Cookie cutter megaphones?

924CarreraGTP · 924CarreraGTP's Garage

I have a black 1970 911T. I'm buying some fuchs this week and I'm planning on some tires soon for the rims. After that I'm contemplating some 904 style cookie cutter megaphones for the exhaust. Has anyone had any experience with these on a 2.2T motor? On the real Porsche race cars I think the megaphones had a distinct muffler bracket. Can these megaphones really just be bolted to the heat exchangers without causing problems?

ajwans · 08-08-2011, 12:03 AM

Here's a photo of a NOS bracket:

andy

Reaper930 · 08-08-2011, 12:51 AM

GT-Racing.com sells the setup with support.

carr914 · 08-08-2011, 05:27 AM

Quote:

Originally Posted by Reaper930

GT-Racing.com sells the setup with support.

I Agree

And be ready for the Police to pull you over for the beautiful noise that will be coming from your car. But I get away with "What about all the Harley's with open-pipes"

BK911 · BK911's Garage

Would the carbs need to be rejetted?

lane912 · 08-08-2011, 06:05 AM

Quote:

Originally Posted by carr914

I Agree

And be ready for the Police to pull you over for the beautiful noise that will be coming from your car. But I get away with "What about all the Harley's with open-pipes"

this did not work for me one day standing before the man but the judge in your county may see it differently-

harley displaces about the same cc too....

carr914 · 08-08-2011, 06:28 AM

Everytime I see the Po-Po, I just dump the Clutch & sink the Revs, I have had people hear from miles away

Jeff Higgins · 08-08-2011, 06:49 AM

Stock heat exchangers, or SSI's, have an "S" shaped pipe that runs from the collector (where the three primaries merge together) back to the stock muffler. Headers do not have this "S" pipe; as a matter of fact, you can see a set of "street adapter" or "muffler adapter" pipes advertised on GTS's site that are meant to bridge this gap from a header collector to a stock muffler. Megaphones are meant to mount to headers, with that forward, collector mounted flange. Mounting them on stock heat exchangers or SSI's will place them much too far back.

Like others, I have tried megaphones in the past. They absolutely kill power on a street motor. They are, essentially, meant for 7,000 rpm and up race motors, not 7,000 rpm and down street motors. They will make your already somewhat anemic 2.2 T motor even more so. That, and they are simply too loud for a street car. Every time you decide to "play", you will attract attention from miles around, and you won't be at all hard to find.

stownsen914 · 08-08-2011, 09:51 AM

You're brave if you want to drive on the street with megaphones! I do so love the sound though ...

If you decide to do it for track or whatever, do plan to rejet the carbs. I understand that the factory jetted the T's on the lean side to begin with. Open exhaust will make this worse. It will probably not run as well without rejetting, and may shorten the life of the engine too.

Scott

924CarreraGTP · 924CarreraGTP's Garage

I had megaphones on a 1966 triumph street bike that I had. It ran better with open exhausts. What would you guys recommend for more HP in an exhaust setup? The Automotion catalog says the megaphones are bolted right onto the heat exchangers, but I agree it looks as though they would be way too long.
See I would think that more flow in the exhaust would make temperatures lower and be better for the congested muffler area.
I do understand the less torque from no back pressure. Who cares about the police or noise? lol

ErVikingo · 08-08-2011, 02:06 PM

The best but not street friendly:

Fantor · 08-08-2011, 02:47 PM

Hey 924CarreraGTP :

I am your new best friend..:-) I also have a 1970 911T and ran megaphones on it. Let me tell yea DON'T do it. Yea they sound wicked cool but low end power is gone, and I mean GONE. It's almost like driving a 911 turbo without the mid/high-end power. Super low-end lagggg. That said. Don't worry about the fuzz. The one time I was pulled over I just told the cop that the megaphones were an original optional exhaust for the year and he believed me...:-0 Anyways, I went with the M&K 2in/2out polished SS muffler setup. My 911 already had RS headers so the M&K just bolted right up. The sound is great, "a little lower end rumble then the megaphones" and I would say the low-end power is equal to a stock exhaust setup. I have no problems running idle to 6500 rpm with good pull throughout the power band. I bought my M&K from an eBay seller. After I talked to the guy on the phone I got the setup for $600.00 shipped to my house. A very good deal. Hope this helps....

Fantor

carr914 · 08-08-2011, 03:06 PM

Vrroom

TimT · 08-08-2011, 05:01 PM

If you want the look of megaphones, and don't want the headache legally or physically, you can mount a pair of Super Traps... they look like megaphones, and the baffles can be adjusted in a noise/power ratio

This is something I put together for my 914/6 with 3.2 when the Supercraps I had fell apart... the batting blew out and clogged the baffles on one side

These are Coast Fab stainless cans.. the are rebuild able, and available in many sizes..

