Builds Big Red Toy (1 Viewer)

[boots4]

Interesting. I have a working wastegate on my small turbo that I've tuned to share the load. With your small turbo's gate sealed you are probably using all small turbo and hardly none of the big. Your small will boost quicker but your large will add the airflow that will keep things cool. If you list some boost pairings I can do some math and get you some info to look at. This is assuming you have two boost gauges, a total boost gauge and a gauge hooked up to just the big turbo. The little turbo has to be calculated. Fill in the X

Total boost: 10 Big turbo boost: X
Total boost: 20 Big turbo boost: X
Total boost: 30 Big turbo boost: X
Total boost: 40 Big turbo boost: X

 

[The Phoenician]

There's usually a 9 or 11 psi difference between the large turbo boost and the total boost. My big turbo gauge would read 4 psi if my total boost is around 15 for sustained highway speeds. When I really get on it, I've seen the large turbo got up to 7psi, which seems like nothing, but you feel the difference.

I've suspected my large one isn't working to full potential, but I'm honestly happy with the upgrade compared to before and would rather have reliability over performance. I'm constantly worried I'll break down in the middle of nowhere. But I'm up for some experimentation so long as it doesn't blow gaskets.

 

[boots4]

If you are able to get me those numbers we can see what the little turbo is doing. I just want to be a little more accurate. I think we want to get your big turbo doing some more work and that will bring down your egts and increase your power. I think some tuning onthe turbos could help out power and reliability.

A wastegate on the small turbo will allow you to tune how the load is shared between the two. A wastegate on the big will allow you to limit total boost or tuning fueling on the IP will limit total boost. With no wastegate on the small you may be choking it and causing higher egts. You should be able to get into the mid to upper 40's comfortably.

Side questions (they are probably in your thread somewhere but I haven't looked yet): Do you have head studs? What were they torqued down too? What is your timing set at? Do you know what injectors you have? I do remember that you have bigger delivery valves in the IP. What kind of lift pump do you have and what pressure is it delivering?

When I get on mine my big turbo is pushing 25-30 psi with a total boost at 55-60 psi. I have mine set for the big turbo to do a little more of the load to get more airflow in the system. Egts are 1200F pushing that but do rise up a little more on longer pulls up the hill.

 

[The Phoenician]

I'll get you the numbers, but it will be a few weeks, I'm out of town for work and it's just going to be sitting in the backyard until I come back.. I do have head studs in. I blew out a gasket so we changed it out and I think they were torqued down to 115 or 125, no issues there since. The injectors were replaced with a +50 hp I believe and I do have larger delivery valves, but need to go back in my thread to remember what size exactly.

 

[boots4]

No problem, thanks for answering my questions. One last question for the calculations, what elevation are you normally at?

We'll revisit this once you get back.

 

[The Phoenician]

No problem, thanks for answering my questions. One last question for the calculations, what elevation are you normally at?

We'll revisit this once you get back.

Elevation fluctuates between 650 and 755 feet, depending if I'm in San Antonio or Georgetown that week.

Thanks for all your help. Happy New Year.

 

[The Phoenician]

@boots4

Here are some numbers from memory. I remember looking at this a lot when I first got the compounds on there. Big turbo numbers might be off by plus or minus 1.

Total boost: 10 Big turbo boost: 2
Total boost: 15 Big turbo boost: 4
Total boost: 20 Big turbo boost: 9

I'll get you more accurate numbers once I get it repaired, but interested in your thoughts in the meanwhile.

 

[boots4]

Total boost: 10 Big turbo boost: 2
Total boost: 15 Big turbo boost: 4
Total boost: 20 Big turbo boost: 9

Here's how you find out what the turbos are doing. I'll post up the formula stuff for the whole teach a man to fish... thing.

Formulas:

PR = (PSIg + At pressure)/At pressure
PR = pressure ratio, PSIg = gauge boost pressure reading, At pressure = atmospheric pressure (this changes depending upon your elevation, for you the calculators said 14.3 so that's the value I'll use).

Total PR = (10 + 14.3)/14.3 = 1.70
Big Turbo (Primary) PR = (2 + 14.3)/14.3 = 1.14

Then take Total PR/Big Turbo PR to get the Little Turbo (secondary) PR

Little turbo (Secondary) PR = 1.70/1.14 = 1.49

Then to get Little turbo psi work the top formula backwards

Little turbo psi = ( 1.49 * 14.3) - 14.3 = 7.0 psi

So, running the formula gets us the following boost numbers:

Total boost: 10 Big: 2 Little: 7.0
Total boost: 15 Big: 4 Little: 8.6
Total boost: 20 Big: 9 Little: 6.7

Here's how I'm interpreting this and why we run the numbers. Up to 15psi total boost your little turbo is doing more work. This is good because it spools faster and that's what you want. Then at 20psi total we are seeing the big turbo come alive and start working more than the little turbo. This looks like a decent transition so far. When you get a new set of numbers let's run these calculations again to see what the load sharing looks like in the upper psi. To me the load sharing is Ok from these numbers so far. My hunch is that the little is just not flowing enough exhaust out (it's choking the flow) at higher boost due to no active wastegate. This will reduce power and increase egts at current fuel settings. I want to see if the numbers will or will not support/show that. It may be that the little is not doing enough work as well. If the turbos are working well together then it is fueling or intercooling settings/issues.

