[Atg]

Hx35/hx52 coal smoke racing is 517whp at 3 bar on 210cc

 

[Dougal]

Sorry this was a double post of the above. My browser did not update. I edited it down.

Stamsas in Norway is "coal smoke racing" on facebook in case anyone is interested.

Hoping not to melt the wheel in the hx30 super. I will run a d200 logger to capture egt by cylinder and maybe afr as well as iat, boost, and emp. Maybe run two intercoolers to save the little

So whether the small turbine maintains a pressure differential with the wastegate open depends mostly on the size of the wastegate. Going higher fuel than 120cc would then require a smaller wastegate if it requires compounding to get enough air.

I saw dieselmeken ab recent runs on two om606 engine dyno on facebook. They got about 490 crank hp on the stock manifold with 140cc and a big turbo at 35psi boost. They got about 550 crank on a twin turbo with 180cc minimum so on an 8mm pump at 50psi. Stock cams. No egts were plotted. 180cc appears far too much fuel to do anything but burn out for a bit on 50psi. The twin turbo motor had more down low but still not fully spooled before 3500rpm. Check it out on the videos. He posted photos of the data sheets.

I have seen Alcaid talk about an audi valve but I think it is for blow off. I do not know of a good diverted valve for the compressor bypass. I will study blacksmoke racing's sequential setup. I think their wastegate actuator diverts a flap in the exhaust stream away from the small turbine. They have both turbos plumbed straight to the intercooler I think, or a flap which bypasses the small compressor by opening when the large turbo begins to make more boost than the small. That flap is inside the intercooler in their build, and has no actuator. It just seals when pressure in intercooler exceeds pressure in small turbo boost tube I think. Their exhaust diverter flap was pretty bent by exhaust when they pulled it apart after last race though. Why they used that instead of a wastegate I don't know. Maybe it provides a smoother pressure transition.

A bit to figure out. I plan to use a synapse engineering wastegate 50mm, but could just use tial x2 big and small, and control them both with solenoids and the d200. Or use d200 to control the compressor diverted if needed.

Cheers,
Atg

Hx35/hx52 coal smoke racing is 517whp at 3 bar on 210cc

Yeah all these guys are running far richer. I'd also be interested to know how gearboxes hold up! If they're drifting then actual power and torque used will be a lot lower anyway.

For the bypass valve I think a bypass tube with a butterfly and vacuum or boost actuator. My Nissan actually runs one I think as a soft shut-down valve on the intake. You could modify any throttle body to work that is strong enough to take the boost.

 

[Atg]

I think they are all BMW gearboxes from diesels or v12 or something.

Here is that hx35/hx52 compound spooling on dyno. Even after the hx35 spools it seems an eternity before the hx52 comes on line.

https://m.facebook.com/story.php?story_fbid=1095176327182221&id=822341374465719

Here is one of the pump builders comparing a big turbo on stock manifold with 140cc to twin turbo setup on a second motor with 180cc:

https://m.youtube.com/watch?v=cS60QRf8X_s&feature=share

 

[Dougal]

I think they are all BMW gearboxes from diesels or v12 or something.

Here is that hx35/hx52 compound spooling on dyno. Even after the hx35 spools it seems an eternity before the hx52 comes on line.

https://m.facebook.com/story.php?story_fbid=1095176327182221&id=822341374465719

Here is one of the pump builders comparing a big turbo on stock manifold with 140cc to twin turbo setup on a second motor with 180cc:

https://m.youtube.com/watch?v=cS60QRf8X_s&feature=share

That's a great chance to run in a dyno cell. It takes all the BS straight out. It's just a real shame they didn't have AFR hooked up but it's a lot richer than we're planning here.

 

[Atg]

That's a great chance to run in a dyno cell. It takes all the BS straight out. It's just a real shame they didn't have AFR hooked up but it's a lot richer than we're planning here.

They had egt but did not post the data! You can hear them talking about fixing the egt sensors in one of the other videos.

 

[Atg]

So I've got a few spare minutes to run some calcs. So is the intent to run the 16cm 451 ungated or with an external gate?

I'll do a run with the 451-16cm ungated at 120cc and see how it looks.

*edit*
So I've run some ungated calcs and this is looking surprisingly good. You'll need a huge wastegate to bypass the HX30 pretty much completely from 4000rpm to 6000rpm.
Power should be around 350kw (crank).
Drive pressure is below boost from 4000-6000rpm.
The 451 runs straight up the middle of the compressor map.

You may or may not find the HX30 compressor to be a restriction at higher rpm. It's too close to call A flap valve to bypass it (with a wastegate actuator set to ~35psi triggered off the HE451) would cure that.

Would a passive check valve work for the compressor bypass? I guess it would never open until the wastegate opens, because it would have to open against compounded boost on the back side before the wastegate opens and takes drive away from small turbo. After wastegate opens, all drive goes to the 451 and it's boost should rapidly exceed the boost from the small turbo, which is unspooling. Could be a valley of death before big one gets up to full speed, but it should already be spooled...

 

[Dougal]

Would a passive check valve work for the compressor bypass? I guess it would never open until the wastegate opens, because it would have to open against compounded boost on the back side before the wastegate opens and takes drive away from small turbo. After wastegate opens, all drive goes to the 451 and it's boost should rapidly exceed the boost from the small turbo, which is unspooling. Could be a valley of death before big one gets up to full speed, but it should already be spooled...

