I posted over on rennlist about this, but figured I'd share my experience with you guys as well. If you read both forums, sorry for the cross-post.

For those who don't know, John D of DGI/Speedtech has a new option available for his exhasut. He has engineered a small reducer ring that you can insert into the exhaust tips. It basically necks down the 70mm piping a few mm in the last centimeter before the exhaust gases exit. It makes the exhaust slightly quieter in the cabin, but still aggressive sounding. It really mellows it out in the 2k-2.5k range. How such a small metal ring can make such a big difference is beyond me, but I'll leave that to the engineers.

I drove it around for the last 2 weeks without the tailpipe inserts and I thought I was reaching the end of my wife's patience. It's not obnoxiously loud, but it has that muscle car rumble at that 2k-2.5k rpm range. If I was driving up hill in that rpm range, I could see her making that "I don't like it, but if I tell him, he's going to get upset" face.

Yesterday afternoon I installed the tailpipe inserts and now she loves it. And more importantly, I love it too. It's quieter, but still way more aggressive sounding than stock. With what other exhaust at this price point do you have the option of making it louder or quieter as your mood desires (5 minutes with a ratchet to pop off the tail pipes, drop in the reducer and put them back on)? Granted the 9ff valvtronic and Krisskreig (sp?) exhausts let you do it from inside the cabin, but those exhausts are much heavier and more than twice the cost.

If you're trying to decide between a europipe loud or quiet, buy the DGI and get both options. Bottom line, I love it and the wife approves. And incase you've already got one, John tells me that the rings are retro-actively compatible with all of his exhausts sold to date.

 

Is there a corresponding decrease in performance?

 

Nothing I can feel, but I haven't had it up on a dyno. When I went for a shake down drive after install, I cut all four tires loose merging onto the highway (probably due to cold tires though). Also, it still slips my clutch pretty handily.
Even if there is a slight decline, it's definitely a vast improvement over stock (both performance and weight wise) and it's a compromise I'm willing to make.
I'll be going in for a re-tune and dyno test at EPL once I get my clutch installed (it was tough to finalize the tune when the clutch kept letting go on the dyno) so I'll re-check then.

 

Great post, I will have to get some of these for my long drives!

Do you have any pics of what they look like? Pricse on them?

 

smistry007,

In short, No, there is no detectable decrease in performance, only a decrease in sound in the cabin. There may be a dyno difference and we were going to dyno test them on Seals car, but his clutch started slipping and we were not able to do it at that time. I can tell you that from my testing experience with the inserts, there is no "seat of the pants" difference that I could detect. The Speedtech exhaust with 70mm piping made so much more power than the stock exhaust on Michaels car, IMO, even with a small dyno loss, it would still make more power than you are likely to achieve with other options. Even with the inserts installed, the exit pipe is larger and flows more air than many other exhausts that use the factory tips. Some very popular exhausts that re-use the OEM factory tips have even smaller piping than stock, so you are still at a big advantage with the 70mm SpeedTech, even with the quiet inserts.

Don,

The insetrs are $69.95 per set, delivered in the continental USA. I packed the last set today, so I do not have any pictures. I will be running additional sets immediately and will have some available to ship next week. If you would like to order a set, there is a buy it now button 1/2 way down the 996TT exhaust web page where you can order...

Here's the link: http://www.speedtechexhausts.com/page9.html

FYI - This idea was born through testing the Speedtech exhaust in various configurations before deciding on the 70mm. I noticed the variation in sound with the changes we made and envisioned a system whereby I could alter the sound without altering the entire exhaust. I tested the insert principal last fall and was pleased with the results, then when Michael was on the fence about buying an exhaust due to his wife requiring a quiet exhaust...I told him I had the answer. He took a chance on it and I am happy to learn it met his goals.

 

Hey everyone,

We will test with and with out the rings next time Seal's car is up on the dyno.

I look forward to seeing the results myself!

 

Very cool. Thanks John D! I just ordered a set.

 

might consider a set.

 

John, I put my new exhaust on last night and did my first little run with it this morning. Wow, very aggressive sound and my acceleration is smoother and very responsive. I have not had the wife in the car yet. If it is too loud for her we might have to think about this add on piece. But for now, it's perfect. Thanks John.

 

Your welcome, Kab. It's great to hear you are happy with it. I like it at the full 70mm, as well. The option to quiet it down if you would like is nice to have, too.

 

It's great to know there is an option available to help reduce drone if it becomes an issue. I just installed straight pipes and will be removing them this weekend as the drone on my 3 hour drive to the airport today almost killed me! Just wondering, can you hear the turbos spool at all with the Speedtech exhaust (thats the only cool part about the straight pipes). Thanks!

 

Thanks John. Got mine today. I will be installing tomorrow. I will let you guys know what I think.

 

Hey,
John D
Are you making this exhaust for 997TT?
My buddy wants an exhaust and tune.
Elliot

 

Jonny,

Your welcome! I hope you enjoy the exhaust...

Hi Elliot,

Our 997TT exhaust is in the development stage and almost ready. The design and sound will be very similar to the 996TT. If he is willing to wait a little bit, please forward this email to your friend and have him send it to me and I will contact him as soon as they are ready.

997ttcontactlist@speedtechexhausts.com

 

Hey John... finally got the car running like i wanted it to.