For some time now, I've been reading that if you're going to buy a new exhaust system, you need to go to the 70mm piping. I had the chance to buy a well priced new Europipe Stage I with 60mm piping and did it...flashed the car, put in headers, DV's etc....car runs fantastic....takes my breath away.

(**Please note disclaimer...this is NOT a slam against tuners) Tuners will tell you that it's imperative you buy the 70mm piping because of less restriction...but the difference in price can be pretty substantial. I wrote (PM'd) several forum members who are running 60mm piping and they responded that they are running VERY FAST 1/4 mile and trap times with the 60mm setups. (Not Europipe) They may chime in and give their personal observations...I hope they do because they have actual times and specs and provide personal knowledge, and thereby....some credibility.

***EDIT: The EP figures didn't display in the format I transferred from the EP website....please go to Europipe's website (Google Europipe Exhaust) and look in their technical specs section for the 996 Turbo to see the specs in a more understandable format.

I went to the Europipe (EP)technical site and extracted the following information on backpressure restriction between the 60 and 70mm piping. Although not labelled, the first line of numbers (.36; .18; .15) relates to backpressure:

StockStage 1Stage 2 loudStage 2 quiet6500 rpm0.36 bar
5.30 psi0.18 bar
2.65 psi0.15 bar
2.20 psi0.15 bar
2.20 psi
By way of explanation, EP Stage I uses 60mm and Stage II uses 70mm, however both use the same 100 cell cats and never throw CEL's. As you can see, the Stage I appears to cut the backpressure by 50% over the stock setups. I can see that there's a .45 advantage on bar with the 70mm piping...but how much difference does that really make if you're running a Stage II or III tune at say 550-600 HP? This is usually where a lot of the guys stop mostly due to fiscal issues....plus at this level the car is fast enough for the majority of the P car crowd.

I know that larger piping might be more suitable if you're going for BIG HP ranges like the 700-1000 engines....but for the more conservative folks who don't want to spend money on internals and are content with a bolt-on approach....my question is why do you need 70mm piping if you are running into choke points like turbo inlet/outlet specs, throttle body sizes, and other choke points?

I know tuners want to sell the 70mm systems...but I also realize that by going with the 70mm it gives tuners the opportunity to sell you the bigger and bigger systems without requiring you to spend the additional money to swap out and invest in another larger 70mm system. (absolutely required for big HP) So there's a logical reason for guiding you to the larger piping.

I realize there are going to be a lot of "What if" issues....like what if I throw on the larger Garrett or hybrid turbos....but even taking those issues into consideration....keep the focus on the 550-600 HP range and tell me why I need 70 mm piping? What am I really going to get for the extra 10mm? What do I LOSE by not going to the 70mm?

 

Chuck, I think you need an engineer to answer that question. I will be watching this thread because I'd like to hear the answers myself. I bought the 70mm Europipe stage 2 quiet but only have an ECU reflash. Sometimes think of upgrading to K24's but that's about it.

 

I've run stock, 70mm and 60mm. I ran my 7.01 60-130 on the 60mm setup. I would guess my car was faster with the 70mm setup, but my butt dyno couldn't really feel a difference. All I really care about is the sensation from the driver's seat. I'm not trying to win races here.

 

I can't answer any of the above. However 10MM is just less than 1/2inch in tubing size. Somehow I don't see a large gain in power for that kind of "upgrade"...

What I can tell you is that most of the systems I've heard from most of the aftermarket makers is just to damned loud, over time they get louder...

I'm hoping that someone will come up with a cost effective solution that will not sacrifice interior QUIET for power. I'll probably end up buying an EP2 Quiet unless something else comes along that does the job for less...

Mike

 

I woudn't think the difference would be noticeable at the power levels you're discussing and certainly not worth the expense. We sometimes get programmed to get the biggest, most expensive items just because. I say save your money.

 

at 600 crank HP most decent exhaust systems will be fine....
If you going for more power, Obviosuly bigger diameter piping is less restrictive...
I find it odd when guys spend all this money on turbos and headers , ecu etc... and then run 200 cell cats with a $4K price tag...
you might as well not upgrade then....

here is what I have been working on.... all SS 3 inch with custom mufflers and 100 cel cats.

 

Only reason why I have my Switzer is for daily driving because I cannot stand the sound of straight pipe 24/7. I know I lose power, about 20-25rwhp or so, but the drone kills me on my 45min drive to work. Plus the constant fear of getting pulled over and getting a ticket sucks.

Though if I am going to the track or looking to make max HP I will put my straight pipes on. There is no doubt in my mind about that!

 

I was considering hacking up my stock exhaust to make a "straight pipe" setup, just for the track. Leaving the cat and just running straight out from the cat. Anyone done this, or does everyone do this?

 

I have done it, I made a thread on data comparing them. Seach under threads i have made.

 

Thanks F1. searchin now...

 

You can consider Speedtech's X-ccelerator, u have lots of flexibilities and combinations.

 

Chuck, thanks for starting this thread. I think it would be a great question for many because many people don't push their cars past 550-600hp

 

Here's the "other" rubb... The question always gets belabored when a new "kit" hits the market... Does the system DRONE??? Many times the system will NOT initially, but over time does change and start to exhibit different characteristics... This has happened with a number of popular kits out there, and just yesterday Gunther and I were having this discussion over his Militek and my DGI, both of which are now droning.

To the manufacturers out there, if you want to make us happy, make a system that doesn't sacrifice quiet comforts of the interior for the gain in performance... There has to be a balance, and maybe the real answer IS going with the Europipe system. It seems to be the only system on the market that no one comes back to complain about a year or so later...

Mike

 

Do you know what it is with the Europipe design that would allow one to make that claim?

I would think a series of mechanical (fixed\welded) baffles rather than rockwool wrapped in perforated metal would be superior. The later will certainly fail over time and become louder.

My system appears quieter when cold and after driving for a while it appears to get louder. I've questioned this many times while driving, and I'm not sure if it really gets louder or I have just become fatigued by the sound and thus more sensitive to it.

It's one of the systems that claim no drone but it most certainly does between idle - 2800 rpms. After that, it becomes very quite and quite possibly better than stock IMO.

I guess if I could have my dreams fulfilled, it would be a system that has the sound of a GT3 or something similar and just as exotic; not like a Jeep.

 

The Miltek has gotten louder over time.

I think the comments about the mechanical design of the EP vice the wrapped whatever it is also makes sense. To bad we can't get someone to do a EP style exhaust at a better price point.