A passive check valve will always be a pretty good restriction or risk sticking open if it doesn't have a spring closing it. Where an actuated valve can be fully open as it's needed.

I think the compressor bypass needs to open a fraction after the small turbo wastegate is fully open. This should be pretty easy to acheive with only a small boost window where you are still blowing through the small turbo.

 

[Atg]

A passive check valve will always be a pretty good restriction or risk sticking open if it doesn't have a spring closing it. Where an actuated valve can be fully open as it's needed.

I think the compressor bypass needs to open a fraction after the small turbo wastegate is fully open. This should be pretty easy to acheive with only a small boost window where you are still blowing through the small turbo.

Audi has a nice passive check valve on their 3.0 tdi motor that looks pretty slick. about $150 usd. it Should open shortly after the wastegate opens I would think.

actuated butterfly valves are not as easy to find. Retrofitting throttle bodies sounds like a pain and they are not designed to work under any real pressure. Maybe turbo smart makes one. not sure.

I would like to be able to turn up the fuel at some point. I suppose either passive or actuated compressor bypass could work at a higher boost level.

 

[Atg]

A passive check valve will always be a pretty good restriction or risk sticking open if it doesn't have a spring closing it. Where an actuated valve can be fully open as it's needed.

I think the compressor bypass needs to open a fraction after the small turbo wastegate is fully open. This should be pretty easy to acheive with only a small boost window where you are still blowing through the small turbo.

OK so here is the valve.
http://forums.tdiclub.com/showpost.php?p=3982485&postcount=14

More I found at this thread:

https://forums.tdiclub.com/showthread.php?p=4004413#post4004413

Pressure drop at 1000kg/hr is 11mbar apparently. So like 2psi at 0.8kg/s? If total boost were 40psi this would be a 2% efficiency loss. Seems like quite a lot. Maybe I need two in parallel?

 

[Dougal]

OK so here is the valve.
http://forums.tdiclub.com/showpost.php?p=3982485&postcount=14

More I found at this thread:

https://forums.tdiclub.com/showthread.php?p=4004413#post4004413

Pressure drop at 1000kg/hr is 11mbar apparently. So like 2psi at 8kg/s? If total boost were 40psi this would be a 2% efficiency loss. Seems like quite a lot. Maybe I need two in parallel?

Great, if you can get one then use it.

A throttle body has to hold at least 15 psi normally and in this application it will have positive pressure on both sides so it's holding back a lot less than total boost when closed. So I think it is still an option too.

 

[Atg]

It is ordered. Www.oemvwshop.com

 

[Dougal]

It is ordered. Www.oemvwshop.com

Nevermind, found it. 136 Euro.

Part Number: 059 145 901 b

 

[Atg]

Not exactly cheap but should work and might even be weldable. The check spring is very mild so orientation probably matters.

 

[Atg]

Czech valve arrived today, literally two day shipping and I ordered it on the 12th. Amazing world.

 

[Atg]

I am wondering if the large turbo will be spooled up enough when the wastegate opens to prevent the wastegate from closing again. If there isn't 40psi from the big turbo, then the wategate will open, intake pressure will drop and the gate will close, and the system will never switch over to the large turbo. Seems like the internal gate on the hx30 needs to open around 35psi, allowing the big turbo to spool up a bit while the small turbo is still on line. Then have a second 50mm wastegate kick open at 40 psi and shut the small turbine down completely.

 

[Dougal]

I am wondering if the large turbo will be spooled up enough when the wastegate opens to prevent the wastegate from closing again. If there isn't 40psi from the big turbo, then the wategate will open, intake pressure will drop and the gate will close, and the system will never switch over to the large turbo. Seems like the internal gate on the hx30 needs to open around 35psi, allowing the big turbo to spool up a bit while the small turbo is still on line. Then have a second 50mm wastegate kick open at 40 psi and shut the small turbine down completely.

Wastegates open gradually to regulate boost so that shouldn't be an issue. You will likely have some tuning to do with the opening pressure of each gate to get it feeling seamless.

 

[hcetretsam]

Hey dougal, I've tried messaging you privately but for some reason they won't send? I have a question to ask you and don't want to derail this thread. Thanks!

 

[Dougal]

Hey dougal, I've tried messaging you privately but for some reason they won't send? I have a question to ask you and don't want to derail this thread. Thanks!

Messaging worked. I got three of them!

 

[Atg]

What about putting the 451 on the exhaust manifold, and letting its compressor feed the small turbine before feeding the small compressor? Seems like it could result in cool air for the small turbo. Coild do interstage cooling and drop to below ambient after the small turbine. Not sure how much compounding there would be, but probably some. Seems like it would be slow to spool though.

 

[Dougal]

What about putting the 451 on the exhaust manifold, and letting its compressor feed the small turbine before feeding the small compressor? Seems like it could result in cool air for the small turbo. Coild do interstage cooling and drop to below ambient after the small turbine. Not sure how much compounding there would be, but probably some. Seems like it would be slow to spool though.

You lost me at "compressor feed the small turbine".