3.3TT What's the truth about downpipe/midpipe performance?

[Mr. Tech]

@Mr. Tech I've got empirical data. Several dyno plots showing the power difference. And I'm just like you (intakes and JB4...and colder plugs). If low end "grunt" is your goal, you don't want secondary pipes. IATs are important, but only for back to back runs. You'll net more power with cat back exhaust than pipes.

Interesting. So are you suggesting that replacing the midpipes would give you more high end power at the cost of low end? So a net zero increase, but a shift in where the power is? And a cat back will give better low end performance? I wonder what the physics is behind that. Both are increasing airflow. And thanks for the data driven response!

 

[Mr. Tech]

Enkei flow-formed wheels are generally considered decent bang-for-buck AFAIK - I found TY-5s in black for under $300/wheel for 18s from getyourwheels.com. The Pilot Sport 4s (245 front, 285 back) cost more than the wheels . TFR is even a bit cheaper. Depends on what look you're going for.

Prices seem to have gone up a bit, but still under $300 for TFR in 18 or 19, under $350 for 18/19 TY-5.

WAY lighter than OEM.

Thanks for the recommendations! I'll take a look

 

[RUFFSTUFF]

What's your best trap time now?

 

[Mr. Tech]

What's your best trap time now?

I don't actually run full 1/4 miles. Just 0-60. I might go to a track eventually, but I'm currently just enjoying stoplight to stoplight and getting on the highway haha.

My fastest 0-60 was 4.35 measured by a dragy.

 

[Stiletto]

Interesting. So are you suggesting that replacing the midpipes would give you more high end power at the cost of low end? So a net zero increase, but a shift in where the power is? And a cat back will give better low end performance? I wonder what the physics is behind that. Both are increasing airflow. And thanks for the data driven response!

I can't prove anything for catback on my vehicle, since I don't have one. But here is OEM secondary vs. Ark secondary (no tune):

And this is the same comparison, on map 2:

 

[Mr. Tech]

As I'm thinking more about this, I'm wondering if the performance gains from midpipes and exhaust on a tuned car aren't seen because the tune needs to be adjusted. Like, maybe you can push the tune harder with midpipes/cat back and maintain good timing. So if you could run Map 2 on a JB4 without midpipes/cat back maybe you could run Map 3 with them?

I suppose Tonkabob would have figured this out since Tork is custom tuning his car and he said he didn't see any difference.

@Tonkabob, did you adjust the tune after putting on the midpipes or did you just do a few 1/4 mile / dragy runs? Seems like you've been doing this for a long time so you probably already know the answer to my question based on experience.

 

[Mr. Tech]

I can't prove anything for catback on my vehicle, since I don't have one. But here is OEM secondary vs. Ark secondary (no tune):

And this is the same comparison, on map 2:

Wow, interesting results. Looks like you lost some low end but made up for it on the top end. How does it feel when you're driving it? Any noticeable difference either way?

 

[Stiletto]

Wow, interesting results. Looks like you lost some low end but made up for it on the top end. How does it feel when you're driving it? Any noticeable difference either way?

The response is quicker. It feels like there's more pull when I mash the skinny pedal.

I have read that our ECM doesn't react quickly to a new power adder. It has to learn the new parameters. How long this takes...I don't know.

 

[Tonkabob]

Interesting. So are you suggesting that replacing the midpipes would give you more high end power at the cost of low end? So a net zero increase, but a shift in where the power is? And a cat back will give better low end performance? I wonder what the physics is behind that. Both are increasing airflow. And thanks for the data driven response!

Opposite. Dynos before and after show about 15 more tq but really low and narrow like from 2500-2900 rpm. So if anything mids help your launch just a little. Dyno of primaries the same but bigger and broader low end tq gain. Both help the turbo spool faster.

 

[General_Vodka]

Opposite. Dynos before and after show about 15 more tq but really low and narrow like from 2500-2900 rpm. So if anything mids help your launch just a little. Dyno of primaries the same but bigger and broader low end tq gain. Both help the turbo spool faster.

Interesting. I got mids but leaving primaries because of the oil issues.

