What OD resonator do I need?
 

Hi,

I installed a performance catback and a catless header and I'm finding there's too much drone in my car's cabin.

My mechanic is telling me to order a 12 inch bottle style resonator by Vibrant.

My exhaust is the Invidia gemini r400. Specs say it is a 70mm or 2.756" OD.

what 12" bottle resonator do I need? I don't see a 2.75 inch x 12"



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I just spoke to Vibrant and my mechanic. This is the correct resonator for my 2.75" tubing. Vibrant does not have 2.75 but tell me (along with my mechanic) that the pipe on my car can be stretched by 1/8" to fit inside the 3" resonator because the steel itself makes up the other 1/8".

What front pipe are you running?

stock front pipe. Gruppe-s over pipe and UEL header.

We are going to move the stock resonator closer to the front and put the Vibrant 1794 12" x 3" bottle resonator closer to the axle back.

If you're putting flanges on it, you'll be fine with a 3".

Hes going to use a conical expander of some kind and then TIG weld

That'll work too.

Is there a reason you dont just get a new front pipe with a double resonator?

Correct me if i am wrong but isn't the stock front pipe 2.25" and your header and catback are 2.5"-2.75"?
So your smaller diameter FP is not only a bottleneck in your exhaust, it is probably what is causing most of the drone. Seems like a double res FP could fix all your problems. Just my 2 cents.

It's a good thought for sure, but, I want to keep my secondary cat as my header is catless. Also, the slight bottle neck is not too much of a concern as I have flashed the ECU as well and I'm quite happy with the performance. Lastly, a new front pipe with performance cat and resos only I'm told is louder. Not to mention, a lot more money than 2 hours of labour and 100 bucks for the resonator I'm adding.

1320 has a double res FP for 175$. Easy bolt so no labor. And double res FP is just as quiet maybe even more then stock. It’s mostly the header and exhaust for DB lvls and a FP for noise refinement. And then you don’t mangle your exhaust up so it retains resell value.

Thanks. I assume 175 USD plus shipping? I'm paying 275 Canadian including labour.

Not too worried about resale. Also, the combo of stock resonator and vibrant resonator sounds great.

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Also, after looking it up, I see this would delete my secondary cat, which, is currently my only cat.

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