Running full "straight pipes" ??

[135forthewin]

I was just wondering if anyone out there has done a complete straight-through exhaust system.
What I mean by this is catless downpipes, catless midpipes, and a berk/afe/aa axleback.
If any has, I wanted to know how it sounds. I'm sure it SCREAMS!

So, is anyone planning on doing this/doing this already?

[NihonX]

Originally Posted by 135forthewin

I was just wondering if anyone out there has done a complete straight-through exhaust system.
What I mean by this is catless downpipes, catless midpipes, and a berk/afe/aa axleback.
If any has, I wanted to know how it sounds. I'm sure it SCREAMS!

So, is anyone planning on doing this/doing this already?

Not like Riss Racing, right?

[onefastman]

I have the RR system with vk dp's and I enjoy it a lot. I have thought about having a custom strait pipe instead of the muffler

[ridin135]

I had stock downpipes with striaght midpipes and the berk axle back. It sounded really good but I didn't want any drone. Here is a video of it

of course it was louder in person

[135forthewin]

Originally Posted by NihonX

Not like Riss Racing, right?

Correct, not like riss racing. I'm talking about no mufflers, resonators, or cats.

and ridin135, your car sounds good

[ridin135]

Ya the only thing that was restricting my exhaust was the first cats straight pipe the rest of the way, it got annoying after awhile though.

[NihonX]

Originally Posted by 135forthewin

Correct, not like riss racing. I'm talking about no mufflers, resonators, or cats.

and ridin135, your car sounds good

Yeah, they are mostly straight until the muffler in the end.

[6spdMSport]

Im thinking about deleted my rear muffler, but i think our cars need the back pressure.

[onefastman]

From what I understand we dont need back pressure because they are FI. someone correct me if I am wrong

[WhiteOne]

I believe the twin turbos should provide "some" exhaust backpressure.

[SpacE82]

I have the CP-E full exhaust. Catless downpipes, catless midpipes, but it does have a muffler...its loud. I posted a video of it after i got it installed.

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Thread: http://www.1addicts.com/forums/showthread.php?t=293982

[onefastman]

Please post vids! Also how much did you pay for the pipes?

[Schn3ll]

Originally Posted by onefastman

Please post vids! Also how much did you pay for the pipes?

I will have a video of my setup soon, there is a group buy on n54tech for BB Fabrication downpipes, $425 for 3"... great deal and great quality (just got mine today).

[onefastman]

Nice, I would have gone with them if I hadnt gotten such a good buy on some vk's a while back. I was asking about the custom exhaust. I have RR and am considering having an axle back made and would like need to know what I should look to pay.

[RaceTime]

Well, last Friday, I had a custom axel back 'ish system made. LOL!

I got a heck of a deal. We, muffler tech and I cut the stock pipe about 8" infront of the stock muffer and ended up expanding to 3.5" mandrel bent straight pipes out of the back. It took an expansion 3" to 3.5" and then two 90 degree bends to make it out the back. I decided to go with no exhaust tip to save some weight and cost. We went to 3.5 inch to improve sound. It sounds deep and rumbles which I love!

The largest advantage for me will be losing the 30 pound muffer over the rear axel (should help handling as I mostly track the car). I am not sure of the DB's, but it is substantially louder. I will find out at the next race as autocrosses in my area are DB regulated... I am sure that I gained a few horses, but the butt dyno will never be able to tell the difference.

[BroDoze]

Keep in mind the bigger the diameter, is not necessarily the better, depending on power output.
Yes it's true we want absolutely zero backpressure, however, you can still go "too big" on your piping, especially using stock trubos.

The point in a turbo-charged car is to get the exhaust out as fast as possible (if we could run our downpipes right out through the wheel well, we should (if that was realistic, which it's not)).

Anyway, as the diameter gets bigger, the air can actually cool a little too much which slows down the air flow. Hot air exits through the pipes faster. The hotter the air the faster it moves. This is one of the main reasons DP's are wrapped or ceramic coated - to keep the internal air as hot as possible.

There was a ton of R&D done on the Subaru turbo exhausts and it was found that on a stock turbo setup, anything more than 3" resulted in a slight loss of power. Obviously with huge GT35R/65R setups pushing 500AWHP or more, bigger diameter was better, simply because of the amount of flow required.

Just something to think about - especially if you're getting a local exhaust shop to design your setup. And in the end, this is no Subaru, but the same rules applied to the Evo's, SRT-4's etc.

[onefastman]

Very good to know, I have 2.5" dp's and 3" RR mid pipe so I would stay with the 3". I just need to know what I should look to pay for an axle back.

Also for autocross could I get away with taking the muffler off and running just dp's and mid pipe. Would it be too loud?

[Hind]

what is the diameter of our stock dp's, midpipes, exhaust?

[RaceTime]

The actual diameter is metric and just a touch smaller 3" stock.

As far as larger tubing in a prior post, I totally agree and is why it is stock to the rear axel, just loosing weight with the muffler delete.

[BerkTechnology]

Originally Posted by 135forthewin

I was just wondering if anyone out there has done a complete straight-through exhaust system.
What I mean by this is catless downpipes, catless midpipes, and a berk/afe/aa axleback.
If any has, I wanted to know how it sounds. I'm sure it SCREAMS!

So, is anyone planning on doing this/doing this already?

This is what we run on our car, it is a full muffler-less system. Very loud!

The race exhaust is the last one in this video.

[BerkTechnology]

Originally Posted by Hind

what is the diameter of our stock dp's, midpipes, exhaust?

DP = varies in OD from around 80mm at the turbine exit down to 60mm at the flange.
Midpipe = 60mm ~2.38"
Axleback = 70mm ~2.75"

Keep in mind the bigger the diameter, is not necessarily the better, depending on power output.
Yes it's true we want absolutely zero backpressure, however, you can still go "too big" on your piping, especially using stock trubos.

The point in a turbo-charged car is to get the exhaust out as fast as possible (if we could run our downpipes right out through the wheel well, we should (if that was realistic, which it's not)).

Anyway, as the diameter gets bigger, the air can actually cool a little too much which slows down the air flow. Hot air exits through the pipes faster. The hotter the air the faster it moves. This is one of the main reasons DP's are wrapped or ceramic coated - to keep the internal air as hot as possible.

There was a ton of R&D done on the Subaru turbo exhausts and it was found that on a stock turbo setup, anything more than 3" resulted in a slight loss of power. Obviously with huge GT35R/65R setups pushing 500AWHP or more, bigger diameter was better, simply because of the amount of flow required.

Just something to think about - especially if you're getting a local exhaust shop to design your setup. And in the end, this is no Subaru, but the same rules applied to the Evo's, SRT-4's etc

There are only 2 things going on with a turbo car.

1. pressure
2. flow
3. velocity

You're really only concerned with 1&2. Bigger is better up to the point of diminishing returns and packaging realities. Exhaust gas velocity and pressure wave tuning do not have any real effect on exhaust performance once you are past the turbine wheel.

[onefastman]

I can not seem to get rid of the 2c31 codes after several hundred miles so I am going to remove my dp's this weekend and before I do I will take off the rear section of my RR system and see what it sounds like. I will try to get some video.