External Gate. To Plumb, Or Not To Plumb

[Roy]

I have run an external gate for a while now and im happy with the boost curve , no falling off at high rpm. And also happy with the fact that the car makes good enough hp.

At the moment i have the gate to atmosphere. Which hasnt been a problem as i drive like an old lady and never load or boost the engine on the street. So in my case its hear no evil, ppl dont look for evil.

I have been warned though that this year i may be getting pinged at track days as the EPA are enforcing db requirements at the track. Now i dont care about losing the cool noise at WOT, my concern is will the increased gas flow in the exhaust cause back pressure problems...loss of power/boost problems etc?

Anyone had a plumbed back vs atmo experience on the same car, setup and tune? I know of two cars that lost power when they were plumbed back. Is that the norm?

I am running a high flow cat and HKS Hyper exhaust, which has two mufflers. Will it handle all those by-passed gases?

[Mavric]

Keep it

[R31Nismoid]

Plumbed mine back... and the car sucked the wang.

I pulled the pipe out the next day

If your exhaust does not flow enough, you will have an issue.

If it does flow enough, then plumbing it back wont be a problem

I only had a 3" exhaust, not enough for 300rwkw

[Roy]

What brand of exhaust Nismoid?

Like i said, im hoping the HKS Hyper would be ok?!?!?!? It is a pretty quiet exhaust

[Craved]

any thoughts on running a seperate Cat and muffler on the WG pipe by itself ?

Ash, what were the effects of changing it to plumb back ??

[Roy]

Was considering running a bike muffler off a TLR etc but its just more weight and agro that needs to be supported under the car...and also weight hanging off th tubular manifold . At the moment the weight of the wastegate is enough of a worry on the manifold...let alone throwing an exhaust system on it.

[sinistaGTR]

SCREAMER

[Mavric]

In saying that as Nismoid said u have the right exhaust u will be fine... i now have a stock cat an stock exhaust on my car and i cant break 3 psi....

How big is your exhaust and dump???

[Craved]

Was considering running a bike muffler off a TLR etc but its just more weight and agro that needs to be supported under the car...and also weight hanging off th tubular manifold . At the moment the weight of the wastegate is enough of a worry on the manifold...let alone throwing an exhaust system on it.

sounds fair

if i remember correctly i think it was SK that runs a support for the exhaust from the back of the motor

personally i will be setting up a support to run from either the block or the engine mount to load up the manifold so it ill not sink when red hot

[R31Nismoid]

any thoughts on running a seperate Cat and muffler on the WG pipe by itself ?

Ash, what were the effects of changing it to plumb back ??

Drive a stock turbo skyline.

Then put ane exhaust onto it.

Exactly the same, its the easiest way to describe it.

More power everywhere, better response etc etc

What brand of exhaust Nismoid?

Like i said, im hoping the HKS Hyper would be ok?!?!?!? It is a pretty quiet exhaust

Some Jap one

Needed a 3.5" at a minimum

[T04GTR]

i pliumbed mine back. and havent looked back. now i can actually here my motor and the all nice whissel from the 04

11.3@122 with a bog stock bottom end seems to be enough proof for me that theres no power loss.

[T04GTR]

oh.. you got to merge the pipes nicly but at a good 30 degree merge. 2" semmed to do the trick for me

[T04GTR]

i had to because i was sent to gordon highway patrol to get defects cleared.

mines a 3 inch to the cat and 3.5 after.

[BU5TER]

10.5 400rwkw+ plumb back screamer , 90mm exhaust with a centre muffler

[Roy]

I think the HKS Hyper is 80mm. Sounds like it may be worth a try

[Craved]

oh.. you got to merge the pipes nicly but at a good 30 degree merge. 2" semmed to do the trick for me

Dave, will need your assistance regarding this if you have some time.

[Beer Baron]

don't do it troy. it's like clipping the claws on a bird, or milking the fangs on a spider. it lets people know that despite being devestatingly handsome, you also have some nuts!

I say worry about getting pinged for noise if and when it happens.

[N1GTR]

Yeah worry about the noise later, for now, enjoy waking up the whole street when you leave for work

[Guilt-Toy]

Plumbed mine back... and the car sucked the wang.

I pulled the pipe out the next day

If your exhaust does not flow enough, you will have an issue.

If it does flow enough, then plumbing it back wont be a problem

I only had a 3" exhaust, not enough for 300rwkw

Now i dont doubt you know what your talking about... BUT

10.5 400rwkw+ plumb back screamer , 90mm exhaust with a centre muffler

...... ??? I pulled 300rwkw with my 3" plumbed back.. maybe this rule does not go for RB30DET's

[R31Nismoid]

Not saying it wont make the power, i did

The 3" system i had on my car, definately was a problem as the gate had to stay external

Then, my exhaust goes up and over the diff, where most R33's seem to be pretty straight and go under it.

Seen a couple of cars go from 3" to 3.5" and pickup some excellent results.

Nothing beats a flowing exhaust.