Ok, I'm not an expert, or an engineer, and I need some explaining from someone who is!

Most consider the MagnaFlow Exhaust for our cars to be one of the, if not the most powerful aftermarket exhaust systems you can put on the car.

How does this work out? The way it T's and comes back together is just counter intuitive, and I'd really love to hear someones explination of how it makes power.

In my mind, the only sense I can make of it is that the way they exhaust gases collide at the back provides needed backpressure. But doesnt this just increase as the gases continue to accellerate?

I confused. HELP! :impatient

 

Good question I often thought the same. I Know with Mr. Webb's early exhaust design was like this but now his latest isn't. A good person to ask if he was around. I understand that the gasses are going to take the path of least resistance but why the design? So I will be interested to hear why also. -- Johan

 

Honestly im no exhaust expert either, but all i know is that the less restrictive the better for "max performance" and i mean max as in "red-line". Back pressure i do believe helps with low end torque (feel free to correct me if i am wrong, like i said im no expert) But i could honestly care less about sound and low end torque.

For one im not pulling a trailer and i dont race my car at half throttle, so why do you need low end torque? if your rpms are dropping down that much, you need to down shift. I mean it doesnt take very long to get your revs up close to red-line, and once they are there its not extremely hard to keep them up in the higher RPM range. As for sound, if i wanted a nice silent car i would have bought a caddy or something along those lines.

Side note: you only need about 2 bends in the exhaust in order to keep cold air from comming back and hitting your valve stims, everything else is normally just added to quiet the car down.

I personally do not like the design of the magnaflow, If it didnt have 90'o bends in the pipes then i think i would like it alot more. those sharp angle bends cannot be good for air flow especially at the rear where the left and right side merge together almost in a head on colision forcing the air to pop out the side exit tail pipes. The reason i believe it is one of the best peforming exhuasts at this time is due to their resonator/mufflers and the 2.5in secondary pipe used after the "T". Most other exhausts go to smaller secondary pipes after the split. (which is more restrictive) magnaflows resonator right after the cat lookes alot smaller in diamater compaired to others, who try to keep the noise down for those with sensitive ears.

Its extremely hard to make BIG gains in HP/TQ without making the exhaust louder. Be honest with yourself, when was the last time you saw a "quiet" race car? even though i hate NASCAR, their exhaust isnt exactly what i would call "quiet" and neither are F1 cars OR top fuel dragsters, which i might add have almost zero exhaust.

I am not pleased with any of the exhaust currently produced for the MCS, and i will have a custom exhaust built for my MINI when it arrives.

My exhaust will be 2.5in from the cat to the tips, but the "T" will be replaced by a (2.5 - 2.5x2) fully merged Y pipe. The rear will also not come back together flowing against each other, and there will not be any 90 degree bends.

Will it be louder? yes.
Will it make more HP? most likely.
Will it make less low end torque? most likely.

anyways thats my little rant about exhaust, funny how you brought it up, because i had been thinking about it for a while.

Edit: forgot to answer the question you asked, i think the magnaflow exhaust works better then most because it has larger diamiter pipe then most aftermarket exhaust, i also think their resonater is smaller in diamiter and their mufflers are less restrictive. as for the T and sharp bends, i think it is to help back pressure for low end torque and to help muffle the sound due to the small resonater and high flowing mufflers. The more bends the quiet the exhaust especially if they are sharp bends and the air is directed towards each other (as in the rear of the system)

 

I don't know about 'most'. Theres other units out there that are louder and/or more 'powerful', no?

LOTS of modded cars in the DC Metro area, and I can't think of one that has a magnaflow.

 

Now I might be a little off on the diameters, but I have this design with my INVIDIA system. The main pipe Y's off to two serpent-like pipes with no 90 degree bends, and the pipes never come back together to flow against one another. I'm not saying that you should get this system, but I think that there are several out there that meet your requirements without you having it custom-built. But, hey... it's your ride. Do what you want and enjoy it!

 

This probably doesn't help you much, but I love my Magna Flow. Put it on 2 weeks after I got my 05 MCS--nearly 2 yrs ago. I came from a C5 Vette with straight pipes (SLP Loudmouth) and couldn't handle the quiet of the MCS. The Magna Flow wakes it up. Note my signature. "Trumpets" rule. PS--soon to be 63. Who says old farts don't like loud exhausts? Of course my hearing isn't what it use to be .

 

AggieMCS,

I thought the INVIDIA exhaust system was 60mm all the way through, isnt 60mm 2.3 inches? (or is my math off? ) Also im not having my exhaust run out the center, im gonna have it split using the palouber rear valence. This will also eliminate 2 bends after the rear cans. (1 bend to turn the pipe towards the center and 1 bend to turn the pipe out the exit hole in the center) Mine will come off each can straight out the exit hole. I can also make the system for about $400-$500 and save a little coin. Another perk will be that its a little different then the cookie cutter exhaust systems produce by aftermarket. Im not saying there is anything wrong with them, because im sure alot of R&D has gone into them, i just like being a tad different.

 

right on man

 

I have had the Magnaflow since early '03. The only other Mod I had at the time was the CAI, w/ "webb dremel'd out cowl intake." I felt a small increase in overall power.

