3b twin scroll turbo (3 Viewers)

[gerg]

Yeah it is a good thing to compare against. I talked with the dyno guy this morning about he wiggly line on the graph and he said it's very common on 4cylinder diesels at low rpms. It's getting artifact from individual cylinder firings. The more cylinders and the higher the rpms the cleaner the line. He also said they only measure minimum and Max boost and the pressure only shows the trend and doesn't get a value second by second. I thought that was kind of lame. Nice to see the trend though. Throughout the whole pull it didn't burn black but just the usual diesel exhaust. The dyno bay wasn't really very smokey all things considered.

 

[GTSSportCoupe]

It's not the number per say, it's just people talk HP but you drive and feel torque. How often do I take it up to 3000rpm where my HP peaks? Like perhaps 1% of the total driving time. That's sort of what I was getting at.

I can make 200ft/lbs torque on my bicycle. But at 0.5 peak hp, that aint going to move my truck and trailer! When people talk about torque, what they really are talking about is power low in the rpm range. Power is just a function of torque and rpm. Power is what gets the work done.

I get where you are coming from with peak hp specs though. Sort of like the Honda kids back in the day who had turbos that finally spooled by 7000rpm. They were making 600 peak hp, but it was completely useless power.

With my smaller displacement diesel, I depend on extending the torque higher into the rpm range in order to make significant power. And I do use that power. I will tow the big hills at peak power. When cruising along under lower load conditions, I stick around peak torque for better efficiency.

Anyhow, I really like your power curve on that motor. I think you've done very well.

 

[gerg]

That's true Nick. I can make 200ft/lbs of torque sitting on the throne, butt its not its not at cruise rpm! Your engine has electronic timing controls too I think? That is a big plus. I wanted torque to peak a little bit below cruise Rpm so you could lug it and hold a gear without the worry of overstressing the crank out, and more importantly be able to shift and put your foot into it safely when your pulling hills and stuff. Unless you rev it out alot when shifting the rpms drop down to like 1500 and you have a hard time getting back up to 2000. People, including myself, rarely change their driving style so I tried to tune it to me rather then have me adjust to the truck. I think the reality is people don't change their driving habits and end up stressing their engine out to serve their ego. I could advance it more and run additives and get a higher peak HP number, but I would really need to increase my Rpms to utilize that. I don't know where im going with this but coffee really increases motility so I have to cut it short.
g

 

[Dougal]

You're going to be ecstatic with the 4BD1T Gerg. You'll double those numbers easily.

Chop chop!

 

[GTSSportCoupe]

You're going to be ecstatic with the 4BD1T Gerg. You'll double those numbers easily.

Chop chop!

He's probably cooking up something like this already in his spare time:

 

[Dougal]

He's probably cooking up something like this already in his spare time:

That one was running a custom fuel pump delivery ~7x the factory fuel and three figures of boost. It was never dyno'd in that configuration but reportedly made Randy's tweaked duramax pickup feel slow. Stock head-gasket held till 60psi boost.

Then he got divorced when that Ford was apart for a major upgrade and it was parted out. Engine ended up a Jeep Grand Cherokee with a big single turbo putting down 350hp. Someone bought it on Ebay.

Some earlier build specs here: Cummins 4BT & Diesel Conversions Forums

 

[gerg]

I thought it was an he351. That is a large high pressure turbo. I'll have to see about getting a pump done from those guys...who ever those guys are that is. My goal this summer is just to get the 80 swap in and driving and I'll begin building a separate motor for a power up. I have a lot of learning to do on the Isuzu first.
g

 

[Dougal]

I thought it was an he351. That is a large high pressure turbo. I'll have to see about getting a pump done from those guys...who ever those guys are that is. My goal this summer is just to get the 80 swap in and driving and I'll begin building a separate motor for a power up. I have a lot of learning to do on the Isuzu first.
g

Honestly a custom pump is only needed if you really really hate your gearbox, tyres and axles. Stock delivers enough fuel for ~800Nm and 200kW.

