R34 Exhaust Suggestions

[Marcus89]

Recently i bought myself a 2nd hand exhaust which included a 3" mild steel front pipe highflow cat and 3.5" stainless steel catback exhaust.

I haven't installed the system yet as i am still tossing up between getting a new dump and front pipe or just running the stock dump with exhaust as is. The mild steel front pipe is made to bolt straight up to the standard dump as it tapers down to 2.5" at the dump side. Due to this fact i would be looking at replacing both front and dump pipe if changing them is recommended.

Now i am only really going to be street driving this car and not going overboard with mods. Plans are the exhaust, possibly FMIC although may not be getting up to those power levels where it is needed and a Nistune. Plan to keep the standard turbo and run around 11psi.

At this basic level of modification would the factory dump be a restriction at all? And even if the dump isn't a restriction is there going to be much of an issue going 2.5">3">3.5"?

[Marcus89]

Anyone able to give us a hand? I'm sure theres a few people who have a good idea on whether the standard dump is very restrictive or not and whether the changes in size of the exhaust throughout will affect flow/performance.

[dazzvass]

Going from small to big shouldn't hurt the flow. The standard dump pipe would be more restrictive than an aftermarket in some way.

The rule of thumb is the more power you pushing out from the engine, the more power increase a well suited exhaust will give you (to some extent of course).

[Jay11]

The stock dump is still a restriction.

Just get one of them justjap front/dump pipes they're pretty cheap, coz you're not after big gains.

Ideally you would want it to be 3" or larger from the turbo back.

Have you got a better flowing panel filter or pod filter?