full exhaust with a muffler will perform less when compared to say an open DP.

 

[blcknspo0ln]

Just a quick note on this. snowborder714 is my brother. The main reason we wrapped the j-pipe is because it sits EXTREMELY close to his FAL fans because of his thick Koyo radiator. We didn't want to take ANY chances melting those nice fans, so we wrapped the j-pipe.

That's pretty cool, I just put 2 and 2 together. DSM brothers, wicked.

 

[mochilli]

If you have a 3" downpipe but a 2.5" cat-back you're going to get to same performance as a 2.5" exhaust system. To get the best result you got to have a straight flow diameter exhaust without any restricting i.e. dual muffler outputs.

im about to get a 3' cat-back system, i already have a MR 3' downpipe. I wanted to keep the muffler looking the same (2 outputs), because i don't want that ricer look with a one big ass output. You're saying im gonna lose some performance from that?

 

[Cnock]

Did anyone have any problems with the MR downpipe attaching to the 2nd gen O2 housing?

 

[mochilli]

Did anyone have any problems with the MR downpipe attaching to the 2nd gen O2 housing?

There shouldn't be any problems, i havent read ANY posts about this problem and i've been researching exhaust for the past 3 days now so you should be A-ok. Obviously use a new gasket and also spray your bolts with PB blaster a day before you are going to do the install