 

[gerg]

Well I won't make any plans till its in and running.

 

[dare]

So gerg, can we get a list of what's in this engine as it was dyno'd?

Just from what you've posted it's something like this.

Rebuilt bottom end.
Ported head with deshrouded valves and ported precups.
Reground cam, different profile/higher lift?
DN4SD24 injector nozzles
TD04HL-13T turbo, ported 8.5cm twin scroll housing and extended tip 11 blade compressor wheel.
Front mount intercooler of unknown dimensions?
Max egt?
Max fuel screw position?

 

[gerg]

So I spent quite a bit of time on the head. I deshrouded the exhaust valves and removed the restriction in the exhaust throat. Took off all casting but didn't port it per say, just smoothed out flow. Smoothed out the precups inside but left the actual port dimension alone so as to not interfere with the flame angle as it impacts' the piston. Blended the angles on the valves and back cut the exhaust valve. All this lowered the compression ratio to some degree but that is secondary. Stock cam, stock injectors not rebuilt but little wear on the needles when I had them apart. Fuel screw removed with the little arm bent to allow for full rotation of the arm on the pump. max egts were about 1150F pre turbo even soaked going up some nice hills. FMIC I think was 2.5" thich by 9"tall and 18" long core. 2.5 in/out. The turbo you mentioned. Stock bottom end. Lots of room for improvement honestly. I did a high lift cam before but I wouldn't do it again. Lots of work for almost unoticable improvement.

A proper intake manifold would be great, rebuilt injectors would help too.

 

[dare]

Thanks Gerg.

 

[gerg]

No problem. So an intake manifold would not be an easy project but I think it would improve flow to cyl 1 and 4. Also, machining some sort of o ring or something onto the throttle plate shaft would reduce or eliminate the boost leak it causes as it was never designed to handle any pressure and only comes with a bushing from the factory, most of which is worn to nothing by this time. Its actually a very large leak when compared to intake pipe connections. The whole throttle plate is a PIA overall. The only real benefit is very smooth throttle control.

 

[gerg]

So just to add on the cam part, the cam I had cut was not a high lift, but had longer duration on the exhaust side and was a steeper grind opening the valve faster. The intake was not altered much. Colt cams did mine and hes got the profile on record if anyone wants one. There are easier places to get gains though. I based my head work on low lift v8s as the have very similar rpms and cam lift as out engines. High lift on a low rpm engine is a big step back. Porting the runners for low rpms is also a step back. Most of the gains were seen by smoothing the valve cuts and throat work with valve deshrouding. Exhaust valve that is. Deshrouding the intake valve can be a negative very quickly by causing reversion. You always want to encourage flow into the cylinder while discouraging flow from going backwards. The exhaust valve is way more forgiving this was as it doesn't see reversion from the runner. While the intake port is super rough with extra casting and might seem fun to hog out and really open up....I doubt you get any gains from that work. Cutting into a water jack would suck too.

 

[Rumble box]

I just pulled what i think is a twin scroll version of a TD04 off a Volvo S40 and am in the process of getting stuff together to turbo the ol' 3B and just wondering what type of metal you used for your manifold was. Any info on what you used would be greatly appreciated!

 

[gerg]

