3b twin scroll turbo (1 Viewer)

[Dougal]

I added in the data for the last test turbo running the stock 12blade turbine and the 11blade ET 13t compressor after giving it a bit to break in and normalize. It's the one I'm going to stick with. The drive pressure ratios get better as the rpms drop and below 2000rpm they get pretty amazing.

It's not so much 2000rpm that's giving you the best result. It's the best operating point of the turbine which happens to coincide with around 2000rpm as that's where we want and need max boost by.
I've had exactly the same trends with my drive pressure measurements and I can show the same thing with my thermodynamic calculations too.

Basically once you've got max boost that's the rpm where your drive pressure ratios are going to be best. Below that the compressor is inefficient and EGT too low. Above that you need to start wastegating which means the turbine is smaller than ideal for those higher rpm operating points.

It's all a compromise. Finding the best compromise is the hardest part.

 

[gerg]

Ahh cool thanks. Now I'm just going to fix my engine bay mounts and clean up my half finished projects. When I get a chance I'll post a video up. Anyone have a good design on a catch can? I've read about concentric circles. Not exactly sure how that exactly looks but I need to make one for my blow by cus I'm going to run a crank case vent Venturi and I'm pretty sure it'll draw oil to the exhaust.
Cheers
g

 

[Dougal]

I'll email you a catch can design.

 

[gerg]

Ahh cool thanks man.

 

[gerg]

Here is the exhaust I've been working on and the Venturi. 3" 316 stainless with an aero turbine.

 

[mudgudgeon]

Is that the venturi in your last two shots? what's the purpose of it?

 

[gerg]

Creates Vacume and I hook a hose from it to my crankcase blowby tube. At the least it takes the smoke away from my engine bay/air inlet for my heater vent. It also is reported that negative crankcase pressure helps ring seal. The logic is not that wacky. Race cars use electric pumps to get huge amounts of Vacume but I only required a bit. I actually took an hour with the pipe itself when I drilled the hole to use my leaf blower to find the best orientation for Vacumee. Strangely it went against the instructions. I directed the slash cut opening directly opposite the gas stream. I then tacked it in and took it for a drive before final welding and was able to measure about 1/2 inch of Vacume at cruse and just over 1" of Vacume at WOT 2000rpm. It will create a restriction in the stream though so I'll be seeing how much in a day or so when I put it on. It's literally the only one directly in the gas flow and its 6" from the end of the whole exhaust so I'm not overly worried.
g

 

[Wheelingnoob]

The catch can that came with the Isuzu I sold you works amazingly well. It's a 3" pipe with a 2.75 inside to create a cyclonic force and allow the oil to drop out of the air. Try that and see how it work.

 

[gerg]

You know I was wondering about that. I remembered somewhere in the back of my mind that the 4bd1t had some sort of oil separator thing. Thanks for the advice. I'll give it a go.

 

[Wheelingnoob]

Yeah I made it based off some impressive looking engineering from Dougal on the best way to clean the oil out of crankcase gases. It was bolted to the bracket that had the coolant filter and Racor fuel filter.

 

[gerg]

That's awesome thanks.
g

 

[mudgudgeon]

Yeah I made it based off some impressive looking engineering from Dougal on the best way to clean the oil out of crankcase gases. It was bolted to the bracket that had the coolant filter and Racor fuel filter.

Got any pics floating around?

 

[Dougal]

The catch can that came with the Isuzu I sold you works amazingly well. It's a 3" pipe with a 2.75 inside to create a cyclonic force and allow the oil to drop out of the air. Try that and see how it work.

That's the design I was going to send Gerg anyway. Guess I don't have to now.

See kids. Procrastination does pay off!

 

[gerg]

Took the family skiing to manning park today. 350k round trip. Averaged 20.5us mpg. Only a part tank so pretty inaccurate but I did top it off generously and filled it up the same way at the same station so I'm confident it's close. Pulled some long 7% grades and some shorter 8% and 9% ones. Egts maxed at 1100f on the steepest and pulled them all around 2400rpm in 4th which is around 85kmh or so. With the muffler and exhaust picked up a bit more back pressure but boost to drive is still decent. Here is a pic of pulling the hope slide hill. Just over 15lbs drive for roughly 16.5lbs boost. Egts were always below 1100f. Still a fair bit of pedal left for more fuel too. For those who know the crowsnest I only shifted to 3rd for the tight switchbacks and cruised 90kmh the rest of the way. I don't pull hills in 5th so I dint want to rev it up too high. It was actually a nice relaxing drive. We set a new family eta record and no one puked in the car! Major plus.

On the flats at 60mph. Boost is around 13lbs to 12lbs drive with egts around 675f to 700f.

 

[Dougal]

Just in case you're interested.

To pull 3T up an 8% grade at 85km/h needs 72kW to the wheels. If you assume 25% drivetrain loss at 2400rpm that's ~385Nm and 96kw.

Decent improvement on stock.

No puke means you're driving corners too slow!

 

[Mcreight911]

Setups going quite well! You happy with it or more mods to come ?

 

[gerg]

Yeah the switchbacks were fairly icy and some are pretty sharp. Those power calcs are respectable. Nice to know it wasn't maxed out with a bit more throttle left. I should get a dyno I guess. Ive always got so much to do all the time its frustrating. Have a turbo to build for a buddies car and just dug up my lawn to run tech cable to put a sub panel in my garage. Gotta love digging in winter time. So far im crazy happy with the set up but of course I cant leave it alone as long as I own it. If I get time I might put a 16t or a 15g compressor on and see what that does but that's in limbo for now.

 

[GTSSportCoupe]

Just in case you're interested.

To pull 3T up an 8% grade at 85km/h needs 72kW to the wheels. If you assume 25% drivetrain loss at 2400rpm that's ~385Nm and 96kw.

Decent improvement on stock.

No puke means you're driving corners too slow!

Considering most 3B's dyno 30-40kw at the wheels, 72kW+ is very good!

I think cruisers loose a lot more than 25% between the flywheel and tires. More like 40% or worse from what I've seen.... I think the T-Case must loose a lot; the trans and diff are probably fairly average though.

 

[Dougal]

Considering most 3B's dyno 30-40kw at the wheels, 72kW+ is very good!

I think cruisers loose a lot more than 25% between the flywheel and tires. More like 40% or worse from what I've seen.... I think the T-Case must loose a lot; the trans and diff are probably fairly average though.

25% loss means you're generating about 25kw of heat in the diffs and transfer case. I don't think it can be much more than that. 25% seems to fit well with my Rover calculations vs actual performance and I'm running fulltime 4wd.

If you used 40% for Gerg's run it wouild mean 480Nm at the crank. Which isn't realistic at all.

 

[GTSSportCoupe]

25% loss means you're generating about 25kw of heat in the diffs and transfer case. I don't think it can be much more than that. 25% seems to fit well with my Rover calculations vs actual performance and I'm running fulltime 4wd.

If you used 40% for Gerg's run it wouild mean 480Nm at the crank. Which isn't realistic at all.

Yeah, it's sort of a mystery without putting the motor on an engine dyno. But at the end of the day, I think it's safe to say he is making more than twice the stock power of a 3B (at the wheels). Toyota's 90 crank hp figure is probably quite optimistic.