Vadim @ evosport

Pocholin: Sorry we went off topic. I would find a shop that has mandrel bends and have your pipes redone. From your MPH you have lost about 10HP.

The humidity can definitely have an effect as well.

Jeff: The problem with Termination Box is where to put it. There is very little extra room under the car. It might work, but it needs to be tested.

Vraa: You can, the key is the velocity in the first 3-4 feet after the head port.

pocholin

I talked to a couple of friends and we don't seem to have an exhaust shop that does mandrel bending in Houston, I'll wait a little longer until we get better weather (not so humid) to do something else with the car.

speedybenz

Pocholin,

Could I talk you into having a Flowmaster SUV 50 or another model with a very high flow rate installed where the stock resonator was.

Then put a 2nd Flowmaster where the tail pipe muffler is at. It also needs to flow at a high rate but not as much the one located at the resonator location. Say 850cfm or so.

This would answer a lot of questions conserning an Exhaust Termination box placed at the stock resonator location.

The pipe between the two mufflers needs to be 3" in diameter.

Jeff

pocholin

hmm, interesting. . . let me think about it.

stephens

Pocholin
have you had a close look at the mid muffler that was removed? It should be a straight through item that causes very little back pressure. I removed mine, mostly for the sound, on my old E55, but understood at the time that there would be very little if any performance gain from the modification. You will get better results out of a custom dyno mapped ECU setup for premium unleaded. I saw a better than 20Kw rear wheel power gain from this.

Autostream

I disagree, The weight savings alone was well worth the mod.
I removed EVERYTHING. SAVED OVER 75lbs which helped my quarter mile time alone. I will post pics in a few minutes

also, the ricer school of thought that applies here is that if it sounds faster it goes faster too ;-)

Autostream

here you can see from the manifold to the aftermarket muffler including the custom crossover.





Remote o2 sensor mount and crossover


where mid muffler used to be. SAVED ~30lbs in this area alone


Kinks, bends, restrictions YUK!


look at the size of this thing!


dual chamber Flowmaster for a BMW X5 with stock AMG tips .
Now it sounds like a Stock Zo6 Vette. I have some videos with the sound I'll post in a few days on my site

Autostream

now i know this is nowhere near a perfect computer designed free flowing high performance exhaust. But it did 2 things perfectly. It saved considerable weight AND it changed the sound!. Had it done just one of those things I would have done it anyway.
I am more than happy. And if I get any performance gains, well thats just gravy!!!!!!!!!!!!!1

COST: $850 boo-yah!!!

pocholin

I agree, but weight reduction is a nice thing, and remember, I'm experimenting with it.
I've noticed that shifting has changed in the car, this used to happen on my impala when I removed the plugs from the cut outs and there was much less back pressure, so I'm assuming it is affecting the car, for good or for bad? I don't know yet.


Autostream, here in Houston I don't have anybody to do the state inspections for me, and I need those cats there, otherewise I'd do what you did. 75 lbs less is nice!!!

nukblazi

Autostream- try to be nice to some of us lesser folks with Dialup. Please reduce the size of those images

Ouch, thanks.

speedybenz

Autostream,

Nice stuff. Are you going to have a full header built?

Also what are the size of your exhaust pipes you are now using?

Did you use a merge type pipe section to attach the stock manifolds to the new exhaust piping?

Can you measure the pipe diameter of the stock system in 4 to 5 locations for us curious people?

Jeff

speedybenz

Pocholin,

Did I talk you into the dual Flowmaster set-up. I really think it is worth a try as it will be much different than othet exhaust systems on the market and may be the hot ticket.

If I were modding that part of my car right now I would perform this mod.

Go ahead and try it, Please, oh, please.

Jeff

pocholin

I still haven't made up my mind on what to use, that would be about the same weight as the original set up instead of shaving some pounds.

I also measured the pipes on the resonator (and it doesn't look like a straight thru), ID of pipes are 2.25", OD of pipes 2.38" (or something like that).

speedybenz

Buy using a Flowmaster you wont gain that much weight and the opportunity is there to pick up several Hp.

With a pipe diameter so small a Flowmaster in the Resonator location with 3" tubing will really reduce backpressure and by running 3" tubing to the rear muffler you again keep backpressure to a minimum.

Its a question of save 30 lbs and no Hp gain, or save 10 lbs and pickup 10Hp or more.

Jeff

pocholin

OK, I was checking flowmaster's website, they only make dual in and dual out on Series 70 and 80, series 70 is mild/deep sound, series 80 is aggressive sound. Like I said before I don't want it aggressive, I just want less back pressure, so, IMO one series 70 muffler will do.

Series 70 have 2.25" inlet and outlet pipe
Series 80 have 2.50" inlet and outlet pipe

What do you think? Suggestions....

speedybenz

I think it would be best to run the 80 series at the resonator location and then (2) smaller flowmasters at the tail pipe. Again running separate 2.5" piping from the series 80 back.

Or you could run the Series 80 in the resonator location and two 4" diameter by 2.5" core magnaflow or dynaflow mufflers at the tailpipe. There is plenty of room for the two (2) smaller mufflers in the stock tailpipe location.

And remember you are testing and it takes a little work to get things worked out for the best. But when you do it is very rewarding, as I am sure you know.

My guess is that your testing will lead to a complete rethink of the way performance catback exhaust systems are engineered for performance Mercedes Benz, which typically use the Std. Remus, AMG single muffler for their pretty end tips.

Jeff

mbmb

Vadim,

Can you explain this to me? Vraa asked if you could have one big pipe, and you gave the above response. Did you mean that after the first 3-4 feet after the exhaust port, you could have one big pipe?

I ask because my recollection is that fluids will flow slower through a bigger pipe than through a smaller one (think about pushing the same volume of water through a fire hose or a garden hose). Smaller pipes will increase gas velocity, but will also increase backpressure, which is generally not a good thing. Larger pipes will decrease backpressure, but also decrease velocity. So a big pipe right at the exhaust port (headers of 3" tubing, for example ) will slow the gases, resulting in less scavenging, and inefficiency.

Can you maximize power by opening the system up after the first 4 feet?

pocholin

Well, it makes sense, I'm no engineer, but I know that in order to make some things work you need velocity rather than pressure, a good initial pressure is good, but then you trade pressure for velocity, I'm talking about steam turbines, but the same could apply here, but I don't understand exactly how
This is the exhaust, I don't understand how velocity can benefit the exhaust, I understand how back pressure can affect the engine's performance.

Autostream

forget the headers, the price/performance ratio is too high.
i dont know the size, but they are equal to the factory size.
I'm not a scientist, but I know the new exhaust piping attaches to the manifold with the same type of flange the stock exhaust uses.
Hey i wish i had the time to take more measurements, but i'm a busy guy. right now its 430am and I barely have time to check email.
though I will have a profile of my car with pics by the weekend!

speedybenz

Anyone going to try the double Flowmaster idea and provide the test results.

I still think it is a very good test and will provide some good data.

Jeff

WhynotSS

Let me help ya out with this, you're almost there.

At low rpm, smaller pipes will let the exhaust gases escape more efficiently because they allow a higher velocity. However, at high rpm, smaller pipes limit the amount of exhaust that can fit. The same pipes that optimize performance at low rpm will hinder performance at high rpm. The best pipes at high rpm will be wide and long.