I'm not sure what I would feel if I changed the "T" to a "Y" as the flow area is doubling at that point. Turbidity of flow certainly plays a role, but how much I don't know, im sure a hint.
All I know it the Magnaflow still makes me smile when I put my foot down after all of this time and tells the neighbor kids to get out of the way. I do have to laugh when it trips vibration car alarms in a parking structures.

Oh, and it sure is pretty.

 

TonyB has NO BENDS

 

Mini Mizer is on to something. He is describing the custom made exhaust that goes with my headers. I exit it at both sides. I use Magnaflow products.

 

I have the Magnaflow and I was actually planning on using the paloubermini valence and having the Magnaflow modified to be a dual exhaust. Shouldn't cost to much since it will use the existing mufflers and tips. I figure eliminating the two bends on each side should give a little more freedom and make it unique

 

you also custom built your own exhaust?

im thinking about using spintech mufflers left and right side, with no muffler/resonator after the CAT.

think it will be loud?

i just havent decided on what tips i wanna use, i want to get some and paint/powder coat them black. Although it might be hard because i wont know what size to get or length until the exhaust is bing built on the car with it up on the lift. kinda hard to powder coat them when they are welded on.

 

I had to design a custom cat back to work with my headers (but not the MTH headers). I do a few custom parts that are on the web site but none of them come cheap.

 

I was actully thinking about doing that for a long time. But i cannot stand the "T" that the magnaflow has. It just urks me. I figured if i was gonna change all of that, i might as well have something custom-built.

Also, this may come to you as a shocker, but i plan to build mine out of alumanized steel. Not stainless steel, why? because alumanized steel is alot lot cheaper, and its what almost every modern car has on it from the factory, and will most likely last longer then i will actully own the car. Also if it needs to be fixed/replaced, it is cheap.

None of my exhaust parts will be polished either, I dont need $blingbling$ under my car where no one can see it unless they are changing the oil. This will also cut down on costs.

I believe the exhaust system i am going to build will run me about $400-$500 including the labor to build and install it.

Mufflers i plan to use (2.5 in 2.5 out center) $79.49 (x2)
http://www.drgas.com/store/product.p...8&cat=9&page=1

Y-Pipe i plan to use (2.5 - 2.5x2) $79.95
http://www.drgas.com/store/product.p...&cat=14&page=1

this Y-Pipe by far is the best looking fully merged Y-pipe i have seen, i like it alot better then any i have seen on any of the after market systems currently. The split section is not short and stuby, but a full merged unit.

Now i just got to think of what tips i want to use.

Suggestions?

 

That looks like it will be a nice exhaust . Since I have the Magnaflow already, I will have to live with the "T", but I think it will make a nice system even better. Hopefully, someone here can weigh in who has more knowledge than I about modifying the Magnaflow into a dual exhaust.

 

Mizer, you might want to consider just doing a single sided exhaust if you are thinking about a custom system. There are several around my area that had a single sided system done and they sound amazing. They have used a Magnaflow muffler and resonator. You could then go with the 3" system.

 

Just a suggestion for exhaust tips. I have dual square intercooled Borla tips on my 67 mustang. They look pretty cool on my mustang, but I went a sport exhaust from Borla for the MINI. I was going to build my own exhaust but I got a decent deal on a barely used system.

 

Interesting. Magnaflow is a pretty big company with stron R&D. I think the designed a pretty good system. AFAIK it has consistently dyno'd better than all other CBE systems available to date. The WMS is an anacronysm as of now as it isn't in production. I would be surprised if you can put together a system that meets the above stated goals. It certainly is big to you for doing your own thing though.

As far as the exhaust tubing coming back together at the tips ala' Magnaflow and the WMS design. Randy built a prototype that did not do this and it increased the backpressure and thereby reduced overall HP gains. This also was why he went to a 3" system and not a 2.75". Less back pressure and more power. FI cars are a bit wierd and especially SC as they don't seem to need that backpressure a tuboe needs to generate max POWA.

Good discussion. Noce to see one here again.

 

What size mufflers did randy use? the spintech mufflers are: 4x6x12

I also dont plan on using a resonator right after the cat. Straight pipe all the way back to the merged split, and then 1 muffler on each side.

The reason i said 2.5in exhaust system, is because i honestly do not know how much room the mini has for pipe, (i dont have my car yet to check it ) but if the mini can stuff 3 inch pipe under it without problems then i may make the same system i previously stated, except with 3in piping and not 2.5

Because the mufflers/Y-pipe i want will not very in price do to inlet-outlet size. woohoo!

and i would think that not having any bends at all after the two rear mufflers would reduce back pressure, instead of comming together sharing the same unit?

And about the single exhaust...

Although they are lighter, i believe the dual split exahaust works better. Because after the split in the exhaust the volume of the two pipes combined is alot more then 1 single 3in exhaust.

Just an exmaple not actul math:

Its kinda like having a full 2.5in exhaust system that splits. Except when the system splits the volume of both pipes combined is larger then a single 3in.

sorta like two 2.5in pipes = one single 4in pipe.

(again this isnt actully calculated math, just an example. If anyone is good at math feel free to find out the combined volume of two 2.5 inch diameter pipes and two 3 inch diameter pipes and let me know what the over all combined volume is compaired to a single 2.5 or 3inch. )