TurboTommy

A dedicated wastegate dump is good because it will then not interfere with the main exhaust. This then lowers back pressure, which INCREASES torque.

Darwantae951

The real question is does it increase torque at a measurable rate, or is it so minute that it only shows up on a dyno graph?

If it were such an increase that you could feel it, I'm sure everyone else would have gone to such a set-up.

Haven't even seen this on many track cars so can't imagine it's THAT advantageous.

To the OP. Why are you going this route? You have a 3L street car.

toddk911

Lindsey posted some data a while back on their testing before and after wg tied in and wg dump to atm.

As TurboTommy addressed, ANY decrease in back pressure is good and increases power and decreases spool, etc.

ChrisJ951

Modded- Its more of a precaution to reduce backpressure. I will test backpressure before I install the dump pipe. If my BP numbers are good, I'm leaving the car the way it is. If they are high, then it goes on.

87944turbo

I have the same setup as Techno Duck. It is loud, but only when you are at max boost of course, which is a pretty small percentage of the time spent driving, at least for me anyway.

One nice advantage though is that because you can hear it, you know without question that your WG is opening and doing its job. On the flip side, you may also be able to detect if it is leaking (i.e. opening when it is not supposed to).

That said, I don't think I would want it on my DD because it does attract quite a bit of attention!

ChrisJ951

I'm taking my car in to have the AEM A/F kit removed and replaced with a Zietronix ZT-2 data logger kit this week. I've asked my mechanic to check the back pressure levels, if its too high, that open pipe goes on, if its in normal range, then I stick with the exhaust the way it is.

toddk911

I know a RL member, as well as Lindsey, did a test on back pressure and the results were pretty eye opening.

For every 1 psi difference in backpressure, EGT and spool up (increased power band) were greatly affected.

911-32

I dump to atmosphere on my daily driver - can't say its that loud or annoying. I have full trim and sound deadening in the car though. General exhaust noise drowns it out. Compared to an air cooled 911 with minimal track exhaust its pretty quiet even at its most noisy - that is my point of reference.

jerome951

I have a turn-down pipe on mine and it's pretty loud when the wastegate opens. Then again, mine is rarely driven on the street.

For a daily driver I would get tired of it. I suggest you try a turn-down first, and if that is too loud, maybe have a motorcycle muffler welded on?

User 52121

I drove a 944 Turbo Cup replica, 3" exhaust, no cat, Magnaflow muffler, and a WG dump.

It was LOUD. I guess maybe some folks tolerate it more (younger, perhaps?) but it definitely wasn't for me. I do enough stupid sh*t behind the wheel, I don't need the WG calling out even MORE attention every time I lay into it.

dillon410021

wooo, attention! its sure gonna turn heads when i pass

Darwantae951

What makes you think you have a back-pressure issue?

ChrisJ951

Nothing specific, but after talking with Mike Lindsey he just said it was something to be aware of and if I didn't know what my back pressure numbers were at full boost that it would be helpful to know. I'm bringing my car in on Thursday to swap my A/F kits to the Zietronix and I asked my mechanic to check my back pressure numbers. Considering I'd like to run about 20 psi on race fuel on the race map of the M-Tune I'd like to know if its something I should address. Trust me, the last thing I want to do is make my car sound obnoxious with the wastegate muffler.

TurboTommy

You know that "checking back pressure numbers" sounds a little casual. There's a little bit involved. He has to tap in into the cross-over, and take your baby for a hard run to get the measurements
You have a 3 liter with an 8 turbo hotside; which turbine wheel?
3" inch exhaust; intake mods?, stock IC?
I'm guessing 30 psi back pressure at 15 psi boost, probably more at full revs.
Let us know what it ends up being.

dirtyTurbo

I had it with the rest of the exhaust being stock, which is funny with a LBE because when you step on it all you hear is belt whine until the wastegate opens up and then BRAAAAAHHHHH. I have a video somewhere but I never uploaded it anywhere.

As far as backpressure goes, I put it back to stock and added a pressure gauge on the crossover pipe so I could do a before and after with the dump pipe, but I haven't done the after yet. With the stock exhaust and a "cleaned out" cat I'm getting well over 30psi of backpressure