The Frankenstein Build! LT/Expo/Trail rig..and BS

It is real odd. Does your Tim or one of his buddies have a lathe we could borrow? Would not require much. I would estimate maybe a 1/16" or less of material in a very small area. haha.

 

Nah he doesn't have one..might know someone that does though

 

I just read the exchange you guys had, Its not clear whether he is interested in that spare or not. Are you thinking he wants all 5?

 

No idea

 

Hmmm. Would take a fairly large one to be able to handle a 15" diameter object.

 

The local metal shop could do it I'm sure.

 

Lets see what he wants. If he only wants the 4, then maybe you and I can work something out for the 5th.

 

Okay ill ask him

 

Thanks Monte

 

Hmmm... I'm what sure what you mean here. The waste gate can and will open partially on partial throttle. The wastegate is controlled by the wastegate actuator, which is vacuum driven. The actuator is attached to a little arm that controls the wastegate, opening and closing it to maintain your desired boost pressure.

The Blow-off valve, on the other hand, work just like you were describing. It won't actuate until you need to release boost on the compressor side though. The wastegate is on the turbine side of the turbo.

I think of it this way: when I'm at 4-5k, partial throttle, I have enough mass-air-flow to spool my turbo even at partial throttle. To prevent me from getting closed loop boost at that time, my waste gate is partially open.

Here's another way of describing what I'm talking about:

http://www.gencoupe.com/2-0t-discus...tegate-actuator-blow-off-valve-explained.html

Does your system work differently?

 

Just because the turbo is spinning/spooling does not mean it it's making boost. It still has to overcome atmospheric pressure. I'm not sure where you are getting information that the wastegate is open. The only thing that opens a wastegate is boost pressure (which is measured above atmospheric). Any turbo motor can be in vacuum anywhere in the rpm range if there isn't a load on the engine.

 

Recheck my post. I updated it with better information. And I should clarify. They wastegate is not always open, but may be.

Here's a quote for what I'm trying to say:

When this swing arm gate opens exhaust gas is bypassed from the turbo. When the gas is bypassed the turbo doesn't spin as much, which results in a boost drop. So depending on the boost level this swing arm constantly opens and closes to keep the boost level at a desired level. Then what controls this internal swing arm gate(internal wastegate)?

This swing arm gate is controlled (opened and closed) by the actuator.

 

Exactly. The wastegate is only opened by boost pressure at a certain max then closes again till it hits that max again. Say there's a 7 psi spring in the wastegate, it won't open till there's 7 psi boost and stays open till it goes lower than 7. Therefore it is not open to "maintain" vacuum. The turbo just isn't building enough pressure to overcome atmospheric and you can still have vacuum. That's how turbo vehicles get better gas mileage, because the turbo does help compress air even when in vacuum.

I'm not going to "argue" about it but they aren't open till boost pressure has been reached.

 

^I'm not trying to argue either but keep in mind that the system is based on the differential boost pressure from both sides of the turbo. That's my point. I think we agree that the gate is not always open, but it does open (frequently) in cases of partial throttle, even when you are cruising. In my case, I'll sit at 2 psi, partial throttle and, as my foot moves on and off throttle, I will hear both my recirculating blow-off valve and my waste gate cycle. Hence:

"So depending on th eboost level this swing arm CONSTANTLY opens and closes to keep the boost level at a desired level"

Bottom line: Without the wastegate opening, you'll end up with a "closed loop" system and rely on the intermittent use of a blow off valve to prevent a runaway boost situation. The wastegate is especially designed to prevent that.

 

You don't have to have a boost controller to maintain lower boost levels. It's simple there just isn't the full load on the engine to make full boost, thats all there is to it. If I had my old car id take video to prove you can maintain a lower boost level without the wastegate being open.

It's just like having max torque/hp at a certain rpm. It's not always there unless the engine is loaded all the way....

 

The engine doesn't have to be loaded "all the way" to make boost. In fact, most if the time it isn't. (I can hit my peak boost at 70% throttle with my boost spike) Again, I updated my post to clarify.

Bottom Line: The waste gate prevents closed loop boost runaway. You don't need full throttle to be in that condition. In fact, you can hit that condition almost anywhere. That's why the wastegate is "constantly" moving. Not just at full throttle situations.

 

I understand how it works. But the whole reason this started is cause you were saying the wastegate is open while in vacuum which it is not.

 

OH! No, you're right. It's not open in vacuum. I must have been confused I thought you were saying you needed full throttle situations to activate your wastegate.

 

no I understand you don't need full throttle to build boost. But it also won't always have boost which is what I was trying to say (vacuum is still possible at any rpm in other words). This talk makes me miss my turbo 240 I had, so fun. 300hp at 2500 rpm.


Now lets see some moar truck pictars!!!