mahoney944

when i say it doesn make a difference, i mean from a testing point of view, not performance. a duel port has a much better control of the spring pressure then without.

Paulyy

These are the factors Louis and i where discussing. But someone didn't agree.

Paulyy

Clearly it does make a difference as you can see from the 2 dyno charts.

mahoney944

and just pondering the thought of a shim vs dual port. a duel port changes the spring pressure without affecting the travel of the guide valve. where a shim would displace the distance of the shim, on a stock wastegate this means the wastegate cant open as far, meaning exhaust cant get out as well and would be directed through the turbo. this actually explains why you might see a difference from a stock shimmed wastegate to a dual port on the same setting getting different levels of boost.

mahoney944

a dyno chart is a performance check...we were discussion testing purposes of the wastgate for correct operation.

lart951

Okay, lets agree that's case, but it happened to whole load of guys, lots of threads about this occurrence, conclusion the stock wastegate due to it's age is worn and bleeds boost true or false?.

Paulyy

It's also a form of data.

Paulyy

+1

mahoney944

Unfortunately i dont think this is as simple as a true and false. I think each case will vary. its hard to predict with factors like age, rust, soot, broken down diaphrams, shimmed or not shimmed as well as external factory like exhaust flow, engine size, boost/vac leaks, and im sure i could write all day. I dont think the valve will open solely on exhaust pressure. because of the high to low gas exchange. like turbotommy said even if the valve were to crack open the pipe on the other side is low pressure and the pressure would equalize quickly, maybe creating a light pulse, but not enough to regulate boost from over spinning the turbo.

on a side note, from speaking with dave lindsey these springs dont really wear in their opinion, they just are not strong to begin with. this i cant confirm

lart951

WRONG ANSWER, THREAD IS CLOSED

Paulyy

Here's a log of a "weak spring" couldn't get over 12 psi
10psi at 3900 rpm



Here's a log of a good spring. 20 psi.
10psi @ 3750 rpm



The difference on the boost controller? there is none. both done on the same duty cycle of 50.

Oh will you look at that. There is a difference between a **** spring to a good one.

reno808

This is my question why are we arguing about stock wastegates?? Who uses stock wastegates? why not just upgrade to a tial and be done with it. You can make them do what ever you want.

BTW fellas why not just pull out the wastegate and test it with a hand pump. booom problem solved.

67King

Racers (E/F stock, SP3) are not currently allowed to run aftermarket style wastegates, that is who uses stock wastegates. Am I happy about that? No, seems the 12PSI limit they set should be all that is necessary.

Hand pump testing won't tell teh full story, at least the way I understand it (and the disclaimer there is that I may be mistaken.......since being mistaken seems to be a cardinal sin around here wiht this subject ). The spring requires a force to overcome. The force is s result of pressure pushing on an area. WIth the stock wastegate, you get pressure from two areas, the valve itself, which may have a cross sectional area of a couple of square inches. Plus the exhaust pressure will be higher than the intake pressure. So let's say exhaust pressure is 20 PSI, you'll have 40 pounds of pressure acting on the valve from the exhaust side. Contrast that with the aftermarket, which will have 40 pounds trying to keep it closed.

On hte diaphragm side, you have a much larger area, maybe 10 square inches. If you are at 12PSI, you have 120 pounds of force trying to open the valve.

So on the stock style, you'll have 160 pounds of force, and on an aftermarket one, you'll have 80 pounds of force. Using a hand pump would give one a false impression of when it would open in both cases, I believe.

All that said, I SCANNED through 5 pages of this crap, and I honestly don't see nearly as much disagreement as those who are arguing. It is clear to me which wastegate is being considered, but they all seem to think their opponents are talking about the wrong one.

But Mahoney, the insults are completely and totally unnecessary. You are going to wind up getting put on ignore by a LOT of people if you keep it up. And not everyone you are ticking off falls into your tranche of "idiot."

reno808

Lindsey racing sells an "upgrade" wastegate that is called clubsport or something like that if i am not mistaken.

The wastegate spring is the lowest amount of psi you can run. To test this you can hook it up to a air comp with a regulator with a gauge you let air in and you will see the valve will start to open at a given psi. their are few ways of controlling boost. When you use a manual boost controller you set the psi to what ever you want and the wastegate won't see any pressure until that level is reached. When boost level is reached, the valve will open and begin to bypass exhaust gas, preventing boost from increasing.

The issue we are dealing with is the 20+ year old system and many ppl messing with the system. Anything can change to the way the system behaves. for example if you have a not so good source line for the wastegate then your going to get crappy results. weak diaphragms weak valves will alter results. You ppl are not comparing apples to apples but apples to oranges.

lart951

it all started here,

https://rennlist.com/forums/944-turb...ified-car.html