1HDT twin turbo

[Enigma]

We have a number of posts about various tweaks/upgrades/replacements for the venerable CT26 turbo, but has anyone ever looked into a twin turbo set up?

A very small turbo for relatively instant spooling and no lag, and a second larger turbo for higher rpms?

I am definetly not a turbo expert, just thinking out loud from some info I saw on BMW with this set up.

Dodge aftermarket twin turbo for an example:
BD Power - Product: Super B Twin Turbo Kits

Interesting, Toyota used a sequential turbo in the '93 to '98 Supra
Twin-turbo - Wikipedia, the free encyclopedia

 

[lowenbrau]

I was thinking a supercharger -> big turbo -> aftercooler would be the cat's backside but I'm not sure the oiling is up to the low rpm torque. There is some discussion that the reason 1HDTs have BEB problems and 1HZs don't is a result of the lower RPM torque pounding through the oil cushion before the oil pressure comes up.

 

[Dougal]

Compound is the answer for diesels. Andy at Dieseltec in Aussie has done it but keeps quiet on the details of what exactly he used.

The small turbo, just use the smallest turbo that will work as a single and not choke at higher rpm.
Then fit a bigger turbo around it, feeding boost into the little one and feeding off exhaust out the little one.
Set the wastegate on the small turbo at around 10psi and plumb the sense line for it into the large turbos compressor. Set the big turbos wastegate (if you want one) at the max boost pressure you want.

 

[OilHammer]

Would love a sequential on my 13BT...that would be insane. Pretty much my only complaint about the 13 is how long it takes for me to boost with the intercooler in place. Given that the rpms drop out so quick, you only really get to use boost starting in third gear. That bimmer sequential is a nasty complex beast though. Wow...don't think I want to wrap my head around how to plumb and activate a system like that.

 

[Toyo Boyo]

Someone on here has put a compound turbo on either a 3b or 13bt?

I'm off to search

I'll be back

 

[Toyo Boyo]

Well that didn't take long - use this for your basic idea

https://forum.ih8mud.com/diesel-tech-24-volts-systems/407381-3b-compound-turbo-25psi-boost.html

An alternative - use two small turbo's per 3 cylinders - you can get into all sorts of fun exploiting pulse flow and the like

Small = fast spool and many to choose from. Piping would be interesting, but not impossible

 

[Dougal]

Well that didn't take long - use this for your basic idea

https://forum.ih8mud.com/diesel-tech-24-volts-systems/407381-3b-compound-turbo-25psi-boost.html

An alternative - use two small turbo's per 3 cylinders - you can get into all sorts of fun exploiting pulse flow and the like

Small = fast spool and many to choose from. Piping would be interesting, but not impossible

There's little gain to be had from twin turbos (i.e both small and same size) on a diesel, it's only really good for petrol 6's where the layout works and they gain a fraction in spool up time.

Gerg's is a good example to follow.

 

[Toyo Boyo]

There's little gain to be had from twin turbos (i.e both small and same size) on a diesel, it's only really good for petrol 6's where the layout works and they gain a fraction in spool up time.

Gerg's is a good example to follow.

Hi Dougal,

Just throwing it out there.

With your turbo knowledge, is a twin (small) turbo for a diesel a bad idea? Or is a compound a better route to go if you are looking for that extra oomph?

Just thinking about twin turbo V8 diesels - there are a few makes of them in Europe now and they don't use compound (AFAIK). Is it because they treat each side of the V like a separate engine?



BTW - I hope things are getting straightened out in Christchurch - terrible news

 

[Enigma]

There's little gain to be had from twin turbos (i.e both small and same size) on a diesel, it's only really good for petrol 6's where the layout works and they gain a fraction in spool up time.

Gerg's is a good example to follow.

Again, I'm no expert, but the huge hp gains the new Fords/Dodges have with the twin turbos (yes very different engines, but still diesels) is extremely impressive.

 

[Hulsty]

Twin turbo 1HDT - parallel

English
Google Oversetter
Original

Norsk Land Cruiser Klubb • Se emne - Tr-racing s hdj80TwinTurbo garasje.

 

[Dougal]

Hi Dougal,

Just throwing it out there.

With your turbo knowledge, is a twin (small) turbo for a diesel a bad idea? Or is a compound a better route to go if you are looking for that extra oomph?

Just thinking about twin turbo V8 diesels - there are a few makes of them in Europe now and they don't use compound (AFAIK). Is it because they treat each side of the V like a separate engine?



