14BT Turbo Upgrade: Munro GMT upgraded billet (1 Viewer)

crave reFleXion · Aug 2, 2021

Rightio, so I've wanted to upgrade the old CT26 on my 14BT since I first owned Frank and the time to do so has finally arrived. I did a tonne of research before pulling the trigger on one, including G Turbo, Kinugawa and Mambo for off the shelf designs. I also seriously considered building a compound setup similar to @gerg 3B he compounded. In the end, practicality and cost helped make up my mind... And I ended up with a Glenn Munro GMT upgraded billet. The workmanship in this thing is second to none.

Anyways, I'll be doing an install video and review for my YouTube Channel if anyone's interested: https://youtube.com/channel/UC1iC_aERNw4iCjGWMS0V_7A

crave reFleXion · Aug 2, 2021

A few more shots... What do you reckon?

Silveredition · Aug 4, 2021

Gday mate,
Is it on yet, and if so, what are the initial impressions?
Looks great!!

Hulsty · Aug 4, 2021

I'm sure you will love it, Gturbo on my 13BT makes a massive difference.

Dougal · Aug 5, 2021

Hot side appears to be a standard 1HD-T CT26. That's an old turbine wheel design with poor efficiency and response.

What does the seller claim?

KiwiDingo · Aug 5, 2021

@crave reFleXion You can get great response and efficiency from a CT26 turbine, Munro is one of the best turbo builders in the business and he has a few tricks up his sleeve that most wouldn't be able to see or even understand from just looking at some outside pics. I've had turbos running the standard CT26 turbine perform with greater efficiency and far better response than other turbos with so called better tech turbines. Also paddle wheel turbines with radial flow design like the CT26 actually excel in certain areas compared to more modern turbines with axial flow designs you see commonly these days. There's all pros and cons to this stuff and most people are just clueless on the actual tech and how it all works but are quite happy to play keyboard expert

daboheme · Aug 5, 2021

Done with the editing yet? Just wondering if this is your final response...

KiwiDingo · Aug 5, 2021

daboheme said:
Done with the editing yet? Just wondering if this is your final response...

Sure is

crave reFleXion · Aug 5, 2021

Silveredition said:
Gday mate,
Is it on yet, and if so, what are the initial impressions?
Looks great!!

Not yet mate... It's my daily driver so I'm waiting till Saturday to get into it.

crave reFleXion · Aug 5, 2021

Dougal said:
Hot side appears to be a standard 1HD-T CT26. That's an old turbine wheel design with poor efficiency and response.

What does the seller claim?

G'day Dougal... I am hoping to get between 20-25 psi with boost coming on earlier than my standard CT26 basically. The turbo was custom built by Glenn Munro from Munro Racing Turbochargers and is his GMT stock billet upgraded CT26 with a 46mm 6 + 6 compressor wheel, ported turbine housing and adjustable actuator.

crave reFleXion · Aug 5, 2021

KiwiDingo said:
@crave reFleXion You can get great response and efficiency from a CT26 turbine, Munro is one of the best turbo builders in the business and he has a few tricks up his sleeve that most wouldn't be able to see or even understand from just looking at some outside pics. I've had turbos running the standard CT26 turbine perform with greater efficiency and far better response than other turbos with so called better tech turbines. Also paddle wheel turbines with radial flow design like the CT26 actually excel in certain areas compared to more modern turbines with axial flow designs you see commonly these days. There's all pros and cons to this stuff and most people are just clueless on the actual tech and how it all works but are quite happy to play keyboard expert

Yeah, it's really hard cutting through the crap online sometimes... Actually, it made choosing a turbo to upgrade quite a bit harder. I'm not chasing big numbers, but rather something that is an improvement over the stock CT26 that comes on boost earlier and is more efficient at moderately higher than standard boost levels so I can potentially use a bit more fuel without being overly sooty. Currently I've got my waste gate set at 15psi because it seems to be consensus that after that a stock CT26 looses efficiency and I will initially keep the GMT at the same levels so I can compare apples with apples. After that I plan on increasing boost to 20-25 and playing with fuelling and tuning the pump.

FJBen · Aug 5, 2021

Awesome, Munro is one of the options I've been looking at for awhile now. The big pro for me is that it's all bolt on and CT26 are usually pretty reliable. Will be watching this closely.

Dougal · Aug 6, 2021

crave reFleXion said:
G'day Dougal... I am hoping to get between 20-25 psi with boost coming on earlier than my standard CT26 basically. The turbo was custom built by Glenn Munro from Munro Racing Turbochargers and is his GMT stock billet upgraded CT26 with a 46mm 6 + 6 compressor wheel, ported turbine housing and adjustable actuator.

You'll have very similar performance and performance limitations to a stock CT26 with the same 58020 turbine housing. The big issue with a CT26 is the turbine design and you've still got that.

crave reFleXion · Aug 6, 2021

Dougal said:
You'll have very similar performance and performance limitations to a stock CT26 with the same 58020 turbine housing. The big issue with a CT26 is the turbine design and you've still got that.

Fair enough... So what's your prediction in terms of performance limitations?

Owyhee Jackass · Aug 6, 2021

Cool. What were you getting out of the original stock CT26? Had you changed out the actuator with an adjustable one with a higher rated spring?

Just re-read and see you're at 15 psi, was that with the stock actuator?

crave reFleXion · Aug 6, 2021

Owyhee Jackass said:
Cool. What were you getting out of the original stock CT26? Had you changed out the actuator with an adjustable one with a higher rated spring?

Just re-read and see you're at 15 psi, was that with the stock actuator?

Hey mate, 15psi was with an adjustable actuator. I went with 15 because the consensus seems to be that after 15, a stock CT26 looses efficiency

Dougal · Aug 6, 2021

crave reFleXion said:
Fair enough... So what's your prediction in terms of performance limitations?

That turbine design needs more flow to start working so spoolup is slower than a better turbine of the same dimensions. You'll have more drive pressure across the range and that will limit power and engine airflow.

I'm not 100% sure what the boost limits of the CT26 are. You will likely just hit points of limited return with increasing boost.

I had a guide up with the different turbine shapes as designs progressed. My old image hosting got nuked but I've fixed the images here: Turbocharger Turbines. - https://www.4btswaps.com/threads/turbocharger-turbines.77250/#post-771250

crave reFleXion · Aug 7, 2021

Rightio, so managed to get a spare couple of hours this arvo and got the new GMT Turbo bolted up. I took a few comparison photos of the old and new, which I'll attach to this post. Everything bolted up perfectly without any dramas and I did an oil change at the same time. You can see the difference in the compressor size and entry in the photo and the porting Glenn did is excellent. I've gone for a couple of quick burns and it feels better by the 'seat of my pants meter', but I'll do a comparison video tomorrow. I've also started an install video for my YouTube Channel.
Cheers