FN2 muffler taken out and loss of power?

[BloodSugar]

Hi everyone, I am a newbie here and I need help.
I just took the rear muffler off my stock FN2 and welded a straight pipe to the back. I kept the dual exhaust and resonators just before the tips. However, in case I change mind in the future, I purposely left some space for a rear muffler by welding a curved pipe (very short, probably around the size of a palm in S shape) to the straight pipe. This is a cheap alternative for those who wants a deep and louder sound without changing the whole cat back. ( There are some great premade out there such as Milltek, Martelius and the big brands.)

Now the problem starts, I notice I have lost some torque (maybe power too) at low RPMs. But I imagined with a less restrictive piping in contrast to a muffler, the air flow should be more free. I do not know why the loss of power happens. I did not do a dyno before or after, this is just me feeling the car is less powerful than before. I did research and did understand with a setup like this, back pressure and exhaust air stream velocity are the keys. And I know the myth that engine will lose torque if there is no back pressure is a false statement.

So here is my question, does anyone know that a "S" shape pipe will possibly create more back pressure? Or, is the setup I use potentially reduced the stream velocity? Or, for a laugh, maybe I noticed wrongly about the power loss? LOL

Please share your experience as it is frustrating for me. Thankssss:)

[androo]

I think it's in your head

[u mad?]

No not in your head, i did the same thing with my k20 at one stage, just wanted that loud sound, turned into a pile of piss down low, had to mash it to get power. It 'felt' a tiny bit better from 6500rpm on wards, though that may have been placebo effect, cuzz it was loud as fuk!

Now, if you had your tune played with you may get more power out of it.

I ended up putting muffler back on after 6 or so months, was amazed on how much low end power i got back, not too mention how nice the car was to drive again, i could hear myself think.

[BloodSugar]

Thanks u mad:) but I also wonder why this happens. I can't find a explanation

[u mad?]

Im leaning towards the tune, more flow, fuel might need fuking around with, but in saying that it would be silly to buy a kpro and tune just for muffler change.

[BloodSugar]

The tone is nice I reckon. A bit droning if I'm in high speed low gear or low speed high gear. But I think the low end torque loss is noticeable. I'm gonna try the high end power again tonight with vtec. A few people agree on the low end loss and many suggest a high end gain at the same time. Gonna try it out.

[u mad?]

Is it too much effort to make a sound clip? i'd be keen to hear a stock system with rear muffler removed.
Honestly you may gain a tiny bit up to, but without your map been adjusted to suit new muffler there really shouldn't be much improvement.

In saying that kpro and tune for a muffler change is pretty silly lol.

[BloodSugar]

Agreed. I am saving up for a proper catback, header and intake system. With all these stuff, mapping the ECU with kpro/hondata will make more sense.

[BloodSugar]

I will try to record a video, put on YouTube and share it later.

[bennjamin]

you have lost "power" because you have created either more turbulence or less restriction internally - and thus shifted your power band every so slightly up.

[BloodSugar]

you have lost "power" because you have created either more turbulence or less restriction internally - and thus shifted your power band every so slightly up.

So that means I will need to rev up a bit more to get the same torque power than I used to? And the total available power/torque is still there but available at a slightly higher rev?

[bennjamin]

So that means I will need to rev up a bit more to get the same torque power than I used to? And the total available power/torque is still there but available at a slightly higher rev?


My understanding is yes. At the points which ad exact fuel and timing for that rev and gear and load - there is now slightly more or less restriction giving this "feeling" of less power. All it has done is pinched your power band slightly up. Its something thousands of low to mid range car enthusiasts go through every day.

That is , mods on a standard ECU car.

[EG5]

In saying that kpro and tune for a muffler change is pretty silly lol.

FN2 is running Flash Pro , Not Kpro