White 2-105 no boost? Suddenly

[Shadow_storm56]

So this tractor stopped making boost and sofar nothing has been that AHa that's why. Intake had a section of bad gasket and was leaking but that didn't help, turbo is spinning and exhaust manifold is not leaking.

I only noticed one thing which can reduce efficiency but shouldn't make it lose all boost, The divider for the twin scroll turbo is partially rotted out on the manifold. I can imagine that making boost go to 0 though. The turbo itself appears fine.

Ideas?

 

[lugbolt]

do a intake pressure test and see if there's a connection somewhere leaking. Basically you'd attach a piece of pvc with a ball valve and a air hose fitting to the front of the turbo, and apply 10-15 psi to the system. Then use soapy water to find leaks.

I do it periodically on my truck and often find little leaks. Even small leaks cause a huge loss in pressure and big time increase in shaft speed. Since mine is wastegated, it will only make 25 psi, but with an intake system leak, the rotating parts have to turn faster to make 25 psi-which is hard on the turbo. It has a maximum sustained speed, I think 130,000 RPM.

also an engine issue can cause the same thing, misadjusted intake valves, etc-causing a "boost leak".

if it's wastegated, make sure the gate isn't stuck open, arm came off, or perhaps the housing where the "puck" makes contact is rotted/broken/cracked.

 

[Shadow_storm56]

do a intake pressure test and see if there's a connection somewhere leaking. Basically you'd attach a piece of pvc with a ball valve and a air hose fitting to the front of the turbo, and apply 10-15 psi to the system. Then use soapy water to find leaks.

I do it periodically on my truck and often find little leaks. Even small leaks cause a huge loss in pressure and big time increase in shaft speed. Since mine is wastegated, it will only make 25 psi, but with an intake system leak, the rotating parts have to turn faster to make 25 psi-which is hard on the turbo. It has a maximum sustained speed, I think 130,000 RPM.

also an engine issue can cause the same thing, misadjusted intake valves, etc-causing a "boost leak".

if it's wastegated, make sure the gate isn't stuck open, arm came off, or perhaps the housing where the "puck" makes contact is rotted/broken/cracked.

So one of the intake gaskets was gone which was blowing a ton of air out and the divider for the twin scroll was rotted out which further weakens power to the turbo. Fixed both of thoes and now it works again, Started driving and immediately heard it again, I was like "Ah there it is!"

It's an older tractor designed with no intercooler so under heavy load 10-15 psi boost is what's expected and that's around what I get.

Yeeehaw

 

[lugbolt]

So one of the intake gaskets was gone which was blowing a ton of air out and the divider for the twin scroll was rotted out which further weakens power to the turbo. Fixed both of thoes and now it works again, Started driving and immediately heard it again, I was like "Ah there it is!"

It's an older tractor designed with no intercooler so under heavy load 10-15 psi boost is what's expected and that's around what I get.

Yeeehaw

twin scroll doesn't necessarily "weaken the power", all it does is to even out the pulses going to the turbine wheel, which helps it spool sooner (reduces lag, and improves overall turbocharger response). That is it's only purpose. Improving response is nice in automotive applications as the OEM's can use a larger turbine housing than they normally could if it were an "open scroll"--which helps both low end response and top end power. But it only works 'properly' if the manifold is properly divided (on a typical 4 cyl with a 1-3-4-2 firing sequence, you'd pair #1 and #4 into one scroll and #2 and #3 into the other-using a equal length runner manifold.

In the past dealing with cars and trucks (gas and diesel), I have milled the divider completely out, at least as far as I could get in there to do so. It makes the wastgate work a little better in certain applications. Have also replaced twin scroll housing with open housing and noticed little to no difference. So I wouldn't put too much concern into the rotted divider.

 

[Shadow_storm56]

twin scroll doesn't necessarily "weaken the power", all it does is to even out the pulses going to the turbine wheel, which helps it spool sooner (reduces lag, and improves overall turbocharger response). That is it's only purpose. Improving response is nice in automotive applications as the OEM's can use a larger turbine housing than they normally could if it were an "open scroll"--which helps both low end response and top end power. But it only works 'properly' if the manifold is properly divided (on a typical 4 cyl with a 1-3-4-2 firing sequence, you'd pair #1 and #4 into one scroll and #2 and #3 into the other-using a equal length runner manifold.

In the past dealing with cars and trucks (gas and diesel), I have milled the divider completely out, at least as far as I could get in there to do so. It makes the wastgate work a little better in certain applications. Have also replaced twin scroll housing with open housing and noticed little to no difference. So I wouldn't put too much concern into the rotted divider.

Musta mainly been the intake leak then

 

[lugbolt]

probably

build yourself a boost leak checker and pressurize the system. Fix the leaks if you haven't already. It makes a huge difference.

I made mine out of a piece of pvc pipe, a cap on one end and in the cap is a 1/4" ball valve with an air hose fitting, and also a pressure gauge. Open end of the pipe goes on the front of the turbo. Put the air hose on it, turn the ball valve until it shows 10-15 psi (dont put too much in or it'll explode the pvc) and then using soapy water around all the intake joints, you'll find the leaks if there are any.

On my truck (old clattering 7.3L) it made a HUGE difference and the leaks were tiny.

On the car, I had a rich code populating every so often, poorer fuel mileage than I thought it should have, and some weird driveability issues. Fixed the boost leaks (pre throttle body and post throttle body) and it is a different car now. More linear response, idles a lot better, boost hits a lot faster and harder, about 8 mpg better fuel economy and no more codes.

I posted this for all of you turbo junkies not just for the OP. Boost (and exhaust) leaks are a big deal on anything that is forced induction, in particular turbocharged but supercharged also benefits.

 

[Shadow_storm56]

probably

build yourself a boost leak checker and pressurize the system. Fix the leaks if you haven't already. It makes a huge difference.

I made mine out of a piece of pvc pipe, a cap on one end and in the cap is a 1/4" ball valve with an air hose fitting, and also a pressure gauge. Open end of the pipe goes on the front of the turbo. Put the air hose on it, turn the ball valve until it shows 10-15 psi (dont put too much in or it'll explode the pvc) and then using soapy water around all the intake joints, you'll find the leaks if there are any.

On my truck (old clattering 7.3L) it made a HUGE difference and the leaks were tiny.

On the car, I had a rich code populating every so often, poorer fuel mileage than I thought it should have, and some weird driveability issues. Fixed the boost leaks (pre throttle body and post throttle body) and it is a different car now. More linear response, idles a lot better, boost hits a lot faster and harder, about 8 mpg better fuel economy and no more codes.

I posted this for all of you turbo junkies not just for the OP. Boost (and exhaust) leaks are a big deal on anything that is forced induction, in particular turbocharged but supercharged also benefits.

It's all about that whistle haha