azmi951

I recently got the SFR 3 inch DP with the full 3 inch set up. I have no data but with the full set up the car spooled about 200 RPM sooner verses a bursch 2.5 cat bypass.
My .02 is if you are spending the money for the vitesse III and most of SFR's exhaust the $350 extra is not that much more and it will be done top notch. You will not wonder "what would it be like if I would have???"

Be warned though, installing the DP is a BITCH. your best bet is to installthe turbo and DP at the same time.
Also on the fitment side of things, you have to clock the turbo right or the exhaust will hit eather the caster block mount or the floor pan. Take your time and make sure it fits before bolting the turbo down for the last time or you will be fighting the exhaust hitting. It is not a porly fitting exhaust, it just needs to be installed right.

Crazy Eddie

Hey Guys
What really blows my mind is why does a 10 inch piece of pipe cost 450 dollars
and his whole exhaust costs only about 2x more.....
Somehow that doesn't seem to add up
I guess this is like manufacturing a piece for the space shuttle
If not, why the F#$@ doesn't anyone else make it ...
Is it really that hard to make ? I am not trying to take anything away from the quality of their work as I am sure it is top notch. What is also really surprising is that no else even makes one... So much for the concept of competion in the market place
I would think 250 would be a fair price based on what the rest of the exhaust costs but WTFDIK
John, I would think with a Stage II operating mostly at the mid range that the 3 in DP may not be as be called for as it would for a Stage III running at the mid to high end ? My goal would also be more in the low to mid range as opposed to the top end performance. Or am I talking outta my butt
Any input would be greatly appreciated
Kindest regards
Ed

jean_noir

Just for the sake of saying there is competetion. Lindsey and SFR both make a true 3" down pipe - both for approx $325 only thing is that to use the down pipe you must also buy the true 3" cat bypass pipe wich runs $100 more than the normal "wedged" 3" cat bypass pipe. So we are talkin $600 for the TRUE 3" cat bypass + $325 for the TRUE 3" down pipe for a whopping gain of 00.054hp - (i'm just blowing steam - I have already budgeted to buy both pieces).

MR951

IMO if the turbine outlet is less than 3" then you're just putting a step change right there where the DP bolts to the turbo. Using the stock DP and a 3" SFR (or other) exhaust system the increase in diameter is a smoother transition just ~10" further downstream. I wouldn't think that there'd be anything to gain.

However if the BFT (big f'n turbo) you're installing has a 3" turbine outlet then a 3" DP is a must!

azmi951

turbine efficeny is based on the Delta E or potential chainge in energy across the turbine. Make the turbine outlet a lower energy level (lower temp and pressure) and the turbine will extract more energy from the exhaust thus translating into more power to the compressor sooner. x

mein51

I wonder how the flow changes with having a 3" exhaust w/out the 3" DP. With an increase in area from from DP to the exhaust, the flow has to loose velocity (Venturi effect). This change in velocity may create a different backpressure on the turbo than if it had a full 3" system. If a flow changes velocity, its temperature should change also... there again possibly changing the backpressure.

How significant is my bulls%&t rambling? -Beats me I say the only way to really figgure it out is before and after comparisons with only the DP changed.

My guess is you have no actual HP or Tq to "gain" rather than you're picking up spool time and letting the turbo become more efficient. Just my .02

IanS

ATP(vwturbo.com) make turbos with K26 flanges or with V-band flanges if you just want a turbo. They also make an awesome looking 3"->4" V-band 'nozzle' adapter if you've always wanted to go to a true 4" exhaust. Not that you could ever fit the piping.

But going with the K26 flange option should be the cheapest way to get a GT turbo on these cars, unless there are some fitment problems I don't know about.

TurboTim

A good example of this is the stock turbo and downpipe.The stock downpipe is significantly larher then the turbine outlet. 2.25" compared to 2"

Andial951

what is the size of the turbine outlet on a K27/6?

nize

nobody has before/after dyno for just the downpipe swap? hmm.