3b twin scroll turbo (1 Viewer)

[dare]

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!

And to extrapolate that out, stock 3Bs make max power at 3500rpm (the governor starts pulling fuel after that until you get to the 4100rpm limit).

385nm at 3500 = 141kw = 188hp

But it's questionable it would still be making that torque so high up.

Even 350nm at 3500 equals 128kw/171hp.

Impressive stuff for a dinosaur engine on relatively low boost. That's more power than a 1HD-FT!

And yes, please dyno it gerg!

 

[Dougal]

And to extrapolate that out, stock 3Bs make max power at 3500rpm (the governor starts pulling fuel after that until you get to the 4100rpm limit).

385nm at 3500 = 141kw = 188hp

But it's questionable it would still be making that torque so high up.

Even 350nm at 3500 equals 128kw/171hp.

Impressive stuff for a dinosaur engine on relatively low boost. That's more power than a 1HD-FT!

And yes, please dyno it gerg!

The more you boost engines like these the lower they tend to deliver peak power. I reckon 3000rpm would be it. Decrement torque by another 10% to ~350Nm at 3000rpm and it's 110kW.
If it held 350Nm to 3200rpm then it's 117kw which might be it.

 

[gerg]

Something like this Dougal?

 

[Dougal]

Something like this Dougal?
View attachment 1389243

That's a super fancy one. But yes.

 

[gerg]

Hah! Looks like 30$ worth of parts cool.

 

[GTSSportCoupe]

The more you boost engines like these the lower they tend to deliver peak power. I reckon 3000rpm would be it.

I've noticed this with my motor also. Why does this happen?

 

[ERNRAM]

Any update?

 

[gerg]

Sorry Not many changes lately. Tried some different timing settings and pulled some hills to go skiing yesterday. Timing now is at the stock setting but it drives like its retarded with a lot more torque in the lower rpms. Was pulling 8% grades in 4th at 2250 rpm at 17lbs boost, egts 1075-1100f drive pressure was 16lbs. Was going to try out a 15g compressor but we got buried in snow and a made a deal with a contractor to do house rennos for some work on his truck so I'm into that now. If I do any changes I'll keep you posted.

 

[gerg]

So ported the wastegate and cleaned up casting in the housing. Increased boost to 19lbs and pulled the coquahala snow shed today going skiing. 19lbs boost to 18.5 drive. EGTs were like 1100F ish. Water temps got to 208f. 4th gear with all the family and about 500lbs of clothes, food and ski gear. The back was packed. The snow shed is posted at an 8% grade but it's way steeper than 9% grades I've pulled. It's like 10% or more. Some say as much as 12% but I dunno to be honest. It's the steepest part of the pass. Which is why I took a video of it. It's the nastiest hill I could find. Very happy overall.

trim FBBEF4D7 E0CC 4407 BF0A 3FA2278E5B48

 

[dare]

Impressive!

I have the same stereo as you.

 

[gerg]

Best thing about the 62 is the sound deadening. Power windows and lock are cool, but being able to hold a conversation and listen to a stereo without damaging your hearing is a wonderful thing.

 

[dare]

Mine's the same(BJ73 LX). A few people have said "I wouldn't have a 3B, they're rough/loud ect" but I think their experience is with thrashed out BJ40s or old trucks.

 

[gerg]

Yeah my first truck was an fj40 and I had ear muffs for the freeway. everyhting about that truck was loud.

So I did end up trying out a 15g compressor. Rebuilt the turbo and got it balanced and it spooled the same and ran 50f hotter overall. Didn't help much with egts from 2500-3000rpm so I put the 13t back on which is what the latest video was with.

 

[gerg]

Just got back from the ski trip and used my gps to measure elevation drop for the snow shed hill to calculate the grade. From the shed to the top it was 8.75% over 2.4km with the steepest 1.1km section just before the top at 9.1%. Kind of makes me wonder how they calculate other hills as I've pulled the 9% Hope slide grade and it was not even close to the same as the shed. Averaged 19.9 us mpg.

