1.9TDI PD compound sizing

[TDIMeister]

You mean this:


Previously done on the VW Golf 1.4 Twincharger TSI.

The Audi SQ7 does something similar but far more complex with two exhaust-driven turbochargers in a series sequential setup plus an electric centrifugal compressor:

 

[miniCotulla]

You mean this:

View attachment 128196
Previously done on the VW Golf 1.4 Twincharger TSI.

The Audi SQ7 does something similar but far more complex with two exhaust-driven turbochargers in a series sequential setup plus an electric centrifugal compressor:

No, I want to put the supercharger inline after the turbo not infront of it. Packaging is way easier this way.

 

[TDIMeister]

Not a good idea. It's done this way for a reason. Actually at least two reasons.

Edit: upon further thought, if you want to use the supercharger only when the turbo is essentially off-boost, it is possible... The same signal to the electromagnetic clutch that deactivates the compressor can also activate a bypass valve. The problem is really in the control system. I see no easy way where you can avoid the "step" in manifold pressure as well as in the vehicle performance during the switchover. The frequent on-off of the supercharger might also decrease the life compressor and certainly the clutch.

 

[miniCotulla]

Not a good idea. It's done this way for a reason. Actually at least two reasons.

What are the reasons?

The only way I could think of making this work is to move the Air intake over to the right side of the engine(directly above the supercharger) and then using a Water Intercooler to go from Turbo to intake manifold.

 

[TDIMeister]

Reason 1: positive displacement compressors have a polymer coating on the lobes to aid sealing that cannot withstand the temperature of pre-compressed air coming into it.

Reason 2: the compressor work is a function of, among other things, the inlet air temperature. Hot pre-compressed air entering into it raises the compressor work, and this work comes directly from the engine as a parasitic load, which increases the brake specific fuel consumption. Due to the added stress on the drive belt, a wider, higher-rated one may be required.

Reason 3: The aforementioned step in manifold pressure and engine performance.

 

[miniCotulla]

Reason 1: positive displacement compressors have a polymer coating on the lobes to aid sealing that cannot withstand the temperature of pre-compressed air coming into it.

Reason 2: the compressor work is a function of, among other things, the inlet air temperature. Hot pre-compressed air entering into it raises the compressor work, and this work comes directly from the engine as a parasitic load, which increases the brake specific fuel consumption. Due to the added stress on the drive belt, a wider, higher-rated one may be required.

Reason 3: The aforementioned step in manifold pressure and engine performance.

If I have an Intercooler between turbo and supercharger the air temp should be lower. The belt won't be an issue as it replaces the Power steering pump.

 

[altz1]

I had idea to get my twin gtb2260 V8tdi a little sharper in lower rpm the same way. SC from 3.0T audi v6, facelift models have el.magnet clutch. My idea was to bypass the SC with poppet valves (2) from 3.0bitdi. Only reason i havent tested it yet is the location of my oil filter/CP3.

Low rpm SC sucks air trough intercoolers- turbos. As soon as turbos produce higher boost then the SC, poppet valves open for smooth transistion and little later SC clutch is disengaged so SC will put no load at all to engine in higher rpm.

Any downsides?

Also, the 3.0T SC has built in bypass valve, that could be easily pwm controlled if needed (eg. zero boost highway cruising) and sc has built-in watercooler cores if one wants to cool SC air seperatly before sending to engine.

 

[TDIMeister]

If I have an Intercooler between turbo and supercharger the air temp should be lower. The belt won't be an issue as it replaces the Power steering pump.

LOL a power steering pump belt will not be able to transmit the SC drive torque. It's a single, ribbed V-belt when most superchargers will need at least a 9PK (9 rib) serpentine belt or even a toothed belt.

For point of comparison, the AC compressor is connected to a 5PK belt in my B5, so I suspect yours is the same. A SC will require appreciably more drive torque than an AC compressor.

 

[miniCotulla]

LOL a power steering pump belt will not be able to transmit the SC drive torque. It's a single, ribbed V-belt when most superchargers will need at least a 9PK (9 rib) serpentine belt or even a toothed belt.

The Aisin amr500 only needs 4PK

 

[TDIMeister]

 

[TDIMeister]

Apparently you can get the Aisin SCs with different pulleys, a 5PK is an option, so you could just use a longer accessory belt and add a suitable idler,

 

[miniCotulla]

LOL a power steering pump belt will not be able to transmit the SC drive torque. It's a single, ribbed V-belt when most superchargers will need at least a 9PK (9 rib) serpentine belt or even a toothed belt.

For point of comparison, the AC compressor is connected to a 5PK belt in my B5, so I suspect yours is the same. A SC will require appreciably more drive torque than an AC compressor.

