3b twin scroll turbo (1 Viewer)

[mudgudgeon]

good tip on the never seize, I'll use that

got to love a tip that ends with "ask me how I know"
been there, done that, got the Tshirt sooooo many times with those little gotchas on projects

Do you drill and reinstall the dowel pins or leave them out? I'm playing with a ct26 hybrid at the moment, I just left the pin out

 

[gerg]

I leave them out as the only reason I can think for their use is to realign it to the stock orientation. I wasn't sure how she would react and it went ok. Washing the compressor housing in the sink flew under the radar. Whew! Normally I do it in the solvent tank, but it's cold out!
g

 

[mudgudgeon]

yeah. cool. I was thinking the same. cant see that the pin contributes anything other than alignment on assembly.

 

[jb BJ73]

Sucks to hear you've gotta get rid of your rigs gerg. I keep my middy and the new one I've got and the hj60 parts donor at work so the missus can't see them
Not sure if you mentioned or not but what is the twin scroll from? Mate of mine with a 1kd hilux wants to do a compound set up and I reckon it might work well as the small turbo

 

[gerg]

The turbo is a 49189-05200 MHI turbo. A small in a compound for that size engine would need to be quite undersized depending on your boost goals from the large. I think the 13t would be ill suited.
g

 

[gerg]

Without mapping it to your specific goal I think a 49377-06260 would be better suited compressor wise. 12t compressor. It's got a td04l turbine and an 8.5cm twin scroll housing. There off of Volvo s40s. Really small and compact design makes it great for tight fitting engine bays.

 

[gerg]

So I rebuilt an hl turbo and put the extended tip 11 blade 13t compressor on with an 11 blade turbine and bolted it up and expected to see a major difference. Instead I got a huge leak in the stock blowoff valve. I also remembered that I had not gasket matched the housing and gasket to the exhaust manifold when I switched it so I took it all off and blocked off the blowoff valve and ground to housing and gasket so it wouldn't interfere with the gas flow and excitedly bolted it back up a few days ago. Pretty stinkin cold here so wasn't actually fun. I usually love putting a new turbo on. I then took it for a drive like a giddy school girl. Much to my disappointment it runs about 50f hotter and runs slightly worse drive to boost pressure. Almost never gets better than 1:1 and occasionally runs worse.

I suspect that because I'm only running low boost (14lbs Max) that the turbine was actually quite fine flow wise with that before with the 12 blade. The extended tip 13t is also technically a larger compressor due to its smaller hub and extended tips so it will require more torque than the stock one. So I think I'm trying to do more with less which usually doesn't work out. I'll swap the 12blade turbine back on and see what the egts and pressure are like.

Pretty disappointing, but trial and error is finding success in a pile of mistakes. I'll try and not make a huge pile.
g

 

[Dougal]

So I rebuilt an hl turbo and put the extended tip 11 blade 13t compressor on with an 11 blade turbine and bolted it up and expected to see a major difference. Instead I got a huge leak in the stock blowoff valve. I also remembered that I had not gasket matched the housing and gasket to the exhaust manifold when I switched it so I took it all off and blocked off the blowoff valve and ground to housing and gasket so it wouldn't interfere with the gas flow and excitedly bolted it back up a few days ago. Pretty stinkin cold here so wasn't actually fun. I usually love putting a new turbo on. I then took it for a drive like a giddy school girl. Much to my disappointment it runs about 50f hotter and runs slightly worse drive to boost pressure. Almost never gets better than 1:1 and occasionally runs worse.

I suspect that because I'm only running low boost (14lbs Max) that the turbine was actually quite fine flow wise with that before with the 12 blade. The extended tip 13t is also technically a larger compressor due to its smaller hub and extended tips so it will require more torque than the stock one. So I think I'm trying to do more with less which usually doesn't work out. I'll swap the 12blade turbine back on and see what the egts and pressure are like.

Pretty disappointing, but trial and error is finding success in a pile of mistakes. I'll try and not make a huge pile.
g

So what did you change from previous? The turbine or both turbine and compressor wheels?

Pretty chilly here too. Only hit 20C today.

 

[gerg]

Going down to -8 in a day or so. I changed both compressor and turbine but will go back to stock turbine in a few days hopefully.

 

[Dougal]

Going down to -8 in a day or so. I changed both compressor and turbine but will go back to stock turbine in a few days hopefully.

If you just swap one we'll know more!

