4m50 turbo upgrade v2

boostin

Adventurer
Just recently upgraded from a evo 3 to a 9 blade td05h 20g.

It's maybe a touch more laggy, but I also have a large manifold crack so it might get better. But even she spools up, significantly better.

I am also planning on changing the turbine housing to a smaller 7cm to help with spool, will keep updated.

I am up to 24 000 pounds total and it pulls way better
 

Aussie Iron

Explorer
Okay I'm at the other end. I have a TD05H-big 16G 7Cm housing and am going to a TD06SL2-big 16G 8Cm housing. It's my original turbo and fitting a smaller compressor wheel. The setup I'm running now is a lot better than the original choice but I'm running too much drive pressure and this is the reason for trying the bigger housing and AR. Max boost I'm seeing now is 14Psi and the wastegate is wired shut.

Dan.
 

boostin

Adventurer
That's on a 4m50? I can get 20 psi , even 24 when pulling hard.

I just don't get any low rpm boost, hence smaller housing, but the 20g still runs circles around the evo 3 turbo in my opinion on my truck
 

Aussie Iron

Explorer
That's on a 4m50? I can get 20 psi , even 24 when pulling hard.

I just don't get any low rpm boost, hence smaller housing, but the 20g still runs circles around the evo 3 turbo in my opinion on my truck

I realize that you are running a different engine but not that much. Yes I have the same problem as you that I don't get enough boost down low. The thing is that you need to spool up faster and the only way I know is to have a bigger turbine wheel and lesson the load of the compressor size. With our diesel engines we are running low revs all the time compared to other diesels and there in is our problem. I talked about drive pressure and apparently ideal situation is to have 2 or 3 Psi above boost pressure. My best is 5 or 6 Psi above boost and as boost builds I'm into 12 or 14 Psi above boost. Now we know that the exhaust brake slows our motor down and the same happens by increased drive pressure, so we are suffocating our engines. Your engine will probably suffer from the same drive pressure problem if you change to a smaller AR.

Are you using the OE air intake and filter? Do you know the vacuum levels in it?

Yes at this stage I'm still running the OE intake and filter and no I haven't looked at intake vacuum level but I do know that I'm suffering form a problem because we can really hear the turbo sucking on the intake. I do have a larger filter unit to fit and will be also changing out the intake pipes. If I remember I'll try to get a vacuum gauge setup on the intake to get a reading.

Dan.
 

Amesz00

Adventurer
Dan, are you getting enough fuel for it to make >14psi?
Second to turbine setup, biggest influence on spool is fuelling (both volume and timing).
Maybe it needs more fuel both on power and down low.?

The 4m50 has terrible off-boost fuelling, even with the steinbauer it's probly still fairly lean I imagine?
 

Aussie Iron

Explorer
Dan, are you getting enough fuel for it to make >14psi?
Second to turbine setup, biggest influence on spool is fuelling (both volume and timing).
Maybe it needs more fuel both on power and down low.?

The 4m50 has terrible off-boost fuelling, even with the steinbauer it's probly still fairly lean I imagine?

When i fitted the first turbo I increased fuel by 1.5 turns which then gave me overfueling up to about 2000Rpm because of low boost (lucky to see 2 or 3 Psi) up to that Rpm. I haven't touched the fuel since then. My air/fuel ratio at this stage is running at 22.3 at idle and running at 13.7 under full acceleration. I've increased boost under the 2000Rpm with this turbo as now I get about 7Psi. Egt is now controllable and doesn't spike into dangerous territory like it use too under the 2000Rpm and on full throttle in climb we run at 580°C (pre turbo) generally. I'd like to see drive pressure down if I can.

Dan.
 

Amesz00

Adventurer
13.7? That's super rich, even richer than stoich.. idle I would have thought should be closer to 30-35 too. Generally anything under 18-19 @ full power is a smokey tune, and under 16 is piston holing territory...
Pre turbo temps you should be safe up to 700 ay?
What turbo setup is this?
 

Aussie Iron

Explorer
I should add that cruise is 18.1. The turbo is a TD05H big16G. It's certainly not smokey at all. Then, I'll try a reset of my Air/Fuel setup and see if we have any difference.

Dan.
 
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boostin

Adventurer
I have built and tunned a few turbo vehicles in my days, and a bigger turbine wheel always increses lag, it's all about the weight of these wheels.

The new aftermarket 9 blade turbines help spool a quite a bit, even though I went to a 20g, I still ended up with quicker spool.

My stock turbo was a td04hl-15t, and it was instant boost but no power from the low cfm of the 15t.

You need a combination of boost pressure and cfm. The 20g cfm really makes mine move once it boost, I am just going to a smaller ar housing to move the boost pressure to a lower rpm
 

SkiFreak

Crazy Person
Something else to consider is a Sequential or Variable Geometry Turbo setup, as these are specifically designed to overcome slow spooling issues, especially in diesel engines.
Definitely not my area of expertise, but from what I have read it is a possible solution, albeit being a somewhat pricey one.

Plenty of info about these setups on the web, so I will not try to explain them myself.
 

boostin

Adventurer
Yes they are the ultimate, but very expensive, need more maintenance and seem problematic. But they do work awesome when they are working
 

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