BTW - I hope things are getting straightened out in Christchurch - terrible news

Most of the twin turbo V8/V10 diesels out there (toyota, VW, Audi) are running a variable vane turbo on each side. The variable vane has enough operating range to do what they want to do.
The landrover V6 diesel is running a compound/seqential setup which is different again. I don't know what setup the landrover V8 is currently running.
The toyota V8 diesel is basically two Avensis 4 cyl diesels sharing a crankshaft. Not surprisingly it has two avensis turbos.

A compound is certainly the most suitable for our 4 & 6 cyl diesels. VNT's are difficult to find in a suitable size when you're past the 3 litre mark.

AFAIK the new fords are running compound, not twins. The 6.7 cummins uses a variable geometry turbo.

It will take a long time to sort Chch out, I don't live there but I know many people who do. Thankfully they didn't get the Tsunami which Japan got, that's truely terrible.

 

[Dougal]

Twin turbo 1HDT - sequential

English
Google Oversetter
Original

Norsk Land Cruiser Klubb • Se emne - Tr-racing s hdj80TwinTurbo garasje.

That's not sequential, it's parrallel which unfortunately offers no advantage to a diesel. They're only doing 1.2 bar boost which is acheivable with a single turbo. Parallel turbos don't have any advantage at low or high rpm, you might gain a split secong on spool-up but that's largely irrelevant on a diesel.

Some guy in NZ has done similar with a nissan patrol, in spite of all the hype surrounding such work there is no benefit to it. Diesels need more boost to make more power, compounds do that, parrallel doesn't.

*Edit*
That thread is talking about 120cc/1000 shots of diesel. No way is a 1.2 bar non intercooled turbo ever going to burn that clean.

 

[Hulsty]

That's not sequential, it's parrallel which unfortunately offers no advantage to a diesel. They're only doing 1.2 bar boost which is acheivable with a single turbo. Parallel turbos don't have any advantage at low or high rpm, you might gain a split secong on spool-up but that's largely irrelevant on a diesel.

Some guy in NZ has done similar with a nissan patrol, in spite of all the hype surrounding such work there is no benefit to it. Diesels need more boost to make more power, compounds do that, parrallel doesn't.

Correct thats what I meant, they dont feed into eachother.

 

[gerg]

Yeah so I made a compound set up for many reasons, one of which was faster spool. To have a better relationship with my wife was not on the list. I have to say though that with the 20lbs it is at now, I could have done that for much less cost and complexity with one turbo. However, when I get a new head I will jack the boost. If all you want is quick spool go for a small single.
Dougal has mapped that GT 20 something turbo and it has a ridiculously efficient compressor that matches well to the 3B. The turbine is similar to the TD04L that I plan on upgrading to, with a marginally larger exhaust A/R .49(GT) vs .42(TD04L) . Id have to say unless you want alot of boost, be happy with the GT cus it will run into the teens for pressure. With really efficient inter cooling that would be a great set up. By effecient I mean top mount with little dead space to reduce lagg.
g

 

[Wheelingnoob]

Enigma: I would look for a single turbo replacement that fits the engine. I know the GT2052 (I think) is the cats mow on the 3B from what I have read. There must be a GT turbo that would suite to 1HD-T 4.2L engine as well. Maybe something like a GT2860R or a GT28RS? ( I have not looked at any specs on the 1HD engine so do not go out buying one of those turbos with out fully researching them).

There has got to be something out there that is a better performer than the CT26. I would look for something that gives fast spool and more efficient turbine and compressor.

From my Supra days the CT26 is kind of a dud. Its a good turbo for stock engine but it very quickly run out of steam when you start molding the car.

A twin setup although sounds good really does not offer any benefit over a single turbo. I had a twin set up on my Supra and went to a big single (BBT67) and picked up response all over with it. I did make the manifold twin entry and as equal length as possible.

Compounds on Diesels are incredible but useless if you cant use the full boost potential. They also take lots of trail and error with turbo sizing to get right. What works on paper does not always work on the dyno. I was around when PDR was putting together there Compound turbo set up. I saw lots of different turbos go in and out of the test truck till they got it right. Man was it awesome when they got it right though....60psi from if I remember right 2000RPM up (long time ago now and I was not directly involved).

If you can keep it single and get a more modern turbo in it that would be the way to go. I have also had great success with Borg Warner (KKK) turbos, there new stuff is amazing. They spool as fast or faster than the GT Garrett's (the BW turbos are journal bearing) and usually out power them too.

 

[Toyo Boyo]

Dougal,

Variable vane? Forgot about them - and I used to work for Borg Warner - doh!

So much to learn, so little time ha

 

[Tapage]

nice the idea .. but the head and studs can handle that .. ? I mean 30 PSI or more . ? ( to make the hole idea and cost worth .. )