 

[The Phoenician]

Here's how you find out what the turbos are doing. I'll post up the formula stuff for the whole teach a man to fish... thing.

Formulas:

PR = (PSIg + At pressure)/At pressure
PR = pressure ratio, PSIg = gauge boost pressure reading, At pressure = atmospheric pressure (this changes depending upon your elevation, for you the calculators said 14.3 so that's the value I'll use).

Total PR = (10 + 14.3)/14.3 = 1.70
Big Turbo (Primary) PR = (2 + 14.3)/14.3 = 1.14

Then take Total PR/Big Turbo PR to get the Little Turbo (secondary) PR

Little turbo (Secondary) PR = 1.70/1.14 = 1.49

Then to get Little turbo psi work the top formula backwards

Little turbo psi = ( 1.49 * 14.3) - 14.3 = 7.0 psi

So, running the formula gets us the following boost numbers:

Total boost: 10 Big: 2 Little: 7.0
Total boost: 15 Big: 4 Little: 8.6
Total boost: 20 Big: 9 Little: 6.7

Here's how I'm interpreting this and why we run the numbers. Up to 15psi total boost your little turbo is doing more work. This is good because it spools faster and that's what you want. Then at 20psi total we are seeing the big turbo come alive and start working more than the little turbo. This looks like a decent transition so far. When you get a new set of numbers let's run these calculations again to see what the load sharing looks like in the upper psi. To me the load sharing is Ok from these numbers so far. My hunch is that the little is just not flowing enough exhaust out (it's choking the flow) at higher boost due to no active wastegate. This will reduce power and increase egts at current fuel settings. I want to see if the numbers will or will not support/show that. It may be that the little is not doing enough work as well. If the turbos are working well together then it is fueling or intercooling settings/issues.

Thanks for taking the time to walk me thru it. This makes it more interesting, will have to reconsider reusing the waste gate.

 

[The Phoenician]

I took my son to my buddy's ranch to work on his 40 to hopefully get it ready for SAS 4 and do some shooting. Met up with another cruiser head and another shooting buddy. Plan was to change the starter and alternator, do some shooting then some light offroading. It didn't go exactly as planned because it took 4 adults way too long to change out the parts and get the battery to where it recharges. One of us is an engineer. And he cussed all day long the people who did the stupid conversion.

I still need to work on my own truck, but will have to wait until I'm back in town.
On a side note, the Tacoma is more offroad capable than I gave it credit for. I didn't take pics or video, didn't want the wife seeing any evidence

 

[The Phoenician]

Back in town for a few days. About to get a huge storm, so no truck work this evening. But I did get some parts in for my other hobby.

Getting a different red dot sight for this build. This one will go on one of my pistols. Now I'm just waiting on the lower receiver and good weather. This is my first 300 blackout build.

 

[The Phoenician]

Dropped big red off to get looked at. It seemed to drive well, wondering if the cold weather has any effect. I didn't feel a boost leak unless I went over 20 psi. Anyway, I'm back out of town again, so hopefully, it's fixed by the time I return.

Check out the 1942 Ford 4x4 pickup and this old diesel engine.

 

[The Phoenician]

Just a little update. The turbos seem fine, but the mechanic can't get it to over 20psi. He noticed the oil pressure is much higher than boost. He's going to keep digging.

In the meanwhile, I've been traveling and building my guns as well as ordering Tacoma upgrades. I'm dangerously expensive when I'm bored .

Time to zero in and set up a hog hunting weekend. Will keep updates on big red coming as I get them.

 

[Hojack]

Your love for weapons Mike reminds me of the scene from Harry and the Hendersons

 

[The Phoenician]

Still no real progress on Big Red. It's not leaking boost from anywhere, I suggested if the wastegates are stuck open. The mechanic said it's possible it may be stuck open a tad. He managed to get it up to 27psi, but still sees a sudden and significant drop after 15psi. He'll keep digging and I'll keep waiting.

Any thoughts from the experts on here?

 

[Hojack]

I suggested if the wastegates are stuck open.

As far as waste gates go, I've sealed them both.

I thought you sealed off the wastegate on the turbos? Has he checked either turbo for wear? Perhaps leak in the intercooler?

 

[The Phoenician]

So i know that the small one was sealed for sure before the compound build. But since the build and since we're eliminating possibilities of what could be causing this issue, it came up. He did the build and from his answer, i gather the big turbo isn't sealed, but i assumed it was.

He was thinking maybe the fuel filter is too clogged, but i replaced that not too long ago, so that's not it. We're just going through a process of elimination at this point.

 

[Hojack]

So i know that the small one was sealed for sure before the compound build. But since the build and since we're eliminating possibilities of what could be causing this issue, it came up. He did the build and from his answer, i gather the big turbo isn't sealed, but i assumed it was.

He was thinking maybe the fuel filter is too clogged, but i replaced that not too long ago, so that's not it. We're just going through a process of elimination at this point.

If the wastegate is operational it should have an actuator on it.

 

[The Phoenician]

If the wastegate is operational it should have an actuator on it.

I'm going off memory right now, but I think it does have an actuator.

 

[The Phoenician]

While waiting at discount tire, this guy shows up with 3 flats.

Got the wife's truck new meats.

Still no update on Big Red