 

[mudgudgeon]

love your work dude. takes commitment to be working on your car in such cold temps! Although, I was welding a new exhaust system in 38C a couple of days ago!

Couple of questions for you regarding the drive pressure reference. It's the copper line from your exhaust manifold yeah? I'm assuming the copper is just to deal with the heat.
Do you have it plumbed to a gauge on the dash? Is the line copper all the way? or would you able to change back to a nylon line after a couple of feet of copper?

 

[gerg]

So yes I agree changing one thing at a time is always better. Very sorry for that. To clarify ill be running just the compressor as the variable on the nex trial. Sadly Im not in a place to run a lab as much as id like to. Im trying to get some last minute data and put it out there before im done with this engine type. After I sell my 60 ill have no more test bed to work on. Then it will be just the yucky Isuzu engine....blahh. hehe. Actually im really looking forward to mucking around with the 3.9

The drive pressure reference is copper for the heat for about 2 ft then it switches to nylon. Ive not had any heat issues. I think I might plum one is permanently for my next truck,. I find is quite interesting to see what influences it. So 38C is nasty. I think id rather the -8 im afraid.

 

[mudgudgeon]

cheers. I think I'll drill and tap my manifold for one while I have it out. Would be interesting to watch it.
I think I'd prefer -8 too, I'd love to spend a winter in North America somewhere.

 

[Mcreight911]

With a td04HL 16t 12 blade turbine 6cm housing I get 1.2:1 drive pressure with 24psi . I recon your twin scroll 8.5cm housing and 12 blade HL turbine will easily handle the flow of the 13t up to mid 20psi with good drive pressure . Not on a 3b but still relevant

 

[gerg]

Id need a lot more fuel to require 20lbs of boost. Currently Im running around 1100F with only 14lbs and my fuel screw is removed. Before with same fuel I needed 24lbs to achieve the same egts.

What engine was the 16t on?

 

[Mcreight911]

Id need a lot more fuel to require 20lbs of boost. Currently Im running around 1100F with only 14lbs and my fuel screw is removed. Before with same fuel I needed 24lbs to achieve the same egts.

What engine was the 16t on?

1kz te

 

[gerg]

Interesting. That's a fair bit of compressor for a smaller engine. Im guessing you rev it up quite a bit? I have noticed with the 11blade and the 12 blade turbines that boost/drive pressure ratios are best below 2000rpm then trend less efficient as the rpms get higher. Not sure what to make of that. Course im running relatively low boost and egts are also low so I have to do some more testing with the new trial. to top it off all 3B throttle plates leak as they aren't designed for pressure so even thought the ratios are good with this design it wold be even better on a throttless diesel.

 

[Mcreight911]

18psi by 2000 full boost 24psi around 21-2200
The 13t made boost sooner but couldn't do the Top end power . Even making less boost below 2000rpm the 16t makes a fraction less torque below 1500 but more from around 1700 onward . Drive pressure spikes 1.2:1 just before the wastegate opens around 2000rpm and then again at 3600rpm .

Be cool to see the results if you had more fuel

 

[gerg]

So here are the results after a couple weeks of running each of the turbos. After I rebuilt the turbo and put the 11blade turbine with the extended tip 11blade 13t compressor the initial results were disappointing, but over a few hundred kms I guess the bearings broke in a bit and the ratios and egts improved. Do turbos have break in periods? I would post up that it makes X boost at such rpms but honestly it's sort of pointless as the turbo responds so fast and burns clean and the egts are always low its no longer something I think about. When I finally tune it for acceptable egts at WOT I'll post up some videos of it going through the rpms showing its response. Right now I'm just trying to compare the different components. The max boost changed as I made the mistake of adjusting my inline boost controller and couldn't get it back exactly as it was before. Just switch out for a kinugawa wastegate so will be easier to control vs cranking the crap out of the stock spring which is only good for like 7lbs. Currently put the stock turbine back on with the 11blade ET compressor before dinner yesterday so will see how that goes over the next week or so. I think it's the combo I'm going to keep as its always 1:1 and better which the 11blade turbine wasn't consistently doing.

This was done at WOT starting at 80kmh in 4th gear pulling maybe a 3% grade and I ended the run at 100kmh. My fuel pump is maxed as I removed the control screw.

Turbine. Compressor Drive/ boost lbs. egt

12 blade. Stock 13t 14/14. 1075F

11blade. 11 blade ET 13t. 16/18. 1000F

12blade. 11blade ET 13t. 16.5/16. 980F

 

[gerg]

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.