The 2H/12H-T/1HZ/1HD-T/1HD-FT Gturbo Alternative Tech Thread (12 Viewers)

[vwluv10338]

Spending an additional $300 on an electronic boost controller was not part of my plan. That is eating into the cost savings of this turbo over a GTurbo. I don't see anyone complaining of spool times with the GTurbo and they have a stock-looking wastegate actuator.

 

[Dougal]

Have you measured shaft speed before ?

I haven't. But you can approximate shaft speed from boost, flow and compressor maps so I've never worried that much.

Why so focused on "more boost" wouldn't you rather more volume ?

Because boost drives volume flow.

Psi is just a measure of restriction. Volume of air pumped (lb/min) is what we need so we can add more fuel to make more power. The earlier the turbo can supply the volume the better.
The psi to lb/min relationship will depend on you specific turbo .

It doesn't work like that. Your engine flows basically a fixed volume per revolution. The only way to drive more flow through it is to compress the air. Which requires boost.

The whole "boost is a measure of restriction" thing is bollocks. An engine isn't a nozzle.

 

[Dougal]

Spending an additional $300 on an electronic boost controller was not part of my plan. That is eating into the cost savings of this turbo over a GTurbo. I don't see anyone complaining of spool times with the GTurbo and they have a stock-looking wastegate actuator.

Boost controllers are a waste of time and money. Get a pneumatic actuator which you can adjust to the right boost and run it. Problem solved.

Wastegates are self modulating. More boost and they open furthur, less boost and they open less. It's really not that complicated.

 

[MonsterCruiser]

It doesn't work like that. Your engine flows basically a fixed volume per revolution. The only way to drive more flow through it is to compress the air. Which requires boost.

This reaffirms my recent thoughts when trying to practically think about my set up. I was trying to rationalize why my truck seemed to run the same or maybe even a little bit better with the MMP turbo compared to the stock CT26 even though I was seeing lower boost. I figured it had to be down to a better tune.

 

[Tapage]

expansion it's a variable in play when you talk about exhaust flow ..

 

[Mcreight911]

Boost controllers are a waste of time and money. Get a pneumatic actuator which you can adjust to the right boost and run it. Problem solved.

Wastegates are self modulating. More boost and they open furthur, less boost and they open less. It's really not that complicated.

They are handy when you can't get what you need from a spring only

 

[Mcreight911]

I haven't. But you can approximate shaft speed from boost, flow and compressor maps so I've never worried that much.



Because boost drives volume flow.

I should be clearer with my comments, yes you need pressure to drive flow. But there is a point at which it hurts power and we have to look at gains in efficiency in other areas.


It doesn't work like that. Your engine flows basically a fixed volume per revolution. The only way to drive more flow through it is to compress the air. Which requires boost.

The whole "boost is a measure of restriction" thing is bollocks. An engine isn't a nozzle.

Correct . The turbine is the restriction I'm referring to and the waste gate being the variable . Heat is another factor again

I thought you would approach this with an open mind rather then dismissing it based upon an usumption . There are situation where Shaft speed doesn't directly follow pressure . Which is when volume of flow is changing independent of pressure .

You have nothing to loose so why not try it. Log AFR's, boost, Inlet temps, egt's . Whilst measuring power and torque. This isn't something I dreamed up it, I had trouble with a setup and my turbo supplier prompted me to look in certain areas . It was then I saw the whole picture.

 

[Mcreight911]

Spending an additional $300 on an electronic boost controller was not part of my plan. That is eating into the cost savings of this turbo over a GTurbo. I don't see anyone complaining of spool times with the GTurbo and they have a stock-looking wastegate actuator.

An Ebc is not a necessity . It depends on your desired outcome . If you want max boost as soon as possible and don't care about any other factor then run a heavy spring . If you want low emp and can put up with poor spool run a light spring a medium spring could be concidered the goldy locks setting . If you want ease of tuning and best of both worlds with finer control you'll need an ebc .


Graeme turbos are hard to beat . In fact I haven't experienced any turbos designed for similar power match his for spool . But it not all about spool

 

[Dougal]

This reaffirms my recent thoughts when trying to practically think about my set up. I was trying to rationalize why my truck seemed to run the same or maybe even a little bit better with the MMP turbo compared to the stock CT26 even though I was seeing lower boost. I figured it had to be down to a better tune.

The stock CT26 turbine is a very old and inefficient design. It creates a lot more EMP which reduces engine power.

Fit a turbo with a better turbine at the same boost level and you'll record more power. Engine also runs more efficiently.

