Max boost only with WG hose pinched

[SVALIN]

….So, no. Definitely bad to have it plugged. 45 boost, 80 BP (high mark, usually 70 or 60) only 1260 egt though.
 

This was on the smaller 0-100 gauge though, so thats 2 different variables. I feel its pretty accurate though.

 

This makes some sense finally. Above 40s gotta be the near choke point.

 

Definitely want the wastegate to be functional. So next test is reset actuator to 40 lbs and boost adjustable elbow. 

[Tractorman]

3 hours ago, SVALIN said:

So next test is reset actuator to 40 lbs and boost adjustable elbow. 

 

I am interested to hear the results.

 

- John

[SVALIN]

So I made my own adjustable elbow. Im noticing from online photos that there seems to be a vent drilled into it? Or atmosphere pressure? The one I made just put an allen to block off/restrict pathway. So if im missing something may have to try again.

 

it made no difference, several attempts at different amounts. I readjusted waste gate to open at 45 lbs, which has netted me 33 or so boost.

 

I installed a boost reference gauge, very similar to my back pressure setup. It showed the same pressure as my MAP sensor. No higher than 34. 1160 egt. 

So I guess that sorta settles it. Drive pressure has to be assisting the wastegate opening. When I adjust the arm all the way in, im getting more boost from preload, but also limiting how far the door can open, increasing Egt and drive pressure, and cant seem to get enough before running into choke point.

 

Another note about this/these turbos. Ive seen a lot of similar/close 64s on the market, spoologic, cheetah, stealth. So sorta bizzarre I seem to be only one running into this, but not seeing many other conclusions.

 

If Im missing something, let me know. Otherwise I hope I collected some useful data for spinning my wheels for a week.

[Tractorman]

1 hour ago, SVALIN said:

So I made my own adjustable elbow. Im noticing from online photos that there seems to be a vent drilled into it? Or atmosphere pressure? The one I made just put an allen to block off/restrict pathway. So if im missing something may have to try again.

 

The drilled hole is a vent and it is needed to make the boost elbow work.  If there is no vent, the boost flow can be restricted, but air will eventually fill the wastegate actuator chamber resulting in no change of wastegate operation, other than the wastegate will take a bit longer to open.

 

The drilled orifice is downstream of the adjustable restrictor.  The orifice will also act as a restriction, but as pressure builds the flow leaving orifice to atmosphere will match the flow passing through the adjustable restrictor at some point.  When this happens, the new pressure value acting on the the wastegate actuator will now be lower than the actual boost pressure value of the air entering the boost elbow.  The wastegate will not open.

 

1 hour ago, SVALIN said:

Drive pressure has to be assisting the wastegate opening.

 

Yes, this is true.  Exhaust flow that enters the turbine housing is exposed to some of the area of the closed wastegate valve.  That area can be calculated by measuring the diameter of the exposed area.  Example:

 

Formula to calculate force.  Diameter squared times .7854.  (D2 x .7854)  Let's say the exposed diameter of the closed wastegate valve is one-half inch.

 

.5 x .5 x .7854 = .19635 square inches.  I will round that to .20 square inches.  Multiplying .20 square inches by 50 psi (turbine drive pressure) will equal 10 lbs of force pushing against a mechanical spring.

 

The same method can be used to calculate the force of the wastegate actuator rod under a specific boost pressure.

 

- John

 

 

 

 

Edited May 26, 2022 by Tractorman
mistakes

[Mopar1973Man]

Mine is way different its two body halves with a spring and check ball inside the unit. As you screw it together it increases the boost pressure, loosen then there is less boost pressure. I gave up on those boost elbows since its just a controlled boost leak and now a regulator for the wastegate. The check ball keeps the line closed till the boost pressure is enough to open and push the wastegate. This also has a small bleed hole too to release the waste gate after the pressure falls again but works way better than those boost elbows. 

 

I got mine off of eBay from a place in China it took awhile but it was a mere $15 bucks or so. 

[SVALIN]

@Tractorman All very good information, paper calculations with BP are matching up closely with the WG numbers. This should be fairly true across the board, Even with units that have a lot less BP. I guess not many complaints though if say gate is set to 40 and getting 38.

 

@Mopar1973Man Pray tell more about this fingertrap invention. Having a constant boost leak isn’t ideal. I found a PPE 116030000 Boost valve that looks like what your describing. Its preset though much lower, 25 psi, and designed for a LB7. Ebay search resulted in nil.

 

 

[Mopar1973Man]

20 hours ago, SVALIN said:

@Mopar1973Man Pray tell more about this fingertrap invention. Having a constant boost leak isn’t ideal. I found a PPE 116030000 Boost valve that looks like what your describing. Its preset though much lower, 25 psi, and designed for a LB7. Ebay search resulted in nil.

 

 

Here you go...

 

Inside is a check ball and spring but still has a small bleed hole to allow for the pressure to be released after the boost pressure falls. The check ball will close again keeping the boost going strong. 

 

Tested and proven at least on my truck. I pulled the wastegate hose loose and left it open not plugged. Then pulled 1 manifold bolt out as a open hole leak. As for max boost pressure was only down 5 PSI and had ZERO impact on EGT's on my truck made little to no different even while WOT operation. So as for the tiny pin hole boost leak has ZERO impat on performance nor will it change the EGT's when I've had a leak that was MASSIVE comparing it didn't run hot or smoke any differently. 

Edited May 31, 2022 by Mopar1973Man

[SVALIN]

Thanks! @Mopar1973Man

 

I couldn’t find that specific unit. I did find a Swagelok 4-CPA2-3. Prefix SS for stainless, B for brass. Couldnt find brass in stock. About 40$. Adjustable poppet check valve from 3-50 psi. I set it to 40, starts to crack at 38. I attached 1/4” hose barbs on either side, and drilled a .040 hole on actuator side. Planning to mount as close to actuator for hose bleed off reasons.

 

I haven’t installed it yet, because I swapped back to RV275s for moment, and putting everything on it, can only get to 34 psi. So Ill have to wait before posting results on that. 

[IBMobile]

This is where my manual boost adjuster is mounted, the top of the alternator bracket.