12H-T performance Build (4 Viewers)

[gbentink]

*EDIT* after measurements

I think this is correct, by memory

3SGTE 1st gen. Round Port - CT26 (40mm or 43mm? Comp Inducer)
3SGTE 2nd gen. Split Port - CT26 (40mm or 43mm? Comp Inducer)
3SGTE 3rd gen. Round port - CT20B (slightly smaller turbine, 47mm? inducer)
1HDT Auto(manual?) Round Port - CT26 (43mm Comp Inducer, larger A/R Ex housing than 3SGTE)
1HDFT Auto(manual?) Round Port - CT26 (43mm Comp Inducer, larger A/R Ex housing than 1HDT)
1HDFTE (CT20B?) - only says "Toyota" on compressor cover which is typical of CT20B (so called)
7MGTE Round Port - CT26 (47mm Comp Inducer, largest A/R exhaust stamped 42010)

Currently I have 2 x 12HT exh housings (stamped 58010), 2 x Supra housings stamped 42010, 1 x 3SGTE twin entry stamped 74020. I cant remember what was stamped on my 1HDT - I will check a friends.

Some CT26 turbines fitted to the CT26 were ceramic, the one I used on my 1HDT was ceramic. It definately spooled like it had low intertia.... I was out to prove ceramic doent die because of boost - they die because of too high EGT's. I proved it too. 27psi no problem. Turbo was not efficient at 27psi however....

I have read many "statements" that the ceramic turbine flowed more or was bigger than the steel counterpart. They measured the same and looked the same dimensionally.... I only tried it for the reasons mentioned earlier and it worked fine. Ultimately though, the metal turbine is easier to modify - if indeed the/a modification is beneficial. I had a real problem with exhaust backpressure on my 1HDT due, I expect, to the small exhaust housing. It was able however to make terrific torque very early in the rev range, so as a driver/tow horse, it was really something special. After driving a 100 series auto, my 80 series really felt "strong" off the bottom end and to ~ 2400rpm. I have not got anywhere near that performace from my 12HT....yet. The key is low backpressure/boostpressure ratio for whatever boost you are making in my opinion - which is the reason for the twin idea (increase overall turbo efficiency).

 

[gbentink]

Dougal: I have not *ever* understood the way exhaust flow is done. The problem is regarding the fact that they use mass flow, when I thought the *plug* performance was also relative to exhaust temperature.

Your input here would be apprecaited. I am looking at a turbo a little differently now, especially since the exhaust mass flow of some of these engines must be up to 50% turbine bypass.... Hardly efficient!

Perhaps I need to match compressor flow vs turbine flow (mass flow). If that is the case, I should use a 20lb primary turbine with a 40lb secondary turbine if both are running PR=2. Both should be VNT......... Now that would be a nightmare to tune. My GT3782VA has a HUGE trim turbine - I should measure it, but greater than 60mm exducer. Exhaust A/R up to 0.9.

The engine that the GT3782VA comes from is the 6.0 litres powerstroke 2004. This is a std 325hp engine that with more boost, fuel etc makes 450HP easily - I think that is at the wheels HP.

This is far more than the max flow of ~ 35lbs/min of exhaust the graph indicates is the maximum, even at vastly reduced AF ratios

 

[Dougal]

Dougal: I have not *ever* understood the way exhaust flow is done. The problem is regarding the fact that they use mass flow, when I thought the *plug* performance was also relative to exhaust temperature.

This has always intruiged me too. The crux of it I believe is that hotter air even though it is less dense, can be compressed more. So at a higher pressure ratio you still hit choke at a similar mass flow to cooler flow.
The turbine maps you see from Garrett etc are lines drawn through the peaks of a whole lot of individual curves. I think it's the best efficiency point of each curve, but it might not be.

Your input here would be apprecaited. I am looking at a turbo a little differently now, especially since the exhaust mass flow of some of these engines must be up to 50% turbine bypass.... Hardly efficient!

That's the other major difference between ricer turbos and diesel turbos. A lot of diesel turbos don't run wastegates, especially the big turbo in compound setups.

