Does stock section 3 give better torque?

[Nico]

I had a BillyBoat section 3 + headers + tune for the past 5 years and just went back to a stock section 3.

The throttle response feels smoother and there seems to be more torque down low. Placebo?

[S54Mickey]

I noticed the same thing when I switched out the SCZA to the stock section 3. On the highway I used to have to drop down to 5th to pass. Now I just floor 6th and she goes. Now maybe in the upper rev range, it’s more restrictive, but I can’t confirm that.

[L0okitzRaj]

I also feel like the section 3 with headers is a bit too 'free' and the torque dropped a bit going from stock w/headers to a milltek.

....Off Topic but do you have any sound clips of the BB with headers?

[Nico]

I also feel like the section 3 with headers is a bit too 'free' and the torque dropped a bit going from stock w/headers to a milltek.

....Off Topic but do you have any sound clips of the BB with headers?

Yes, I have a lot on my YouTube channel actually. One of the best I’ve heard for this car to be honest, really is an amazing sound with headers especially at high RPM. It’s really really loud though. I missed the raspiness of the stock exhaust and being able to hear the induction sound.

https://m.youtube.com/watch?v=53alRgI47UE

[Mr.wReckless]

IDK, but when I swapped OEM for an Eisenmann Sport I noticed a definitive improvement in performance, so IMO the stock backbox doesn't flow as well as at least the Eisenmann,

Regards

[Arith2]

I would say mostly no. If your exhaust has too much flow to cause an issue with scavenging then MAYBE and that's a big maybe. Anything that creates back pressure is not good for torque. The design is to muffle, and the pipes aren't even connected internally so flow is not ideal. Back pressure is never good. Scavenging is what should optimized and it sounds like the tune is not ideal for a high flowing Sec 3. If it's a can tune then it's probably set up for less flow.

[c watson]

That’s very common with Billy Boats. I read a few posts on here and the old M3F were previous BB owners said their cars felt peppier when going back to stock.

I went from BB to Scza after 16 years with the BB and it kinda felt the same for me. I may install my stock sec 3 to give it a try.

[maw1124]

IDK, but when I swapped OEM for an Eisenmann Sport I noticed a definitive improvement in performance, so IMO the stock backbox doesn't flow as well as at least the Eisenmann,

Regards

Is that possibly just weight though? Pulling less weight will make you feel like there's more torque.

maw

[Gt4]

Is that possibly just weight though? Pulling less weight will make you feel like there's more torque.

maw

I don’t think 25lbs is that much noticeable…

[maw1124]

I don’t think 25lbs is that much noticeable…

Maybe. Racers will tell you that gas in the tank matters.

I'm having trouble believing any air dynamics that far downstream of the engine create additional torque though.

maw

[Mr.wReckless]

Is that possibly just weight though? Pulling less weight will make you feel like there's more torque.

maw

Doubt that the weight difference will be that noticeable, although the stock Sec3 is rather heavy and the Eisenmann is relatively light, it is still just a small % weight saving when you consider the total car weight.

I've got CSL intake, cams and full exhaust otherwise so whilst I think the stock Sec3 flows well, it was now a restriction compared to the Eisenmann. I could also feel a slight difference going from stock Sec2 to a Supersprint resonated x-pipe, although now it seemed to breathe better with stock Sec2.

Regards

[maw1124]

IDK… I’ve done this exercise on multiple performance Germans… exhausts are the lowest of low hanging fruit for power, so they all seem maxed out from the factory there — the factory being BMW M, MB AMG, Audi RS, Porsche GTX.

Not surprisingly, when you change them, you get lighter components that may or may not breathe better at the peak of the band, but that flow doesn’t translate to power. It translates to the sensation of power because it’s lighter, and to different sound, but not to actual power. This makes sense to me (I like a different sound and less weight sometimes). Beyond that, nah not more power.

Now Reckless’ engine is putting out more power (CSL, cams, etc.), and he has the freer flowing exhaust to go with it. That makes some sense. And under forced induction conditions v factory, sure you need matching exhaust changes. And I can even see how a stock Sec3 can handle the CSL components and power, but not CSL + cams, maybe.

But on a stock factory motor changing nothing but the back box, you should expect nothing but more sound, less weight (“sensation”), bragging rights and a lighter wallet. Which might still be good enough reason for the change IMO

maw

[digger]

Maybe. Racers will tell you that gas in the tank matters.

I'm having trouble believing any air dynamics that far downstream of the engine create additional torque though.

maw

There is a difference between perception and detecting things on timing equipment not to mention that full tank to quarter is a decent amount more. Nobody is picking up less than 1% seat of pants

It’s not about how far back, it’s about what the gasses have passed through upto that point.

I find that difference in noise can mask one’s perception though so the dyno is the best way to measure changes like this. A dragy could also work but need to control a few variables to see small changes

[Obioban]

No change to section 2? The crossover location is HUGELY important to torque. Unless you have an exceptionally poorly flowing muffler (e.g. the original el Diablo), muffler doesn’t normally influence power very much.

[Sharocks]

It's a placebo and I would say it's mostly because it's much quieter so you're flooring it more to compensate for the lack of sound you are used to experiencing.