K2420

Hey Guys,

I have a semi-built K24/20.. before it had a 3 inch exhaust and was tuned.. made 250whp and 200tq. However, it was extremely loud! (no cat or anything).

I might have done something very stupid, but I sold my 3" exhaust and got a 2.5" (T1R) installed instead to try and be more quiet. (still super loud!) I have not gotten it tuned yet and it now runs like **** --> in lower rpm's (mainly second gear) the car just jerks and isn't smooth.. how should i go about fixing this?? Do i need to get the car re-tuned? Does changing the exhaust from a 3" to 2.5" make such a big difference????

Thanks!!

2x0

Should not make much difference at all. My guess, something messed up with ur O2 sensor when you swapped exhaust.


Once you get it running right, put a couple magnaflows on there to tone it down.

K2420

hmm.. how can i get it to run right again? you don't think i need to get it tuned again?? it is making city driving impossible!!!

Chance EG

3 -> 2.5" definitely won't help performance, but shouldn't completely kneecap your car. Definitely issues with the tune.

Why did you just put in a resonator instead of switching the entire exhaust?

K2420

my friend told me the 2.5 inch would sound WAY more quieter yet not hurt performance... but now when im just going slow speeds and at low rpm's, the car does not accelerate smoothly at all and is super uncomfortable - jerks a lot - until i start to really give it gas... does that make sense at all LOL.

so now i dont know what to do... do i:

A) get another 3" and put that back on
B) re-tune the car for the now 2.5"

AHHHHH!!!

Chance EG

2.5" isn't ideal but I don't think that's your problem. Something either went wrong with the O2 sensor or the tune is off.

A 2.5" won't really be any quieter than a 3" exhaust, assuming we're comparing them with equal resonators/mufflers or whatever. Resonators and a good muffler are the way to go to quiet things done.

Chemi421

The car was running fine though on this tune with the 3 inch.. this just started happening once I put the 2.5 inch on..

What I think I will do is get it re tuned with the 2.5 inch now and then once I have more money, I will get a quality 3 inch exhaust with resonator and maybe silcencer?? Would the silencer reduce HP by a lot though??

theYBLEGAL

Turbocharging makes it quieter

Chance EG

Do you have any resonator at all right now?

Look into a vibrant ultra quiet resonator. You may even want to run an additional bottle resonator behind that. It will not impact performance at all, by all means you'll still have a "straight pipe" design with no interruptions for the exhaust gases, you're just adding baffled chambers to absorb the sound.

2x0

You can go back to your 3" but it'll still run like crap when it's in closed loop cuz your o2 sensor or a wire to it is messed up.

Changing exhaust diameter 1/2" will not have a noticeable difference on the tune.

theYBLEGAL

In my experience tuning, a change in back pressure will change how power is made. I would say that is enough of a change to warrant a tune. Changing from a cat to a straight pipe is a great example.

2x0

Warrant a retune for optimum power, sure.

Enough change to cause the car to run like complete crap, bucking and missing? Eh no.