Perhaps I need to match compressor flow vs turbine flow (mass flow). If that is the case, I should use a 20lb primary turbine with a 40lb secondary turbine if both are running PR=2. Both should be VNT......... Now that would be a nightmare to tune. My GT3782VA has a HUGE trim turbine - I should measure it, but greater than 60mm exducer. Exhaust A/R up to 0.9.

Remember, you don't need to actively tune them. You need to set them up with the necessary pressure signals so they look after themselves.
Easiest way to compound is to start with a single turbo that you know works well. CT26?

 

[gbentink]

Quote: "The turbine maps you see from Garrett etc are lines drawn through the peaks of a whole lot of individual curves. I think it's the best efficiency point of each curve, but it might not be"

I wondered about that, since they state maximum efficiency. Could it be that the line is the curve at the efficiency stated on the graph - it makes much more sense to me. I would like to see how drastically the efficiency changes with mass flow over and above what is listed in the graph.

Case in point below for extra performance, taken from "Fourwheeler.com"

Rear-Wheel Horsepower and Torque
DynoJet 224 Chassis Dyno*
Dyno Test Results: ’05 Ford F-350 Super Duty 6.0L, SR100 five-speed automatic
Condition Power Torque
Stock, with 800 miles 275.6 hp 469.6 lb-ft (325 flywheel HP stock)
With Airaid & Magnaflow 283.9 hp 477.2 lb-ft
With Airaid, Magnaflow & TorquePro 359.4 hp 675.8 lb-ft
With Airaid, Magnaflow & Edge L1 313.6 hp 577.4 lb-ft
With Airaid, Magnaflow, Edge L1 & TorquePro 369.6 hp 689.5 lb-ft
With Airaid, Magnaflow & Edge L5 376.7 hp 784.7 lb-ft
With Airaid, Magnaflow, Edge L5 & TorquePro 423.6 hp 838.8 lb-ft
*DynoJet located at University of Northwestern Ohio

The Torquepro is Propane, the other stuff is intake/exhaust/fuelling mods.

Stock turbo - GT3782VA

 

[gbentink]

Trouble is with the CT26 option, it that it is a bit large on the hot end. I guess a viable and possibly interesting option would be to use the MR2 dual port housing on the primary turbo (the 12ht manifold is basically dual port anyway....) and use a back cut, high flowed CT26 with Supra housing as the secondary...

Might be good for 180-200rwhp in that configuration and make good torque off the bottom also.

Andy at "Dieseltec" in Melbourne put a second turbo on his 1HDT, leaving stock CT26 in place. With no intercooler and 40psi, he dynoed 138rwkw - I have seen the dyno curve on the machine. Low smoke configuration. The second turbo looked like a GT30R or Gt35. Using this turbo on the GT2860RS gave 55psi (no intercooler) on a TD42 Nissan and 175rwkw and a broken rod!

 

[Dougal]

Andy was keeping the second turbo secret. But yes it'd be around that size.

I wouldn't worry about the stock turbo hot side being a little big. It's probably better a little big than a little small. It may get a push from the big one as well and spool sooner than we think.

I'll see if I can dig out some graphs from a reference book later.

 

[gbentink]

Well, I have done some measurements and have really suprised myself at the results, seems I was wrong about the compressor on the CT26 and also the exhaust side..... The CT26 compressors are bigger than I had thought. There is a website which states the GT4 has a 1.575" inducer compressor, I mesured the others myself however it is hard when there is an uneven number of blades! Anyway...

See below:

12HT/1HDT compressor: Inducer 43mm, exducer 65mm
7MGTE compressor: Inducer 47mm, exducer 65mm

All have CT26 Turbine 68mm Inducer, 52mm Exducer

My VNT Garrett: compressor: Inducer 42.5mm, exducer 60mm, Turbine 51mm Inducer, 47mm Exducer So this makes it a GT25, but very big trim!

The blades on the VNT on both ends are very thin, but the metal seems of a higher yield strength than the CT26. So, I would expect the compressor to flow at least as much as the CT26 43mm version.

I will edit my post above in case anyone refers to it.

From previous measurements, a version of the TD06 series turbines will fit with minor mods in the CT26.

