Boosting problem need help.

[Whiteturbot87]

So i need some help i have a boost issue. Ive got a t70 turbo and a wastegate with an 8lb spring. Its been like that since i first got the car, and whenever i had my foot in it always showed 8lbs of boost on the gauge at wot. Note i have one line from turbo to bottom of wastegate and a T in that line with another hose to top of wastegate. So recently my car went to a shop to get some brake and suspension work done but the guy at the shop said he noticed i had no controller in that bottom line and that he checked it with a manual guage and said it was making over 30psi! He added a basic mbc and said he left it turned to 12 psi boost. Now when i drive the car i barely see any movement in the boost gauge and it feels like its barely making any boost. Whats wrong here? How could my 8lb spring possibly make 30#?? Especially if my guage also reads 8, ive heard of bad guages but that seems pretty coincidental if so. Also why does it seem like the cars barely builsing boost? Ill get pictures, any advice greatly appreciated.

 

[Whiteturbot87]

 

[No disintegrations]

He goofed somehow. The surface area of the waste gate is important. Psi and spring pounds are not always going to be the same. It prob takes 30 psi exhaust pressure to make 20 psi in the intake. When desired boost is made in the intake the gate needs to start opening to stop boost from rising more.

Also sound like you've had a leak in the boost gauge hose. 8psi is way low boost.

 

[Whiteturbot87]

View attachment 286183

He goofed somehow. The surface area of the waste gate is important. Psi and spring pounds are not always going to be the same. It prob takes 30 psi exhaust pressure to make 20 psi in the intake. When desired boost is made in the intake the gate needs to start opening to stop boost from rising more.

Also sound like you've had a leak in the boost gauge hose. 8psi is way low boost.

So why do you think its making so little boost now? How could he have got 30psi? And should i pull the controller out and go back to how it was, when it seemed like it was actually making a fair amount of boost

 

[Whiteturbot87]

View attachment 286183

He goofed somehow. The surface area of the waste gate is important. Psi and spring pounds are not always going to be the same. It prob takes 30 psi exhaust pressure to make 20 psi in the intake. When desired boost is made in the intake the gate needs to start opening to stop boost from rising more.

Also sound like you've had a leak in the boost gauge hose. 8psi is way low boost.

So why do you think its making so little boost now? How could he have got 30psi? And should i pull the controller out and go back to how it was, when it seemed like it was actually making a fair amount of boost

 

[Whiteturbot87]

Also i found a leak in the boost gauge line where its attached. Replacing that today, but i still dont see how that means i was making 30psi without a regulator, especially when i saw 8-9. And why is it barely ahowing any boost with the tegukator hooked up??

 

[No disintegrations]

I just think he went backwards on his thinking. I'm not sure how or what he tested. You need to begin at the beginning again! lol

 

[No disintegrations]

Try to turn it up gradually, but verify that boost gauge first.

Is the reg knob turned all the way clockwise or counter clockwise?

 

[TURBOELKY]

30psi of boost with a T70, unless you really know how to tune....would have ended as a post in the "engine tech" with you asking what the big boom and puff of smoke is?

 

[TurboTGuy]

Is that a GN1 3" downpipe?

 

[Jerryl]

.

 

[bison]

I see several things that will get you in a lot of trouble just looking at those pics. Those hoses are prone to failure and blow off coming off that block and your cheap external wastegate is not ideally plumbed for good linear boost control. If you're not sure if your manifold pressure is 8psi or 30psi you need to bring the car to a shop that has the proper logging equipment and get your wastegate configuration straitened out


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[TURBOELKY]

Is that an oil pressure gauge on top of the turbo???

 

[strungout6]

You stated that when you took the car originally in to the shop it didn't have a manual boost controller on it? That it was plumbed basically off the compressor housing and T'ed to the top and bottom of the waste gate. If that's the case you were forcing the waste gate shut under boost and you were probably getting "all the boost" that turbo could spit out. When he installed the adjustable controller and turned it down to 12lbs it would feel completely different to you after riding in it at 30lbs. It must be on e85 or have alky or you would have toasted it. You said your gauge had a leak you found and that explains why it was only reading 8lbs before.

 

[Mike Horak]

So recently my car went to a shop to get some brake and suspension work done but the guy at the shop said

I think I would recommend starting at square one after seeing the "brake and suspension" work scenario. Not saying "the guy" was not knowledgeable but.............