 

[Mr. Tech]

Enkei flow-formed wheels are generally considered decent bang-for-buck AFAIK - I found TY-5s in black for under $300/wheel for 18s from getyourwheels.com. The Pilot Sport 4s (245 front, 285 back) cost more than the wheels . TFR is even a bit cheaper. Depends on what look you're going for.

Prices seem to have gone up a bit, but still under $300 for TFR in 18 or 19, under $350 for 18/19 TY-5.

WAY lighter than OEM.

Finally got around to checking out the Enkei TY-5s.... WOW those look great! And the price point is awesome. Do you have a picture with them on your car? I can't seem to find a picture with them on a Stinger, but they look great on other cars.

 

[Tonkabob]

Hey I have a correction on the primary dp Dyno. The 3 hp gain was with just a dp with stock exhaust. Other more recent dynos with full bolt ons and tune that then added a primary dp added 15-20 hp.
Secondary dps still do nearly nothing I'm afraid.

 

[Mr. Tech]

The response is quicker. It feels like there's more pull when I mash the skinny pedal.

I have read that our ECM doesn't react quickly to a new power adder. It has to learn the new parameters. How long this takes...I don't know.

I've noticed the same with it taking a long time to adjust. I actually disconnected my battery for 30 minutes to reset the parameters and it made a huge difference when I made my last modifications.

And glad to hear that you've noticed a difference. After all this discussion. I may get wheels, then an Ark secondary soon after as it seems that most of the fastest cars use Ark.

Have you noticed any drone with just the secondary? I read about that in another forum, but it may have been because of other mods they made.

 

[Stiletto]

Have you noticed any drone with just the secondary? I read about that in another forum, but it may have been because of other mods they made.

None. But, I'm also stock catback.

 

[Mr. Tech]

Hey I have a correction on the primary dp Dyno. The 3 hp gain was with just a dp with stock exhaust. Other more recent dynos with full bolt ons and tune that then added a primary dp added 15-20 hp.
Secondary dps still do nearly nothing I'm afraid.

Oof, primary DP for the bigger gains? Looks like I'm out on that one. I still need my Stinger to pass emissions here in NH and I highly doubt that replacing the primary and secondary DPs would even come close.

Though it does seem that, anecdotally, some people notice the difference with secondaries. Could be placebo, or what they are feeling is something that wouldn't be picked up on a dyno. I'm assuming throttle response can't be seen on a dyno.

 

[Mr. Tech]

None. But, I'm also stock catback.

Good to know, Thanks! One more question, any issues passing emissions (if your state has that inspection)?

 

[Stiletto]

Good to know, Thanks! One more question, any issues passing emissions (if your state has that inspection)?

Virginia only has emission testing in certain counties. Thankfully, I don't live in one that requires it. Since you are losing two cats, it's probable you aren't as clean as some states would like. Fortunately, putting the stock tubes back on isn't a major chore.

 

[Stiletto]

I'm assuming throttle response can't be seen on a dyno.

Dyno doesn't measure throttle response. You could graph the voltage to the TPS over time to compare between mods. But that doesn't require a dyno.

 

[Tonkabob]

Oof, primary DP for the bigger gains? Looks like I'm out on that one. I still need my Stinger to pass emissions here in NH and I highly doubt that replacing the primary and secondary DPs would even come close.

Though it does seem that, anecdotally, some people notice the difference with secondaries. Could be placebo, or what they are feeling is something that wouldn't be picked up on a dyno. I'm assuming throttle response can't be seen on a dyno.

Secondarys do make it feel faster as the sound goes up and gives it a mean snarl. If I didn't dragy or slip everything my butt dyno would say there are gains. Secondarys don't make the drone louder just everything is a little louder and it seems to broaden the drone RPM range. Silenced secondarys keep the sound the same or reduce a little and also reduce drone a little. But that gets expensive for little change in sound and almost no change in power.

 

[SKStinger]

I wouldn’t change a thing with my setup. I love the burbles on deceleration and how you can hear the turbos at start up. The catless midpipes really bring the MBRP exhaust to life.

Zero drone at all rpms with exhaust tips on. Can’t even tell I have a modified exhaust when I’m cruising on the highway.