 

[VTCruiser]

Well, I have done some measurements and have really suprised myself at the results, seems I was wrong about the compressor on the CT26 and also the exhaust side..... The CT26 compressors are bigger than I had thought. There is a website which states the GT4 has a 1.575" inducer compressor, I mesured the others myself however it is hard when there is an uneven number of blades! Anyway...

See below:

12HT/1HDT compressor: Inducer 43mm, exducer 65mm
7MGTE compressor: Inducer 47mm, exducer 65mm

All have CT26 Turbine 68mm Inducer, 52mm Exducer

My VNT Garrett: compressor: Inducer 42.5mm, exducer 60mm, Turbine 51mm Inducer, 47mm Exducer So this makes it a GT25, but very big trim!

The blades on the VNT on both ends are very thin, but the metal seems of a higher yield strength than the CT26. So, I would expect the compressor to flow at least as much as the CT26 43mm version.

I will edit my post above in case anyone refers to it.

From previous measurements, a version of the TD06 series turbines will fit with minor mods in the CT26.

Interesting, the CT26 that came with my kit for the 1HZ is supposedly some kind of hybrid, different than the OE 1HDT version. I am trying to get details, so I'll post up what I find. But, since I burned up the bearings recently I'll have an extra/unused CHRA to take measurements of if they don't disclose the specs. I'd be curious to know exactly how it compares to the other OE CT26's.

 

[gbentink]

Hi VT Cruiser,

Based on my experience with the CT26, I am hoping yours is not one of the T03/4 comp wheel options like one I have at home with a monster 57 Trim T04e wheel! They just don't last (bearings) and are plain inefficient due to poor match from turbine to compressor.

The huge comp wheel will *work*, however the question is how well will it work.

The answer is, not very in a Diesel, unless EGT's are very high (probably = smoke) and you are better off matching the comp wheel as best as possible and or moving to a different turbo if you need bigger.

What I have very recently realised is that for a given capacity, a diesel under full load has much less exhaust energy, therefore it requires a turbo that relies on minimizing bypass via the wastegate through the correct choice of size matching.

This is to be expected since EGT's are much lower than with Gasoline, AND the engine is more efficient, hence less energy lost to exhaust that could be used to drive a turbine.

I am hoping that you have a 7MGTE comp wheel.

PS: These turbos (untouched) often outlast the motors - that is 500kkm. So if it isnt, it is worth considering why.

When I push the turbo to 18 or so psi, I am fully aware that 100,000km might be all I could expect and I would be happy to get 50kkm, since a rebuild kit is under $100.

 

[Dougal]

When I push the turbo to 18 or so psi, I am fully aware that 100,000km might be all I could expect and I would be happy to get 50kkm, since a rebuild kit is under $100.

Although, often when a turbo becomes in need of a rebuild kit, it's compressor and turbine wheels have committed suicide against the inside of their housings.
A GT2860R I recently bought was like this. Only usable parts are the housings. The price matched the condition though.

 

[gbentink]

Dougal:

I think a good non VNT match may be the GT3776 1.12 Ex AR. Otherwise, as a VNT option, even my GT3782VA.....

 

[gbentink]

Although, often when a turbo becomes in need of a rebuild kit, it's compressor and turbine wheels have committed suicide against the inside of their housings. QUOTE]

Fair comment, though I have not seen a CT26 that this has happened too. I have only pulled down 9, so a fairly small sample size. Mostly oil starts leaking on the compressor side.

Build quality is great, big shafts etc

 

[VTCruiser]

Hi VT Cruiser,

Based on my experience with the CT26, I am hoping yours is not one of the T03/4 comp wheel options like one I have at home with a monster 57 Trim T04e wheel! They just don't last (bearings) and are plain inefficient due to poor match from turbine to compressor.
...

I don't believe it is, the comp inducer doesn't look that large and only has 5 blade pairs (i think the T04e has 6?). I guess I'll know when I take it apart and can measure the trim...

 

[mudgudgeon]

very interesting thread guys, a bit heavy on the jargon for me to understand it all though :whoops:

My ct 26 on 1HD-T died a couple of weeks ago, "committed suicide" is a slight understatement

this is the result of some shaft play (worn bushes and worn shaft) combined with 22psi boost at 3000rpm (waste gate disabled) the comp wheel contacted the housing and exploded, shaft is bent and broken, thrust bearings were broken and ended up in the sump

I knew the shaft play was getting dubious and had sourced a rebuild kit for the turbo and a ct26 from a 7MGTE (turned out to be not rebuildable, shaft was shot).

