porshhhh951

Never said it didn't however changing out from the stock wastegate does increase spool up times and hold boost for longer. That means more power. My car was completely different after I changed out from my stock wastegate and btw I already had a LBE.

I'm not repeating anything. I'm speaking from personal expeirence. Infact is was soo much different I initially thought I was holding ALL the boost till redline. I was still loosing a few pounds but, not nearly as much. Car felt much stronger.

btw who pee'd in your cheerios this morning?

eniac

The stock wastegate is a single port unit which relies solely on the light spring to keep it closed. It WILL bleed boost to a certain extent no matter how new it is. A new stock wastegate will bleed off less boost then a worn one of course and with a large turbo running a lower PSI, it may not be noticable.

It is also difficult to dial in a single port wastegate as shown above. A dual port design is far better in every way and does not require modifying pipes to "mask" boost issues. The dual port use the turob's own boost pressure to keep the wastegate closed along with the spring, this allows boost to hit much harder.

A single port with gradually open over a longer period of time as boost rises.

A dual port will stay closed until you want it to open, making the opening time much shorter and thus more power earlier on. All of this is dependant on how you set up the boost controller.

If comparing a stock wastegate to an aftermarket run in single port mode, then there will still be some gain from something like a Tial due to the design of the valve and direction of movement. Tial's also allow you to easily swap springs.

There's a good reason Tial wastegates and such are not legal in PCA stock racing.

TurboTommy

Guys;
alot of us have to replace our wastegates because they are simple getting old. So, that's why we're all going to see some sort of an increase in performance, going to a fresh wastegate.
It's the same thing if we replace an ignition component, or do a valve job; we are renewing, and we feel the difference, no doubt.
And, I'm not for a second disputing that if we use a wastegate with a stiffer spring and/or the wastegate valve gets pressed into its' seat from the exhaust, that we will have a change (to most of us, for the better) in the way boost is controlled. But, that's what it is: the way boost is controlled, which can be done number of different ways; it doesn't have to be a wastegate.
When I read: "A DP wastegate WILL give you more hp even at stock boost levels", well, I just like to keep it real. It's like saying: "I change from a MBC to an EBC and I"m gettin' more power at the same boost levels", which is not so.
I know the stock wastegate system is a little wierd, but it optimizes the relationship between intake manifold pressure and exhaust back pressure. Another words: two 944 turbos achieving the same boost pressure; the one with the stock wastegate will most likely make more power than the one with the after-market wategate. Note, that does not mean that the stock wastegate makes more power, it just means that the after-market wastegate possibly masks an inefficiency somewhere.

ehall

cool. thanks. That's pretty much what I thought you were saying.

Lorax

You have some kind of data to back that up?

theedge

That really only applies with a stock turbo/engine/exhaust or a poorly chosen setup. Otherwise that goes completely against logic. If you have two 951s with properly selected exhausts, turbos, etc, to make sure backpressure and all that isnt exessive then the dual port wastegate will make more power than a stock wastegate. The way youre explaining it is completely backwards IMHO. Bleeding off boost doesnt make power.

TurboTommy

eniac;
"A dual port design is far better in every way and does not require modifying pipes to "mask" boost issues."
I'm not sure if you're referring to my issues of boost creep. Boost creep can never be solved by dual port design or any other type of control for that matter.

"A single port with gradually open over a longer period of time as boost rises."
Just use a heavier spring and it will not open even in single port.

"A dual port will stay closed until you want it to open, making the opening time much shorter and thus more power earlier on. All of this is dependant on how you set up the boost controller."
You can do the same thing with a boost controller of your choice in front of a single port.

TurboTommy

theedge;
I never said anything about two 944 turbos, both with proper turbos and exhaust ,etc.
I just said two 944 turbos running the same boost.
That's the whole point: an aftermarket wastegate MIGHT mask an inefficiency somewhere, whereas the stocker shows a weakness right away.
Ya see, if it was up to me, I'd upgrade my airflow producing components so that I can get great results even with the stock wastegate and if I don't like how the boost is controlled, I'll swap out the wastegate or different boost controller.

TurboTim

Well if two cars with the same mods,running the same boost levels with the difference being only the wastegate,the DP wastegate will make more power 99 out of 100 times.It will hit full boost sooner and make its peak torque sooner and will hold boost(the same amount of boost) longer in the rpm range which is the hp gain.

eniac

Really? Because I had boost creeping up in 4th and 5th gears only so I went into my AVC-R and adjusted the solenoid duty cycle for those 2 gears starting at 4500rpm. Once it was dialed in, my boost was rock steady even at up to 30psi.

I wasn't aware there was a place that sold heavier springs for the stock wastegate. Besides that, once any pressure is applied to the spring, it starts to open, maybe not much but it does. Also a heavier spring has it's own issues as well. I.E. boost creep and boost spikes in the lower gears. Maybe it's just me but I much prefer to reach down and change a few settings over getting under the car to pull the WG off to change a spring.

The fact is that you get more control and fine tuning with a dual port wastegate, Also as mentioned the better newer wastegate out now have a better valve system then what was designed over 30 years ago.

More adjustabilty and greater fine tuning + a better design = more power.

I do agree that replacing a worn stock wastegate with a brand new one will make most cars feel faster, but I also do know from personal experience that replacing an almost new(2 months old) stock wastegate with a Lindsey dp wategate using the same MBC at the same boost level made it feel like a different beast. The turbo spooled sooner and the low gear boost spikes were able to be dialed out with the MBC.

porshhhh951

Precisely.

eniac

Yes, that's all that really needs to be said. I am confident Tim made this statemate based on results that he saw personally. I also made my comments based on what I saw personally.

It's pretty tough to argue with real world results.

TurboTommy

TurboTim;
I'm not knocking a dual port wastegate; I think it's a great way to control boost.
But, if you install a boost controller (an EBC, for example) that stops any boost signal from going to a wastegate would it not achieve the same thing as a dual port?

TurboTommy

Besides, if one says "it will hold boost longer in the rpm range", then that's not really running the same boost levels now, is it. (Because, you're running more at certain high RPMs)

eniac

If boost is set at 18 psi then you make changes that allow you to get to that 18 psi sooner and hold it longer, your still at the same boost level, 18 psi. The boost curve does obviously change so boost @ a certain RPM will change, that's the benefit. If it didn't change then there would be no difference. The peak boost however can be exactly the same(set at 18 psi in this example).

It's not where you end up, it's getting that makes these cars so fun.