Factory turbo/ats 093 low rpm boost.

[Black dawg]

I find there are many variables here. Biggest one is air density. I see much more boost down low with cold air.
Load is a big factor. Spooling is another.
Example, If I know I have a hill coming up, if I get it to spool prior to the load increase from the hill I will see good boost as low as 1600rpm.
If I get the load from the hill before getting the turbo spooled I will see low boost if any, smoke like a 3rd gen Dodge Cummins truck piloted by a wanna-be truck driver with an 18" exhaust tip, and have to back out of it due to my EGT's climbing above 12-1300 really quickly. Then a downshift is required to prevent further loss of momentum.
For clarity I am on a stock Ford/ATS turbo kit I added to an NA engine, 3" downpipe and a Gen 1 (#4) moose pump from 2007.

I really don't see any appreciable boost, under any conditions, below 1500 rpm. Sad but true. On a cold day, turbo spooled and load applied, I've seen 12 psi at 2500 rpm with the stock turbo.

For contrast, my stock 2019 Titan XD 5.0 Cummins will make 20 lbs of boost as low as 1400 rpm all year round. I would love the IDI to even get close to half that. There is a thing about compounds that is just beautiful. Edit, the Nissan isn't compounds. They are sequential.

I find there are many variables here. Biggest one is air density. I see much more boost down low with cold air.
Load is a big factor. Spooling is another.
Example, If I know I have a hill coming up, if I get it to spool prior to the load increase from the hill I will see good boost as low as 1600rpm.
If I get the load from the hill before getting the turbo spooled I will see low boost if any, smoke like a 3rd gen Dodge Cummins truck piloted by a wanna-be truck driver with an 18" exhaust tip, and have to back out of it due to my EGT's climbing above 12-1300 really quickly. Then a downshift is required to prevent further loss of momentum.
For clarity I am on a stock Ford/ATS turbo kit I added to an NA engine, 3" downpipe and a Gen 1 (#4) moose pump from 2007.

I really don't see any appreciable boost, under any conditions, below 1500 rpm. Sad but true. On a cold day, turbo spooled and load applied, I've seen 12 psi at 2500 rpm with the stock turbo.

For contrast, my stock 2019 Titan XD 5.0 Cummins will make 20 lbs of boost as low as 1400 rpm all year round. I would love the IDI to even get close to half that. There is a thing about compounds that is just beautiful. Edit, the Nissan isn't compounds. They are sequential. Still kicks a**.

Sequential is interesting. Very complicated over compounds. Must be so that the first turbo can be really small, and then not have to deal with it as a restriction, or risk overspeeding it?

 

[Dirtleg]

Sequential is interesting. Very complicated over compounds. Must be so that the first turbo can be really small, and then not have to deal with it as a restriction, or risk overspeeding it?

Yes there is a switching valve in the exhaust path to the turbines and it will direct all of the flow if deemed acceptable to the smaller turbo at lower rpms. At some crossover point, I am sure determined by load, throttle RPMS' etc, it starts directing the exhaust to the larger turbo as well and I am sure at some point it is probably 100% going that way.

The sequential setup has had a few reliability issues, and I was regularly (4 times total) having it in, under warranty, for delayed switching valve operation which would throw a check engine light.
The dealer would replace the switching valve and the next time I would get into the throttle too far it would throw the code again.
After doing some research on my own, it turns out there was a known issue with the vacuum actuation hoses for the switching valve collapsing and causing the delay. The last time I had it in for that, I told the dealer they needed to correct that issue. They actually tested it and saw it happen. That was 2 1/2 years ago. Problem has never returned. I can't help but think of how much money they must have wasted on warranty claims for that issue. Or how many out of warranty repairs were done at the customers expense.

 

[Clb]

Gimmie mechanical ALLDAYLONG
Can you imagine how $$$ that crap is to fix?

Of course I cut my teeth on a big cam with a blower.

 

[Black dawg]

Re visiting this, just did the math for my possible double od setup, and it will run just under 1500 at 65, and hits 1800 by 80mph.
With 355
With 410,
1800 at 65
2100 at 80.
The 4.10 sounds way better, except the fact that when towing wont be in double od and will be at 2300 at 70....which would be great for the idi, but plans have evolved to include a 6 banger.
Maybe it will pull those stupid low rpms double od 355 unloaded on flat ground?????? And in just od, makes 2k at 70 (just in 5th in the zf) which should be great, or 4th in the zf and od unit engaged will be 2100.