As you can see in the pic above, there is not much left of the comp wheel, in the 30-40 seconds it took to get off the road safely and shut it down, most of the compressor wheel went through the engine and was mashed by the pistons and blown out through the turbine. The turbine and housing where all covered in little beads of burnt alloy, and the engine was starting to run on its own oil.

Upshot is engine is getting a full rebuild, pistons were damaged, valves, head, conrods etc survived, turbo is toast. There was all sorts of debri in the sump and combustion chambers



gbentink,

rebuild kit may be only $100, but the shafts tend to wear as well as the bronze bush bearings, so they have limited rebuildability, also if they go pop, as mine did, cost lots more then $100.

for what its worth, a couple of comments after reading the last couple of pages here,

1HD-T aneroid functions to reduce fuel delivery when off boost, boost pressure will allow fuel to ramp up to its max as set by the main fuel screw.

A comment was made re size of waste gate on a petrol turbo being larger, the ct 26's that I have (7MGTE and 1HD-T) both have the same size waste gate ports and turbine outlet port.

Casting number on 1HD-T turbine housing is 58020

some usefull info re ct26 parts and model applications herehttp://www.melett.com/turbo-parts-catalogue/toyota/Toyota.pdf



VTCruiser,

post a pic showing the full compressor housing, they are easy to distinguish between LC and Supra housings. Its reasonably common to combine the landcruiser turbine housing with the larger Supra 7MGTE front housing and compressor wheel

 

[mudgudgeon]

That's the other major difference between ricer turbos and diesel turbos. A lot of diesel turbos don't run wastegates, especially the big turbo in compound setups.

I think its common for large deisels to run no wastegate, mostly on static installations such as generators and pumps that have a continuous load.

I disabled my wastegate and found I could vary the peak boost from around 14psi to 22psi depending on the fuel pump tune.

 

[mudgudgeon]

gbentink and Dougal,

have either of you considered using a supercharger in compound with a turbo?

I have a Eaton m112 supercharger I am contemplating using on my 1HD-T with a large turbo for secondary boost.
I have read of guys having a lot of success with this on petrol V8s, beyond a lot of peoples expectations.
The supercharger provides boost from Idle and helps the turbo spool up quicker due to scavenging action and increased exhaust volume. Once the turbo is producing boost it increases the volume of air available for the supercharger to pump.
I know lots of people regard superchargers as a parasitic drain on the engine, but it seems to me that S/C and T/C would work beneficially with each other and give the best of both worlds.

just wondering if you guys have any thoughts on this without hijacking gbentink's thread too much

 

[Stone]

Fair comment, though I have not seen a CT26 that this has happened too. I have only pulled down 9, so a fairly small sample size. Mostly oil starts leaking on the compressor side.

Build quality is great, big shafts etc

I know how you can make a freshly rebuilt CT26 do this...just send it to ADP for the rebuild.

 

[Tapage]

I have a Eaton m112 supercharger I am contemplating using on my 1HD-T with a large turbo for secondary boost.

interesting point and alternative .. but aren't the SC limited by the amount of air that they can flow .. talking about a SC that boost from low ( said 2 - PSI ) end to 1800 rpm ( said 8 PSI ) . ?

maybe if should be a restriction more than a help when the turbo it's producing 20 plus PSI ..

 

[VTCruiser]

Interesting, the CT26 that came with my kit for the 1HZ is supposedly some kind of hybrid, different than the OE 1HDT version. I am trying to get details, so I'll post up what I find. But, since I burned up the bearings recently I'll have an extra/unused CHRA to take measurements of if they don't disclose the specs. I'd be curious to know exactly how it compares to the other OE CT26's.

Here's Maarten's reply to my email. Pardon the grammar, English is not his first language:

I DO NOT HAVE REAL SPECS BESIDES THAT THE COMPRESSORWHEEL WE USE IS Ø 46mm VERSUS Ø 43 OF THE 1HD-T. IT’S A LIGHTER WHEEL ALSO.