That is a td04l version of this turbo. Would be a very good match and would essentially perform the same but would spool faster and run higher back pressure in the upper rpms due to the smaller turbine. The problem with that turbo is the inlet is funky and will require you to customize the flange and create your own gasket for it. I use mr gasket to make gaskets. The runners also will need to mate to it in a strange fation as well. If your ok with a lot of die grinding it's a project worth doing as you will love the performance. I have that turbo on the shelf and studied it a lot and decided it was too much work for me. I use 1.25" schedual 40 mild steel elbows to build the manifold. Bevel the inside lip of the downstream piping to smooth flow as the piping rarely mates pefectly. Make all your pieces fit tight to minimize warpage. I tac the runners together and mock the entire build then remove them off the cylinder head flanges and weld each separately and fit them to the turbo flange then grind the set up to lay true onto the cylinder head flanges with no gaps. Welding gaps leads to shrinkage and warping. I heat everything before welding. I never grind my welds anymore. If the cylinder head flange is warped after your build you can often bolt it down and find one runner is wacky. I cut that runner free and rebolt it to get the flange flush and reweld the runner. I belt sand the flanges lastly to eliminate leaks. 1/4 npt bung for egt probe I mock up to lay mid gas stream. Header wrap the whole thing. I've spent several hundred hours building manifolds and your first will suck and leak. I suggest building an easier one first, but you will probably do it anyway. suspend the turbo in the precise location you wish it to lay in the engine bay and fit and measure your downpipe and intake and oil lines Cus it absolutely sucks ass to spend 50 hr building a manifold just to have it not fit by 1/2 an inch somewhere. Building a cool high speed turbo to have a downpipe built out of 90 degree box tubing that touches your firewall is a great way to destroy huge gains in effecient gas flow. A turbo only requires one serious bottleneck to suck. Engine bay fires and melted wires suck too.

 

[cruisedeisel]

My turbo caught my hood insulation on fire going up mt washing years back. I ripped it out, game on.

 

[Rumble box]

Holy toledo gerg,wasn't expecting that much info but thank you! I have access to AutoCAD and a local laser cutting guy that works cheap so I should be able to make flanges fairly easily. Only other thing I'm concerned with is the coolant lines. Seems like it's a 50/50 split on if you should or shouldn't use them from what I've read.

 

[gerg]

Laser cut stuff is nice as you can decrease your production time for sure. I didn't like the inlet step on that turbo which I believe is to avoid using a gasket. I thought I'd have to get a flange CnC milled. Do provide your turbo sereal number as there is a 12t version which is too small for a 3B. The 13t variety is well matched.

Unless you intentionally plan on hot shut downs or sell turbos and don't trust your customer to idle before shut down then coolant is a big help. It's only bennifit is to prevent coking which can be avoided by idling to get your pre turbo egts in the mid to low 300s F. I experienced engine temp issues when I ran turbo cooling lines but I suspect it was due to an old system and the flow the turbo steals which decreases flow through your rad as well as advanced timing. I don't recommend it and will not ever do it myself in the forseable future.

Here the runners are welded individually after mocking the fitment and tacking together. Strangely lateral Y connections are much harder to create than a simple y. I'll see if I can dig up some of my experiments in my bone collection. The true Y is easy, you just chop each 90 in half. Buy a cheapo 12" fixed belt sander with a rotary disk feature and put the heaviest grit paper you can find on it and it makes getting a true tight fit infinitely easier. Take your time fitting and cutting and don't be in a hurry to "get it done" and weld it together. Cutting corners in the welding department suck several orders more in the grinding department.

Always leave room for bolts. This has caught me off guard many times. The 1.25" pipe does not fit naturally to the cylinder head ports so I cut 1" slices down the pipe to flair it to match each port. I weld externally and spend considerable time in all my transitions. It's a great way to destroy flow if your not careful. I use carbide burrs and take my clothes off before I come in the house. Hats are nice. You will take a metal filing shower. Taping a shop vac to the other end of the runner can decrease your miserable life hating grinding experience. Think of it like porting a head for better flow and it makes the slow tedious work less agonizing.

I "texture" all bends with booger welds to help header wrap from slipping. Ive never seen pics of that on the intraweb and my ego likes to tell me I invented it, so out of respect I think we should call it "boogering. I offer that up to the shade tree hord to pervert as they see fit. I double, triple and quadroople header wrap to minimize heat. Header wrap is an investment that pays dividends forever. Excessive Underhood temps is a critical component of the love removal machine that can make you hate your truck.

 

[gerg]

These sanders are a dime a dozen on Craigslist but aren't long enough to sand the 3b manifold all at once. Larger sander than this get expensive imediately.