They don't pass sound at Lime Rock, but would be fine for the street

Jeff Higgins · 08-08-2011, 06:01 PM

Here are some photos of a pair of cookie cutter megaphones on my car. I have them mounted on SSI's, but I have cut the "S" shaped portion of the SSI's out, shortening them to the length of a pair of headers. You can see how far they stick out, even mounted at the correct forward location. Add about ten inches more if mounted on unmodified SSI's or stock heat exchangers.

This photo gives a good look at what I did to modify the SSI's. You can see how far forward I moved the flange:

My motor lost over ten horsepower and twenty foot pounds of torque over the muffler shown in the third photo. Between that and the noise, I can't see any reason to run them on anything less than a very high rpm race motor.

924CarreraGTP · 924CarreraGTP's Garage

As I said, this is America, If some redneck can run his Harley with no mufflers, I can run street unfriendly Porsches all I want. We don't have inspections or anything in Arkansas.
Fantor, I got asked about that by a cop on my Triumph once and I did the same thing. I told him the '66 Triumph Bonneville TT Special had no mufflers (technically true). He said "okay" probably because he had never seen a 1960's triumph and had no idea what I was talking about, but it worked.
Ervikingo, do you build these exhausts or is this the only one you have? I like it alot. It looks to cause back pressure into the muffler connectors. I bet this is a very nice exhaust. Street friendly or even race track friendly is not something I care about. Street racing cars are not meant to be friendly to any rule book guys.
Let me rephrase my question. Whats the best outlaw exhaust for horsepower on a 2.2 liter 911?

Jeff Higgins · 08-09-2011, 05:28 AM

Yes, and like the rednecks on their overly loud Harleys, you too can choose an exhaust that just screams "dipschyte poser". This is America, and that is your right. Understand, however, that just like the fools on their loud Harleys, open megaphones kill power on street motors. Your outlaw street racer will be loud as hell, but that much easier to catch. That little 2.2 T needs all the help it can get.

Enough of that... The exhaust shown in my third photo has made more power and torque than anything else I have ever run on my car. It consists of a Magnaflow two in, two out muffler and a few pieces of mandrel bent tubing. It took me all of a couple of hours to fab this up in my garage, and maybe a total of $180 in muffler and tubing. Any decent muffler shop should be able to do the same, and have you out the door for a couple hundred bucks. In the world of 911 mufflers, that is well and truly chump change. Here is a better pic:

ErVikingo · 08-09-2011, 05:32 AM

Quote:

Originally Posted by 924CarreraGTP

Ervikingo, do you build these exhausts or is this the only one you have? I like it alot. It looks to cause back pressure into the muffler connectors. I bet this is a very nice exhaust. Street friendly or even race track friendly is not something I care about. Street racing cars are not meant to be friendly to any rule book guys.
Let me rephrase my question. Whats the best outlaw exhaust for horsepower on a 2.2 liter 911?

It is what I have on my race cars and we have yielded more power when compared to any other setup out there (and I have tried them all literally). You can get it at: 901 Shop

There is a 914 version also.

They have an X Pipe setup that sounds wicked (F1 like) but in my experience does not make as much power as their megaphones.

ninesixfour · 08-09-2011, 05:42 AM

Quote:

Originally Posted by Jeff Higgins

Enough of that... The exhaust shown in my third photo has made more power and torque than anything else I have ever run on my car. It consists of a Magnaflow two in, two out muffler and a few pieces of mandrel bent tubing. It took me all of a couple of hours to fab this up in my garage, and maybe a total of $180 in muffler and tubing. Any decent muffler shop should be able to do the same, and have you out the door for a couple hundred bucks. In the world of 911 mufflers, that is well and truly chump change.

Is that Magnaflow 11385? I have one on order to replace my megaphone exhaust.

The Coast/Burns Stainless mufflers mentioned above are nice, make good power, and are much quieter but they are about $300 each.

To the OP, I love the look and sound of the megs, and my car is 99% track, but I can't even pull it on and off the trailer in front of my house without waking up the entire neighborhood. I know it's annoying because there are a few rice muffler guys that drive by my house and I can't stand the sound and they are much quieter than mine.

In case you still decide to go with them, here is my setup. I used the shorter headers, street adapters, and 13" megaphones. You can order the megs in any length you want from Smart Racing Products.

Jeff Higgins · 08-09-2011, 06:51 AM

Yes, it is the Magnaflow #11385. I can't say enough about it. More peak power than megaphones and way more mid range. Plus, it meets noise requirements at even the most restrictive tracks. You'll love it.

Say, I didn't realize one could get shorter megaphones like that. I always assumed they only came in one length. Just the ticket for the guys who want to quick drop the sport muffler and raise a bit more hell on the weekends or something. Too bad everything needs to be drastically re-tuned to make them even begin to work.

What do you run for induction? Whatever it is (I run MFI), it will likely need to be fattened up substantially in the mid range to take advantage of the increased scavenging (and thus better cylinder filling) that the cross-flow style Magnaflow will provide.