Exhaust Comparison

[MotherTucker]

Here's something interesting. There are big differences in how the different makes of R8 exhausts route the exhaust gasses, especially around the vacuum actuated exhaust valves.

Here's the OEM exhaust. The exhaust gases all go into the muffler, and part of the gasses come out the holes and go into the other pipe, where they are allowed out if the exhaust valves are opened. So there is apparently always some muffling happening. It's butt ugly, but who cares - you can't see it on the car.



Here's the Miltek exhaust (alongside the OEM exhaust). That one has no exhaust valves at all. So it's all muffled the same amount - presumably louder - all the time. It is nice and pretty polished stainless - too bad you can't see it when it's on the car.



Here's the PPI exhaust. This one has the exhaust valves, and when they are opened, the gasses are routed directly out the nearby tip. So you get a muffled sound when the valves are closed (although presumably louder than OEM), and when the valves open, you're essentially running open headers. Well, open cats really. It must be really loud. It's all stainless steel, with a brushed finish. Not quite as pretty.



I bought the PPI exhaust, and will be fitting it soon. It looks like it's very high quality. I'll try to take a video to post the sound when I get it on.

cheers
mt

[rayc]

Presumably the aftermarket exhausts are just packed with wadding . Therefore
they will get louder with time.

[SiNzz]

Any info on the kreissieg exhaust? Presumably it's pretty much the same except it looks like you electronically control the valves.

[biggie27]

I just heard the PPI exhaust on the R8 a few weeks back.....ur a lucky man :P, ur gonna love it. but word of warning it is pretty loud and sounds brutal at full throttle....alot of people are gonna try to race u with that on :P

[resonate]

Any info on the kreissieg exhaust? Presumably it's pretty much the same except it looks like you electronically control the valves.

I'm also interested in the Kreissieg also. I will be in Japan this week. I'm gonna try to stop by their shop.

[MotherTucker]

Thanks, Biggie - that's the first I've heard of any report on the PPI. The dealer says my 2009 should be delivered this week. I'm going to have them put the PPI on before I take delivery. Can't wait!

OEMPL.US sells 2 exhausts for the R8 - the PPI and the less expensive MTM exhaust. This is a picture of the MTM. It looks like it has no valves either.




-- UPDATE --

For completeness, here's a picture of the Capristo exhaust. It's similar to the PPI in that the exhaust valve completely bypasses the muffler.




And here's the new Statis exhaust:

[MotherTucker]

I was talking with a certified R8 technician at an Audi dealer today, and he said that the factory has not recommended any aftermarket exhausts because some of them get so hot when driven hard (tracked), that they are melting the rear bumper cover. He was skeptical about mounting my PPI exhaust. He said he personally knew of a situation where an R8 was bumped in the rear, and the heat shield was damaged, and driving it afterwards caused the rear bumper cover to be melted. So you sure have to make sure the exhaust heat shield is all there.

I'm going to go ahead and have it done anyway. I think that the PPI would be a good one to address this problem, since when driven hard the exhaust gasses are routed directly out the tips instead of into the muffler, so it probably runs cooler when wide open. We'll see.

Ah, life on the edge...

[MotherTucker]

Well I got the car and I got the PPI exhaust mounted on it. I did have the car with the OEM exhaust in it for a few days, so I can compare them. Oh my gosh! The PPI exhaust is wicked. But it's different than I expected - it's controllable, for the most part.

Basically, there are 2 modes for exhausts with the vacuum actuated valves. Quiet mode and Loud mode. Consider rating the loudness on a scale of 1 to 10, with 1 being quietest. I would rate the OEM exhaust a 2 in quiet mode, and a 4 on loud mode. I would rate the PPI as 3 on the quiet mode, and a 9 on loud mode. It is deafening, race car loud on loud mode. But in quiet mode, it's nice and moderate. Since the OEM exhaust's 2 modes are so close together, you don't really realize when it switches modes. With the PPI, it slaps you in the face.

It turns out the exhaust valve is open when starting the engine, idling, and starting to take up drive. It stays open till about 15 miles per hour (depending on what gear you're in), and then if you don't give it massive throttle, it goes to quiet mode until it gets to about 5,000 RPMs. Thereafter, it remains in loud mode. 5,000 RPMs in 6th gear is 120 MPH.

So when sitting at a stop light idling (or just after you start it up and you're showing your fancy new car to your friends), if you blip the throttle a few times, it's the equivalent of a dragster taking off. It is ungodly loud. My dog was standing behind the car when I revved it, and it scared the snot out of him, the poor fellow! It is tremendously loud in that situation. Like painfully loud. Did I mention it was loud? The sound reminds me very much of a Lamborgini. So, you take off (giving it very gentle gas if you don't want to make a huge ruckus) and about the time you settle in 2nd gear, it switches to quiet mode, and this very noticable and refreshing hush settles in, and then you're cruising along nice and quiet, without that annoying resonation or much loud noise at all, all the way up to 120 mph or so in 6th gear. You kind of have to get used to that sudden quietness, it's that noticable. So it's great for highway cruising or discreet traveling in your subdivision. But if you downshift and get on the throttle, you're driving an open header race car, screaming thru your neighborhood. It is absolutely killer. I really like it. And the black tips look very cool on the red car with the black grills right above them.

The technician thought that there should be no harmful increase in the heat with this model - at least he couldn't see any obvious reason. He wondered if the larger diameter pipes on some of the other aftermarket exhausts caused problems by being closer to other surfaces back there. It's certainly fine after an hour of highway driving, the back end didn't feel very hot at all. I'll have to see what happens when I track it.

I'll try to get a video with sound of it, and post it. It's awesome.

One other thing - the stock exhaust is much heavier than the PPI. The Audi tech who installed it estimated it at about 30 pounds lighter. That combined with less restriction likely means there is a noticable performance improvement. I'm still in the break-in period, so I haven't pushed the car at all yet or gone above 5,000 rpm. So I haven't noticed that - yet.

[resonate]

Wow. Thanks for the review MT. Sounds like an animal. Post video clips ~ !! I wasn't able to stop by Kreissig in Japan. Their shops were no where near Tokyo. But I did see a Jet Blue R8 with OVAL pipes in the back. I wonder where he got it.

[Ti-Mike]

I was talking with a certified R8 technician at an Audi dealer today, and he said that the factory has not recommended any aftermarket exhausts because some of them get so hot when driven hard (tracked), that they are melting the rear bumper cover.

Thats a good one, because before i have had mounted my non res version of Miltek i had a melted rear cover WITH THE FACTORY EXHAUST , because on the outside of the OEM heat cover was some wax left this got so hot that the rear mount of my license plate melted and i had a dent in the rear cover, this has been replaced by Audi.

Since i got my Milltek no more issues. Specially because we have used some racing heat tape on the R8 and left the OEM heat cover out.