Is it possible to run lower than wastegate pressure?

[mezzio]

Right now my car is running the super special idiot went to town on vacuum hoses mod of only running WG pressure, which if I'm not mistake is down to 9psi from the stock 15psi or so, correct?

I bought an MBC and boost gauge, and was curious, is it possible to run lower than WG pressure? like 5psi or so? My buddy and I got into a debate about it, I don't think it would be possible, running anything lower than the 9psi would just not allow the WG to open at all by just venting off anything the turbo is putting out, hence having essentially a really cool looking NA motor, he says setting the MBC lower than the 9psi would boost at whatever level you set it to.

This comes up because we were talking about keeping the boost lower for winter to make it easier to drive if the roads are bad. If I'm wrong, oh well, I'm always up for learning something new.

 

[dented_coffee]

I don't know id it's not good to but my uncle drove a turbo'd NA dsm for a long time with a rusted shut wastegate arm. He had a MBC running 7psi. It never gave him any problems at all.

He still has it as his winter beater and runs like a champ.

So I'm sure you should be fine with a low level of boost like that. I also drove my 1994 on the highway for over 4 hours with no BOV and a rusted shut wastegate a few months ago. I had a peice of PVC pip in place of the BOV hard pipe so I wouldn't have major boost leaks. My talon is stll running strong with no signes of stopping. I just had to stay out of boost as much as possible, but couldnt help it so i boosted a few times just to feel the DSM power again .

Just make sure your BOV can open with such a small amount that your running and you should be ok. I know they sell kits for 7psi and the wastegate is only a 9psi rating.

 

[crash89]

my uncle drove a turbo'd NA dsm for a long time with a rusted shut wastegate arm. He had a MBC running 7psi. It never gave him any problems at all.

First, I dont know how he could run 7 psi with a seized SHUT wastegate flapper. If thats not opening youll just keep building and building boost until you hit fuel cut.

I dont really understand your first sentence at all?? Stock boost is around 9-12 psi. If you turn your MBC all the way out youll just run whatever psi the wastegate was designed to open at. However, you could take the arm off of the wastegate flapper. Then you wouldnt be able to build any boost at all because there would be no pressure holding the flapper shut.

 

[91Bomb]

Stock boost is 11 lbs not 15.

When boost control solenoid is activated by knock sensor bcs limits boost to 5-7 lbs so perhaps find a way to keep bcs activated

 

[CardShark]

First, I dont know how he could run 7 psi with a seized SHUT wastegate flapper. If thats not opening youll just keep building and building boost until you hit fuel cut.

I dont really understand your first sentence at all?? Stock boost is around 9-12 psi. If you turn your MBC all the way out youll just run whatever psi the wastegate was designed to open at. However, you could take the arm off of the wastegate flapper. Then you wouldnt be able to build any boost at all because there would be no pressure holding the flapper shut.

+1 The simple answer to your question is no, the WG pressure is the minimum boost you can run without just leaving the WG flapper open.

Here is some good info on how a MBC and Wastegate works: Intro to Boost Control

 

[rock1t]

I don't know id it's not good to but my uncle drove a turbo'd NA dsm for a long time .

i'm just wondering how you can have a turbocharged naturally aspirated engine

doesn't sound right. i have heard of the turbocharged, supercharged, naturally aspirated, and even twin charged, but not a turbocharged n/a.

 

[Locke]

+1 The simple answer to your question is no, the WG pressure is the minimum boost you can run without just leaving the WG flapper open.

Here is some good info on how a MBC and Wastegate works: Intro to Boost Control

^^ This.

 

[mezzio]

Stock boost is 11 lbs not 15.

When boost control solenoid is activated by knock sensor bcs limits boost to 5-7 lbs so perhaps find a way to keep bcs activated

wasn't the boost turned up from 12 in the 1g's to something like 14.8 in the 2g's?

 

[CardShark]

i'm just wondering how you can have a turbocharged naturally aspirated engine

Perhaps he meant they put a turbo on a non-turbo engine

wasn't the boost turned up from 12 in the 1g's to something like 14.8 in the 2g's?

Boost on a completely stock 2G can be anywhere from 12-14 psi depending on when the crappy plastic BOV starts to leak.