For anyone who hasn't seen it, this tech article from the folks at Cobb can be a real eye-opener. http://www.cobbtuning.com/Technical-...es-s/70676.htm In short, it suggests that opening up the exhaust at the front end can be more beneficial than opening it up at the tail end. This could well explain why at least one person has reported large gains in torque from the downpipe and test-pipe, even though he still has an (albeit modified) OE muffler.

 

I had this exact problem with my Megan dp. Had a buddy mark the spot where it was touching and hit it with a hammer to dent it there. Fits perfect now!! Lol.

 

Thanks for the heads up Jookies. I was looking at Megan to replace my AP. Looks like I'd be back at square one and pissed I spent the extra money only to end up with the same problem.

 

Good stuff there. I agree. My son went from a test pipe/Magnaflow 3" exhaust to adding an ETS downpipe. He picked up more ponies and it is certainly quantifiable on the butt dyno. Iowa, I love your posts. Pretty good comments from someone from Iowa, me being from Minnesota and all. I should probably post some tasteless Iowa joke that we Minnesotans love to tell from time to time...

 

Thanks (I think).

I'm not an engine-guy by any means, but I've been reading all I can on exhausts (and learning a lot more about fluid dynamics than I ever wanted to) because I'm shooting for that impossible combination of a quiet system that doesn't hold the car back when autocrossing or rallycrossing. After reading that article on the greater benefits of opening the system up near the front than near the rear (with both being open being the best, of course, but also the loudest), I started looking for more evidence of this and it's out there. At this point I'm seriously looking at 2.75" downpipes, high-flow cats, 3" mid-pipes with a resonator before the rear axle, but then something like a Works- or RRE-modified OE exhaust. The other extra constraint that I have besides quiet and low torque is that it must be as close to the subframe as possible when it goes under the diff for rallycrossing. This has me now wondering if it should come back down smoothly to 2.75" after the resonator, to get the extra .25" in ground clearance.

Hey, Mr. Dave B! Are you listening? Ultimate STU/P-AWD/street exhaust: your downpipe, an HFC, 3" midpipe with resonator, drop back to 2.75" before ducking under the diff, then your Magnaflow-style muffler. It would sell. Well, at least one would.

 

^ Well, given the fact that you are from Iowa I suppose there should be some kind of animosity, not that Minnesota is any great shucks of a place to live in. There is a joke depending on whether you live in Iowa or Minnesota that goes like this: "What's the best thing to come out of Iowa/Minnesota?" and the answer would be: 35W! LOL And, a compliment was thrown your way. You do post very thoughtful and insightful comments. Personally, I appreciate people who write intelligently and post information that is not just a bunch of forum drivel.

 

Thanks, again, but would it ruin the joke if I said I'm originally from a small island off the coast of Maine where you have to take a boat to get to your garage?

 

^ It would ruin it. However, I am sure I could come up with some George Bush and Kennebunkport jokes. It is some kind of a ruse to have an Iowa license plate when you are really from Maine? Personally, I would not advertise anything from Iowa except for hog jowls, pork rind, bacon and ham. Regardless of your home state, you are good people.

 

Would anyone happen to have and info on the invidia DPTP?

http://www.invidia-usa.com/Products.aspx?ProductID=182

I have the invida Q300 catback..

 

I have no information for you, but have actually considered the crazy idea of getting one of these one-piece downpipe & testpipe/cats to combine with an OE cat-back to test the idea that you can have more low torque without more noise. However, the 100-cell HFC versions of these things are often in $500+ range (with the Invidia being over $600), so it's more of an experiment than my marriage can handle right now.

If someone would be willing to try this - as in: large downpipe and HFC cat with OE or other small cat-back - I'd be very grateful.

ps. if you haven't seen this video from the brilliant folks "down under," it's worth a look; the part that got my attention was the statement that the resonator right before the rear axle is key to avoiding drone; that's exactly what I've seen before and it matches my theoretical understanding, as well: http://www.youtube.com/watch?v=yZ2aX2CLud8

 

So, if I purchased an AMS widemouth DP I should have it ceramic coated since the heatshields are gone or run the risk of melting the transfer case? Or does the O2 housing stay? Seems that the MAP DPs eliminate the O2 housing (and the heat shields) hence all the options such as a ceramic coating.

From what i have read, seems that eliminating the 02 housing is key to larger power gains.

I like the widemouth because of the power gains needed to reach power goals.

Any clarification would be helpful and greatly appreciated.

 

I will be going with a custom downpipe. Will heatwrapping it work too? i will probably get mine ceramic coated.

 

The AMS DP allows you to keep the stock heat shield just like the stock DP