 

[GTSSportCoupe]

Nice work on this setup Greg! I'd love to see the power curve for this motor. You should give that 'PerfExpert' program a try. Enter your data accurately and the wheel power curves are pretty accurate. It really is a impressive program. If you don't have time, I could send you my old G-Tech to play around with if you're interested. It only gives peak power estimates though.

I do those same hills at the same speed, but I think my rig is lighter than yours. My motor is currently making 85whp with torque convert un-locked. Torque converter is dyno proven to loose 10kw (13hp) when not locked. Auto trans is known to loose about 5% more than manual. So I think that if I had a manual transmission I'd be about 100whp. Close to that when the torque converter locks in 3rd/4th anyhow.

So I'm thinking you are well over 100whp. Impressive!

Wonder how your water temps will be this summer under heavy load? Are you still running Evans Coolant? Always the limit on these old IDI's.....

 

[gerg]

That's funny cus I've got an old g tech as well but could never get it to work right. I'll check out that program. Sounds pretty cool. I'm not too worried about water temps. I had my foot into it on those hills for like 30kmh and the temp only climbed on the last part of the steepest hill so that's not a biggie to me. 208 is not going to break any records. Funny cus my stock Toyota gauge didn't move much at all. Can't trust those things. I do run Evans as well.

 

[GTSSportCoupe]

I'm not too worried about water temps. I had my foot into it on those hills for like 30kmh and the temp only climbed on the last part of the steepest hill so that's not a biggie to me. 208 is not going to break any records. Funny cus my stock Toyota gauge didn't move much at all. Can't trust those things. I do run Evans as well.

I never have high water temps in cool ambient weather either. Towing my camper trailer in 35C summer up those sorts of hills is another story though!

 

[mudgudgeon]

@gerg got any pics, or more details of the porting you did on the turbine housing?
was it just to port match to the manifold, or something else?

 

[gerg]

So I ported the wastegate and removed casting that really encroached into the main wastegated gas flow. I have no pics of that, but nothing revolutionary. I do leave a generous 2-2.5mm of overlap for the flapper to seal over as I never want to leak and sacrifice spool. Really easy to get carried away with a die grinder. One problem with tools that do a lot of work quickly is....you can make mistakes quickly. I was happy to note that higher rpm boost vs drive pressure improved considerably after porting the gate which was what I was aiming for as its when the gate is flowing the most gas.

I shouldn't have said I ported the housing but rather removed casting and gasket matched it. Gasket matching is not as easy as one might think and I had to sandwich the mls gasket in between another flange and bolt it together tight or the grinder would have warped it and lead to leaks.

I also oversized the housing reciever ports to eliminate having a mismatched port which can easily happen from the slight play you get from the bolts when you put it into the manifold. You can always cheat fitment a few mm this way and that way. The problem is you have no clue what is and what isn't lining up when you bolt it together. By oversizing the housing ports you will get slightly less effecient flow but will avoid the disasterous flow you get when they are off and a step is created that encroaches into the gas stream. Ok so now a show of hands of all the folks who just said that's probably not happening to my turbo. Guess again. I've never had a turbo that mated perfectly.

The housing had some leftover casting that would decrease gas speed and waste energy. I had to resort to a dremel.....puke....cough.....slow as molasses....arg...I'm dying here...to do the work, but it can fit into small spaces which is a must. It also could vary speed which is nice inside the scroll to control the work. I used a a flex shaft and just bought a 90degree attachment. Tough to fit a tool inside that thing. Thanks mcreight for the tips on the casting. I don't know why, but I've never cleaned up inside a scroll before......maybe cus it sucks! Hah! It's worth it, but it is a painstakingly frustrating job. It's like trying to do a root canal throught the maxillary sinus floor. I mean common. Can't you just extruded hone the nerve out?

 

[mudgudgeon]

makes sense, cheers