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

[SKStinger]

Just an update for anyone reading this thread in the future. I decided to start with lighter wheels (Stance SF03 Brushed Titanium to drop 10lbs on each corner), then I'll get the FMIC in the next couple months (possibly the Mishimoto FMIC), then, later this year, I'll pick up an Ark secondary downpipe. Once I get the Ark secondary downpipe, I'll do a handful of before and after 0-60 pulls with a dragy and post them here, along with any anecdotal differences I notice.

Good choice for the wheels. Those are nice and the stock ones are 35lbs each so yeah, nice weight savings.

 

[Mr. Tech]

Good choice for the wheels. Those are nice and the stock ones are 35lbs each so yeah, nice weight savings.

Thanks! Can't wait to get them on, but I've gotta wait another 20 days for Stance to finish cutting them for the Stinger. A true test of patience haha.

 

[Tonkabob]

Just an update for anyone reading this thread in the future. I decided to start with lighter wheels (Stance SF03 Brushed Titanium to drop 10lbs on each corner), then I'll get the FMIC in the next couple months (possibly the Mishimoto FMIC), then, later this year, I'll pick up an Ark secondary downpipe. Once I get the Ark secondary downpipe, I'll do a handful of before and after 0-60 pulls with a dragy and post them here, along with any anecdotal differences I notice.

Here are my tests before and after Mids. Be sure to do correction for DA.
Absolutely no change unfortunately.

 

[xot1]

Here are my tests before and after Mids. Be sure to do correction for DA.
Absolutely no change unfortunately.
View attachment 41783

I respect this but I have a completely different experience with primary DP.

 

[cncBilly]

I respect this but I have a completely different experience with primary DP.

Do you have data?

 

[xot1]

Do you have data?

Not in the form of what Tim has.
But I know that my car got significantly faster once I did downpipes.

 

[MrSmoofy]

TonkaBob is talking about his mid pipe only change I believe xot1 is talking about primary only maybe or the entire exhaust primary secondary and cat back.

Totally different things. With Only Secondary or as others call them Mid very little HP gains if any at all mostly just different sound.

 

[Tonkabob]

TonkaBob is talking about his mid pipe only change I believe xot1 is talking about primary only maybe or the entire exhaust primary secondary and cat back.

Totally different things. With Only Secondary or as others call them Mid very little HP gains if any at all mostly just different sound.

Mine was secondary with cat back.
Primaries should do 15 -20 HP if the rest of the exhaust is also replaced. The +3 HP exhaust dyno for Primary was with all the rest stock exhaust.

 

[xot1]

Oh ok. Then I agree. Secondary downpipes only increase the sound. People who say they add performance are liars.

 

[xot1]

Primaries should do 15 -20 HP if the rest of the exhaust is also replaced. The +3 HP exhaust dyno for Primary was with all the rest stock exhaust.

On this I cannot agree. My car had primary DP and stock exhaust and it made a huge difference. Like 3 to 4 car lengh difference on a 40mph pull.

Also, this isn't an exact before and after but here are two dyno numbers (same dyno) I do have:
- JB4 WMI 440whp
- JB4 WMI + intakes + fmic + primary dp 490whp
As you know fmic does not do much on a dyno and intakes do not add 40 horsepower.

 

[Tonkabob]

On this I cannot agree. My car had primary DP and stock exhaust and it made a huge difference. Like 3 to 4 car lengh difference on a 40mph pull.

Also, this isn't an exact before and after but here are two dyno numbers (same dyno) I do have:
- JB4 WMI 440whp
- JB4 WMI + intakes + fmic + primary dp 490whp
As you know fmic does not do much on a dyno and intakes do not add 40 horsepower.

Are you saying the above was with stock secondary Cat and stock exhaust? If not the FMIC and Intake are 25 (10 and 15) and Primary 25.

 

[xot1]

Are you saying the above was with stock secondary Cat and stock exhaust? If not the FMIC and Intake are 25 (10 and 15) and Primary 25.

Yes exhaust was stock except the primaries.
Actually 439 and 494 are the exact dyno numbers (best out of 3 runs).

I also see a lot of dyno results of cars with other piggybacks that do primaries and gain 30hp. It is a commonly expected gain. You're the only case I have seen yet of someone reporting almost no power increase on the dyno.

 

[Tonkabob]

Yes exhaust was stock except the primaries.
Actually 439 and 494 are the exact dyno numbers (best out of 3 runs).

I also see a lot of dyno results of cars with other piggybacks that do primaries and gain 30hp. It is a commonly expected gain. You're the only case I have seen yet of someone reporting almost no power increase on the dyno.

This wasn't my car - Lockes. He did get 25 HP with no "tune", but with tune, primary and stock exhaust, only 3 HP. "Tune" is Lap3 Pro.

So what is your HP now? 500?

 

[xot1]

This wasn't my car - Lockes. He did get 25 HP with no "tune", but with tune, primary and stock exhaust, only 3 HP. "Tune" is Lap3 Pro.

So what is your HP now? 500?

Haven't measured recently. I am not a big dyno fan.

His car is weird.
Here there are many lap3 cars and when they do primaries they pick up about 30whp all the time.

 

[Tonkabob]

Haven't measured recently. I am not a big dyno fan.

His car is weird.
Here there are many lap3 cars and when they do primaries they pick up about 30whp all the time.

But don't most people do full exhaust? Just a primary and stock back is weird. But exhaust mods are illegal in California.

 

[xot1]

But don't most people do full exhaust? Just a primary and stock back is weird. But exhaust mods are illegal in California.

Here the most common configuration is:
Primary DP + Stock secondary cat + Aftermarket catback
but there are some people who leave the stock exhaust after doing primaries.

only very few people delete both cats because of overboost.

 

[General_Vodka]

But don't most people do full exhaust? Just a primary and stock back is weird. But exhaust mods are illegal in California.

Did someone say commifornia? *Laughs in illegally passed smog*. The car laws here are the BEST! *laughs in registered out of state vehicle*

 

[Mr. Tech]

I just did some research on pedal tuners and, from what I've seen in some videos, people are saying it makes their car feel considerably faster, due to "faster" throttle response. I'm wondering if replacing the secondaries just gives you noticeably better throttle response which would definitely make the car "feel" faster without actually affecting the 0-60 or 1/4 miles times.

I suppose one way to test this would be to do some 0-60 pulls without launch control and, instead, just switching from the brake to mashing the gas. If there is actually a significant increase in throttle response, the car will be faster from 0-60 with the new secondaries. However, most people use launch control when getting their 0-60 times, in which case, the throttle is already open and any increased throttle response won't be seen.

In other words, maybe this is good for stoplight to stoplight pulls, but won't make a difference on an actual drag strip? What do you guys think about this?

 

[SKStinger]

Not totally sure I understand where you're going with this but I have the SSR catless secondaries and still have throttle lag. I purchased a pedal tuner because it's annoying having to mash the throttle to get the car to respond.

 

[Mr. Tech]

Basically, some people say their Stinger felt faster after they replaced their secondaries, but 0-60 and dyno tests suggest that the gains are negligible. Which makes it odd that so many people say they noticed a difference. Even Tonkabob thought there was a difference until he tested it on the track. Throttle response is one of the only things I can think of that would cause people to think their car is faster when it actually isn't. But now you're stating that you didn't see an improvement in throttle response so maybe that's not the case.

On a side note, which pedal tuner did you get and, now that you have it, do you think it is worth it?