I'm seriously considering picking up a Tubi Style street exhaust for my 2007 Turbo. My interest is based on two things: 1) sound, and 2) reduced turbo lag (faster spool up). All of the exhaust makers tout higher HP and faster spool up, but my question is: Is the reduced lag noticeable without having to really look for it? I don't care much about the extra 15-20 HP.

On the subject of engine breathing, my reading leads me to understand that the stock airbox is fine until I get really serious. I am, however, considering a BMC air filter. Should I be concerned that too much fine dust will get through the higher-flow filter? I can't find any specs on the BMC particulate efficiency versus stock.

Thirdly, are oiled filters, such as the BMC, okay/approved for the intake system? I've got nearly two years on my CPO warranty left.

Thanks,
LP

 

Based on your stated interests, all high quality aftermarket exhausts would produce similar effects in reduced turbo lag at your level which I assume is stock tune. The biggest gain would be seen in a combo ecu tune + exhaust. So the main focus should be the quality and type of sound you are looking for. If you want a more aggressive sounding exhaust with cats then Tubi is not the way to go, imho.

 

Tubi isn't the greatest sounding exhaust.

 

I have a Fabspeed V3 which sounds good. There are a few that sound good but I don't think any exhaust on the TT sounds great! The only way that happens is when you run straight pipes off the turbos!!!

 

I also have a 2007. Install a Europipe EP-1 and your wish list will come true.

 

"...all high quality aftermarket exhausts would produce similar effects in reduced turbo lag at your level which I assume is stock tune. The biggest gain would be seen in a combo ecu tune + exhaust."

TTdude,
If I read between the lines here, are you meaning to imply that without the tune, the reduction in turbo lag is negligible?

All,
Please forget that I mentioned any particular brand in my statement and try to focus on the actual questions I asked. I'm not interested in anyone's opinion of any given exhaust sound. As TTdude says, they all have about the same effect on lag/hp. I want to know if that effect is actually noticeable. If the advertised reduction in turbo lag is not really noticeable without a tune or other mods, then I will stop thinking about an exhaust until I'm ready to do more--if that day ever comes, which it may not.

Doc GTO,
Was any reduction in turbo lag noticeable from just the addition of your aftermarket exhaust?

LP

 

I found there was a very slight reduction in turbo lag with a catless exhaust, turbo whistle is nice as well. The biggest gain however was exhaust + apr tune...

 

The effect is not necessarily less turbo lag. The way I perceive it is faster turbo spool especially on highway driving, easier kickdown if your Car is a tip and dare I say even better (faster) tip gear shifting.

However all my observations with Europipe 1 which I realize is the most expensive option but the best IMHO.

I can't help you on the BMC however would live to see the answers myself.

 

L_Perm,

You should try our 997TT X-Flow system. The sound is absolutely fantastic. And it's available in quiet or Loud versions, too. PM if you would like more information or pricing...

 

Imho, short answer is yes. Exhaust manufacturers may disagree. What I think you're experiencing is the time to reach boost threshold rather than lag since vtgs are not considered laggy (Bbywu can elaborate here). When you're cruising along at lowish rpm in third or fourth and then stomp on it, do you feel a delay/hesitation? It's been about 4 years since last drove a stock turbo but I remember how annoying that delay/hesitation was. My first mod was installing an aftermarket exhaust (before installing a tune) and I don't recall feeling much difference. It's hard to tell because the sound changes plus one gets used to added power really fast, especially if it's only incremental in nature which an exhaust-only mod would afford. If you're planning on an exhaust-only mod then you better do it for the sound rather than performance. You won't get rid of the "lag" that you are feeling. For that, I would recommend an exhaust + tune combo.

 

Thanks for the elaboration. Is the mildest, easiest tune the Softronic? And, what does Porsche think about the 550-ish tunes? I assume I won't need more than a BMC filter and AM exhaust to do one of the mild tunes, right?

LP

 

Well, my favorite tuner is Protomotive but many on this forum run Softronic and other tunes as well. It just depends how deep you want to explore. Plus I feel that post sales support is critical. If you're asking what does Porsche think about mods and aftermarket tunes--you can be assured that if you have engine related problems and PCNA determines that your car has been flashed, they will decline your warranty claim.

 

TTdude,
That's what I figured. I'll just look into an exhaust for now and decide on a possible tune once my CPO warranty is gone. Then, of course, I'll have to decide about other extended warranties, but we'll see. Thanks for your replies.

John,
Thanks for the note. I'll call you. I wrote a nice long PM last night only to be told that I don't have enough posts to send a PM. I read your whole website and am intrigued.

LP

 

I like a good discussion, so don't take my response as anything other than my take on the issue off the top of my head.

This distinction seems semantic to me. If I understand, someone is making a distinction between the lag associated with overcoming the inertia of the turbo impeller and the lag associated with the time it takes a spinning impeller to compress the air to maximum boost. The VTG's address the first, but not the second. In fact, it seems possible that they may add to the second, given that the impeller blades have to open up, though this may happen very quickly. Please correct me if I've mischaracterized.

In any case, it seems the throttle response is non-linear due to the turbos. Whether or not you call the initial hesitation "turbo lag" is a decision concerning how one defines turbo lag, but it doesn't change the fact that there is an initial amount of acceleration upon opening the throttle at lower rpms, followed by a fairly abrupt increase in acceleration, and this phenomenon is turbo-related--as far as I know.

I guess it's possible with today's drive-by-wire systems that the initial hesitation is caused by the computer trying to decide if you really want to go fast. It wouldn't surprise me at all if that is some of the lag.

I would like to read what Bbywu has to say about it. I'll search around.

LP

 

Catless Exhaust = more flow and help to avoid HIGH EGT.
Forge Diveter Valves = much better boost response and keep it steady.
BMC airfilter = no gain but littel whoosh turbo sound.

E85 u will get great boost response, more power,more torque and cooler IAT!