 

[Dougal]

Correct . The turbine is the restriction I'm referring to and the waste gate being the variable . Heat is another factor again

I thought you would approach this with an open mind rather then dismissing it based upon an usumption . There are situation where Shaft speed doesn't directly follow pressure . Which is when volume of flow is changing independent of pressure .

You have nothing to loose so why not try it. Log AFR's, boost, Inlet temps, egt's . Whilst measuring power and torque. This isn't something I dreamed up it, I had trouble with a setup and my turbo supplier prompted me to look in certain areas . It was then I saw the whole picture.

The turbine restriction is how it works, that determines where you're working on the turbine map and (along with flow and temp) how much power your turbine is producing.
Turbine maps don't include shaft speed, compressor maps do. Shaft speed matters for the boost side only.

The wastegates sole job is to regulate boost and it does this by bypassing exhaust around the turbine. Reducing turbine drive pressure and flow.

I'm not sure what you're claiming or what your argument is.

 

[Mcreight911]

I

The turbine restriction is how it works, that determines where you're working on the turbine map and (along with flow and temp) how much power your turbine is producing.
Turbine maps don't include shaft speed, compressor maps do. Shaft speed matters for the boost side only.

The wastegates sole job is to regulate boost and it does this by bypassing exhaust around the turbine. Reducing turbine drive pressure and flow.

I'm not sure what you're claiming or what your argument is.

I'm saying high or excessive emp isn't always desirable. With Careful setup of the wastegate control it can be manged and still maintain enough boost wilst having a positive effects on torque and power . Particularly torque and power holding ability

 

[Mcreight911]

The stock CT26 turbine is a very old and inefficient design. It creates a lot more EMP which reduces engine power.

Fit a turbo with a better turbine at the same boost level and you'll record more power. Engine also runs more efficiently.

You make this comment but disagree with my emp managemt comment?

Its somhing that won't be apparent untill you test it and measure all paremerters .

 

[Dougal]

I'm saying high or excessive emp isn't always desirable. With Careful setup of the wastegate control it can be manged and still maintain enough boost wilst having a positive effects on torque and power . Particularly torque and power holding ability

I don't see anyone arguing for high or excessive EMP. I also don't see any numbers for what high or excessive EMP is.

I first measured drive pressure about 10 years ago. I've probably done the most testing, measuring, modelling and prediction out of all the hobbiests worldwide.

But I still don't know what you're claiming. Unless you have a VNT or raise exhaust temp you cannot drop drive pressure without also dropping boost.

 

[mudgudgeon]

you cannot drop drive pressure without also dropping boost.

This in reference to a fixed turbo turbine/compressor configuration?
Changing turbine or compressor characteristics will potentially change the EMP - boost ratio.

I may be wrong on this, but don't some OEM waste gate set ups also apply boost to the back of the actuator diaphragm to prevent the waste gate from opening early? And sliding a lighter spring tension?

 

[Dougal]

This in reference to a fixed turbo turbine/compressor configuration?
Changing turbine or compressor characteristics will potentially change the EMP - boost ratio.

I may be wrong on this, but don't some OEM waste gate set ups also apply boost to the back of the actuator diaphragm to prevent the waste gate from opening early? And sliding a lighter spring tension?

Yes you need to change the turbo configuration (unless you've got variable vanes).

Some OEM's are running vacuum wastegates. Often so they can drop boost and raise EGT for burning clean DPF's etc.

 

[Mcreight911]

I don't see anyone arguing for high or excessive EMP. I also don't see any numbers for what high or excessive EMP is.

I first measured drive pressure about 10 years ago. I've probably done the most testing, measuring, modelling and prediction out of all the hobbiests worldwide.

But I still don't know what you're claiming. Unless you have a VNT or raise exhaust temp you cannot drop drive pressure without also dropping boost.

Dougal I make mention of high emp as I read mmp customers were cranking up preload in an effort to build boost .

The turbo is often blamed for lack of boost but it's not always the problem . It can only do as it's told .

I suspect fueling as I've had better than reported results with larger/ less suited turbos . I could be wrong though, It could be something intenally causing resistance . Also the .42 a/r turbine housing will see higher emp at high power levels .

Other bolt ons, intake or exhaust and intecooling will vary results too.

I'm not accusing you of not knowing anything or not testing anything, I've read your info (no just this forum) for years and hoped I may be able to give something back .