I guess you have a late B5 as the early ones only have 4PK but the AC Compressor has it's own separate belt. On mine the belt would only need to drive the generator and the SC.

 

[TDIMeister]

I say go for it, man!

 

[[486]]

What does that mean for this setup?

it cannot be blown through like a centrifugal

Though I have heard people say that the rotors just paddle along in the airflow with the clutch disengaged, and it doesn't actually block airflow

 

[[486]]

Reason 1: positive displacement compressors have a polymer coating on the lobes to aid sealing that cannot withstand the temperature of pre-compressed air coming into it.

Reason 2: the compressor work is a function of, among other things, the inlet air temperature. Hot pre-compressed air entering into it raises the compressor work, and this work comes directly from the engine as a parasitic load, which increases the brake specific fuel consumption. Due to the added stress on the drive belt, a wider, higher-rated one may be required.

Reason 3: The aforementioned step in manifold pressure and engine performance.

dunno man, detroit 2-strokes always had the turbo atmospheric and the supercharger at the engine
many of them also did not run any aftercooling, either interstage or overall

Feeding the turbo hot air is kinda just as bad if not worse, when you play around with the calculators it is real easy to find 650F+ compressor outlet temperatures, and aluminum (compressor wheel) loses a lot of strength up around those temperatures.

 

[[486]]

I'm not seeing a clutch pulley on the pictures of the AMR units. I was looking to see if they're of the type with the air-beaters geared together or the type that they rely on them rubbing together for drive like the IHI screw type one I've got with solid teflon rotors.

Why wouldn't you just simplify the setup entirely and run it continuously belted to the engine? Run a flapper style check valve to allow the turbo to blow past it and it'll functionally disconnect itself whenever it is being overrun by the turbocharger. It only consumes significant belt horsepower when it is creating a pressure differential, and when the bypass valve is being blown open there is clearly not a pressure differential across it.
That is how the detroits did it, except they ran the blower directly off the timing gears.

 

[miniCotulla]

I'm not seeing a clutch pulley on the pictures of the AMR units. I was looking to see if they're of the type with the air-beaters geared together or the type that they rely on them rubbing together for drive like the IHI screw type one I've got with solid teflon rotors.

Why wouldn't you just simplify the setup entirely and run it continuously belted to the engine? Run a flapper style check valve to allow the turbo to blow past it and it'll functionally disconnect itself whenever it is being overrun by the turbocharger. It only consumes significant belt horsepower when it is creating a pressure differential, and when the bypass valve is being blown open there is clearly not a pressure differential across it.
That is how the detroits did it, except they ran the blower directly off the timing gears.

They are geared together. The problem with running it all the time is that I might not get the benefit of the SC in lower RPMs as I have to size the pulley according to the SCs RPM Limit. When I don't disengage it I have to plan for 5K engine RPM, with a clutch I could drop this to 2K. Allowing me to use a different pulley and spin the SC faster in lower RPMs. A flapper style check valve? you mean like a flap with no control just a little spring to close it again and as soon as Turbo pressure > SC pressure it opens? The SC spinning freely not taking any power of the engine after that point?

 

[[486]]

They are geared together. The problem with running it all the time is that I might not get the benefit of the SC in lower RPMs as I have to size the pulley according to the SCs RPM Limit. When I don't disengage it I have to plan for 5K engine RPM, with a clutch I could drop this to 2K. Allowing me to use a different pulley and spin the SC faster in lower RPMs.

well, you don't really need it to make crazy amounts of boost down low, 7psi or 500mbar is going to be plenty motivation to get even something like an s300 turbo spooled up, with the greater exhaust energy...
Think of the supercharger and engine just as a 3-liter engine rather than a 2.0.

A flapper style check valve? you mean like a flap with no control just a little spring to close it again and as soon as Turbo pressure > SC pressure it opens? The SC spinning freely not taking any power of the engine after that point?

Yes.
There are actually many applications where you unload a mechanically coupled compressor just by venting/recirculating the discharge. There is very little parasitic loss when there is no pressure differential across it.

 

[turbobrick240]

As long as you're going with somewhat complicated boost arrangement ideas, I say add some water/methanol injection for interstage/after cooling. You could put the res&pump in the trunk if there's too much going on under the hood.

 

[miniCotulla]

well, you don't really need it to make crazy amounts of boost down low, 7psi or 500mbar is going to be plenty motivation to get even something like an s300 turbo spooled up, with the greater exhaust energy...
Think of the supercharger and engine just as a 3-liter engine rather than a 2.0.

Yes.
There are actually many applications where you unload a mechanically coupled compressor just by venting/recirculating the discharge. There is very little parasitic loss when there is no pressure differential across it.