TURBINE SIDE IS LIGHTER AS WELL AND SHAFT DIAMETER IS REDUCED. ALTOGETHER A TURBOCHARGER THAT SPOOLS UP MORE QUICKLY AND CAN WITHSTAND HIGHER RPM THAN THE UNIT FROM THE 1HD-T.

...

FOR INDIRECT INJECTION ENGINES WE HAVE CHOSEN A DIFFERENT RATIO TURBINE HOUSING. COMPARED TO GARRETT T3 YOU SHOULD THINK ABOUT A .70 A/R.

yeah, sorry for the hijacking the thread...!

 

[gbentink]

Interesting Info and discussion:

Re: Supercharger - I considered this as well. You could use a Toyota Sc12 or Sc14 with the clutch (or a Merc clutched model) and run a bypass when the SC is not needed or inefficient. In fact, even without a clutch the engine drive is largely eliminated using a bypass. the only reason I didnt do this was because of under bonnet pulleys etc and that with a Compound Turbos and or VNT you could achieve similar results with higher overall efficiency. Laggy respose of the bottom is the only issue and for me with an auto, doesnt make a difference. If manual box, would be a tempting option is to twin charge using a SC off the bottom. There was a Green Merc Wagon in Europe running around like that for a while - real masterpiece too, made ~ 400hp and did great donuts!. My younger Brother is a Diesel Mechanic and put an SC14 on his TD42 Nissan. It was set for 2.5:1 ratio and made 4psi at 800rpm, 14psi at 1500rpm, intercooled. Zero diesel knock and throttle response was extrordinary - like the engine had half the inertia as before. Didnt make huge power, however torque off the bottom was very impressive. Broke many CV joints off doing extreme off-road such was the instant throttle response in low revs.

Regarding CT 26 From Maarten.

Maarten really knows his stuff and raced the 1HDT and 1HDFT. He told me 240/280hp from T/FT respectively and he used a factory Toyota Offering. I am wondering if in fact it is a 1HDFTE Turbo! He also said that he got 280/320hp respectively when using LPG fumigation. Torque was 640/660nm for T/FT respectively. The smaller turbo will build boost earlier than the larger CT26. I considered buying a turbo from him however the price was the issue - I am pretty tight with what I spend my money on AND I like to work things out for myself, so an off the shelf proven option is (stupidly?) not interesting to me.

Re: Blown CT26

Wow, now that is what I call catastrophic compressor failure! Your turbo may well have been out of balance as well, which doesnt help. It certainly isnt in balance now

re: 1HDT Turbine Housing

Thanks for the numbers. Is that from a manual or an Auto? If manual, thats great because I can check my friends auto and solve the riddle if the housings are different. So 58010 vs 58020 for 12HT/1HDT respectively. The 74020 3SGTE turbine housing has dual scroll AND dual port wastegate. My theory was the "020" was for that aspect, so you have blown that theory out of the water. The other theory is that the smaller the first twon numbers, the larger the A/R...so far this is still a possibility. Certainly looks that way as far as the physical sizes are concerned.

WASTEGATE DISCONNECTED

Guys, if a turbo has the wastegate disconnected, like I do for testing purposes, and the compressor goes to choke flow, then the load on the compressor is reduced which will increase turbine speed. This is Bad. I do not plan to leave mine wide open with std compressor.

As was mentioned, you can control boost with fuel. When I upgraded my CT26 with a TD05 18G comp wheel, I KNEW that I would not get into a choke flow situation, so leaving the wastegate hose disconnected was not so much an issue. With such a small inlet (43mm) 22psi will hit choke flow fairly early in th revs (2800rpm or so at that boost probably). This may not happen with stock fueling, but increased fueling means more drive power from exhaust = possible dangerous scenarios (perhaps that has just been proven). Good to keep in mind. basically, if you care about loosing your turbo, dont do it. For me, I have a few turbos and it means a few hours mucking around and changing it, so not a biggy for me. Also, I drive on weekends only....

Looks like the good ol Supra comp wheel, big exhaust, possbly clipped turbine (yet to be determined effectiveness) makes for a very attractive option on the 12HT/1HDT/1HDFT as a budget upgrade.