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Raamo appreciate you sharing this on the Aussie car. No disrespect was taken. Sounds like both cars are very similar aside from the Munro turbos vs the Stu GT28r turbos in mine, and he has a ported head. Although mine does not have a ported head, it does have some porting to the exhaust y pipe, and has a 4 inch down pipe.

Do you know the spec difference for the Munro Turbos vs the GT28R?

At full kill setting 5, I was at 29 lbs boost, at 615 whp with same transmission and same 4K stall. Different Dyno numbers cold be just that... different Dynos... assuming his was not a DynoJet.

So not sure if there is much difference other than he has a ported head. That is my best guess but since we are talking about tenths of a second difference in our elapsed times, this is just guessing. Actual difference could Also be due to different track and air conditions, air temps, altitude, slight incline at Fontana track per my GPS. I was told Fontanna is not considered a fast track. Only way to compare 100% accurate, would be to run on same track, same day.

Thanks for sharing. Good stuff! This is cool to see on 2 different similar stock twin housing setups, although not exact same, with very close times.
Hey Brian, here is a link to Munroe ct20 stage 4 upgrade via his website.

Toyota Supra Twin Turbo ct20

Keep an eye out because within that page there is a link that will eventually detail the full stage 4 turbo specs. There is further development though. A couple of years ago Munro developed a stage 5 kit using Toyota triple ball bearing centers but does not seem to have the time to go in to full production. His services wait list is long!!

The assumption with dyno's is correct. More than likely tuned on a Mainline dyno, but what I do know is that Alpha remotely tuned the car being ProEFI engine management. Regardless of dyno sheet horse power, it will be safe to say that both cars are producing similar rear end horsepower going off 1/4 mile times .

Yes, It's fantatstic to know that there are viable options catered for all US, Euro and JDM spec Supra owners who want the "stock" look and have a 9 second potential car without going single. Big thanks again must be given to Stu Hagen persistence and visions for continuous improvement so that people like Munro can further develop and apply the ideas with their particular skills set for all to benefit.
 

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Stock Twins King
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Stock Twins King
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судя по данным Ct12 и CT20, которые были представлены в этой теме, AR меньше в Ct12, почему - JDM ct20 работает хуже после обновлений? Более того, это может быть связано с
более узкая средняя часть - между турбинами? Или узкая часть, где установлен клапан EGCV? about the narrow outlet I know.


judging by the data of Ct12 and CT20, which were presented in this topic, AR is less in Ct12, why - does the JDM ct20 work worse after the updates? Moreover, this may be due to narrower middle part - between turbines? Or the narrow part where the EGCV valve is installed? about the narrow outlet I know
The JDM (GT28) type upgrade is NOT a Garrett CHRA. It is a Mitsubishi 16G, Theses CHRAs are VERY close to the same. To REALLY answer your question...I actually have a set of these JDM turbos on my USDM supra right now. I dynoed 10% less than the GT28s at 620whp, 28psi, E85. This set up had everything possible thrown in. Artec diverted enlarged collector, 4" DP conversion, etc. The issue with the CT20 does have something to do with the different A/R and more so Scroll. Too much back pressure on the CT20. But then, what is wrong with 620whp??? Plus the JDM sets are 100% P&P no parts needed whereas the GT28s require a $500 installation kit. So for around $1800 they are relatively a bargain to achieve good HP and in Sequential.

The issue for years was converting JDM (3-hole) to USDM (4-hole) but my new cast manifold is universal and will bolt up to either Turbo sets.
 

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Stock Twins King
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AR for the exhaust housings in the JDM turbine version (the hot turbine section) is higher AR=0.61 than AR= 0.41 for the USDM. Why after an upgrade the JDM turbine version is less efficient? I mean your study says that the difference between the GT 28 turbine and the СТ20 turbine is about 2% except for AR. What specifically causes a reduction in efficiency: the exhaust housing itself, its middle part connecting both turbines, or the EGCV system? I have read that the outlet is also smaller in the JDM version requiring further modification to achieve the max. efficiency of the USDM version.
There are certain flow characteristics between these 2 that are more of science to explain. There needs to be a good "match" to make a higher efficiency. All of this makes for a better flow. TBH reasons are above my knowledge level for turbo tech.

These are the spec differences.

Turbos: (CT12B Japanese) / CT12B U.S.
Turbine Size: (60mm/48mm) / 52mm/44mm
Compressor Size: (62mm/39mm) / 58mm/39mm
Turbine material: (Ceramic) / Steel
Scroll area (mm^2): (600) / 740 (USDM +23%)
A/R ratio: (0.42) / 0.53 (USDM +26%)
 

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not if china is busy making masks and getting locked in from going to the factories since i dont know... beginning of 2020? haha we will soon be mandated shelter-in nationwide. its already happening here in Sacramento tonight.
 

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not if china is busy making masks and getting locked in from going to the factories since i dont know... beginning of 2020? haha we will soon be mandated shelter-in nationwide. its already happening here in Sacramento tonight.
Just heard about that. Really wanted to get out and drive too lol. Shift sector would have been this weekend too.
 

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Stu thanks for the heads up on the turbos at Moore. Looks like someone else had already snagged them by the time I saw your post. I’m definitely in for a manifold when they come available.
 

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Well good news and not so good. Manifolds are indeed all casted and ready. Issue is the machine shop isn't operating right now so there is a delay to getting them machined. It is only a days worth of work to machine, so I am hoping soon that these can start shipping out.

250260



250261
 

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Stock Twins King
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Here are all 20 of them lined up ready to machine. God Damn these better be coming...I spent half my life on these damn things and I am waiting myself to pull my engine for this and new cams. Plus the new V4 Comp wheel is coming real soon.

250269
 

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It's like Christmas in April. Thanks for all the cool reveals to keep us optimistic during the lock down.
 

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Hey guys, so I read the first and last 20 pages of the thread, I am so amazed at how everyone contributed and to see so many owners that want the stock look of the sequentials. Sadly, I don't own a supra, I am located in China so the restrictions on used cars are ridiculous. Either way, I am planning on running a 2JZGTE on my Reiz/Mark X here and was wondering is it cost effective to get a setup from Stu all the way over from the US. Since I am not too familiar with anyone running aftermarket sequentials here. Or if anyone has a connection in the far east that does the same type of setups. Thanks a lot guys.
 
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