You said you hadn't measured shaft speed, only assumed it based on boost . You also said emp kills power . But then disagree with what I say

I may not have have worded things clearly but That is what I'm saying . You need enough spring tension to keep the gate closed to build boost but it needs to open when flow suffers from high emp.

High or excessive emp is turbo dependent and has to be aproached on a case by case basis . When you can see shaft rpm not just boost the emp limit for your turbo will become apparent


I'm saying it's a balance between fueling (not just total cc) total boost and flow to make nice early torque rise that make our diesel feel strong and hold that torque in the higher rpm


Shaft speed can change independent to boost when emp is excessive . In this situation Boost can stay the Same but shaft speed actually drops . So you have less volume . This is confirmed buy egt's and afrs . This is why I say emp needs to be managed, I'm not saying it needs to be low at all costs .

 

[Mcreight911]

Boost controllers are a waste of time and money. Get a pneumatic actuator which you can adjust to the right boost and run it. Problem solved.

Wastegates are self modulating. More boost and they open furthur, less boost and they open less. It's really not that complicated.

With the performance turbos I use for builds all the hard work(r&d) has been done for me regarding wastegate actuator setup.

I can get better results with the addition of electronic control but it's not really worth the cost so only use them for the "I must have the best, I don't care about cost" builds.

 

[vwluv10338]

@Mcreight911
As far as tuning goes I guess we can't fault the turbo completely either when both @diby 2000 and I are still on the stock pin and @MonsterCruiser didnt tune his himself so we don't know what was done there.

 

[diby 2000]

Shaft speed can change independent to boost when emp is excessive . In this situation Boost can stay the Same but shaft speed actually drops . So you have less volume . This is confirmed buy egt's and afrs . This is why I say emp needs to be managed, I'm not saying it needs to be low at all costs .

So I can understand this.
Is this the case because with high EMP, the exhaust gasses can not exit the cylinder as well as they otherwise would have with a lower EMP due to the less differential pressure from inside the cylinder to into the exhaust manifold.
This effectively means when the intake valves open, there is a higher pressure in the cylinder (due to there being more already burnt exhaust gasses from the last combustion cycle) than there would have been if the exhaust gasses could have been removed completely.
This then means there is less volume for the fresh air to occupy in the cylinder, meaning you can not burn as much fuel for that combustion cycle.
This effectively means the volume (mass flow) of air (compressed or not) consumed by the engine per combustion cycle is lower but the boost level at the intake manifold remains the same. This means that the shaft speed of the turbo will be lower for the same boost level.
This translates to less torque and power from the same boost level.

Did I get that right or what have I missed?

This would also explain how a more efficient turbine can deliver more power and torque at the same boost levels without changing other factors.

The stock CT26 turbine is a very old and inefficient design. It creates a lot more EMP which reduces engine power.

Fit a turbo with a better turbine at the same boost level and you'll record more power. Engine also runs more efficiently.

This could also help explain why @MonsterCruiser feels that his truck is going better even with lower boost numbers.
This could also explain the decrease in smoke levels at the same time.
I personally think its more to do with the tune though.

 

[mudgudgeon]

@Mcreight911
As far as tuning goes I guess we can't fault the turbo completely either when both @diby 2000 and I are still on the stock pin and @MonsterCruiser didnt tune his himself so we don't know what was done there.

I think a slightly sub-optimal tune will have less impact on torque curve and power levels than a mismatched turbo.

If you guys are close with your tune, you should see a decent increase in power, even with stock pump and stock aneroid pin.
No amount of tuning will change the physical limitations of the turbo.

Stock pump is capable of supporting a pretty substantial increase in power.
If the turbo characteristics are close, and your tune is close, you should be amped, not under-whelmed.

With stock turbo, and stock pump, I had my 1HD-T running at 15psi, then upped it to 18psi and upped the fuel (had it boosting to 22psi for a while).
The difference between 15psi and 18psi would have been about 1/2 turn on the main fuel screw, and a long way of maxing it out.
The difference in performance was significant, definitely very noticeable.
I ground my aneroid pin to stop it cutting fuel when boosting above 15psi, apart from that, the pump was stock, and I was simply trying to maximise fuel setting and boost while staying within "safe" EGTs.

This was 10yrs ago (Graeme was still tinkering with stock ct26, and hadn't looked at IPs) with a stock turbo, therefore larger turbine than what is currently being used, so less responsive, and with smaller compressor than current upgrades, so less air volume, and well outside it's efficient range by a long way, so excessively heating the intake air.

Far from optimal turbo parameters, but it still ran like a scalded cat.