blue89turbo

Hey guys,

I am wanting to buy a DP before starting the install.

What are todays best options?

I am thinking of a 3" DP and 3" back with a magnaflow.


Is it worth it using 3" or are there other bottle necks with the Greddy that cancel the benefits? (such as manifold etc)
Should I just go with 2.5"?


Thanks

Stripes

iTrader: (8)

A three inch downpipe is a great idea if it fits. The turbo placement might make this size a little difficult on a greddy kit.

m2cupcar

iTrader: (5)

Word is that the tubing "donuts" make the tight bends needed to get the downpipe going down help immensely.

Al Hounos

Go for it. It may not make more power for the lil' greddy, but you know it's there and ready if you ever want to go crazy.

magnamx-5

iTrader: (7)

Agreed ^^^

Savington

iTrader: (31)

Yes, it's always worth it.

Ben

iTrader: (33)

I think the turbine outlet is only 2"
I'd match and swage. A 3" would be tough.

Braineack

iTrader: (62)

I betcha Corky would recommend against it.

match and swage is just as benefitial for flow/velocity.

blue89turbo

I think you are right the outlet is probably ~2"
what do you mean by match and swage?
2" seems kind of small though.

Braineack

iTrader: (62)

start at something like 2.25" or 2.5" and step it up to 3"

like for example, my t3 has a 2.25" turbine exit, my DP is 2.5" and then steps up to 2.75". My cat and exhaust is 3".

TurboTim

iTrader: (9)

Yah step it up. Big right at the turbo flange isn't ideal if the turbine outlet is comparitively tiny.

But all things considered i'd go as big as you can fit. Wo hoo

Zabac

iTrader: (39)

3" exhaust is the same as vagina
whether you need is arguable
whether you want it is obvious

Braineack

iTrader: (62)

I betcha next time I dyno will make you think twice about a 3"

Ben

iTrader: (33)

with your new breathing mods, let's shoot for 10 psi at idle

Braineack

iTrader: (62)

10psi at idle would mean a .5" exhaust and tons of backpressure.

lets shoot for 10psi at 2000RPM

Zabac

iTrader: (39)

10 psi @ 2K.....that would be very boner inducing

Braineack

iTrader: (62)

Seeing 12psi @ 3800RPM with my turbo vs 4200RPM is pretty close.

Zabac

iTrader: (39)

indeed...what size is your DP/exhaust?

Braineack

iTrader: (62)

right now it's a 2.5" to 2.75"

however my cat and catback is 2.25"

the muffler is also a dual exit with dual 2" outlets.


so I have absolutely the worst setup for flow, as it progressively gets smaller.

I did minor headwork and have shaved about 500RPM off my spoolup time.

I have a 3" on the way, so I'm excepting to see even better results. Hopefully something like 20rwhp at the same boost level.

Zabac

iTrader: (39)

that would be great success...
are you gonna do a write up on your head-work?
did you do it yourself or at a machine shop, i hear a lot of people saying they did it at home, but have no info to back it up, etc...
i have a spare motor, so i may want to experiment myself with some headwork
let me know if you did it yourself

I did minor headwork and have shaved about 500RPM off my spoolup time
thats impressive