I did some research and this AMR 500 would need an impossibly small pulley to even get to 0.5 bars. I found an alternative, the Eaton M62 from a Mercedes. This should give 0.7 bars of boost with stock pulley on 1.9TDI. It already includes a clutch too. Packaging will be harder and the 5PK belt might not be enough as it uses a 6PK pulley.

 

[miniCotulla]

As long as you're going with somewhat complicated boost arrangement ideas, I say add some water/methanol injection for interstage/after cooling. You could put the res&pump in the trunk if there's too much going on under the hood.

Not possible, there is no way to fit this system.

 

[miniCotulla]

I guess you have a late B5 as the early ones only have 4PK but the AC Compressor has it's own separate belt. On mine the belt would only need to drive the generator and the SC.

Correction: I was wrong, I think B5 always has 5PK+4PK belts. The later 1.9TDIs(BKE for example, late A4 B6s too) had a single 6PK belt.

 

[adamss24]

I still think you guys barking on the wrong tree ! Since the OP has a 3.0 tdi gearbox, why not fit a 3.0 tdi with a turbo of its choice (ball bearing proffered!) and have best of both worlds ! Low down torque to pull away and still decent economy off boost at highway cruising ! I am sure you can get a edc16 to talk with your cluster, ABS pump might be a problem but it’s doable with a newer revision pump !
thisway will be reliable as well, also I drove a Touareg 2012 the last few days with the Aisin 8 speed gearbox and I could get it under 7L/100km with reasonable accelerations ! I am sure the 3.0 tdi will have absolutely no problem pulling what you tow !

 

[miniCotulla]

I still think you guys barking on the wrong tree ! Since the OP has a 3.0 tdi gearbox, why not fit a 3.0 tdi with a turbo of its choice (ball bearing proffered!) and have best of both worlds ! Low down torque to pull away and still decent economy off boost at highway cruising ! I am sure you can get a edc16 to talk with your cluster, ABS pump might be a problem but it’s doable with a newer revision pump !
thisway will be reliable as well, also I drove a Touareg 2012 the last few days with the Aisin 8 speed gearbox and I could get it under 7L/100km with reasonable accelerations ! I am sure the 3.0 tdi will have absolutely no problem pulling what you tow !

That's not really an option. While it could be registered. It would cost a lot of money. I would need to change the front suspension too. Fit the DPF. And if all that is done it needs a full emissions test. This costs thousands!

 

[adamss24]

Every project ends as a non runner sooner or later…you best finding a dependable daily to tow with and drive everywhere and get a project to tinker with in the spare time…you just cannot have both unless you’re like a pig in mud covered in grease and oils while you work on it when it breaks ! I had allroads v6 tdi as tow rigs, fantastic cars- better than later 3.0 tdi Touareg or q7…

 

[miniCotulla]

Every project ends as a non runner sooner or later…you best finding a dependable daily to tow with and drive everywhere and get a project to tinker with in the spare time…you just cannot have both unless you’re like a pig in mud covered in grease and oils while you work on it when it breaks ! I had allroads v6 tdi as tow rigs, fantastic cars- better than later 3.0 tdi Touareg or q7…

This will be a daily once it's finished. It's a 1.9TDI, it always runs.

 

[adamss24]

Not with a twin turbo strapped on it ! I bet you’re into your low 20’s early 30’s and you have time to spare. We all been like you in the beginning, happy to work on our “projects” but with age there seems to be more important things that comes first: children, family, a house you can call home !
Don’t get me wrong, I am 45 years old, I tinker with cars day in/day out, I am sick and tired of ****ters ! I even have fast projects myself but they’re “work in progress”…kudos to you if you can make your dream come true !

 

[miniCotulla]

Not with a twin turbo strapped on it ! I bet you’re into your low 20’s early 30’s and you have time to spare. We all been like you in the beginning, happy to work on our “projects” but with age there seems to be more important things that comes first: children, family, a house you can call home !
Don’t get me wrong, I am 45 years old, I tinker with cars day in/day out, I am sick and tired of ****ters ! I even have fast projects myself but they’re “work in progress”…kudos to you if you can make your dream come true !

Cars will always come first for me. No kids planned, I already have a house so lots of time to work on my cars. While I'm working on the passat I just drive my BMW. But once it's finished it will be my daily again. Supercharger + Turbo seems easier to control and I might go that route.

 

[turbobrick240]

Carpe diem. I imagine diesel is already around $8/gal there, or whatever in metric units that's equivalent to.

 

[miniCotulla]

Carpe diem. I imagine diesel is already around $8/gal there, or whatever in metric units that's equivalent to.

It's 6.77$/gal.